2014 |
Yang, Qing-Yuan ; Pan, Mei ; Wei, Shi-Chao ; Hsu, Chien-Wei ; Lehn, Jean-Marie ; Su, Cheng-Yong Photoluminescent 3D lanthanide MOFs with a rare (10,3)-d net based on a new tripodal organic linker Journal Article In: CRYSTENGCOMM, 16 (28), pp. 6469–6475, 2014, ISSN: 1466-8033. @article{yang_photoluminescent_2014, title = {Photoluminescent 3D lanthanide MOFs with a rare (10,3)-d net based on a new tripodal organic linker}, author = {Yang, Qing-Yuan and Pan, Mei and Wei, Shi-Chao and Hsu, Chien-Wei and Lehn, Jean-Marie and Su, Cheng-Yong}, doi = {10.1039/c4ce00586d}, issn = {1466-8033}, year = {2014}, date = {2014-01-01}, journal = {CRYSTENGCOMM}, volume = {16}, number = {28}, pages = {6469--6475}, abstract = {A new semi-rigid tripodal ligand, namely 1,1',1 `'-((2,4,6-triethylbenzene-1,3,5 triyl)tris(methylene))tris(pyridin-4(1H)-one) (L1), has been prepared by direct alkylation of 4-hydroxypyridine at the nitrogen site with 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene. The tripodal ligand has been used for the assembly of a series of isomorphous lanthanide metal-organic frameworks (Ln-MOFs) [Ln(L1)center dot(NO3)(3)]center dot nH(2)O (Ln = Eu (1), Tb (2), Sm (3), Ce (4), Gd (5); n = 3 or 4) which exhibit an unusual non-interpenetrated (10,3)-d (or utp net) topology. The photophysical properties of these lanthanide MOFs have been assessed, in which the Tb3+ complex 2 displays bright green luminescence with quite high efficiency (Phi(overall) = 50%) and a long excited state lifetime (tau(obs) = 1.1ms).}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new semi-rigid tripodal ligand, namely 1,1',1 `'-((2,4,6-triethylbenzene-1,3,5 triyl)tris(methylene))tris(pyridin-4(1H)-one) (L1), has been prepared by direct alkylation of 4-hydroxypyridine at the nitrogen site with 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene. The tripodal ligand has been used for the assembly of a series of isomorphous lanthanide metal-organic frameworks (Ln-MOFs) [Ln(L1)center dot(NO3)(3)]center dot nH(2)O (Ln = Eu (1), Tb (2), Sm (3), Ce (4), Gd (5); n = 3 or 4) which exhibit an unusual non-interpenetrated (10,3)-d (or utp net) topology. The photophysical properties of these lanthanide MOFs have been assessed, in which the Tb3+ complex 2 displays bright green luminescence with quite high efficiency (Phi(overall) = 50%) and a long excited state lifetime (tau(obs) = 1.1ms). |
Hirsch, Anna K H; Sirlin, Claude ; Harrowfield, Jack M; Lehn, Jean-Marie A doubly hermaphroditic chiral crown ether Journal Article In: CRYSTENGCOMM, 16 (27), pp. 5984–5988, 2014, ISSN: 1466-8033. @article{hirsch_doubly_2014, title = {A doubly hermaphroditic chiral crown ether}, author = {Hirsch, Anna K. H. and Sirlin, Claude and Harrowfield, Jack M. and Lehn, Jean-Marie}, doi = {10.1039/c4ce00879k}, issn = {1466-8033}, year = {2014}, date = {2014-01-01}, journal = {CRYSTENGCOMM}, volume = {16}, number = {27}, pages = {5984--5988}, abstract = {A single-crystal structure determination on the S-protected form of a chiral 18-crown-6 derivative known to be a selective catalyst for thiolysis reactions of amino acid derivatives has shown the molecule to crystallise in an unsolvated form where the macrocyclic ring has a conformation in which the dipoles of substituent amide units are aligned parallel. The resulting polar entities are linked through NH center dot center dot center dot O H-bonds and weaker interactions which can be considered to result in doubly hermaphroditic links, the whole crystal proving to be polar. The possible consequences of the observed secondary interactions, some being intramolecular, are considered in relation to the mechanism of catalysis by the isolated molecule.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A single-crystal structure determination on the S-protected form of a chiral 18-crown-6 derivative known to be a selective catalyst for thiolysis reactions of amino acid derivatives has shown the molecule to crystallise in an unsolvated form where the macrocyclic ring has a conformation in which the dipoles of substituent amide units are aligned parallel. The resulting polar entities are linked through NH center dot center dot center dot O H-bonds and weaker interactions which can be considered to result in doubly hermaphroditic links, the whole crystal proving to be polar. The possible consequences of the observed secondary interactions, some being intramolecular, are considered in relation to the mechanism of catalysis by the isolated molecule. |
