2015 |
Hermans, Thomas M; Bishop, Kyle J M; Stewart, Peter S; Davis, Stephen H; Grzybowski, Bartosz A Vortex flows impart chirality-specific lift forces Journal Article In: NATURE COMMUNICATIONS, 6 , 2015, ISSN: 2041-1723. @article{hermans_vortex_2015, title = {Vortex flows impart chirality-specific lift forces}, author = {Hermans, Thomas M. and Bishop, Kyle J. M. and Stewart, Peter S. and Davis, Stephen H. and Grzybowski, Bartosz A.}, doi = {10.1038/ncomms6640}, issn = {2041-1723}, year = {2015}, date = {2015-01-01}, journal = {NATURE COMMUNICATIONS}, volume = {6}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Conti, Simone ; Cecchini, Marco Accurate and Efficient Calculation of the Desorption Energy of Small Molecules from Graphene Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY C, 119 (4), pp. 1867–1879, 2015, ISSN: 1932-7447. @article{conti_accurate_2015, title = {Accurate and Efficient Calculation of the Desorption Energy of Small Molecules from Graphene}, author = {Conti, Simone and Cecchini, Marco}, doi = {10.1021/jp5104774}, issn = {1932-7447}, year = {2015}, date = {2015-01-01}, journal = {JOURNAL OF PHYSICAL CHEMISTRY C}, volume = {119}, number = {4}, pages = {1867--1879}, abstract = {Understanding the energetics of molecular adsorption at nanostructured carbon materials opens up to outstanding applications in the postgraphene era. The accurate determination of the adsorbate binding affinity remains however a challenge both experimentally and computationally. Here, we report on the determination of the desorption energy of 25 chemically diverse compounds from graphite using computational methods at different levels of theory: empirical force fields (FF), semiempirical quantum mechanics (SQM), and density functional theory (DFT). By comparing the computational predictions with literature temperature-programmed desorption (TPD) experiments we found that the dispersion-corrected semiempirical method PM6-DH+ yields desorption energies in quantitative agreement with the experiments with an average error of 1.25 kcal mol(-1). The discovery of a fast and accurate approach to molecular adsorption at surfaces prompted us to search the chemical space of the adsorbate to optimize the binding affinity for graphene. We found that polarizable groups containing sulfur and halogen atoms significantly enhance the interaction strength with the substrate. In particular, we predict that per-chlorination of aliphatic hydrocarbons doubles the desorption energy from graphene in vacuum. The efficiency of the PM6-DH+ calculations, which allows for screening libraries of compounds, guided the design of potentially improved graphene surfactants, which are commercially available.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Understanding the energetics of molecular adsorption at nanostructured carbon materials opens up to outstanding applications in the postgraphene era. The accurate determination of the adsorbate binding affinity remains however a challenge both experimentally and computationally. Here, we report on the determination of the desorption energy of 25 chemically diverse compounds from graphite using computational methods at different levels of theory: empirical force fields (FF), semiempirical quantum mechanics (SQM), and density functional theory (DFT). By comparing the computational predictions with literature temperature-programmed desorption (TPD) experiments we found that the dispersion-corrected semiempirical method PM6-DH+ yields desorption energies in quantitative agreement with the experiments with an average error of 1.25 kcal mol(-1). The discovery of a fast and accurate approach to molecular adsorption at surfaces prompted us to search the chemical space of the adsorbate to optimize the binding affinity for graphene. We found that polarizable groups containing sulfur and halogen atoms significantly enhance the interaction strength with the substrate. In particular, we predict that per-chlorination of aliphatic hydrocarbons doubles the desorption energy from graphene in vacuum. The efficiency of the PM6-DH+ calculations, which allows for screening libraries of compounds, guided the design of potentially improved graphene surfactants, which are commercially available. |
Prock, J; Strabler, C; Viertl, W; Kopacka, H; Obendorf, D; Mueller, T; Tordin, E; Salzl, S; Knoer, G; Mauro, M; De Cola, L; Brueggeller, P Unusual stability of dyads during photochemical hydrogen production Journal Article In: DALTON TRANSACTIONS, 44 (48), pp. 20936–20948, 2015, ISSN: 1477-9226. @article{prock_unusual_2015, title = {Unusual stability of dyads during photochemical hydrogen production}, author = {Prock, J. and Strabler, C. and Viertl, W. and Kopacka, H. and Obendorf, D. and Mueller, T. and Tordin, E. and Salzl, S. and Knoer, G. and Mauro, M. and De Cola, L. and Brueggeller, P.}, doi = {10.1039/c5dt03414k}, issn = {1477-9226}, year = {2015}, date = {2015-01-01}, journal = {DALTON TRANSACTIONS}, volume = {44}, number = {48}, pages = {20936--20948}, abstract = {Dyads for photochemical water splitting often suffer from instability during irradiation with visible light. However, the use of bis(bidentate) phosphines forming a five-membered ring enhances their stability. The coordination of these phosphor based chelates to soft metals like Pd(II) prolongs the photocatalytic activity to 1000 hours. To avoid contribution to hydrogen production by colloidal metal, a small amount of Hg is added to the reaction mixture. In the course of our investigations, it turned out that colloidal palladium was not able to produce hydrogen under our irradiation conditions. As soon as metallic palladium emerged in our reaction vessels, no further hydrogen production was detected. This is confirmed by the observation that the hydrogen production depends on the kind of ancillary ligands present in the dyads. The first dyads of the type [M-I(bpy)(2)(dppcb)M-II(bpy)](4+) are presented (M-I = Os}, keywords = {}, pubstate = {published}, tppubtype = {article} } Dyads for photochemical water splitting often suffer from instability during irradiation with visible light. However, the use of bis(bidentate) phosphines forming a five-membered ring enhances their stability. The coordination of these phosphor based chelates to soft metals like Pd(II) prolongs the photocatalytic activity to 1000 hours. To avoid contribution to hydrogen production by colloidal metal, a small amount of Hg is added to the reaction mixture. In the course of our investigations, it turned out that colloidal palladium was not able to produce hydrogen under our irradiation conditions. As soon as metallic palladium emerged in our reaction vessels, no further hydrogen production was detected. This is confirmed by the observation that the hydrogen production depends on the kind of ancillary ligands present in the dyads. The first dyads of the type [M-I(bpy)(2)(dppcb)M-II(bpy)](4+) are presented (M-I = Os |
Robinson, Matthew E; Lunn, David J; Nazemi, Ali ; Whittell, George R; De Cola, Luisa ; Manners, Ian Length control of supramolecular polymeric nanofibers based on stacked planar platinum(II) complexes by seeded-growth Journal Article In: CHEMICAL COMMUNICATIONS, 51 (88), pp. 15921–15924, 2015, ISSN: 1359-7345. @article{robinson_length_2015, title = {Length control of supramolecular polymeric nanofibers based on stacked planar platinum(II) complexes by seeded-growth}, author = {Robinson, Matthew E. and Lunn, David J. and Nazemi, Ali and Whittell, George R. and De Cola, Luisa and Manners, Ian}, doi = {10.1039/c5cc06606a}, issn = {1359-7345}, year = {2015}, date = {2015-01-01}, journal = {CHEMICAL COMMUNICATIONS}, volume = {51}, number = {88}, pages = {15921--15924}, abstract = {The formation of high aspect ratio supramolecular polymeric nanofibers from square-planar platinum(II) complexes through Pt...Pt and pi-pi stacking interactions has been achieved with a small width (textbackslashtextbackslashtextless15nm), tunable length, and relatively narrow length distributions up to ca. 400 nm under conditions of kinetic control using small seed fibers as initiators.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The formation of high aspect ratio supramolecular polymeric nanofibers from square-planar platinum(II) complexes through Pt...Pt and pi-pi stacking interactions has been achieved with a small width (textbackslashtextbackslashtextless15nm), tunable length, and relatively narrow length distributions up to ca. 400 nm under conditions of kinetic control using small seed fibers as initiators. |
Mroz, Wojciech ; Ragni, Roberta ; Galeotti, Francesco ; Mesto, Ernesto ; Botta, Chiara ; De Cola, Luisa ; Farinola, Gianluca Maria ; Giovanella, Umberto Influence of electronic and steric effects of substituted ligands coordinated to Ir(III) complexes on the solution processed OLED properties Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 3 (28), pp. 7506–7512, 2015, ISSN: 2050-7526. @article{mroz_influence_2015, title = {Influence of electronic and steric effects of substituted ligands coordinated to Ir(III) complexes on the solution processed OLED properties}, author = {Mroz, Wojciech and Ragni, Roberta and Galeotti, Francesco and Mesto, Ernesto and Botta, Chiara and De Cola, Luisa and Farinola, Gianluca Maria and Giovanella, Umberto}, doi = {10.1039/c5tc01278c}, issn = {2050-7526}, year = {2015}, date = {2015-01-01}, journal = {JOURNAL OF MATERIALS CHEMISTRY C}, volume = {3}, number = {28}, pages = {7506--7512}, abstract = {Orange and green phosphorescent heteroleptic iridium complexes 1 and 2 [(1): iridium(III) bis[2-(5'-benzylsulfonyl)phenylpyridinato-N,C2'](2,4-decanedionate) and (2): iridium(III) bis[2-(5'-benzylsulfonyl-3',6'-difluoro)phenylpyridinato-N,C2'](2,4-de canedionate)] are used as dopant emitters in solution processed organic light-emitting diodes. These emitters bear one sterically hindered 2,4-decanedionate and two phenylpyridine (ppy) ligands functionalized with electron withdrawing benzylsulfonyl groups and fluorine atoms. The steric and electronic effects of such substituents on the photophysical properties and performance of devices of 1 and 2 are investigated by making comparison with the green emitting reference phosphor Ir(ppy)(2)(acac) [iridium(III)bis(2-phenylpyridinato-N, C2')-acetylacetonate]. In particular, the functionalization of ppy ligands with the benzylsulfonyl group enhances the photoluminescence quantum yield (Phi) and red shifts the emission of complex 1 with respect to Ir(ppy)(2)(acac). Further substitution of the same ligands with two fluorine atoms in 2 restores the green emission of the reference complex, increasing its Phi. Hence, the combination of the two kinds of substituents represents a suitable functionalization pattern to increase the photoluminescence efficiency of 2 vs. the unfunctionalized Ir(ppy)(2)(acac). Interestingly, a fully solution processed phosphorescent light-emitting device (PHOLED) made using complex 2 as an emitter and with properly tailored architecture, which includes an electron transporting layer of a PEG substituted polyfluorene (PEG: poly(ethylene glycol)), exhibits high external emission quantum efficiency (EQE up to 12%) and a high luminous efficiency (LE up to 24.2 cd A (1)). We attribute such a high performance to the bulky effect of both benzylsulfonyl groups in ppy and of the alkyl chain in the beta-diketonate ligand, as well as to the enhanced electron mobility induced by fluorine atoms. This device outperforms the control diode based on Ir(ppy)(2)(acac) (EQE 5.5% and LE 17 cd A(-1)) and approaches the best efficiencies achieved so far for green Ir(III) complex based PHOLEDs.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Orange and green phosphorescent heteroleptic iridium complexes 1 and 2 [(1): iridium(III) bis[2-(5'-benzylsulfonyl)phenylpyridinato-N,C2'](2,4-decanedionate) and (2): iridium(III) bis[2-(5'-benzylsulfonyl-3',6'-difluoro)phenylpyridinato-N,C2'](2,4-de canedionate)] are used as dopant emitters in solution processed organic light-emitting diodes. These emitters bear one sterically hindered 2,4-decanedionate and two phenylpyridine (ppy) ligands functionalized with electron withdrawing benzylsulfonyl groups and fluorine atoms. The steric and electronic effects of such substituents on the photophysical properties and performance of devices of 1 and 2 are investigated by making comparison with the green emitting reference phosphor Ir(ppy)(2)(acac) [iridium(III)bis(2-phenylpyridinato-N, C2')-acetylacetonate]. In particular, the functionalization of ppy ligands with the benzylsulfonyl group enhances the photoluminescence quantum yield (Phi) and red shifts the emission of complex 1 with respect to Ir(ppy)(2)(acac). Further substitution of the same ligands with two fluorine atoms in 2 restores the green emission of the reference complex, increasing its Phi. Hence, the combination of the two kinds of substituents represents a suitable functionalization pattern to increase the photoluminescence efficiency of 2 vs. the unfunctionalized Ir(ppy)(2)(acac). Interestingly, a fully solution processed phosphorescent light-emitting device (PHOLED) made using complex 2 as an emitter and with properly tailored architecture, which includes an electron transporting layer of a PEG substituted polyfluorene (PEG: poly(ethylene glycol)), exhibits high external emission quantum efficiency (EQE up to 12%) and a high luminous efficiency (LE up to 24.2 cd A (1)). We attribute such a high performance to the bulky effect of both benzylsulfonyl groups in ppy and of the alkyl chain in the beta-diketonate ligand, as well as to the enhanced electron mobility induced by fluorine atoms. This device outperforms the control diode based on Ir(ppy)(2)(acac) (EQE 5.5% and LE 17 cd A(-1)) and approaches the best efficiencies achieved so far for green Ir(III) complex based PHOLEDs. |
Cebrian, Cristina ; Natali, Mirco ; Villa, Davide ; Panigati, Monica ; Mauro, Matteo ; D'Alfonso, Giuseppe ; De Cola, Luisa Luminescent supramolecular soft nanostructures from amphiphilic dinuclear Re(I) complexes Journal Article In: NANOSCALE, 7 (28), pp. 12000–12009, 2015, ISSN: 2040-3364. @article{cebrian_luminescent_2015, title = {Luminescent supramolecular soft nanostructures from amphiphilic dinuclear Re(I) complexes}, author = {Cebrian, Cristina and Natali, Mirco and Villa, Davide and Panigati, Monica and Mauro, Matteo and D'Alfonso, Giuseppe and De Cola, Luisa}, doi = {10.1039/c5nr01668a}, issn = {2040-3364}, year = {2015}, date = {2015-01-01}, journal = {NANOSCALE}, volume = {7}, number = {28}, pages = {12000--12009}, abstract = {Luminescent metallo-surfactants based on highly emissive dinuclear Re(I) complexes have been synthesized combining the peculiar photophysical behaviour of this class of neutral hydrophobic complexes with new properties imparted by hydrophilic chains anchored on the coordinated chromophoric ligand. In solution, the resulting neutral amphiphiles tend to self-assembly in soft structures. The aggregation properties have been thoroughly investigated in dioxane-water mixtures, where all the complexes assembly in globular-like supramolecular architectures with well-defined size (hydrodynamic diameter = 200-400 nm). The morphology of these nano-objects has been completely characterized with Dynamic Light Scattering (DLS) analysis, Scanning Transmission Electron Microscopy (STEM) and cryo-TEM to determine the size, polydispersity, and stability of the nanoparticles in relationship with the structure of the metallo-surfactants. The photophysical properties of both the isolated metal complexes and their aggregates have been investigated by means of UV-Vis absorption, steady-state and time-resolved emission spectroscopy. Noteworthy, the self-assembly properties of the reported luminescent rhenium metallo-amphiphiles can be modulated by solvent polarity. Even more importantly, such aggregation process yielded a small hypsochromic shift of the emission energy accompanied by a sizeable elongation of the excited-state lifetime and an enhancement of the photoluminescence quantum yield, reaching a remarkably high value of 0.20 despite the air-equilibrated aqueous condition. The presented findings endorse novel possibilities for the efficient use of soft-nanostructures based on metallo-amphiphiles in dual (electron and optical microscopy) bio-imaging applications and theranostics where the non-covalent nature of the intermolecular interactions would offer the powerful and unique possibility to reversibly assemble and disassemble imaging agents.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Luminescent metallo-surfactants based on highly emissive dinuclear Re(I) complexes have been synthesized combining the peculiar photophysical behaviour of this class of neutral hydrophobic complexes with new properties imparted by hydrophilic chains anchored on the coordinated chromophoric ligand. In solution, the resulting neutral amphiphiles tend to self-assembly in soft structures. The aggregation properties have been thoroughly investigated in dioxane-water mixtures, where all the complexes assembly in globular-like supramolecular architectures with well-defined size (hydrodynamic diameter = 200-400 nm). The morphology of these nano-objects has been completely characterized with Dynamic Light Scattering (DLS) analysis, Scanning Transmission Electron Microscopy (STEM) and cryo-TEM to determine the size, polydispersity, and stability of the nanoparticles in relationship with the structure of the metallo-surfactants. The photophysical properties of both the isolated metal complexes and their aggregates have been investigated by means of UV-Vis absorption, steady-state and time-resolved emission spectroscopy. Noteworthy, the self-assembly properties of the reported luminescent rhenium metallo-amphiphiles can be modulated by solvent polarity. Even more importantly, such aggregation process yielded a small hypsochromic shift of the emission energy accompanied by a sizeable elongation of the excited-state lifetime and an enhancement of the photoluminescence quantum yield, reaching a remarkably high value of 0.20 despite the air-equilibrated aqueous condition. The presented findings endorse novel possibilities for the efficient use of soft-nanostructures based on metallo-amphiphiles in dual (electron and optical microscopy) bio-imaging applications and theranostics where the non-covalent nature of the intermolecular interactions would offer the powerful and unique possibility to reversibly assemble and disassemble imaging agents. |