Vantomme, Ghislaine ; Hafezi, Nema ; Lehn, Jean-Marie A light-induced reversible phase separation and its coupling to a dynamic library of imines Journal Article In: CHEMICAL SCIENCE, 5 (4), pp. 1475–1483, 2014, ISSN: 2041-6520. @article{vantomme_light-induced_2014, title = {A light-induced reversible phase separation and its coupling to a dynamic library of imines}, author = {Vantomme, Ghislaine and Hafezi, Nema and Lehn, Jean-Marie}, doi = {10.1039/c3sc53130a}, issn = {2041-6520}, year = {2014}, date = {2014-01-01}, journal = {CHEMICAL SCIENCE}, volume = {5}, number = {4}, pages = {1475--1483}, abstract = {Irradiation of a 3 : 2 acetonitrile-water solution of the bis-pyridyl hydrazone 1 and calcium chloride causes a photo-induced phase separation, due to an increase in free calcium cations as a consequence of the photo-conversion of 1 from its E form to the Z configuration. Complexation studies confirmed that the former binds calcium more strongly that the latter. Acid-catalyzed back-conversion from 1-Z to 1-E, followed by basification, leads to the regeneration of the initial single phase. The process thus involves a photo-thermal cycle with reversible interconversion between monophasic and biphasic states. In the presence of a dynamic library of imines generated from hydrophilic and hydrophobic aldehyde and amine components, a coupling to the phase interconversion processes is achieved, leading to a dynamic redistribution of the imine constituents, whereby amplification of the most lipophilic and the most hydrophilic imine constituents, in the organic and the aqueous phase, respectively, is achieved by component selection. The system thus undergoes an adaptation by the up-regulation of the fittest constituent for its specific phase. The process is reversible, regenerating the initial distribution of constituents upon phase reunification. It also represents the coupling of a dynamic covalent library to out-of-equilibrium conditions resulting from the photo-generation of a kinetically trapped entity.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Irradiation of a 3 : 2 acetonitrile-water solution of the bis-pyridyl hydrazone 1 and calcium chloride causes a photo-induced phase separation, due to an increase in free calcium cations as a consequence of the photo-conversion of 1 from its E form to the Z configuration. Complexation studies confirmed that the former binds calcium more strongly that the latter. Acid-catalyzed back-conversion from 1-Z to 1-E, followed by basification, leads to the regeneration of the initial single phase. The process thus involves a photo-thermal cycle with reversible interconversion between monophasic and biphasic states. In the presence of a dynamic library of imines generated from hydrophilic and hydrophobic aldehyde and amine components, a coupling to the phase interconversion processes is achieved, leading to a dynamic redistribution of the imine constituents, whereby amplification of the most lipophilic and the most hydrophilic imine constituents, in the organic and the aqueous phase, respectively, is achieved by component selection. The system thus undergoes an adaptation by the up-regulation of the fittest constituent for its specific phase. The process is reversible, regenerating the initial distribution of constituents upon phase reunification. It also represents the coupling of a dynamic covalent library to out-of-equilibrium conditions resulting from the photo-generation of a kinetically trapped entity. |