Colombo, Alessia ; Fiorini, Federica ; Septiadi, Dedy ; Dragonetti, Claudia ; Nisic, Filippo ; Valore, Adriana ; Roberto, Dominique ; Mauro, Matteo ; De Cola, Luisa Neutral NCN terdentate luminescent Pt(II) complexes: their synthesis, photophysical properties, and bio-imaging applications Journal Article In: DALTON TRANSACTIONS, 44 (18), pp. 8478–8487, 2015, ISSN: 1477-9226. @article{colombo_neutral_2015, title = {Neutral NCN terdentate luminescent Pt(II) complexes: their synthesis, photophysical properties, and bio-imaging applications}, author = {Colombo, Alessia and Fiorini, Federica and Septiadi, Dedy and Dragonetti, Claudia and Nisic, Filippo and Valore, Adriana and Roberto, Dominique and Mauro, Matteo and De Cola, Luisa}, doi = {10.1039/c4dt03165b}, issn = {1477-9226}, year = {2015}, date = {2015-01-01}, journal = {DALTON TRANSACTIONS}, volume = {44}, number = {18}, pages = {8478--8487}, abstract = {An emerging field regarding NtextbackslashtextbackslashtextlessˆtextbackslashtextbackslashtextgreaterCtextbackslashtextbackslashtextlessˆtextbackslashtextbackslashtextgreaterN terdentate Pt(II) complexes is their application as luminescent labels for bio-imaging. In fact, phosphorescent Pt complexes possess many advantages such as a wide emission color tunability, a better stability towards photo- and chemical degradation, a very large Stokes shift, and long-lived luminescent excited states with lifetimes typically two to three orders of magnitude longer than those of classic organic fluorophores. Here, we describe the synthesis and photophysical characterization of three new neutral NtextbackslashtextbackslashtextlessˆtextbackslashtextbackslashtextgreaterCtextbackslashtextbackslashtextlessˆtextbackslashtextbackslashtextgreaterN terdentate cyclometallated Pt complexes as long-lived bio-imaging probes. The novel molecular probes bear hydrophilic (oligo-) ethyleneglycol chains of various lengths to increase their water solubility and bio-compatibility and to impart amphiphilic nature to the molecules. The complexes are characterized by a high cell permeability and a low cytotoxicity, with an internalization kinetics that depends on both the length of the ethyleneglycol chain and the ancillary ligand.}, keywords = {}, pubstate = {published}, tppubtype = {article} } An emerging field regarding NtextbackslashtextbackslashtextlessˆtextbackslashtextbackslashtextgreaterCtextbackslashtextbackslashtextlessˆtextbackslashtextbackslashtextgreaterN terdentate Pt(II) complexes is their application as luminescent labels for bio-imaging. In fact, phosphorescent Pt complexes possess many advantages such as a wide emission color tunability, a better stability towards photo- and chemical degradation, a very large Stokes shift, and long-lived luminescent excited states with lifetimes typically two to three orders of magnitude longer than those of classic organic fluorophores. Here, we describe the synthesis and photophysical characterization of three new neutral NtextbackslashtextbackslashtextlessˆtextbackslashtextbackslashtextgreaterCtextbackslashtextbackslashtextlessˆtextbackslashtextbackslashtextgreaterN terdentate cyclometallated Pt complexes as long-lived bio-imaging probes. The novel molecular probes bear hydrophilic (oligo-) ethyleneglycol chains of various lengths to increase their water solubility and bio-compatibility and to impart amphiphilic nature to the molecules. The complexes are characterized by a high cell permeability and a low cytotoxicity, with an internalization kinetics that depends on both the length of the ethyleneglycol chain and the ancillary ligand. |
Godeau, Amelie ; Riveline, Daniel Key Effects of Confinement on Cell Motility Journal Article In: BIOPHYSICAL JOURNAL, 108 (2, 1), pp. 455A–456A, 2015, ISSN: 0006-3495. @article{godeau_key_2015, title = {Key Effects of Confinement on Cell Motility}, author = {Godeau, Amelie and Riveline, Daniel}, doi = {10.1016/j.bpj.2014.11.2486}, issn = {0006-3495}, year = {2015}, date = {2015-01-01}, journal = {BIOPHYSICAL JOURNAL}, volume = {108}, number = {2, 1}, pages = {455A--456A}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Comelles, Jordi ; Caballero, David ; Voituriez, Raphael ; Hortigueela, Veronica ; Wollrab, Viktoria ; Godeau, Amelie L; Samitier, Josep ; Martinez, Elena ; Riveline, Daniel Cells as Active Particles in Asymmetric Potentials: Motility under External Gradients Journal Article In: BIOPHYSICAL JOURNAL, 108 (2, 1), pp. 456A, 2015, ISSN: 0006-3495. @article{comelles_cells_2015, title = {Cells as Active Particles in Asymmetric Potentials: Motility under External Gradients}, author = {Comelles, Jordi and Caballero, David and Voituriez, Raphael and Hortigueela, Veronica and Wollrab, Viktoria and Godeau, Amelie L. and Samitier, Josep and Martinez, Elena and Riveline, Daniel}, doi = {10.1016/j.bpj.2014.11.2487}, issn = {0006-3495}, year = {2015}, date = {2015-01-01}, journal = {BIOPHYSICAL JOURNAL}, volume = {108}, number = {2, 1}, pages = {456A}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Comelles, J; Hortigueela, V; Martinez, E; Riveline, D Methods for rectifying cell motions in vitro: breaking symmetry using microfabrication and microfluidics Incollection In: {Paluch, EK} (Ed.): BIOPHYSICAL METHODS IN CELL BIOLOGY, 125 , pp. 437–452, 2015, ISBN: 978-0-12-801103-4. @incollection{comelles_methods_2015, title = {Methods for rectifying cell motions in vitro: breaking symmetry using microfabrication and microfluidics}, author = {Comelles, J. and Hortigueela, V. and Martinez, E. and Riveline, D.}, editor = {{Paluch, EK}}, doi = {10.1016/bs.mcb.2014.10.012}, isbn = {978-0-12-801103-4}, year = {2015}, date = {2015-01-01}, booktitle = {BIOPHYSICAL METHODS IN CELL BIOLOGY}, volume = {125}, pages = {437--452}, series = {Methods in Cell Biology}, abstract = {Cell motility is an important phenomenon in cell biology, developmental biology, and cancer. Here we report methods that we designed to identify and characterize external factors which direct cell motions by breaking locally the symmetry. We used microfabrication and microfluidics techniques to impose and combine mechanical and chemical cues to moving fibroblasts. Gradients can thereby be engineered at the cellular scale and this approach has allowed to disentangle roles of the nucleus and protrusion activity in setting cell directions.}, keywords = {}, pubstate = {published}, tppubtype = {incollection} } Cell motility is an important phenomenon in cell biology, developmental biology, and cancer. Here we report methods that we designed to identify and characterize external factors which direct cell motions by breaking locally the symmetry. We used microfabrication and microfluidics techniques to impose and combine mechanical and chemical cues to moving fibroblasts. Gradients can thereby be engineered at the cellular scale and this approach has allowed to disentangle roles of the nucleus and protrusion activity in setting cell directions. |
Canaguier-Durand, Antoine ; Genet, Cyriaque ; Lambrecht, Astrid ; Ebbesen, ThomasW. ; Reynaud, Serge Non-Markovian polariton dynamics in organic strong coupling Journal Article In: EUROPEAN PHYSICAL JOURNAL D, 69 (1), 2015, ISSN: 1434-6060. @article{canaguier-durand_non-markovian_2015, title = {Non-Markovian polariton dynamics in organic strong coupling}, author = {Canaguier-Durand, Antoine and Genet, Cyriaque and Lambrecht, Astrid and Ebbesen, ThomasW. and Reynaud, Serge}, doi = {10.1140/epjd/e2014-50539-x}, issn = {1434-6060}, year = {2015}, date = {2015-01-01}, journal = {EUROPEAN PHYSICAL JOURNAL D}, volume = {69}, number = {1}, abstract = {Strongly coupled organic systems are characterized by unusually large Rabi splitting, even in the vacuum state. They show the counter-intuitive feature of a lifetime of the lower polariton state longer than for all other excited states. Here we build up a new theoretical framework to understand the dynamics of such coupled system. In particular, we show that the non-Markovian character of the relaxation of the dressed organic system explains the long lifetime of the lower polariton state.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Strongly coupled organic systems are characterized by unusually large Rabi splitting, even in the vacuum state. They show the counter-intuitive feature of a lifetime of the lower polariton state longer than for all other excited states. Here we build up a new theoretical framework to understand the dynamics of such coupled system. In particular, we show that the non-Markovian character of the relaxation of the dressed organic system explains the long lifetime of the lower polariton state. |
George, Jino ; Wang, Shaojun ; Chervy, Thibault ; Canaguier-Durand, Antoine ; Schaeffer, Gael ; Lehn, Jean-Marie ; Hutchison, James A; Genet, Cyriaque ; Ebbesen, Thomas W Ultra-strong coupling of molecular materials: spectroscopy and dynamics Journal Article In: FARADAY DISCUSSIONS, 178 , pp. 281–294, 2015, ISSN: 1359-6640. @article{george_ultra-strong_2015, title = {Ultra-strong coupling of molecular materials: spectroscopy and dynamics}, author = {George, Jino and Wang, Shaojun and Chervy, Thibault and Canaguier-Durand, Antoine and Schaeffer, Gael and Lehn, Jean-Marie and Hutchison, James A. and Genet, Cyriaque and Ebbesen, Thomas W.}, doi = {10.1039/c4fd00197d}, issn = {1359-6640}, year = {2015}, date = {2015-01-01}, journal = {FARADAY DISCUSSIONS}, volume = {178}, pages = {281--294}, abstract = {We report here a study of light-matter strong coupling involving three molecules with very different photo-physical properties. In particular we analyze their emission properties and show that the excitation spectra are very different from the static absorption of the coupled systems. Furthermore we report the emission quantum yields and excited state lifetimes, which are self-consistent. The above results raise a number of fundamental questions that are discussed and these demonstrate the need for further experiments and theoretical studies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report here a study of light-matter strong coupling involving three molecules with very different photo-physical properties. In particular we analyze their emission properties and show that the excitation spectra are very different from the static absorption of the coupled systems. Furthermore we report the emission quantum yields and excited state lifetimes, which are self-consistent. The above results raise a number of fundamental questions that are discussed and these demonstrate the need for further experiments and theoretical studies. |
Shalabney, A; George, J; Hutchison, J; Pupillo, G; Genet, C; Ebbesen, T W Coherent coupling of molecular resonators with a microcavity mode Journal Article In: NATURE COMMUNICATIONS, 6 , 2015, ISSN: 2041-1723. @article{shalabney_coherent_2015, title = {Coherent coupling of molecular resonators with a microcavity mode}, author = {Shalabney, A. and George, J. and Hutchison, J. and Pupillo, G. and Genet, C. and Ebbesen, T. W.}, doi = {10.1038/ncomms6981}, issn = {2041-1723}, year = {2015}, date = {2015-01-01}, journal = {NATURE COMMUNICATIONS}, volume = {6}, abstract = {The optical hybridization of the electronic states in strongly coupled molecule-cavity systems have revealed unique properties, such as lasing, room temperature polariton condensation and the modification of excited electronic landscapes involved in molecular isomerization. Here we show that molecular vibrational modes of the electronic ground state can also be coherently coupled with a microcavity mode at room temperature, given the low vibrational thermal occupation factors associated with molecular vibrations, and the collective coupling of a large ensemble of molecules immersed within the cavity-mode volume. This enables the enhancement of the collective Rabi-exchange rate with respect to the single-oscillator coupling strength. The possibility of inducing large shifts in the vibrational frequency of selected molecular bonds should have immediate consequences for chemistry.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The optical hybridization of the electronic states in strongly coupled molecule-cavity systems have revealed unique properties, such as lasing, room temperature polariton condensation and the modification of excited electronic landscapes involved in molecular isomerization. Here we show that molecular vibrational modes of the electronic ground state can also be coherently coupled with a microcavity mode at room temperature, given the low vibrational thermal occupation factors associated with molecular vibrations, and the collective coupling of a large ensemble of molecules immersed within the cavity-mode volume. This enables the enhancement of the collective Rabi-exchange rate with respect to the single-oscillator coupling strength. The possibility of inducing large shifts in the vibrational frequency of selected molecular bonds should have immediate consequences for chemistry. |
Dinesh, Bhimareddy ; Squillaci, Marco A; Menard-Moyon, Cecilia ; Samori, Paolo ; Bianco, Alberto Self-assembly of diphenylalanine backbone homologues and their combination with functionalized carbon nanotubes Journal Article In: NANOSCALE, 7 (38), pp. 15873–15879, 2015, ISSN: 2040-3364. @article{dinesh_self-assembly_2015, title = {Self-assembly of diphenylalanine backbone homologues and their combination with functionalized carbon nanotubes}, author = {Dinesh, Bhimareddy and Squillaci, Marco A. and Menard-Moyon, Cecilia and Samori, Paolo and Bianco, Alberto}, doi = {10.1039/c5nr04665c}, issn = {2040-3364}, year = {2015}, date = {2015-01-01}, journal = {NANOSCALE}, volume = {7}, number = {38}, pages = {15873--15879}, abstract = {The integration of carbon nanotubes (CNTs) into organized nanostructures is of great interest for applications in materials science and biomedicine. In this work we studied the self-assembly of beta and gamma homologues of diphenylalanine peptides under different solvent and pH conditions. We aimed to investigate the role of peptide backbone in tuning the formation of different types of nanostructures alone or in combination with carbon nanotubes. In spite of having the same side chain, beta and gamma peptides formed distinctively different nanofibers, a clear indication of the role played by the backbone homologation on the self-assembly. The variation of the pH allowed to transform the nanofibers into spherical structures. Moreover, the co-assembly of beta and gamma peptides with carbon nanotubes covalently functionalized with the same peptide generated unique dendritic assemblies. This comparative study on self-assembly using diphenylalanine backbone homologues and of the co-assembly with CNT covalent conjugates is the first example exploring the capacity of beta and gamma peptides to adopt precise nanostructures, particularly in combination with carbon nanotubes. The dendritic organization obtained by mixing carbon nanotubes and peptides might find interesting applications in tissue engineering and neuronal interfacing.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The integration of carbon nanotubes (CNTs) into organized nanostructures is of great interest for applications in materials science and biomedicine. In this work we studied the self-assembly of beta and gamma homologues of diphenylalanine peptides under different solvent and pH conditions. We aimed to investigate the role of peptide backbone in tuning the formation of different types of nanostructures alone or in combination with carbon nanotubes. In spite of having the same side chain, beta and gamma peptides formed distinctively different nanofibers, a clear indication of the role played by the backbone homologation on the self-assembly. The variation of the pH allowed to transform the nanofibers into spherical structures. Moreover, the co-assembly of beta and gamma peptides with carbon nanotubes covalently functionalized with the same peptide generated unique dendritic assemblies. This comparative study on self-assembly using diphenylalanine backbone homologues and of the co-assembly with CNT covalent conjugates is the first example exploring the capacity of beta and gamma peptides to adopt precise nanostructures, particularly in combination with carbon nanotubes. The dendritic organization obtained by mixing carbon nanotubes and peptides might find interesting applications in tissue engineering and neuronal interfacing. |
Raimondo, Corinna ; Kenens, Bart ; Reinders, Federica ; Mayor, Marcel ; Uji-i, Hiroshi ; Samori, Paolo Au nanoparticle scaffolds modulating intermolecular interactions among the conjugated azobenzenes chemisorbed on curved surfaces: tuning the kinetics of cis-trans isomerisation Journal Article In: NANOSCALE, 7 (33), pp. 13836–13839, 2015, ISSN: 2040-3364. @article{raimondo_au_2015, title = {Au nanoparticle scaffolds modulating intermolecular interactions among the conjugated azobenzenes chemisorbed on curved surfaces: tuning the kinetics of cis-trans isomerisation}, author = {Raimondo, Corinna and Kenens, Bart and Reinders, Federica and Mayor, Marcel and Uji-i, Hiroshi and Samori, Paolo}, doi = {10.1039/c5nr03688g}, issn = {2040-3364}, year = {2015}, date = {2015-01-01}, journal = {NANOSCALE}, volume = {7}, number = {33}, pages = {13836--13839}, abstract = {pi-pi Intermolecular interactions among adjacent conjugated azobenzenes chemisorbed on (non-) flat Au surfaces can be tuned by varying the curvature of the Au nanoparticles. Here we show that such interactions rule the thermal cis-trans isomerization kinetics, towards a better control on the azobenzene bistability for its optimal integration as a responsive material.}, keywords = {}, pubstate = {published}, tppubtype = {article} } pi-pi Intermolecular interactions among adjacent conjugated azobenzenes chemisorbed on (non-) flat Au surfaces can be tuned by varying the curvature of the Au nanoparticles. Here we show that such interactions rule the thermal cis-trans isomerization kinetics, towards a better control on the azobenzene bistability for its optimal integration as a responsive material. |
El Garah, Mohamed ; Perone, Rosaria C; Bonilla, Alejandro Santana ; Haar, Sebastien ; Campitiello, Marilena ; Gutierrez, Rafael ; Cuniberti, Gianaurelio ; Masiero, Stefano ; Ciesielski, Artur ; Samori, Paolo Guanosine-based hydrogen-bonded 2D scaffolds: metal-free formation of G-quartet and G-ribbon architectures at the solid/liquid interface Journal Article In: CHEMICAL COMMUNICATIONS, 51 (58), pp. 11677–11680, 2015, ISSN: 1359-7345. @article{el_garah_guanosine-based_2015, title = {Guanosine-based hydrogen-bonded 2D scaffolds: metal-free formation of G-quartet and G-ribbon architectures at the solid/liquid interface}, author = {El Garah, Mohamed and Perone, Rosaria C. and Bonilla, Alejandro Santana and Haar, Sebastien and Campitiello, Marilena and Gutierrez, Rafael and Cuniberti, Gianaurelio and Masiero, Stefano and Ciesielski, Artur and Samori, Paolo}, doi = {10.1039/c5cc03197d}, issn = {1359-7345}, year = {2015}, date = {2015-01-01}, journal = {CHEMICAL COMMUNICATIONS}, volume = {51}, number = {58}, pages = {11677--11680}, abstract = {We report on the synthesis and self-assembly of three novel lipophilic guanosine derivatives exposing a ferrocene moiety in the C(5') position of the sugar unit. Their self-association in solution, and at the solid/liquid interface, can be tuned by varying the size and nature of the C(8)-substituent, leading to the generation of either G-ribbons, lamellar G-dimer based arrays or the G(4) cation-free architectures.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report on the synthesis and self-assembly of three novel lipophilic guanosine derivatives exposing a ferrocene moiety in the C(5') position of the sugar unit. Their self-association in solution, and at the solid/liquid interface, can be tuned by varying the size and nature of the C(8)-substituent, leading to the generation of either G-ribbons, lamellar G-dimer based arrays or the G(4) cation-free architectures. |
Boerjesson, K; Herder, M; Grubert, L; Duong, D T; Salleo, A; Hecht, S; Orgiu, E; Samori, P Optically switchable transistors comprising a hybrid photochromic molecule/n-type organic active layer Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 3 (16), pp. 4156–4161, 2015, ISSN: 2050-7526. @article{boerjesson_optically_2015, title = {Optically switchable transistors comprising a hybrid photochromic molecule/n-type organic active layer}, author = {Boerjesson, K. and Herder, M. and Grubert, L. and Duong, D. T. and Salleo, A. and Hecht, S. and Orgiu, E. and Samori, P.}, doi = {10.1039/c5tc00401b}, issn = {2050-7526}, year = {2015}, date = {2015-01-01}, journal = {JOURNAL OF MATERIALS CHEMISTRY C}, volume = {3}, number = {16}, pages = {4156--4161}, abstract = {Organic semiconductors can be easily combined with other molecular building blocks in order to fabricate multifunctional devices, in which each component conveys a specific (opto)electronic function. We have fabricated photoswitchable hybrid thin-film transistors based on an active bi-component material, consisting of an n-type fullerene derivative and a photochromic diarylethene that possesses light-tunable energy levels. The devices can be gated in two independent ways by either using an electrical stimulus via the application of a voltage to the gate electrode or an optical stimulus causing interconversion of the diarylethene molecules between their two isomers. Fine control over the device output current is achieved by engineering the diarylethenes' LUMO that can act as an intra-gap state controlled by a distinct wavelength in the UV or in the visible range. Importantly, the devices based on a mixed diarylethene/fullerene active layer preserve the high mobility of the pristine semiconductor.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Organic semiconductors can be easily combined with other molecular building blocks in order to fabricate multifunctional devices, in which each component conveys a specific (opto)electronic function. We have fabricated photoswitchable hybrid thin-film transistors based on an active bi-component material, consisting of an n-type fullerene derivative and a photochromic diarylethene that possesses light-tunable energy levels. The devices can be gated in two independent ways by either using an electrical stimulus via the application of a voltage to the gate electrode or an optical stimulus causing interconversion of the diarylethene molecules between their two isomers. Fine control over the device output current is achieved by engineering the diarylethenes' LUMO that can act as an intra-gap state controlled by a distinct wavelength in the UV or in the visible range. Importantly, the devices based on a mixed diarylethene/fullerene active layer preserve the high mobility of the pristine semiconductor. |
Fenwick, Oliver ; Van Dyck, Colin ; Murugavel, Kathiresan ; Cornil, David ; Reinders, Federica ; Haar, Sebastien ; Mayor, Marcel ; Cornil, Jerome ; Samori, Paolo Modulating the charge injection in organic field-effect transistors: fluorinated oligophenyl self-assembled monolayers for high work function electrodes Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 3 (13), pp. 3007–3015, 2015, ISSN: 2050-7526. @article{fenwick_modulating_2015, title = {Modulating the charge injection in organic field-effect transistors: fluorinated oligophenyl self-assembled monolayers for high work function electrodes}, author = {Fenwick, Oliver and Van Dyck, Colin and Murugavel, Kathiresan and Cornil, David and Reinders, Federica and Haar, Sebastien and Mayor, Marcel and Cornil, Jerome and Samori, Paolo}, doi = {10.1039/c5tc00243e}, issn = {2050-7526}, year = {2015}, date = {2015-01-01}, journal = {JOURNAL OF MATERIALS CHEMISTRY C}, volume = {3}, number = {13}, pages = {3007--3015}, abstract = {The rapid increase in charge carrier mobility in organic field-effect transistors (OFETs) in the past few years, with a number of reports textbackslashtextbackslashtextgreater10 cm(2) V-1 s(-1), calls for a simultaneous improvement in charge injection at the electrode-semiconductor interface. Chemical modification of the electrodes with self-assembled monolayers (SAMs) allows the optimization of three key properties for lowering the contact resistance, thus fine-tuning the charge injection into OFET channels: the electrode work function, the surface energy of the modified electrodes and tunnelling resistance of the SAM. Understanding of the interplay of these properties is of vital importance for organic device design. In this paper, we report a model study based on the modulation of all three of these properties via chemisorption of fluorinated mono- or biphenylthiol molecules (PFBT and PF2BT, respectively) onto gold electrodes. Density functional theory simulations confirm the higher work function of the PFBT monolayers compared to PF2BT and provide evidence that this work function difference is entirely due to differences in the bond dipole to the gold surface. This observation is of importance for the development of future SAM molecules both for organic electronics and across the field of surface chemistry. Incorporation of these SAM-modified Au surfaces as the source and drain electrodes of an OFET with prototypical polymer semiconductors exhibiting different transport levels makes it possible to unravel the role of energetic alignment as well as surface energy and tunnelling resistance on the device performance. Interestingly, our results show that it is not always the high work function PFBT-modified electrodes that give the lowest contact resistance.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The rapid increase in charge carrier mobility in organic field-effect transistors (OFETs) in the past few years, with a number of reports textbackslashtextbackslashtextgreater10 cm(2) V-1 s(-1), calls for a simultaneous improvement in charge injection at the electrode-semiconductor interface. Chemical modification of the electrodes with self-assembled monolayers (SAMs) allows the optimization of three key properties for lowering the contact resistance, thus fine-tuning the charge injection into OFET channels: the electrode work function, the surface energy of the modified electrodes and tunnelling resistance of the SAM. Understanding of the interplay of these properties is of vital importance for organic device design. In this paper, we report a model study based on the modulation of all three of these properties via chemisorption of fluorinated mono- or biphenylthiol molecules (PFBT and PF2BT, respectively) onto gold electrodes. Density functional theory simulations confirm the higher work function of the PFBT monolayers compared to PF2BT and provide evidence that this work function difference is entirely due to differences in the bond dipole to the gold surface. This observation is of importance for the development of future SAM molecules both for organic electronics and across the field of surface chemistry. Incorporation of these SAM-modified Au surfaces as the source and drain electrodes of an OFET with prototypical polymer semiconductors exhibiting different transport levels makes it possible to unravel the role of energetic alignment as well as surface energy and tunnelling resistance on the device performance. Interestingly, our results show that it is not always the high work function PFBT-modified electrodes that give the lowest contact resistance. |
Orgiu, Emanuele ; Squillaci, Marco A; Rekab, Wassima ; Boerjesson, Karl ; Liscio, Fabiola ; Zhang, Lei ; Samori, Paolo The dramatic effect of the annealing temperature and dielectric functionalization on the electron mobility of indene-C-60 bis-adduct thin films Journal Article In: CHEMICAL COMMUNICATIONS, 51 (25), pp. 5414–5417, 2015, ISSN: 1359-7345. @article{orgiu_dramatic_2015, title = {The dramatic effect of the annealing temperature and dielectric functionalization on the electron mobility of indene-C-60 bis-adduct thin films}, author = {Orgiu, Emanuele and Squillaci, Marco A. and Rekab, Wassima and Boerjesson, Karl and Liscio, Fabiola and Zhang, Lei and Samori, Paolo}, doi = {10.1039/c5cc00151j}, issn = {1359-7345}, year = {2015}, date = {2015-01-01}, journal = {CHEMICAL COMMUNICATIONS}, volume = {51}, number = {25}, pages = {5414--5417}, abstract = {Herein we report on the charge transport properties of spin-coated thin films of an n-type fullerene derivative, i.e. the indene-C-60 bis-adduct (ICBA). In particular, the effects of annealing temperature and duration as well as surface functionalization are explored. Electron mobilities approaching 0.1 cm(2) V-1 s(-1) are reported.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Herein we report on the charge transport properties of spin-coated thin films of an n-type fullerene derivative, i.e. the indene-C-60 bis-adduct (ICBA). In particular, the effects of annealing temperature and duration as well as surface functionalization are explored. Electron mobilities approaching 0.1 cm(2) V-1 s(-1) are reported. |
2014 |
Vantomme, Ghislaine ; Lehn, Jean-Marie Reversible Adaptation to Photoinduced Shape Switching by Oligomer-Macrocycle Interconversion with Component Selection in a Three-State Constitutional Dynamic System Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (49), pp. 16188–16193, 2014, ISSN: 0947-6539. @article{vantomme_reversible_2014, title = {Reversible Adaptation to Photoinduced Shape Switching by Oligomer-Macrocycle Interconversion with Component Selection in a Three-State Constitutional Dynamic System}, author = {Vantomme, Ghislaine and Lehn, Jean-Marie}, doi = {10.1002/chem.201404561}, issn = {0947-6539}, year = {2014}, date = {2014-12-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {20}, number = {49}, pages = {16188--16193}, abstract = {Light irradiation of the molecular photoswitch 1-E causes isomerization into the 1-Z configuration stabilized by an internal hydrogen bond. 1-E bears aldehyde groups allowing for dynamic covalent reaction with linear diamines. On photoinduced E/Z shape switching of 1 in presence of diamines, the system undergoes interconversion between two states, a non-cyclic oligomeric one and a macrocyclic one, corresponding respectively to the E and Z configurations of 1. With a mixture of linear ,-diamines, 1-E yields non-selective dynamic oligomers by random incorporation of diamine components. Photoswitching to the 1-Z form leads to constitutional adaptation with preferential formation of the macrocycle incorporating the best suited diamine, H2N(CH2)(7)NH2. In presence of metal cations, the E form switches from its unbound W shape to its coordinated U shape and yields the macrocycle resulting from the selective incorporation of the diamine H2NCH2CH2OCH2CH2NH2 that contains an additional O coordination site. Taken together, the results obtained describe constitutional adaptation in a triple state system: an oligomeric one and two different macrocyclic ones generated in response to two orthogonal agents, a physical stimulus, light, or a chemical effector, metal cations. These three states present, towards the incorporation of diamine components, respectively no selection, photoselection and metalloselection.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Light irradiation of the molecular photoswitch 1-E causes isomerization into the 1-Z configuration stabilized by an internal hydrogen bond. 1-E bears aldehyde groups allowing for dynamic covalent reaction with linear diamines. On photoinduced E/Z shape switching of 1 in presence of diamines, the system undergoes interconversion between two states, a non-cyclic oligomeric one and a macrocyclic one, corresponding respectively to the E and Z configurations of 1. With a mixture of linear ,-diamines, 1-E yields non-selective dynamic oligomers by random incorporation of diamine components. Photoswitching to the 1-Z form leads to constitutional adaptation with preferential formation of the macrocycle incorporating the best suited diamine, H2N(CH2)(7)NH2. In presence of metal cations, the E form switches from its unbound W shape to its coordinated U shape and yields the macrocycle resulting from the selective incorporation of the diamine H2NCH2CH2OCH2CH2NH2 that contains an additional O coordination site. Taken together, the results obtained describe constitutional adaptation in a triple state system: an oligomeric one and two different macrocyclic ones generated in response to two orthogonal agents, a physical stimulus, light, or a chemical effector, metal cations. These three states present, towards the incorporation of diamine components, respectively no selection, photoselection and metalloselection. |
Nam, Kwangho ; Pu, Jingzhi ; Karplus, Martin Trapping the ATP binding state leads to a detailed understanding of the F-1-ATPase mechanism Journal Article In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 111 (50), pp. 17851–17856, 2014, ISSN: 0027-8424. @article{nam_trapping_2014, title = {Trapping the ATP binding state leads to a detailed understanding of the F-1-ATPase mechanism}, author = {Nam, Kwangho and Pu, Jingzhi and Karplus, Martin}, doi = {10.1073/pnas.1419486111}, issn = {0027-8424}, year = {2014}, date = {2014-12-01}, journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, volume = {111}, number = {50}, pages = {17851--17856}, abstract = {The rotary motor enzyme FoF1-ATP synthase uses the protonmotive force across a membrane to synthesize ATP from ADP and P-i (H2PO4-) under cellular conditions that favor the hydrolysis reaction by a factor of 2 x 10(5). This remarkable ability to drive a reaction away from equilibrium by harnessing an external force differentiates it from an ordinary enzyme, which increases the rate of reaction without shifting the equilibrium. Hydrolysis takes place in the neighborhood of one conformation of the catalytic moiety F-1-ATPase, whose structure is known from crystallography. By use of molecular dynamics simulations we trap a second structure, which is rotated by 40 degrees from the catalytic dwell conformation and represents the state associated with ATP binding, in accord with single-molecule experiments. Using the two structures, we show why Pi is not released immediately after ATP hydrolysis, but only after a subsequent 120 degrees rotation, in agreement with experiment. A concerted conformational change of the alpha(3)beta(3) crown is shown to induce the 40 degrees rotation of the gamma-subunit only when the beta(E) subunit is empty, whereas with Pi bound, beta(E) serves as a latch to prevent the rotation of gamma. The present results provide a rationalization of how F-1-ATPase achieves the coupling between the small changes in the active site of beta(DP) and the 40 degrees rotation of gamma.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The rotary motor enzyme FoF1-ATP synthase uses the protonmotive force across a membrane to synthesize ATP from ADP and P-i (H2PO4-) under cellular conditions that favor the hydrolysis reaction by a factor of 2 x 10(5). This remarkable ability to drive a reaction away from equilibrium by harnessing an external force differentiates it from an ordinary enzyme, which increases the rate of reaction without shifting the equilibrium. Hydrolysis takes place in the neighborhood of one conformation of the catalytic moiety F-1-ATPase, whose structure is known from crystallography. By use of molecular dynamics simulations we trap a second structure, which is rotated by 40 degrees from the catalytic dwell conformation and represents the state associated with ATP binding, in accord with single-molecule experiments. Using the two structures, we show why Pi is not released immediately after ATP hydrolysis, but only after a subsequent 120 degrees rotation, in agreement with experiment. A concerted conformational change of the alpha(3)beta(3) crown is shown to induce the 40 degrees rotation of the gamma-subunit only when the beta(E) subunit is empty, whereas with Pi bound, beta(E) serves as a latch to prevent the rotation of gamma. The present results provide a rationalization of how F-1-ATPase achieves the coupling between the small changes in the active site of beta(DP) and the 40 degrees rotation of gamma. |
Roman-Duval, Julia ; Gordon, Karl D; Meixner, Margaret ; Bot, Caroline ; Bolatto, Alberto ; Hughes, Annie ; Wong, Tony ; Babler, Brian ; Bernard, Jean-Philippe ; Clayton, Geoffrey C; Fukui, Yasuo ; Galametz, Maud ; Galliano, Frederic ; Glover, Simon ; Hony, Sacha ; Israel, Frank ; Jameson, Katherine ; Lebouteiller, Vianney ; Lee, Min-Young ; Li, Aigen ; Madden, Suzanne ; Misselt, Karl ; Montiel, Edward ; Okumura, Koryo ; Onishi, Toshikazu ; Panuzzo, Pasquale ; Reach, William ; Remy-Ruyer, Aurelie ; Robitaille, Thomas ; Rubio, Monica ; Sauvage, Marc ; Seale, Jonathan ; Sewilo, Marta ; Staveley-Smith, Lister ; Zhukovska, Svitlana DUST AND GAS IN THE MAGELLANIC CLOUDS FROM THE HERITAGE HERSCHEL KEY PROJECT. II. GAS-TO-DUST RATIO VARIATIONS ACROSS INTERS℡LAR MEDIUM PHASES Journal Article In: ASTROPHYSICAL JOURNAL, 797 (2), 2014, ISSN: 0004-637X. @article{roman-duval_dust_2014, title = {DUST AND GAS IN THE MAGELLANIC CLOUDS FROM THE HERITAGE HERSCHEL KEY PROJECT. II. GAS-TO-DUST RATIO VARIATIONS ACROSS INTERS℡LAR MEDIUM PHASES}, author = {Roman-Duval, Julia and Gordon, Karl D. and Meixner, Margaret and Bot, Caroline and Bolatto, Alberto and Hughes, Annie and Wong, Tony and Babler, Brian and Bernard, Jean-Philippe and Clayton, Geoffrey C. and Fukui, Yasuo and Galametz, Maud and Galliano, Frederic and Glover, Simon and Hony, Sacha and Israel, Frank and Jameson, Katherine and Lebouteiller, Vianney and Lee, Min-Young and Li, Aigen and Madden, Suzanne and Misselt, Karl and Montiel, Edward and Okumura, Koryo and Onishi, Toshikazu and Panuzzo, Pasquale and Reach, William and Remy-Ruyer, Aurelie and Robitaille, Thomas and Rubio, Monica and Sauvage, Marc and Seale, Jonathan and Sewilo, Marta and Staveley-Smith, Lister and Zhukovska, Svitlana}, doi = {10.1088/0004-637X/797/2/86}, issn = {0004-637X}, year = {2014}, date = {2014-12-01}, journal = {ASTROPHYSICAL JOURNAL}, volume = {797}, number = {2}, abstract = {The spatial variations of the gas-to-dust ratio (GDR) provide constraints on the chemical evolution and lifecycle of dust in galaxies. We examine the relation between dust and gas at 10-50 pc resolution in the Large and Small Magellanic Clouds (LMC and SMC) based on Herschel far-infrared (FIR), Hi 21 cm, CO, and Ha observations. In the diffuse atomic interstellar medium (ISM), we derive the GDR as the slope of the dust-gas relation and find GDRs of 380(-130)(+250) +/- 3 in the LMC, and 1200(-420)(+1600) +/- 120 in the SMC, not including helium. The atomicto- molecular transition is located at dust surface densities of 0.05M(circle dot) pc(-2) in the LMC and 0.03M(circle dot) pc(-2) in the SMC, corresponding to A(V) similar to 0.4 and 0.2, respectively. We investigate the range of CO-to-H-2 conversion factor to best account for all the molecular gas in the beam of the observations, and find upper limits on X-CO to be 6 x 10(20) cm(-2) K-1 km(-1) s in the LMC (Z = 0.5Z(circle dot)) at 15 pc resolution, and 4 x 10(21) cm(-2) K-1 km(-1) s in the SMC (Z = 0.2Z(circle dot)) at 45 pc resolution. In the LMC, the slope of the dust-gas relation in the dense ISM is lower than in the diffuse ISM by a factor similar to 2, even after accounting for the effects of CO-dark H-2 in the translucent envelopes of molecular clouds. Coagulation of dust grains and the subsequent dust emissivity increase in molecular clouds, and/or accretion of gas-phase metals onto dust grains, and the subsequent dust abundance (dust-to-gas ratio) increase in molecular clouds could explain the observations. In the SMC, variations in the dust-gas slope caused by coagulation or accretion are degenerate with the effects of CO-dark H-2. Within the expected 5-20 times Galactic X-CO range, the dust-gas slope can be either constant or decrease by a factor of several across ISM phases. Further modeling and observations are required to break the degeneracy between dust grain coagulation, accretion, and CO-dark H-2. Our analysis demonstrates that obtaining robust ISM masses remains a non-trivial endeavor even in the local Universe using state-of-the-art maps of thermal dust emission.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The spatial variations of the gas-to-dust ratio (GDR) provide constraints on the chemical evolution and lifecycle of dust in galaxies. We examine the relation between dust and gas at 10-50 pc resolution in the Large and Small Magellanic Clouds (LMC and SMC) based on Herschel far-infrared (FIR), Hi 21 cm, CO, and Ha observations. In the diffuse atomic interstellar medium (ISM), we derive the GDR as the slope of the dust-gas relation and find GDRs of 380(-130)(+250) +/- 3 in the LMC, and 1200(-420)(+1600) +/- 120 in the SMC, not including helium. The atomicto- molecular transition is located at dust surface densities of 0.05M(circle dot) pc(-2) in the LMC and 0.03M(circle dot) pc(-2) in the SMC, corresponding to A(V) similar to 0.4 and 0.2, respectively. We investigate the range of CO-to-H-2 conversion factor to best account for all the molecular gas in the beam of the observations, and find upper limits on X-CO to be 6 x 10(20) cm(-2) K-1 km(-1) s in the LMC (Z = 0.5Z(circle dot)) at 15 pc resolution, and 4 x 10(21) cm(-2) K-1 km(-1) s in the SMC (Z = 0.2Z(circle dot)) at 45 pc resolution. In the LMC, the slope of the dust-gas relation in the dense ISM is lower than in the diffuse ISM by a factor similar to 2, even after accounting for the effects of CO-dark H-2 in the translucent envelopes of molecular clouds. Coagulation of dust grains and the subsequent dust emissivity increase in molecular clouds, and/or accretion of gas-phase metals onto dust grains, and the subsequent dust abundance (dust-to-gas ratio) increase in molecular clouds could explain the observations. In the SMC, variations in the dust-gas slope caused by coagulation or accretion are degenerate with the effects of CO-dark H-2. Within the expected 5-20 times Galactic X-CO range, the dust-gas slope can be either constant or decrease by a factor of several across ISM phases. Further modeling and observations are required to break the degeneracy between dust grain coagulation, accretion, and CO-dark H-2. Our analysis demonstrates that obtaining robust ISM masses remains a non-trivial endeavor even in the local Universe using state-of-the-art maps of thermal dust emission. |
Oezdemir, Berna C; Hensel, Janine ; Secondini, Chiara ; Wetterwald, Antoinette ; Schwaninger, Ruth ; Fleischmann, Achim ; Raffelsberger, Wolfgang ; Poch, Olivier ; Delorenzi, Mauro ; Temanni, Ramzi ; Mills, Ian G; van der Pluijm, Gabri ; Thalmann, George N; Cecchini, Marco G The Molecular Signature of the Stroma Response in Prostate Cancer-Induced Osteoblastic Bone Metastasis Highlights Expansion of Hematopoietic and Prostate Epithelial Stem Cell Niches Journal Article In: PLOS ONE, 9 (12), 2014, ISSN: 1932-6203. @article{oezdemir_molecular_2014, title = {The Molecular Signature of the Stroma Response in Prostate Cancer-Induced Osteoblastic Bone Metastasis Highlights Expansion of Hematopoietic and Prostate Epithelial Stem Cell Niches}, author = {Oezdemir, Berna C. and Hensel, Janine and Secondini, Chiara and Wetterwald, Antoinette and Schwaninger, Ruth and Fleischmann, Achim and Raffelsberger, Wolfgang and Poch, Olivier and Delorenzi, Mauro and Temanni, Ramzi and Mills, Ian G. and van der Pluijm, Gabri and Thalmann, George N. and Cecchini, Marco G.}, doi = {10.1371/journal.pone.0114530}, issn = {1932-6203}, year = {2014}, date = {2014-12-01}, journal = {PLOS ONE}, volume = {9}, number = {12}, abstract = {The reciprocal interaction between cancer cells and the tissue-specific stroma is critical for primary and metastatic tumor growth progression. Prostate cancer cells colonize preferentially bone (osteotropism), where they alter the physiological balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption, and elicit prevalently an osteoblastic response (osteoinduction). The molecular cues provided by osteoblasts for the survival and growth of bone metastatic prostate cancer cells are largely unknown. We exploited the sufficient divergence between human and mouse RNA sequences together with redefinition of highly species-specific gene arrays by computer-aided and experimental exclusion of cross-hybridizing oligonucleotide probes. This strategy allowed the dissection of the stroma (mouse) from the cancer cell (human) transcriptome in bone metastasis xenograft models of human osteoinductive prostate cancer cells (VCaP and C4-2B). As a result, we generated the osteoblastic bone metastasis-associated stroma transcriptome (OB-BMST). Subtraction of genes shared by inflammation, wound healing and desmoplastic responses, and by the tissue type-independent stroma responses to a variety of non-osteotropic and osteotropic primary cancers generated a curated gene signature (”Core” OB-BMST) putatively representing the bone marrow/bone-specific stroma response to prostate cancer-induced, osteoblastic bone metastasis. The expression pattern of three representative Core OB-BMST genes (PTN, EPHA3 and FSCN1) seems to confirm the bone specificity of this response. A robust induction of genes involved in osteogenesis and angiogenesis dominates both the OB-BMST and Core OB-BMST. This translates in an amplification of hematopoietic and, remarkably, prostate epithelial stem cell niche components that may function as a self-reinforcing bone metastatic niche providing a growth support specific for osteoinductive prostate cancer cells. The induction of this combinatorial stem cell niche is a novel mechanism that may also explain cancer cell osteotropism and local interference with hematopoiesis (myelophthisis). Accordingly, these stem cell niche components may represent innovative therapeutic targets and/or serum biomarkers in osteoblastic bone metastasis.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The reciprocal interaction between cancer cells and the tissue-specific stroma is critical for primary and metastatic tumor growth progression. Prostate cancer cells colonize preferentially bone (osteotropism), where they alter the physiological balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption, and elicit prevalently an osteoblastic response (osteoinduction). The molecular cues provided by osteoblasts for the survival and growth of bone metastatic prostate cancer cells are largely unknown. We exploited the sufficient divergence between human and mouse RNA sequences together with redefinition of highly species-specific gene arrays by computer-aided and experimental exclusion of cross-hybridizing oligonucleotide probes. This strategy allowed the dissection of the stroma (mouse) from the cancer cell (human) transcriptome in bone metastasis xenograft models of human osteoinductive prostate cancer cells (VCaP and C4-2B). As a result, we generated the osteoblastic bone metastasis-associated stroma transcriptome (OB-BMST). Subtraction of genes shared by inflammation, wound healing and desmoplastic responses, and by the tissue type-independent stroma responses to a variety of non-osteotropic and osteotropic primary cancers generated a curated gene signature (”Core” OB-BMST) putatively representing the bone marrow/bone-specific stroma response to prostate cancer-induced, osteoblastic bone metastasis. The expression pattern of three representative Core OB-BMST genes (PTN, EPHA3 and FSCN1) seems to confirm the bone specificity of this response. A robust induction of genes involved in osteogenesis and angiogenesis dominates both the OB-BMST and Core OB-BMST. This translates in an amplification of hematopoietic and, remarkably, prostate epithelial stem cell niche components that may function as a self-reinforcing bone metastatic niche providing a growth support specific for osteoinductive prostate cancer cells. The induction of this combinatorial stem cell niche is a novel mechanism that may also explain cancer cell osteotropism and local interference with hematopoiesis (myelophthisis). Accordingly, these stem cell niche components may represent innovative therapeutic targets and/or serum biomarkers in osteoblastic bone metastasis. |
Zhang, Shuanming ; Pattacini, Roberto ; Braunstein, Pierre ; De Cola, Luisa ; Plummer, Edward ; Mauro, Matteo ; Gourlaouen, Christophe ; Daniel, Chantal Synthesis, Structure, and Optical Properties of Pt(II) and Pd(II) Complexes with Oxazolyl- and Pyridyl-Functionalized DPPM-Type Ligands: A Combined Experimental and Theoretical Study Journal Article In: INORGANIC CHEMISTRY, 53 (24), pp. 12739–12756, 2014, ISSN: 0020-1669. @article{zhang_synthesis_2014, title = {Synthesis, Structure, and Optical Properties of Pt(II) and Pd(II) Complexes with Oxazolyl- and Pyridyl-Functionalized DPPM-Type Ligands: A Combined Experimental and Theoretical Study}, author = {Zhang, Shuanming and Pattacini, Roberto and Braunstein, Pierre and De Cola, Luisa and Plummer, Edward and Mauro, Matteo and Gourlaouen, Christophe and Daniel, Chantal}, doi = {10.1021/ic501566u}, issn = {0020-1669}, year = {2014}, date = {2014-12-01}, journal = {INORGANIC CHEMISTRY}, volume = {53}, number = {24}, pages = {12739--12756}, abstract = {New square-planar complexes [Pt(1(-H))(2)] (2a) [1(-H) = (oxazolin-2-yl)bis(diphenylphosphino)methanide] and [Pd(1(-H))(2)] (2b), of general formula [M(Ph2P)(2)C— C—NCH2CH2O (2)] (M = Pt, 2a; M = Pd, 2b), result from deprotonation of 2-bis(diphenylphosphino)methyloxazoline (1) at the PCHP site. The new, functionalized dppm-type ligand 4-bis(diphenylphosphino)methylpyridine, (Ph2P)(2)CH((4)-C5H4N) (4), was prepared by double lithiation and phosphorylation of 4-picoline. In the presence of NEt3, the reactions of 2 equiv of 4 with [PtCl2(NCPh)(2)] and [Pd(acac)2] (acac = acetylacetonate) afforded [Pt(4(-H))(2)] (5a) [4-H = bis(diphenylphosphino)(pyridin-4-yl)methanide] and [Pd(4-H)2] (5b), of general formula [M(Ph2P)(2)C(4(-)C(5)H(4)N)(2)] (M = Pt, 5a; M = Pd, 5b), respectively. In the absence of base, the reactions of 2 equiv of 4 with [PtCl2(NCPh)(2)] and [PdCl2(NCPh)(2)] afforded (5a center dot 2HCl) (6a) and (5b center dot 2HCl) (6b), respectively, in which the PCHP proton of 4 has migrated from carbon to nitrogen to give a pyridinium derivative of general formula [M(Ph2P)(2)C(4-C5H4NH)(2)]Cl-2 (M = Pt, 6a; M = Pd, 6b). The complexes 3a, 5a center dot 2MeOH, and 6b center dot 4CH(2)Cl(2) have been structurally characterized by X-ray diffraction. The absorption/emission properties of the Pt(II) complexes 2a and 5a and the Pd(II) complexes 2b and 5b have been investigated by UV-vis spectroscopy and theoretical analysis based on density functional theory. The UV-vis absorption spectra of the neutral complexes recorded in dilute N,N'-dimethylformamide solutions are dominated by intense spin-allowed intraligand transitions in the region below 350 nm. The complexes exhibit charge-transfer bands between 350 and 500 nm. The experimental and theoretical absorption spectra agree qualitatively and point to two low-lying ligand-to-metal charge transfer states that contribute to the bands observed between 350 and 500 nm. The complexes are emissive in frozen solutions at 77 K, in the pure solid state, and when doped into films of poly(methyl methacrylate) but are nonemissive in solution. A red shift is observed when Pt(II) is replaced by Pd(II).}, keywords = {}, pubstate = {published}, tppubtype = {article} } New square-planar complexes [Pt(1(-H))(2)] (2a) [1(-H) = (oxazolin-2-yl)bis(diphenylphosphino)methanide] and [Pd(1(-H))(2)] (2b), of general formula [M(Ph2P)(2)C— C—NCH2CH2O (2)] (M = Pt, 2a; M = Pd, 2b), result from deprotonation of 2-bis(diphenylphosphino)methyloxazoline (1) at the PCHP site. The new, functionalized dppm-type ligand 4-bis(diphenylphosphino)methylpyridine, (Ph2P)(2)CH((4)-C5H4N) (4), was prepared by double lithiation and phosphorylation of 4-picoline. In the presence of NEt3, the reactions of 2 equiv of 4 with [PtCl2(NCPh)(2)] and [Pd(acac)2] (acac = acetylacetonate) afforded [Pt(4(-H))(2)] (5a) [4-H = bis(diphenylphosphino)(pyridin-4-yl)methanide] and [Pd(4-H)2] (5b), of general formula [M(Ph2P)(2)C(4(-)C(5)H(4)N)(2)] (M = Pt, 5a; M = Pd, 5b), respectively. In the absence of base, the reactions of 2 equiv of 4 with [PtCl2(NCPh)(2)] and [PdCl2(NCPh)(2)] afforded (5a center dot 2HCl) (6a) and (5b center dot 2HCl) (6b), respectively, in which the PCHP proton of 4 has migrated from carbon to nitrogen to give a pyridinium derivative of general formula [M(Ph2P)(2)C(4-C5H4NH)(2)]Cl-2 (M = Pt, 6a; M = Pd, 6b). The complexes 3a, 5a center dot 2MeOH, and 6b center dot 4CH(2)Cl(2) have been structurally characterized by X-ray diffraction. The absorption/emission properties of the Pt(II) complexes 2a and 5a and the Pd(II) complexes 2b and 5b have been investigated by UV-vis spectroscopy and theoretical analysis based on density functional theory. The UV-vis absorption spectra of the neutral complexes recorded in dilute N,N'-dimethylformamide solutions are dominated by intense spin-allowed intraligand transitions in the region below 350 nm. The complexes exhibit charge-transfer bands between 350 and 500 nm. The experimental and theoretical absorption spectra agree qualitatively and point to two low-lying ligand-to-metal charge transfer states that contribute to the bands observed between 350 and 500 nm. The complexes are emissive in frozen solutions at 77 K, in the pure solid state, and when doped into films of poly(methyl methacrylate) but are nonemissive in solution. A red shift is observed when Pt(II) is replaced by Pd(II). |
Leydecker, Tim ; Duong, Duc Trong ; Salleo, Alberto ; Orgiu, Emanuele ; Samori, Paolo Solution-Processed Field-Effect Transistors Based on Dihexylquaterthiophene Films with Performances Exceeding Those of Vacuum-Sublimed Films Journal Article In: ACS APPLIED MATERIALS & INTERFACES, 6 (23), pp. 21248–21255, 2014, ISSN: 1944-8244. @article{leydecker_solution-processed_2014, title = {Solution-Processed Field-Effect Transistors Based on Dihexylquaterthiophene Films with Performances Exceeding Those of Vacuum-Sublimed Films}, author = {Leydecker, Tim and Duong, Duc Trong and Salleo, Alberto and Orgiu, Emanuele and Samori, Paolo}, doi = {10.1021/am506245v}, issn = {1944-8244}, year = {2014}, date = {2014-12-01}, journal = {ACS APPLIED MATERIALS & INTERFACES}, volume = {6}, number = {23}, pages = {21248--21255}, abstract = {Solution-processable oligothiophenes are model systems for charge transport and fabrication of organic field-effect transistors (OFET) . Herein we report a structure vs function relationship study focused on the electrical characteristics of solution-processed dihexylquaterthiophene (DH4T)-based OFET. We show that by combining the tailoring of all interfaces in the bottom-contact bottom-gate transistor, via chemisorption of ad hoc molecules on electrodes and dielectric, with suitable choice of the film preparation conditions (including solvent type, concentration, volume, and deposition method), it is possible to fabricate devices exhibiting field-effect mobilities exceeding those of vacuum-processed DH4T transistors. In particular, the evaporation rate of the solvent, the processing temperature, as well as the concentration of the semiconducting material were found to hold a paramount importance in driving the self-assembly toward the formation of highly ordered and low-dimensional supramolecular architectures, confirming the kinetically governed nature of the self-assembly process. Among the various architectures, hundreds-of-micrometers long and thin DH4T crystallites exhibited enhanced charge transport.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Solution-processable oligothiophenes are model systems for charge transport and fabrication of organic field-effect transistors (OFET) . Herein we report a structure vs function relationship study focused on the electrical characteristics of solution-processed dihexylquaterthiophene (DH4T)-based OFET. We show that by combining the tailoring of all interfaces in the bottom-contact bottom-gate transistor, via chemisorption of ad hoc molecules on electrodes and dielectric, with suitable choice of the film preparation conditions (including solvent type, concentration, volume, and deposition method), it is possible to fabricate devices exhibiting field-effect mobilities exceeding those of vacuum-processed DH4T transistors. In particular, the evaporation rate of the solvent, the processing temperature, as well as the concentration of the semiconducting material were found to hold a paramount importance in driving the self-assembly toward the formation of highly ordered and low-dimensional supramolecular architectures, confirming the kinetically governed nature of the self-assembly process. Among the various architectures, hundreds-of-micrometers long and thin DH4T crystallites exhibited enhanced charge transport. |
Schlierf, Andrea ; Cha, Kitty ; Schwab, Matthias Georg ; Samori, Paolo ; Palermo, Vincenzo Exfoliation of graphene with an industrial dye: teaching an old dog new tricks Journal Article In: 2D MATERIALS, 1 (3), 2014, ISSN: 2053-1583. @article{schlierf_exfoliation_2014, title = {Exfoliation of graphene with an industrial dye: teaching an old dog new tricks}, author = {Schlierf, Andrea and Cha, Kitty and Schwab, Matthias Georg and Samori, Paolo and Palermo, Vincenzo}, doi = {10.1088/2053-1583/1/3/035006}, issn = {2053-1583}, year = {2014}, date = {2014-12-01}, journal = {2D MATERIALS}, volume = {1}, number = {3}, abstract = {We describe the exfoliation, processing and inclusion in polymer composites of few-layers graphene nanoplatelets (GNPs) by using the molecule indanthrone blue sulphonic acid sodium salt (IBS), a very common industrial dyestuff and intermediate for liquid crystal preparation. We show how IBS can be used to successfully exfoliate graphite into few-layers graphene yielding highly stable dispersions in water. To demonstrate that the method is suitable for applications in composites, these graphene-organic hybrids are processed into a commercial commodity polymer (polyvinyl alcohol, PVA), enhancing its electrical bulk conductivity by ten orders of magnitude by adding as few as 3% of GNP. We attribute the good performance of IBS in dispersing GNPs in water to its amphiphilic nature and the tendency to self-assemble through pi-pi interaction of its large aromatic core with the graphene surface. The molecule studied here, unlike many specialty organic surfactants or solvents commonly known to exfoliate graphene, is already used as a blue pigment dispersant additive in the industrial production of polymers and thus does not need to be removed from the final product.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We describe the exfoliation, processing and inclusion in polymer composites of few-layers graphene nanoplatelets (GNPs) by using the molecule indanthrone blue sulphonic acid sodium salt (IBS), a very common industrial dyestuff and intermediate for liquid crystal preparation. We show how IBS can be used to successfully exfoliate graphite into few-layers graphene yielding highly stable dispersions in water. To demonstrate that the method is suitable for applications in composites, these graphene-organic hybrids are processed into a commercial commodity polymer (polyvinyl alcohol, PVA), enhancing its electrical bulk conductivity by ten orders of magnitude by adding as few as 3% of GNP. We attribute the good performance of IBS in dispersing GNPs in water to its amphiphilic nature and the tendency to self-assemble through pi-pi interaction of its large aromatic core with the graphene surface. The molecule studied here, unlike many specialty organic surfactants or solvents commonly known to exfoliate graphene, is already used as a blue pigment dispersant additive in the industrial production of polymers and thus does not need to be removed from the final product. |
Musumeci, Chiara ; Liscio, Andrea ; Palermo, Vincenzo ; Samori, Paolo Electronic characterization of supramolecular materials at the nanoscale by Conductive Atomic Force and Kelvin Probe Force microscopies Journal Article In: MATERIALS TODAY, 17 (10), pp. 504–517, 2014, ISSN: 1369-7021. @article{musumeci_electronic_2014, title = {Electronic characterization of supramolecular materials at the nanoscale by Conductive Atomic Force and Kelvin Probe Force microscopies}, author = {Musumeci, Chiara and Liscio, Andrea and Palermo, Vincenzo and Samori, Paolo}, doi = {10.1016/j.mattod.2014.05.010}, issn = {1369-7021}, year = {2014}, date = {2014-12-01}, journal = {MATERIALS TODAY}, volume = {17}, number = {10}, pages = {504--517}, abstract = {The performances of organic (opto) electronic devices strongly depend on the order at the supramolecular level. Unraveling the relationship between structural and electronic properties in nanoscale architectures is therefore key for both fundamental studies and technological applications. C-AFM and KPFM provide an immediate correlation between the morphology of a material and its electrical/electronic properties such as local conductivity and surface potential. Thus, they are unrivaled techniques offering crucial information toward the optimization of the real devices, ultimately providing an important contribution to a hot field at the cross-road between nanoscience and organic (opto) electronics. Herein we focus on the application of C-AFM and KPFM on self-assembled monolayers (SAMs), organic (semi) conducting materials for thin film transistors (TFTs) and organic blends for photovoltaics (OSCs).}, keywords = {}, pubstate = {published}, tppubtype = {article} } The performances of organic (opto) electronic devices strongly depend on the order at the supramolecular level. Unraveling the relationship between structural and electronic properties in nanoscale architectures is therefore key for both fundamental studies and technological applications. C-AFM and KPFM provide an immediate correlation between the morphology of a material and its electrical/electronic properties such as local conductivity and surface potential. Thus, they are unrivaled techniques offering crucial information toward the optimization of the real devices, ultimately providing an important contribution to a hot field at the cross-road between nanoscience and organic (opto) electronics. Herein we focus on the application of C-AFM and KPFM on self-assembled monolayers (SAMs), organic (semi) conducting materials for thin film transistors (TFTs) and organic blends for photovoltaics (OSCs). |
Tignone, Edoardo ; Pupillo, Guido ; Genes, Claudiu Transmissive optomechanical platforms with engineered spatial defects Journal Article In: PHYSICAL REVIEW A, 90 (5), 2014, ISSN: 2469-9926. @article{tignone_transmissive_2014, title = {Transmissive optomechanical platforms with engineered spatial defects}, author = {Tignone, Edoardo and Pupillo, Guido and Genes, Claudiu}, doi = {10.1103/PhysRevA.90.053831}, issn = {2469-9926}, year = {2014}, date = {2014-11-01}, journal = {PHYSICAL REVIEW A}, volume = {90}, number = {5}, abstract = {Linear optomechanical photon-phonon couplings in the membrane-in-the-middle setup can be enhanced by taking a multielement approach as it was recently shown [A. Xuereb, C. Genes, and A. Dantan, Phys. Rev. Lett. 109, 223601 ( 2012)]. The particular example considered consists of a periodic array of membranes embedded in a high-finesse optical cavity and operating in the transmissive regime, i.e., around resonances of the compound cavity-membrane system. Here we propose further improvements in such a setup by breaking the translational invariance of the array, i.e., by considering quasiperiodic arrays with engineered quadratic spatial defects in the membrane positions. The localization of light modes induced by the defect combined with the access of the aforementioned transmissive regime window can lead to additional enhancement of the strength of both linear and quadratic optomechanical couplings.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Linear optomechanical photon-phonon couplings in the membrane-in-the-middle setup can be enhanced by taking a multielement approach as it was recently shown [A. Xuereb, C. Genes, and A. Dantan, Phys. Rev. Lett. 109, 223601 ( 2012)]. The particular example considered consists of a periodic array of membranes embedded in a high-finesse optical cavity and operating in the transmissive regime, i.e., around resonances of the compound cavity-membrane system. Here we propose further improvements in such a setup by breaking the translational invariance of the array, i.e., by considering quasiperiodic arrays with engineered quadratic spatial defects in the membrane positions. The localization of light modes induced by the defect combined with the access of the aforementioned transmissive regime window can lead to additional enhancement of the strength of both linear and quadratic optomechanical couplings. |
Gilet, Guillaume ; Sauvage, Basile ; Vanhoey, Kenneth ; Dischler, Jean-Michel ; Ghazanfarpour, Djamchid Local Random-Phase Noise for Procedural Texturing Journal Article In: ACM TRANSACTIONS ON GRAPHICS, 33 (6), 2014, ISSN: 0730-0301. @article{gilet_local_2014, title = {Local Random-Phase Noise for Procedural Texturing}, author = {Gilet, Guillaume and Sauvage, Basile and Vanhoey, Kenneth and Dischler, Jean-Michel and Ghazanfarpour, Djamchid}, doi = {10.1145/2661229.2661249}, issn = {0730-0301}, year = {2014}, date = {2014-11-01}, journal = {ACM TRANSACTIONS ON GRAPHICS}, volume = {33}, number = {6}, abstract = {Local random-phase noise is a noise model for procedural texturing. It is defined on a regular spatial grid by local noises, which are sums of cosines with random phase. Our model is versatile thanks to separate sampling in the spatial and spectral domains. Therefore, it encompasses Gabor noise and noise by Fourier series. A stratified spectral sampling allows for a faithful yet compact and efficient reproduction of an arbitrary power spectrum. Noise by example is therefore obtained faster than state-of-the-art techniques. As a second contribution we address texture by example and generate not only Gaussian patterns but also structured features present in the input. This is achieved by fixing the phase on some part of the spectrum. Generated textures are continuous and non-repetitive. Results show unprecedented framerates and a flexible visual result: users can control with one parameter the blending between noise by example and structured texture synthesis.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Local random-phase noise is a noise model for procedural texturing. It is defined on a regular spatial grid by local noises, which are sums of cosines with random phase. Our model is versatile thanks to separate sampling in the spatial and spectral domains. Therefore, it encompasses Gabor noise and noise by Fourier series. A stratified spectral sampling allows for a faithful yet compact and efficient reproduction of an arbitrary power spectrum. Noise by example is therefore obtained faster than state-of-the-art techniques. As a second contribution we address texture by example and generate not only Gaussian patterns but also structured features present in the input. This is achieved by fixing the phase on some part of the spectrum. Generated textures are continuous and non-repetitive. Results show unprecedented framerates and a flexible visual result: users can control with one parameter the blending between noise by example and structured texture synthesis. |
Miyako, Eijiro ; Russier, Julie ; Mauro, Matteo ; Cebrian, Cristina ; Yawo, Hiromu ; Menard-Moyon, Cecilia ; Hutchison, James A; Yudasaka, Masako ; Iijima, Sumio ; De Cola, Luisa ; Bianco, Alberto Photofunctional Nanomodulators for Bioexcitation Journal Article In: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 53 (48), pp. 13121–13125, 2014, ISSN: 1433-7851. @article{miyako_photofunctional_2014, title = {Photofunctional Nanomodulators for Bioexcitation}, author = {Miyako, Eijiro and Russier, Julie and Mauro, Matteo and Cebrian, Cristina and Yawo, Hiromu and Menard-Moyon, Cecilia and Hutchison, James A. and Yudasaka, Masako and Iijima, Sumio and De Cola, Luisa and Bianco, Alberto}, doi = {10.1002/anie.201407169}, issn = {1433-7851}, year = {2014}, date = {2014-11-01}, journal = {ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, volume = {53}, number = {48}, pages = {13121--13125}, abstract = {A single organism comprises diverse types of cells. To acquire a detailed understanding of the biological functions of each cell, comprehensive control and analysis of homeostatic processes at the single-cell level are required. In this study, we develop a new type of light-driven nanomodulator comprising dye-functionalized carbon nanohorns (CNHs) that generate heat and reactive oxygen species under biologically transparent near-infrared (NIR) laser irradiation. By exploiting the physicochemical properties of the nanohorns, cellular calcium ion flux and membrane currents were successfully controlled at the single-cell level. In addition, the nanomodulator allows a remote bioexcitation of tissues during NIR laser exposure making this system a powerful tool for single-cell analyses and innovative cell therapies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A single organism comprises diverse types of cells. To acquire a detailed understanding of the biological functions of each cell, comprehensive control and analysis of homeostatic processes at the single-cell level are required. In this study, we develop a new type of light-driven nanomodulator comprising dye-functionalized carbon nanohorns (CNHs) that generate heat and reactive oxygen species under biologically transparent near-infrared (NIR) laser irradiation. By exploiting the physicochemical properties of the nanohorns, cellular calcium ion flux and membrane currents were successfully controlled at the single-cell level. In addition, the nanomodulator allows a remote bioexcitation of tissues during NIR laser exposure making this system a powerful tool for single-cell analyses and innovative cell therapies. |
Bertucci, Alessandro ; Luelf, Henning ; Septiadi, Dedy ; Manicardi, Alex ; Corradini, Roberto ; De Cola, Luisa Intracellular Delivery of Peptide Nucleic Acid and Organic Molecules Using Zeolite-L Nanocrystals Journal Article In: ADVANCED HEALTHCARE MATERIALS, 3 (11), pp. 1812–1817, 2014, ISSN: 2192-2640. @article{bertucci_intracellular_2014, title = {Intracellular Delivery of Peptide Nucleic Acid and Organic Molecules Using Zeolite-L Nanocrystals}, author = {Bertucci, Alessandro and Luelf, Henning and Septiadi, Dedy and Manicardi, Alex and Corradini, Roberto and De Cola, Luisa}, doi = {10.1002/adhm.201400116}, issn = {2192-2640}, year = {2014}, date = {2014-11-01}, journal = {ADVANCED HEALTHCARE MATERIALS}, volume = {3}, number = {11}, pages = {1812--1817}, abstract = {The design and synthesis of smart nanomaterials can provide interesting potential applications for biomedical purposes from bioimaging to drug delivery. Manufacturing multifunctional systems in a way to carry bioactive molecules, like peptide nucleic acids able to recognize specific targets in living cells, represents an achievement towards the development of highly selective tools for both diagnosis and therapeutics. This work describes a very first example of the use of zeolite nanocrystals as multifunctional nanocarriers to deliver simultaneously PNA and organic molecules into living cells. Zeolite-L nanocrystals are functionalized by covalently attaching the PNA probes onto the surface, while the channel system is filled with fluorescent guest molecules. The cellular uptake of the PNA/Zeolite-L hybrid material is then significantly increased by coating the whole system with a thin layer of biodegradable poly-L-lysine. The delivery of DAPI as a model drug molecule, inserted into the zeolite pores, is also demonstrated to occur in the cells, proving the multifunctional ability of the system. Using this zeolite nanosystem carrying PNA probes designed to target specific RNA sequences of interest in living cells could open new possibilities for theranostic and gene therapy applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The design and synthesis of smart nanomaterials can provide interesting potential applications for biomedical purposes from bioimaging to drug delivery. Manufacturing multifunctional systems in a way to carry bioactive molecules, like peptide nucleic acids able to recognize specific targets in living cells, represents an achievement towards the development of highly selective tools for both diagnosis and therapeutics. This work describes a very first example of the use of zeolite nanocrystals as multifunctional nanocarriers to deliver simultaneously PNA and organic molecules into living cells. Zeolite-L nanocrystals are functionalized by covalently attaching the PNA probes onto the surface, while the channel system is filled with fluorescent guest molecules. The cellular uptake of the PNA/Zeolite-L hybrid material is then significantly increased by coating the whole system with a thin layer of biodegradable poly-L-lysine. The delivery of DAPI as a model drug molecule, inserted into the zeolite pores, is also demonstrated to occur in the cells, proving the multifunctional ability of the system. Using this zeolite nanosystem carrying PNA probes designed to target specific RNA sequences of interest in living cells could open new possibilities for theranostic and gene therapy applications. |
Soldati, Roberto ; Aliprandi, Alessandro ; Mauro, Matteo ; De Cola, Luisa ; Giacomini, Daria beta-Lactam Bioconjugates Bearing Luminescent Platinum(II) Tags: Synthesis and Photophysical Characterization Journal Article In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, (32), pp. 7113–7121, 2014, ISSN: 1434-193X. @article{soldati_beta-lactam_2014, title = {beta-Lactam Bioconjugates Bearing Luminescent Platinum(II) Tags: Synthesis and Photophysical Characterization}, author = {Soldati, Roberto and Aliprandi, Alessandro and Mauro, Matteo and De Cola, Luisa and Giacomini, Daria}, doi = {10.1002/ejoc.201402740}, issn = {1434-193X}, year = {2014}, date = {2014-11-01}, journal = {EUROPEAN JOURNAL OF ORGANIC CHEMISTRY}, number = {32}, pages = {7113--7121}, abstract = {Two novel neutral complexes based on platinum metal ions, a tridentate ligand, and a pyridine bearing a beta-lactam unit have been synthesized and their photophysical properties investigated. The complexes show interesting emission properties that, in the solid state, are dominated by the formation of aggregates due to the square-planar geometry of the Pt-II species. Importantly, the formation of closed-shell metal center dot center dot center dot metal interactions in such aggregates leads to new excited states that conveniently allow excitation in the visible region. The combination of the biologically active azetidinone agent and the intense and long-lived emission are of particular interest for developing efficient multifunctional biomedical systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two novel neutral complexes based on platinum metal ions, a tridentate ligand, and a pyridine bearing a beta-lactam unit have been synthesized and their photophysical properties investigated. The complexes show interesting emission properties that, in the solid state, are dominated by the formation of aggregates due to the square-planar geometry of the Pt-II species. Importantly, the formation of closed-shell metal center dot center dot center dot metal interactions in such aggregates leads to new excited states that conveniently allow excitation in the visible region. The combination of the biologically active azetidinone agent and the intense and long-lived emission are of particular interest for developing efficient multifunctional biomedical systems. |
Ciesielski, Artur ; El Garah, Mohamed ; Haar, Sebastien ; Kovaricek, Petr ; Lehn, Jean-Marie ; Samori, Paolo Dynamic covalent chemistry of bisimines at the solid/liquid interface monitored by scanning tunnelling microscopy Journal Article In: NATURE CHEMISTRY, 6 (11), pp. 1017–1023, 2014, ISSN: 1755-4330. @article{ciesielski_dynamic_2014, title = {Dynamic covalent chemistry of bisimines at the solid/liquid interface monitored by scanning tunnelling microscopy}, author = {Ciesielski, Artur and El Garah, Mohamed and Haar, Sebastien and Kovaricek, Petr and Lehn, Jean-Marie and Samori, Paolo}, doi = {10.1038/NCHEM.2057}, issn = {1755-4330}, year = {2014}, date = {2014-11-01}, journal = {NATURE CHEMISTRY}, volume = {6}, number = {11}, pages = {1017--1023}, abstract = {Dynamic covalent chemistry relies on the formation of reversible covalent bonds under thermodynamic control to generate dynamic combinatorial libraries. It provides access to numerous types of complex functional architectures, and thereby targets several technologically relevant applications, such as in drug discovery, (bio)sensing and dynamic materials. In liquid media it was proved that by taking advantage of the reversible nature of the bond formation it is possible to combine the error-correction capacity of supramolecular chemistry with the robustness of covalent bonding to generate adaptive systems. Here we show that double imine formation between 4-(hexadecyloxy)benzaldehyde and different alpha,omega-diamines as well as reversible bistransimination reactions can be achieved at the solid/liquid interface, as monitored on the submolecular scale by in situ scanning tunnelling microscopy imaging. Our modular approach enables the structurally controlled reversible incorporation of various molecular components to form sophisticated covalent architectures, which opens up perspectives towards responsive multicomponent two-dimensional materials and devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Dynamic covalent chemistry relies on the formation of reversible covalent bonds under thermodynamic control to generate dynamic combinatorial libraries. It provides access to numerous types of complex functional architectures, and thereby targets several technologically relevant applications, such as in drug discovery, (bio)sensing and dynamic materials. In liquid media it was proved that by taking advantage of the reversible nature of the bond formation it is possible to combine the error-correction capacity of supramolecular chemistry with the robustness of covalent bonding to generate adaptive systems. Here we show that double imine formation between 4-(hexadecyloxy)benzaldehyde and different alpha,omega-diamines as well as reversible bistransimination reactions can be achieved at the solid/liquid interface, as monitored on the submolecular scale by in situ scanning tunnelling microscopy imaging. Our modular approach enables the structurally controlled reversible incorporation of various molecular components to form sophisticated covalent architectures, which opens up perspectives towards responsive multicomponent two-dimensional materials and devices. |
Smetana Jr., Karel ; Dvorankova, Barbora ; Mateu, Rosana ; Kueera, Jan ; Mifkova, Alzbeta ; Fik, Zdenek ; Lehn, Jean-Marie ; Gabius, Hans-Joachim GALECTIN-1 IN CROSSTALK BETWEEN CANCER CELLS AND CANCER-ASSOCIATED FIBROBLASTS Journal Article In: ANTICANCER RESEARCH, 34 (10), pp. 6174, 2014, ISSN: 0250-7005. @article{smetana_galectin-1_2014, title = {GALECTIN-1 IN CROSSTALK BETWEEN CANCER CELLS AND CANCER-ASSOCIATED FIBROBLASTS}, author = {Smetana, Jr., Karel and Dvorankova, Barbora and Mateu, Rosana and Kueera, Jan and Mifkova, Alzbeta and Fik, Zdenek and Lehn, Jean-Marie and Gabius, Hans-Joachim}, issn = {0250-7005}, year = {2014}, date = {2014-10-01}, journal = {ANTICANCER RESEARCH}, volume = {34}, number = {10}, pages = {6174}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Vodola, Davide ; Lepori, Luca ; Ercolessi, Elisa ; Gorshkov, Alexey V; Pupillo, Guido Kitaev Chains with Long-Range Pairing Journal Article In: PHYSICAL REVIEW LETTERS, 113 (15), 2014, ISSN: 0031-9007. @article{vodola_kitaev_2014, title = {Kitaev Chains with Long-Range Pairing}, author = {Vodola, Davide and Lepori, Luca and Ercolessi, Elisa and Gorshkov, Alexey V. and Pupillo, Guido}, doi = {10.1103/PhysRevLett.113.156402}, issn = {0031-9007}, year = {2014}, date = {2014-10-01}, journal = {PHYSICAL REVIEW LETTERS}, volume = {113}, number = {15}, abstract = {We propose and analyze a generalization of the Kitaev chain for fermions with long-range p-wave pairing, which decays with distance as a power law with exponent a. Using the integrability of the model, we demonstrate the existence of two types of gapped regimes, where correlation functions decay exponentially at short range and algebraically at long range (a textbackslashtextbackslashtextgreater 1) or purely algebraically (a textbackslashtextbackslashtextless 1). Most interestingly, along the critical lines, long-range pairing is found to break conformal symmetry for sufficiently small a. This is accompanied by a violation of the area law for the entanglement entropy in large parts of the phase diagram in the presence of a gap and can be detected via the dynamics of entanglement following a quench. Some of these features may be relevant for current experiments with cold atomic ions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We propose and analyze a generalization of the Kitaev chain for fermions with long-range p-wave pairing, which decays with distance as a power law with exponent a. Using the integrability of the model, we demonstrate the existence of two types of gapped regimes, where correlation functions decay exponentially at short range and algebraically at long range (a textbackslashtextbackslashtextgreater 1) or purely algebraically (a textbackslashtextbackslashtextless 1). Most interestingly, along the critical lines, long-range pairing is found to break conformal symmetry for sufficiently small a. This is accompanied by a violation of the area law for the entanglement entropy in large parts of the phase diagram in the presence of a gap and can be detected via the dynamics of entanglement following a quench. Some of these features may be relevant for current experiments with cold atomic ions. |
Huda, Sabil ; Pilans, Didzis ; Makurath, Monika ; Hermans, Thomas M; Kandere-Grzybowska, Kristiana ; Grzybowski, Bartosz A Microfabricated Systems and Assays for Studying the Cytoskeletal Organization, Micromechanics, and Motility Patterns of Cancerous Cells Journal Article In: ADVANCED MATERIALS INTERFACES, 1 (7), 2014, ISSN: 2196-7350. @article{huda_microfabricated_2014, title = {Microfabricated Systems and Assays for Studying the Cytoskeletal Organization, Micromechanics, and Motility Patterns of Cancerous Cells}, author = {Huda, Sabil and Pilans, Didzis and Makurath, Monika and Hermans, Thomas M. and Kandere-Grzybowska, Kristiana and Grzybowski, Bartosz A.}, doi = {10.1002/admi.201400158}, issn = {2196-7350}, year = {2014}, date = {2014-10-01}, journal = {ADVANCED MATERIALS INTERFACES}, volume = {1}, number = {7}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Comelles, Jordi ; Caballero, David ; Voituriez, Raphael ; Hortigueela, Veronica ; Wollrab, Viktoria ; Godeau, Amelie Luise ; Samitier, Josep ; Martinez, Elena ; Riveline, Daniel Cells as Active Particles in Asymmetric Potentials: Motility under External Gradients Journal Article In: BIOPHYSICAL JOURNAL, 107 (7), pp. 1513–1522, 2014, ISSN: 0006-3495. @article{comelles_cells_2014, title = {Cells as Active Particles in Asymmetric Potentials: Motility under External Gradients}, author = {Comelles, Jordi and Caballero, David and Voituriez, Raphael and Hortigueela, Veronica and Wollrab, Viktoria and Godeau, Amelie Luise and Samitier, Josep and Martinez, Elena and Riveline, Daniel}, doi = {10.1016/j.bpj.2014.08.001}, issn = {0006-3495}, year = {2014}, date = {2014-10-01}, journal = {BIOPHYSICAL JOURNAL}, volume = {107}, number = {7}, pages = {1513--1522}, abstract = {Cell migration is a crucial event during development and in disease. Mechanical constraints and chemical gradients can contribute to the establishment of cell direction, but their respective roles remain poorly understood. Using a microfabricated topographical ratchet, we show that the nucleus dictates the direction of cell movement through mechanical guidance by its environment. We demonstrate that this direction can be tuned by combining the topographical ratchet with a biochemical gradient of fibronectin adhesion. We report competition and cooperation between the two external cues. We also quantitatively compare the measurements associated with the trajectory of a model that treats cells as fluctuating particles trapped in a periodic asymmetric potential. We show that the cell nucleus contributes to the strength of the trap, whereas cell protrusions guided by the adhesive gradients add a constant tunable bias to the direction of cell motion.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cell migration is a crucial event during development and in disease. Mechanical constraints and chemical gradients can contribute to the establishment of cell direction, but their respective roles remain poorly understood. Using a microfabricated topographical ratchet, we show that the nucleus dictates the direction of cell movement through mechanical guidance by its environment. We demonstrate that this direction can be tuned by combining the topographical ratchet with a biochemical gradient of fibronectin adhesion. We report competition and cooperation between the two external cues. We also quantitatively compare the measurements associated with the trajectory of a model that treats cells as fluctuating particles trapped in a periodic asymmetric potential. We show that the cell nucleus contributes to the strength of the trap, whereas cell protrusions guided by the adhesive gradients add a constant tunable bias to the direction of cell motion. |
Cebrian, Cristina ; de Mata Munoz, Juan ; Strassert, Cristian Alejandro ; Prieto, Pilar ; Diaz-Ortiz, Angel ; De Cola, Luisa ; de la Hoz, Antonio Synthesis of Bright Alkenyl-1H-1,2,4-triazoles: A Theoretical and Photophysical Study Journal Article In: CHEMPLUSCHEM, 79 (10), pp. 1489–1497, 2014, ISSN: 2192-6506. @article{cebrian_synthesis_2014, title = {Synthesis of Bright Alkenyl-1H-1,2,4-triazoles: A Theoretical and Photophysical Study}, author = {Cebrian, Cristina and de Mata Munoz, Juan and Strassert, Cristian Alejandro and Prieto, Pilar and Diaz-Ortiz, Angel and De Cola, Luisa and de la Hoz, Antonio}, doi = {10.1002/cplu.201402153}, issn = {2192-6506}, year = {2014}, date = {2014-10-01}, journal = {CHEMPLUSCHEM}, volume = {79}, number = {10}, pages = {1489--1497}, abstract = {A sustainable synthesis of alkenyl-1H-1,2,4-triazoles through the Hiyama reaction is reported, which employs water as solvent and sodium hydroxide to activate the silyl group under microwave irradiation, thereby leading to high product yields (51-93%) in very short reaction times. Two substitution patterns were attained owing to the different reactivity of the third and fifth positions of the 1H-1,2,4-triazole unit, as evidenced by calculated condensed Fukui functions. Moreover, all compounds are good blue emitters (phi(F) up to 0.69) in THF solution, although they exhibit an optical behavior dependent on the substitution. Excited-state theoretical investigations by the configuration interaction singles method and time-dependent density functional theory were performed not only to support and elucidate the studied photophysical properties, but also to create a predictive model to reduce the cost and optimize the search for new blue emitters based on this class of alkenyl-1H-1,2,4-triazoles.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A sustainable synthesis of alkenyl-1H-1,2,4-triazoles through the Hiyama reaction is reported, which employs water as solvent and sodium hydroxide to activate the silyl group under microwave irradiation, thereby leading to high product yields (51-93%) in very short reaction times. Two substitution patterns were attained owing to the different reactivity of the third and fifth positions of the 1H-1,2,4-triazole unit, as evidenced by calculated condensed Fukui functions. Moreover, all compounds are good blue emitters (phi(F) up to 0.69) in THF solution, although they exhibit an optical behavior dependent on the substitution. Excited-state theoretical investigations by the configuration interaction singles method and time-dependent density functional theory were performed not only to support and elucidate the studied photophysical properties, but also to create a predictive model to reduce the cost and optimize the search for new blue emitters based on this class of alkenyl-1H-1,2,4-triazoles. |
Pathipati, Srinivasa Rao ; Pavlica, Egon ; Schlierf, Andrea ; El Gemayel, Mirella ; Samori, Paolo ; Palermo, Vincenzo ; Bratina, Gvido Graphene-Induced Enhancement of n-Type Mobility in Perylenediimide Thin Films Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY C, 118 (43), pp. 24819–24826, 2014, ISSN: 1932-7447. @article{pathipati_graphene-induced_2014, title = {Graphene-Induced Enhancement of n-Type Mobility in Perylenediimide Thin Films}, author = {Pathipati, Srinivasa Rao and Pavlica, Egon and Schlierf, Andrea and El Gemayel, Mirella and Samori, Paolo and Palermo, Vincenzo and Bratina, Gvido}, doi = {10.1021/jp505463v}, issn = {1932-7447}, year = {2014}, date = {2014-10-01}, journal = {JOURNAL OF PHYSICAL CHEMISTRY C}, volume = {118}, number = {43}, pages = {24819--24826}, abstract = {Organic thin-film transistor transfer characteristics and time-of-flight (TOF) photoconductivity measurements were used to investigate the effect of the addition of liquid-phase exfoliated graphene nanoflakes (GNs) on the electron mobility in thin films of N,N'-bis(1H,1H-perfluorobutyl)dicyanoperylenecarboxydiimide (PDIF-CN2). Transfer characteristics measurements reveal that the charge carrier mobility of PDIF-CN2 increases by almost 3 orders of magnitude via blending with GNs. TOF photocurrent measurements confirm that the GNs improve the charge carrier transport in PDIF-CN2. We have found a strong dependence of the TOF-determined electron mobility on the excitation wavelength and obtained a maximum mobility of 0.17 cm(2)/(V s) for charge carriers produced in GN:PDIF-CN2 blends using a photon energy of 5.9 eV. This value is in good agreement with the field-effect mobility of 0.2 cm(2)/(V s) determined from transfer characteristics.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Organic thin-film transistor transfer characteristics and time-of-flight (TOF) photoconductivity measurements were used to investigate the effect of the addition of liquid-phase exfoliated graphene nanoflakes (GNs) on the electron mobility in thin films of N,N'-bis(1H,1H-perfluorobutyl)dicyanoperylenecarboxydiimide (PDIF-CN2). Transfer characteristics measurements reveal that the charge carrier mobility of PDIF-CN2 increases by almost 3 orders of magnitude via blending with GNs. TOF photocurrent measurements confirm that the GNs improve the charge carrier transport in PDIF-CN2. We have found a strong dependence of the TOF-determined electron mobility on the excitation wavelength and obtained a maximum mobility of 0.17 cm(2)/(V s) for charge carriers produced in GN:PDIF-CN2 blends using a photon energy of 5.9 eV. This value is in good agreement with the field-effect mobility of 0.2 cm(2)/(V s) determined from transfer characteristics. |
El Garah, Mohamed ; Ciesielski, Artur ; Marets, Nicolas ; Bulach, Veronique ; Hosseini, Mir Wais ; Samori, Paolo Molecular tectonics based nanopatterning of interfaces with 2D metal-organic frameworks (MOFs) Journal Article In: CHEMICAL COMMUNICATIONS, 50 (82), pp. 12250–12253, 2014, ISSN: 1359-7345. @article{el_garah_molecular_2014, title = {Molecular tectonics based nanopatterning of interfaces with 2D metal-organic frameworks (MOFs)}, author = {El Garah, Mohamed and Ciesielski, Artur and Marets, Nicolas and Bulach, Veronique and Hosseini, Mir Wais and Samori, Paolo}, doi = {10.1039/c4cc03622k}, issn = {1359-7345}, year = {2014}, date = {2014-10-01}, journal = {CHEMICAL COMMUNICATIONS}, volume = {50}, number = {82}, pages = {12250--12253}, abstract = {The nanostructuring of the graphite surface with 2D coordination networks, based on a combination of an acentric porphyrin tecton bearing two divergently oriented monodentate pyridyl units and a CoCl2 metallatecton, behaving as a four connecting node, was achieved at the solid-liquid interface and characterized by scanning tunnelling microscopy.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The nanostructuring of the graphite surface with 2D coordination networks, based on a combination of an acentric porphyrin tecton bearing two divergently oriented monodentate pyridyl units and a CoCl2 metallatecton, behaving as a four connecting node, was achieved at the solid-liquid interface and characterized by scanning tunnelling microscopy. |
Greb, Lutz ; Lehn, Jean-Marie Light-Driven Molecular Motors: lmines as Four-Step or Two-Step Unidirectional Rotors Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 136 (38), pp. 13114–13117, 2014, ISSN: 0002-7863. @article{greb_light-driven_2014, title = {Light-Driven Molecular Motors: lmines as Four-Step or Two-Step Unidirectional Rotors}, author = {Greb, Lutz and Lehn, Jean-Marie}, doi = {10.1021/ja506034n}, issn = {0002-7863}, year = {2014}, date = {2014-09-01}, journal = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, volume = {136}, number = {38}, pages = {13114--13117}, abstract = {Chiral N-alkyl imines undergo unidirectional rotation induced by light and heat, thus providing a new class of molecular motors. Depending on the conformational flexibility of the stator part (the carbonyl residue) and the nitrogen inversion barrier of the rotor part (the amine residue) in the molecule, the operation mode of the motor can be controlled as either a four- or a two-step cycling motion of the rotor part.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Chiral N-alkyl imines undergo unidirectional rotation induced by light and heat, thus providing a new class of molecular motors. Depending on the conformational flexibility of the stator part (the carbonyl residue) and the nitrogen inversion barrier of the rotor part (the amine residue) in the molecule, the operation mode of the motor can be controlled as either a four- or a two-step cycling motion of the rotor part. |
Kulchat, Sirinan ; Meguellati, Kamel ; Lehn, Jean-Marie Organocatalyzed and Uncatalyzed C=C/C=C and C=C/C=N Exchange Processes between Knoevenagel and Imine Compounds in Dynamic Covalent Chemistry Journal Article In: HELVETICA CHIMICA ACTA, 97 (9), pp. 1219–1236, 2014, ISSN: 0018-019X. @article{kulchat_organocatalyzed_2014, title = {Organocatalyzed and Uncatalyzed C=C/C=C and C=C/C=N Exchange Processes between Knoevenagel and Imine Compounds in Dynamic Covalent Chemistry}, author = {Kulchat, Sirinan and Meguellati, Kamel and Lehn, Jean-Marie}, doi = {10.1002/hlca.201400187}, issn = {0018-019X}, year = {2014}, date = {2014-09-01}, journal = {HELVETICA CHIMICA ACTA}, volume = {97}, number = {9}, pages = {1219--1236}, abstract = {Molecular diversity generation through reversible component exchange has acquired great importance in the last decade with the development of dynamic covalent chemistry. We explore here the recombination of components linked by C=C and C=N bonds through reversible double-bond formation, and cleavage in C=C/C=C and C=C/C=N exchange processes. The reversibility of the Knoevenagel reaction has been explored, and C=C/C=C C/C exchanges have been achieved among different benzylidenes, under organocatalysis by secondary amines such as l-proline. The substituents of these benzylidenes were shown to play a very important role in the kinetics of the exchange reactions. L-Proline is also used to catalyze the reversible C=C/C=C exchange between Knoevenagel derivatives of barbituric acid and malononitrile. Finally, the interconversion between Knoevenagel derivatives of dimethylbarbituric acid and imines (C=C/C=N exchange) has been studied and was found to occur rapidly in the absence of catalyst. The results of this study pave the way for the extension of dynamic combinatorial chemistry based on C=C/C=C and C=C/C=N exchange systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Molecular diversity generation through reversible component exchange has acquired great importance in the last decade with the development of dynamic covalent chemistry. We explore here the recombination of components linked by C=C and C=N bonds through reversible double-bond formation, and cleavage in C=C/C=C and C=C/C=N exchange processes. The reversibility of the Knoevenagel reaction has been explored, and C=C/C=C C/C exchanges have been achieved among different benzylidenes, under organocatalysis by secondary amines such as l-proline. The substituents of these benzylidenes were shown to play a very important role in the kinetics of the exchange reactions. L-Proline is also used to catalyze the reversible C=C/C=C exchange between Knoevenagel derivatives of barbituric acid and malononitrile. Finally, the interconversion between Knoevenagel derivatives of dimethylbarbituric acid and imines (C=C/C=N exchange) has been studied and was found to occur rapidly in the absence of catalyst. The results of this study pave the way for the extension of dynamic combinatorial chemistry based on C=C/C=C and C=C/C=N exchange systems. |
Karplus, Martin Development of Multiscale Models for Complex Chemical Systems: From Ħ+Ħ-2 to Biomolecules (Nobel Lecture) Journal Article In: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 53 (38), pp. 9992–10005, 2014, ISSN: 1433-7851. @article{karplus_development_2014, title = {Development of Multiscale Models for Complex Chemical Systems: From Ħ+Ħ-2 to Biomolecules (Nobel Lecture)}, author = {Karplus, Martin}, doi = {10.1002/anie.201403924}, issn = {1433-7851}, year = {2014}, date = {2014-09-01}, journal = {ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, volume = {53}, number = {38}, pages = {9992--10005}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Dantan, Aurelien ; Nair, Bhagya ; Pupillo, Guido ; Genes, Claudiu Hybrid cavity mechanics with doped systems Journal Article In: PHYSICAL REVIEW A, 90 (3), 2014, ISSN: 1050-2947. @article{dantan_hybrid_2014, title = {Hybrid cavity mechanics with doped systems}, author = {Dantan, Aurelien and Nair, Bhagya and Pupillo, Guido and Genes, Claudiu}, doi = {10.1103/PhysRevA.90.033820}, issn = {1050-2947}, year = {2014}, date = {2014-09-01}, journal = {PHYSICAL REVIEW A}, volume = {90}, number = {3}, abstract = {We investigate the dynamics of a mechanical resonator in which is embedded an ensemble of two-level systems interacting with an optical cavity field. We show that this hybrid approach to optomechanics allows for enhanced effective interactions between the mechanics and the cavity field, leading, for instance, to ground-state cooling of the mechanics, even in regimes, like the unresolved sideband regime, in which standard radiation pressure cooling would be inefficient.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We investigate the dynamics of a mechanical resonator in which is embedded an ensemble of two-level systems interacting with an optical cavity field. We show that this hybrid approach to optomechanics allows for enhanced effective interactions between the mechanics and the cavity field, leading, for instance, to ground-state cooling of the mechanics, even in regimes, like the unresolved sideband regime, in which standard radiation pressure cooling would be inefficient. |
Mohankumar, Meera ; Monti, Filippo ; Holler, Michel ; Niess, Frederic ; Delavaux-Nicot, Beatrice ; Armaroli, Nicola ; Sauvage, Jean-Pierre ; Nierengarten, Jean-Francois Combining Topological and Steric Constraints for the Preparation of Heteroleptic Copper(I) Complexes Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (38), pp. 12083–12090, 2014, ISSN: 0947-6539. @article{mohankumar_combining_2014, title = {Combining Topological and Steric Constraints for the Preparation of Heteroleptic Copper(I) Complexes}, author = {Mohankumar, Meera and Monti, Filippo and Holler, Michel and Niess, Frederic and Delavaux-Nicot, Beatrice and Armaroli, Nicola and Sauvage, Jean-Pierre and Nierengarten, Jean-Francois}, doi = {10.1002/chem.201402429}, issn = {0947-6539}, year = {2014}, date = {2014-09-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {20}, number = {38}, pages = {12083--12090}, abstract = {Heteroleptic copper(I) complexes have been prepared from a macrocyclic ligand incorporating a 2,9-diphenyl- 1,10-phenanthroline subunit (M30) and two bis-phosphines, namely bis[(2-diphenylphosphino) phenyl] ether (POP) and 1,3-bis(diphenylphosphino) propane (dppp). In both cases, the diphenylphosphino moieties of the PP ligand are too bulky to pass through the 30-membered ring of M30 during the coordination process, hence the formation of C-2v-symmetrical pseudo-rotaxanes is prevented. When POP is used, X-ray crystal structure analysis shows the formation of a highly distorted [Cu(M30)(POP)](+) complex in which the POP ligand is only partially threaded through the M30 unit. This compound is poorly stable as the CuI cation is not in a favorable coordination environment due to steric constraints. By contrast, in the case of dppp, the bis-phosphine ligand undergoes both steric and topological constraints and adopts a nonchelating coordination mode to generate [Cu2(M30) 2(m-dppp)](BF4)(2). This compound exhibits metal-to-ligand charge transfer (MLCT) emission characterized by a very large Stokes' shift (similar to 200 nm) that is not attributed to a dramatic structural distortion between the ground and the emitting states but to very weak MLCT absorption transitions at longer wavelengths. Accordingly, [Cu-2(M30)(2)(mu-dppp)](BF4)(2) shows unusually high luminescence quantum yields for CuI complexes, both in solution and in the solid state (0.5 and 7%, respectively).}, keywords = {}, pubstate = {published}, tppubtype = {article} } Heteroleptic copper(I) complexes have been prepared from a macrocyclic ligand incorporating a 2,9-diphenyl- 1,10-phenanthroline subunit (M30) and two bis-phosphines, namely bis[(2-diphenylphosphino) phenyl] ether (POP) and 1,3-bis(diphenylphosphino) propane (dppp). In both cases, the diphenylphosphino moieties of the PP ligand are too bulky to pass through the 30-membered ring of M30 during the coordination process, hence the formation of C-2v-symmetrical pseudo-rotaxanes is prevented. When POP is used, X-ray crystal structure analysis shows the formation of a highly distorted [Cu(M30)(POP)](+) complex in which the POP ligand is only partially threaded through the M30 unit. This compound is poorly stable as the CuI cation is not in a favorable coordination environment due to steric constraints. By contrast, in the case of dppp, the bis-phosphine ligand undergoes both steric and topological constraints and adopts a nonchelating coordination mode to generate [Cu2(M30) 2(m-dppp)](BF4)(2). This compound exhibits metal-to-ligand charge transfer (MLCT) emission characterized by a very large Stokes' shift (similar to 200 nm) that is not attributed to a dramatic structural distortion between the ground and the emitting states but to very weak MLCT absorption transitions at longer wavelengths. Accordingly, [Cu-2(M30)(2)(mu-dppp)](BF4)(2) shows unusually high luminescence quantum yields for CuI complexes, both in solution and in the solid state (0.5 and 7%, respectively). |
Schaepelynck, Pauline ; Riveline, Jean-Pierre ; Renard, Eric ; Hanaire, Helene ; Guerci, Bruno ; Baillot-Rudoni, Sabine ; Sola-Gazagnes, Agnes ; Catargi, Bogdan ; Fontaine, Pierre ; Millot, Luc ; Martin, Jean-Francois ; Tachouaft, Hocine ; Jeandidier, Nathalie ; Grp, EVADIAC Assessment of a New Insulin Preparation for Implanted Pumps Used in the Treatment of Type 1 Diabetes Journal Article In: DIABETES TECHNOLOGY & THERAPEUTICS, 16 (9), pp. 582–589, 2014, ISSN: 1520-9156. @article{schaepelynck_assessment_2014, title = {Assessment of a New Insulin Preparation for Implanted Pumps Used in the Treatment of Type 1 Diabetes}, author = {Schaepelynck, Pauline and Riveline, Jean-Pierre and Renard, Eric and Hanaire, Helene and Guerci, Bruno and Baillot-Rudoni, Sabine and Sola-Gazagnes, Agnes and Catargi, Bogdan and Fontaine, Pierre and Millot, Luc and Martin, Jean-Francois and Tachouaft, Hocine and Jeandidier, Nathalie and Grp, EVADIAC}, doi = {10.1089/dia.2013.0369}, issn = {1520-9156}, year = {2014}, date = {2014-09-01}, journal = {DIABETES TECHNOLOGY & THERAPEUTICS}, volume = {16}, number = {9}, pages = {582--589}, abstract = {Background: Implanted insulin pumps using the peritoneal route provide long-term improvement of glucose control compared with subcutaneous insulin therapy in type 1 diabetes (T1D) patients. The stability of insulin preparation is critical for a safe use in implanted pumps. Insuman implantable (R) (400 IU/mL) (Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany), a recombinant human insulin, has been developed as a replacement for Insuplant (R) (Aventis Pharma, Frankfurt am Main, Germany), a semisynthetic insulin, the only one used so far. The aim of the study was to demonstrate the noninferiority of Insuman versus Insuplant, in terms of safety and effectiveness when used in implanted pumps. Subjects and Methods: The patients enrolled, currently treated for T1D by the Medtronic MiniMed (North-ridge, CA) implantable pump model 2007 with Insuplant, were randomized into two study arms and received either Insuman or Insuplant for four pump refill cycles. Each pump refill cycle was 40 +/- 5 days. The co-primary end points included glycated hemoglobin (HbA1c) change from baseline and pump infusion accuracy. Results: In total, 169 patients were randomized. Noninferiority of Insuman versus Insuplant was demonstrated both for the HbA1c change from baseline (as a percentage) with intergroup difference of 95% confidence interval (-0.36; +0.11) and for the infusion accuracy assessed by the measured percentage of error at pump refill, as shown by intergroup difference of 95% confidence interval (-5.81; -0.50), in per-protocol populations, although the insulin daily dose was similar. Severe hypoglycemia occurred at least once in 12 versus 11 patients, respectively, and metabolic or technical adverse events were comparable. Conclusions: Findings suggest that Insuman can safely and effectively replace Insuplant in implanted pumps.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Background: Implanted insulin pumps using the peritoneal route provide long-term improvement of glucose control compared with subcutaneous insulin therapy in type 1 diabetes (T1D) patients. The stability of insulin preparation is critical for a safe use in implanted pumps. Insuman implantable (R) (400 IU/mL) (Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany), a recombinant human insulin, has been developed as a replacement for Insuplant (R) (Aventis Pharma, Frankfurt am Main, Germany), a semisynthetic insulin, the only one used so far. The aim of the study was to demonstrate the noninferiority of Insuman versus Insuplant, in terms of safety and effectiveness when used in implanted pumps. Subjects and Methods: The patients enrolled, currently treated for T1D by the Medtronic MiniMed (North-ridge, CA) implantable pump model 2007 with Insuplant, were randomized into two study arms and received either Insuman or Insuplant for four pump refill cycles. Each pump refill cycle was 40 +/- 5 days. The co-primary end points included glycated hemoglobin (HbA1c) change from baseline and pump infusion accuracy. Results: In total, 169 patients were randomized. Noninferiority of Insuman versus Insuplant was demonstrated both for the HbA1c change from baseline (as a percentage) with intergroup difference of 95% confidence interval (-0.36; +0.11) and for the infusion accuracy assessed by the measured percentage of error at pump refill, as shown by intergroup difference of 95% confidence interval (-5.81; -0.50), in per-protocol populations, although the insulin daily dose was similar. Severe hypoglycemia occurred at least once in 12 versus 11 patients, respectively, and metabolic or technical adverse events were comparable. Conclusions: Findings suggest that Insuman can safely and effectively replace Insuplant in implanted pumps. |
Ciesielski, Artur ; Haar, Sebastien ; El Gemayel, Mirella ; Yang, Huafeng ; Clough, Joseph ; Melinte, Georgian ; Gobbi, Marco ; Orgiu, Emanuele ; Nardi, Marco V; Ligorio, Giovanni ; Palermo, Vincenzo ; Koch, Norbert ; Ersen, Ovidiu ; Casiraghi, Cinzia ; Samori, Paolo Harnessing the Liquid-Phase Exfoliation of Graphene Using Aliphatic Compounds: A Supramolecular Approach Journal Article In: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 53 (39), pp. 10355–10361, 2014, ISSN: 1433-7851. @article{ciesielski_harnessing_2014, title = {Harnessing the Liquid-Phase Exfoliation of Graphene Using Aliphatic Compounds: A Supramolecular Approach}, author = {Ciesielski, Artur and Haar, Sebastien and El Gemayel, Mirella and Yang, Huafeng and Clough, Joseph and Melinte, Georgian and Gobbi, Marco and Orgiu, Emanuele and Nardi, Marco V. and Ligorio, Giovanni and Palermo, Vincenzo and Koch, Norbert and Ersen, Ovidiu and Casiraghi, Cinzia and Samori, Paolo}, doi = {10.1002/anie.201402696}, issn = {1433-7851}, year = {2014}, date = {2014-09-01}, journal = {ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, volume = {53}, number = {39}, pages = {10355--10361}, abstract = {The technological exploitation of the extraordinary properties of graphene relies on the ability to achieve full control over the production of a high-quality material and its processing by up-scalable approaches in order to fabricate large-area films with single-layer or a few atomic-layer thickness, which might be integrated in working devices. A simple method is reported for producing homogenous dispersions of unfunctionalized and non-oxidized graphene nanosheets in N-methyl- 2-pyrrolidone (NMP) by using simple molecular modules, which act as dispersion-stabilizing compounds during the liquid-phase exfoliation (LPE) process, leading to an increase in the concentration of graphene in dispersions. The LPE-processed graphene dispersion was shown to be a conductive ink. This approach opens up new avenues for the technological applications of this graphene ink as low-cost electrodes and conducting nanocomposite for electronics.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The technological exploitation of the extraordinary properties of graphene relies on the ability to achieve full control over the production of a high-quality material and its processing by up-scalable approaches in order to fabricate large-area films with single-layer or a few atomic-layer thickness, which might be integrated in working devices. A simple method is reported for producing homogenous dispersions of unfunctionalized and non-oxidized graphene nanosheets in N-methyl- 2-pyrrolidone (NMP) by using simple molecular modules, which act as dispersion-stabilizing compounds during the liquid-phase exfoliation (LPE) process, leading to an increase in the concentration of graphene in dispersions. The LPE-processed graphene dispersion was shown to be a conductive ink. This approach opens up new avenues for the technological applications of this graphene ink as low-cost electrodes and conducting nanocomposite for electronics. |
Ferlauto, Laura ; Liscio, Fabiola ; Orgiu, Emanuele ; Masciocchi, Norberto ; Guagliardi, Antonietta ; Biscarini, Fabio ; Samori, Paolo ; Milita, Silvia Enhancing the Charge Transport in Solution-Processed Perylene Di-imide Transistors via Thermal Annealing of Metastable Disordered Films Journal Article In: ADVANCED FUNCTIONAL MATERIALS, 24 (35), pp. 5503–5510, 2014, ISSN: 1616-301X. @article{ferlauto_enhancing_2014, title = {Enhancing the Charge Transport in Solution-Processed Perylene Di-imide Transistors via Thermal Annealing of Metastable Disordered Films}, author = {Ferlauto, Laura and Liscio, Fabiola and Orgiu, Emanuele and Masciocchi, Norberto and Guagliardi, Antonietta and Biscarini, Fabio and Samori, Paolo and Milita, Silvia}, doi = {10.1002/adfm.201400789}, issn = {1616-301X}, year = {2014}, date = {2014-09-01}, journal = {ADVANCED FUNCTIONAL MATERIALS}, volume = {24}, number = {35}, pages = {5503--5510}, abstract = {The introduction of side chains in pi-conjugated molecules is a design strategy widely exploited to increase molecular solubility thus improving the processability, while directly influencing the self-assembly and consequently the electrical properties of thin films. Here, a multiscale structural analysis performed by X-ray diffraction, X-ray reflectivity, and atomic force microscopy on thin films of dicyanoperylene molecules decorated with either linear or branched side chains is reported. The substitution with asymmetric branched alkyl chains allows obtaining, upon thermal annealing, field-effect transistors with enhanced transport properties with respect to linear alkyl chains. Branched chains induce molecular disorder during the film growth from solution, effectively favouring 2D morphology. Post-deposition thermal annealing leads to a structural transition towards the bulk-phase for molecules with branched chains, still preserving the 2D morphology and allowing efficient charge transport between crystalline domains. Conversely, molecules with linear chains self-assemble into 3D islands exhibiting the bulk-phase structure. Upon thermal annealing, these 3D islands keep their size constant and no major changes are observed in the organic field effect transistor characteristics. These findings demonstrate that the disorder generated by the asymmetric branched chains when the molecule is physisorbed in thin film can be instrumental for enhancing charge transport via thermal annealing.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The introduction of side chains in pi-conjugated molecules is a design strategy widely exploited to increase molecular solubility thus improving the processability, while directly influencing the self-assembly and consequently the electrical properties of thin films. Here, a multiscale structural analysis performed by X-ray diffraction, X-ray reflectivity, and atomic force microscopy on thin films of dicyanoperylene molecules decorated with either linear or branched side chains is reported. The substitution with asymmetric branched alkyl chains allows obtaining, upon thermal annealing, field-effect transistors with enhanced transport properties with respect to linear alkyl chains. Branched chains induce molecular disorder during the film growth from solution, effectively favouring 2D morphology. Post-deposition thermal annealing leads to a structural transition towards the bulk-phase for molecules with branched chains, still preserving the 2D morphology and allowing efficient charge transport between crystalline domains. Conversely, molecules with linear chains self-assemble into 3D islands exhibiting the bulk-phase structure. Upon thermal annealing, these 3D islands keep their size constant and no major changes are observed in the organic field effect transistor characteristics. These findings demonstrate that the disorder generated by the asymmetric branched chains when the molecule is physisorbed in thin film can be instrumental for enhancing charge transport via thermal annealing. |
Roy, Nabarun ; Buhler, Eric ; Lehn, Jean-Marie Double dynamic self-healing polymers: supramolecular and covalent dynamic polymers based on the bis-iminocarbohydrazide motif Journal Article In: POLYMER INTERNATIONAL, 63 (8), pp. 1400–1405, 2014, ISSN: 0959-8103. @article{roy_double_2014, title = {Double dynamic self-healing polymers: supramolecular and covalent dynamic polymers based on the bis-iminocarbohydrazide motif}, author = {Roy, Nabarun and Buhler, Eric and Lehn, Jean-Marie}, doi = {10.1002/pi.4646}, issn = {0959-8103}, year = {2014}, date = {2014-08-01}, journal = {POLYMER INTERNATIONAL}, volume = {63}, number = {8}, pages = {1400--1405}, abstract = {Self-healing polymers are a class of functional polymers that, by the virtue of the presence of certain dynamic chemical linkages, may undergo self-repair at a mechanically cut surface. Herein we report the synthesis of a self-healing polymer giving access to double dynamicity within the polymer network by making use simultaneously of reversible covalent bonds and dynamic non-covalent hydrogen bonding interactions. These features are provided, respectively, by doubly dynamic cassettes comprising chemically reversible imine linkages and multiply hydrogen-bonded urea groups, connected by a siloxane-based backbone that imparts softness to the material. Such a system can be envisaged to give access to a broad spectrum of functional materials, which can be tuned by convenient modulation of the structural motifs of the polymer. (C) 2013 Society of Chemical Industry}, keywords = {}, pubstate = {published}, tppubtype = {article} } Self-healing polymers are a class of functional polymers that, by the virtue of the presence of certain dynamic chemical linkages, may undergo self-repair at a mechanically cut surface. Herein we report the synthesis of a self-healing polymer giving access to double dynamicity within the polymer network by making use simultaneously of reversible covalent bonds and dynamic non-covalent hydrogen bonding interactions. These features are provided, respectively, by doubly dynamic cassettes comprising chemically reversible imine linkages and multiply hydrogen-bonded urea groups, connected by a siloxane-based backbone that imparts softness to the material. Such a system can be envisaged to give access to a broad spectrum of functional materials, which can be tuned by convenient modulation of the structural motifs of the polymer. (C) 2013 Society of Chemical Industry |
Karplus, Martin ; Lavery, Richard Significance of Molecular Dynamics Simulations for Life Sciences Journal Article In: ISRAEL JOURNAL OF CHEMISTRY, 54 (8-9, SI), pp. 1042–1051, 2014, ISSN: 0021-2148. @article{karplus_significance_2014, title = {Significance of Molecular Dynamics Simulations for Life Sciences}, author = {Karplus, Martin and Lavery, Richard}, doi = {10.1002/ijch.201400074}, issn = {0021-2148}, year = {2014}, date = {2014-08-01}, journal = {ISRAEL JOURNAL OF CHEMISTRY}, volume = {54}, number = {8-9, SI}, pages = {1042--1051}, abstract = {This article illustrates by examples the limited acceptance by biologists of predictions made with molecular dynamics simulations of biomolecules. Its purpose is to increase the awareness of biologists of the contribution that simulations can make to our understanding of biomolecule function.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article illustrates by examples the limited acceptance by biologists of predictions made with molecular dynamics simulations of biomolecules. Its purpose is to increase the awareness of biologists of the contribution that simulations can make to our understanding of biomolecule function. |
Publications
2015 |
Vortex flows impart chirality-specific lift forces Journal Article In: NATURE COMMUNICATIONS, 6 , 2015, ISSN: 2041-1723. |
Accurate and Efficient Calculation of the Desorption Energy of Small Molecules from Graphene Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY C, 119 (4), pp. 1867–1879, 2015, ISSN: 1932-7447. |
Unusual stability of dyads during photochemical hydrogen production Journal Article In: DALTON TRANSACTIONS, 44 (48), pp. 20936–20948, 2015, ISSN: 1477-9226. |
Length control of supramolecular polymeric nanofibers based on stacked planar platinum(II) complexes by seeded-growth Journal Article In: CHEMICAL COMMUNICATIONS, 51 (88), pp. 15921–15924, 2015, ISSN: 1359-7345. |
Influence of electronic and steric effects of substituted ligands coordinated to Ir(III) complexes on the solution processed OLED properties Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 3 (28), pp. 7506–7512, 2015, ISSN: 2050-7526. |
Luminescent supramolecular soft nanostructures from amphiphilic dinuclear Re(I) complexes Journal Article In: NANOSCALE, 7 (28), pp. 12000–12009, 2015, ISSN: 2040-3364. |
Neutral NCN terdentate luminescent Pt(II) complexes: their synthesis, photophysical properties, and bio-imaging applications Journal Article In: DALTON TRANSACTIONS, 44 (18), pp. 8478–8487, 2015, ISSN: 1477-9226. |
Key Effects of Confinement on Cell Motility Journal Article In: BIOPHYSICAL JOURNAL, 108 (2, 1), pp. 455A–456A, 2015, ISSN: 0006-3495. |
Cells as Active Particles in Asymmetric Potentials: Motility under External Gradients Journal Article In: BIOPHYSICAL JOURNAL, 108 (2, 1), pp. 456A, 2015, ISSN: 0006-3495. |
Methods for rectifying cell motions in vitro: breaking symmetry using microfabrication and microfluidics Incollection In: {Paluch, EK} (Ed.): BIOPHYSICAL METHODS IN CELL BIOLOGY, 125 , pp. 437–452, 2015, ISBN: 978-0-12-801103-4. |
Non-Markovian polariton dynamics in organic strong coupling Journal Article In: EUROPEAN PHYSICAL JOURNAL D, 69 (1), 2015, ISSN: 1434-6060. |
Ultra-strong coupling of molecular materials: spectroscopy and dynamics Journal Article In: FARADAY DISCUSSIONS, 178 , pp. 281–294, 2015, ISSN: 1359-6640. |
Coherent coupling of molecular resonators with a microcavity mode Journal Article In: NATURE COMMUNICATIONS, 6 , 2015, ISSN: 2041-1723. |
Self-assembly of diphenylalanine backbone homologues and their combination with functionalized carbon nanotubes Journal Article In: NANOSCALE, 7 (38), pp. 15873–15879, 2015, ISSN: 2040-3364. |
Au nanoparticle scaffolds modulating intermolecular interactions among the conjugated azobenzenes chemisorbed on curved surfaces: tuning the kinetics of cis-trans isomerisation Journal Article In: NANOSCALE, 7 (33), pp. 13836–13839, 2015, ISSN: 2040-3364. |
Guanosine-based hydrogen-bonded 2D scaffolds: metal-free formation of G-quartet and G-ribbon architectures at the solid/liquid interface Journal Article In: CHEMICAL COMMUNICATIONS, 51 (58), pp. 11677–11680, 2015, ISSN: 1359-7345. |
Optically switchable transistors comprising a hybrid photochromic molecule/n-type organic active layer Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 3 (16), pp. 4156–4161, 2015, ISSN: 2050-7526. |
Modulating the charge injection in organic field-effect transistors: fluorinated oligophenyl self-assembled monolayers for high work function electrodes Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 3 (13), pp. 3007–3015, 2015, ISSN: 2050-7526. |
The dramatic effect of the annealing temperature and dielectric functionalization on the electron mobility of indene-C-60 bis-adduct thin films Journal Article In: CHEMICAL COMMUNICATIONS, 51 (25), pp. 5414–5417, 2015, ISSN: 1359-7345. |
2014 |
Reversible Adaptation to Photoinduced Shape Switching by Oligomer-Macrocycle Interconversion with Component Selection in a Three-State Constitutional Dynamic System Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (49), pp. 16188–16193, 2014, ISSN: 0947-6539. |
Trapping the ATP binding state leads to a detailed understanding of the F-1-ATPase mechanism Journal Article In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 111 (50), pp. 17851–17856, 2014, ISSN: 0027-8424. |
DUST AND GAS IN THE MAGELLANIC CLOUDS FROM THE HERITAGE HERSCHEL KEY PROJECT. II. GAS-TO-DUST RATIO VARIATIONS ACROSS INTERS℡LAR MEDIUM PHASES Journal Article In: ASTROPHYSICAL JOURNAL, 797 (2), 2014, ISSN: 0004-637X. |
The Molecular Signature of the Stroma Response in Prostate Cancer-Induced Osteoblastic Bone Metastasis Highlights Expansion of Hematopoietic and Prostate Epithelial Stem Cell Niches Journal Article In: PLOS ONE, 9 (12), 2014, ISSN: 1932-6203. |
Synthesis, Structure, and Optical Properties of Pt(II) and Pd(II) Complexes with Oxazolyl- and Pyridyl-Functionalized DPPM-Type Ligands: A Combined Experimental and Theoretical Study Journal Article In: INORGANIC CHEMISTRY, 53 (24), pp. 12739–12756, 2014, ISSN: 0020-1669. |
Solution-Processed Field-Effect Transistors Based on Dihexylquaterthiophene Films with Performances Exceeding Those of Vacuum-Sublimed Films Journal Article In: ACS APPLIED MATERIALS & INTERFACES, 6 (23), pp. 21248–21255, 2014, ISSN: 1944-8244. |
Exfoliation of graphene with an industrial dye: teaching an old dog new tricks Journal Article In: 2D MATERIALS, 1 (3), 2014, ISSN: 2053-1583. |
Electronic characterization of supramolecular materials at the nanoscale by Conductive Atomic Force and Kelvin Probe Force microscopies Journal Article In: MATERIALS TODAY, 17 (10), pp. 504–517, 2014, ISSN: 1369-7021. |
Transmissive optomechanical platforms with engineered spatial defects Journal Article In: PHYSICAL REVIEW A, 90 (5), 2014, ISSN: 2469-9926. |
Local Random-Phase Noise for Procedural Texturing Journal Article In: ACM TRANSACTIONS ON GRAPHICS, 33 (6), 2014, ISSN: 0730-0301. |
Photofunctional Nanomodulators for Bioexcitation Journal Article In: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 53 (48), pp. 13121–13125, 2014, ISSN: 1433-7851. |
Intracellular Delivery of Peptide Nucleic Acid and Organic Molecules Using Zeolite-L Nanocrystals Journal Article In: ADVANCED HEALTHCARE MATERIALS, 3 (11), pp. 1812–1817, 2014, ISSN: 2192-2640. |
beta-Lactam Bioconjugates Bearing Luminescent Platinum(II) Tags: Synthesis and Photophysical Characterization Journal Article In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, (32), pp. 7113–7121, 2014, ISSN: 1434-193X. |
Dynamic covalent chemistry of bisimines at the solid/liquid interface monitored by scanning tunnelling microscopy Journal Article In: NATURE CHEMISTRY, 6 (11), pp. 1017–1023, 2014, ISSN: 1755-4330. |
GALECTIN-1 IN CROSSTALK BETWEEN CANCER CELLS AND CANCER-ASSOCIATED FIBROBLASTS Journal Article In: ANTICANCER RESEARCH, 34 (10), pp. 6174, 2014, ISSN: 0250-7005. |
Kitaev Chains with Long-Range Pairing Journal Article In: PHYSICAL REVIEW LETTERS, 113 (15), 2014, ISSN: 0031-9007. |
Microfabricated Systems and Assays for Studying the Cytoskeletal Organization, Micromechanics, and Motility Patterns of Cancerous Cells Journal Article In: ADVANCED MATERIALS INTERFACES, 1 (7), 2014, ISSN: 2196-7350. |
Cells as Active Particles in Asymmetric Potentials: Motility under External Gradients Journal Article In: BIOPHYSICAL JOURNAL, 107 (7), pp. 1513–1522, 2014, ISSN: 0006-3495. |
Synthesis of Bright Alkenyl-1H-1,2,4-triazoles: A Theoretical and Photophysical Study Journal Article In: CHEMPLUSCHEM, 79 (10), pp. 1489–1497, 2014, ISSN: 2192-6506. |
Graphene-Induced Enhancement of n-Type Mobility in Perylenediimide Thin Films Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY C, 118 (43), pp. 24819–24826, 2014, ISSN: 1932-7447. |
Molecular tectonics based nanopatterning of interfaces with 2D metal-organic frameworks (MOFs) Journal Article In: CHEMICAL COMMUNICATIONS, 50 (82), pp. 12250–12253, 2014, ISSN: 1359-7345. |
Light-Driven Molecular Motors: lmines as Four-Step or Two-Step Unidirectional Rotors Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 136 (38), pp. 13114–13117, 2014, ISSN: 0002-7863. |
Organocatalyzed and Uncatalyzed C=C/C=C and C=C/C=N Exchange Processes between Knoevenagel and Imine Compounds in Dynamic Covalent Chemistry Journal Article In: HELVETICA CHIMICA ACTA, 97 (9), pp. 1219–1236, 2014, ISSN: 0018-019X. |
Development of Multiscale Models for Complex Chemical Systems: From Ħ+Ħ-2 to Biomolecules (Nobel Lecture) Journal Article In: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 53 (38), pp. 9992–10005, 2014, ISSN: 1433-7851. |
Hybrid cavity mechanics with doped systems Journal Article In: PHYSICAL REVIEW A, 90 (3), 2014, ISSN: 1050-2947. |
Combining Topological and Steric Constraints for the Preparation of Heteroleptic Copper(I) Complexes Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (38), pp. 12083–12090, 2014, ISSN: 0947-6539. |
Assessment of a New Insulin Preparation for Implanted Pumps Used in the Treatment of Type 1 Diabetes Journal Article In: DIABETES TECHNOLOGY & THERAPEUTICS, 16 (9), pp. 582–589, 2014, ISSN: 1520-9156. |
Harnessing the Liquid-Phase Exfoliation of Graphene Using Aliphatic Compounds: A Supramolecular Approach Journal Article In: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 53 (39), pp. 10355–10361, 2014, ISSN: 1433-7851. |
Enhancing the Charge Transport in Solution-Processed Perylene Di-imide Transistors via Thermal Annealing of Metastable Disordered Films Journal Article In: ADVANCED FUNCTIONAL MATERIALS, 24 (35), pp. 5503–5510, 2014, ISSN: 1616-301X. |
Double dynamic self-healing polymers: supramolecular and covalent dynamic polymers based on the bis-iminocarbohydrazide motif Journal Article In: POLYMER INTERNATIONAL, 63 (8), pp. 1400–1405, 2014, ISSN: 0959-8103. |
Significance of Molecular Dynamics Simulations for Life Sciences Journal Article In: ISRAEL JOURNAL OF CHEMISTRY, 54 (8-9, SI), pp. 1042–1051, 2014, ISSN: 0021-2148. |