Fallah-Araghi, Ali ; Meguellati, Kamel ; Baret, Jean-Christophe ; El Harrak, Abdeslam ; Mangeat, Thomas ; Karplus, Martin ; Ladame, Sylvain ; Marques, Carlos M; Griffiths, Andrew D Enhanced Chemical Synthesis at Soft Interfaces: A Universal Reaction-Adsorption Mechanism in Microcompartments Journal Article In: PHYSICAL REVIEW LETTERS, 112 (2), 2014, ISSN: 0031-9007. @article{fallah-araghi_enhanced_2014, title = {Enhanced Chemical Synthesis at Soft Interfaces: A Universal Reaction-Adsorption Mechanism in Microcompartments}, author = {Fallah-Araghi, Ali and Meguellati, Kamel and Baret, Jean-Christophe and El Harrak, Abdeslam and Mangeat, Thomas and Karplus, Martin and Ladame, Sylvain and Marques, Carlos M. and Griffiths, Andrew D.}, doi = {10.1103/PhysRevLett.112.028301}, issn = {0031-9007}, year = {2014}, date = {2014-01-01}, journal = {PHYSICAL REVIEW LETTERS}, volume = {112}, number = {2}, abstract = {A bimolecular synthetic reaction (imine synthesis) was performed compartmentalized in micrometer-diameter emulsion droplets. The apparent equilibrium constant (K-eq) and apparent forward rate constant (k(1)) were both inversely proportional to the droplet radius. The results are explained by a noncatalytic reaction-adsorption model in which reactants adsorb to the droplet interface with relatively low binding energies of a few k(B)T, react and diffuse back to the bulk. Reaction thermodynamics is therefore modified by compartmentalization at the mesoscale-without confinement on the molecular scale-leading to a universal mechanism for improving unfavorable reactions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A bimolecular synthetic reaction (imine synthesis) was performed compartmentalized in micrometer-diameter emulsion droplets. The apparent equilibrium constant (K-eq) and apparent forward rate constant (k(1)) were both inversely proportional to the droplet radius. The results are explained by a noncatalytic reaction-adsorption model in which reactants adsorb to the droplet interface with relatively low binding energies of a few k(B)T, react and diffuse back to the bulk. Reaction thermodynamics is therefore modified by compartmentalization at the mesoscale-without confinement on the molecular scale-leading to a universal mechanism for improving unfavorable reactions. |
Khatami, Ehsan ; Pupillo, Guido ; Srednicki, Mark ; Rigol, Marcos Fluctuation-dissipation theorem in isolated quantum systems out of equilibrium Inproceedings In: 25TH IUPAP CONFERENCE ON COMPUTATIONAL PHYSICS (CCP2013), Russian Acad Sci, Landau Inst Theoret Phys; Int Union Pure & Appl Phys; European Phys Soc; Div Computat Phys American Phys Soc; Russian Fnd Basic Res; Russian Acad Sci, Dept Phys Sci; RSC Grp Co, 2014. @inproceedings{khatami_fluctuation-dissipation_2014, title = {Fluctuation-dissipation theorem in isolated quantum systems out of equilibrium}, author = {Khatami, Ehsan and Pupillo, Guido and Srednicki, Mark and Rigol, Marcos}, doi = {10.1088/1742-6596/510/1/012035}, year = {2014}, date = {2014-01-01}, booktitle = {25TH IUPAP CONFERENCE ON COMPUTATIONAL PHYSICS (CCP2013)}, volume = {510}, publisher = {Russian Acad Sci, Landau Inst Theoret Phys; Int Union Pure & Appl Phys; European Phys Soc; Div Computat Phys American Phys Soc; Russian Fnd Basic Res; Russian Acad Sci, Dept Phys Sci; RSC Grp Co}, series = {Journal of Physics Conference Series}, abstract = {We study the validity of the fluctuation-dissipation theorem for an isolated quantum system of harmonically trapped dipolar molecules taken out of equilibrium by means of a quench, a sudden change in the Hamiltonian parameters. We find that the integrability of the system plays a crucial role in the validity of the fluctuation-dissipation theorem. Namely, the system thermalizes according to the eigenstate thermalization hypothesis and the theorem holds if the system is nonintegrable after the quench. However, it fails if the system is integrable, unless the initial state is an eigenstate of a nonintegrable Hamiltonian, in which case the system still thermalizes despite the eigenstate thermalization hypothesis failing to describe it.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } We study the validity of the fluctuation-dissipation theorem for an isolated quantum system of harmonically trapped dipolar molecules taken out of equilibrium by means of a quench, a sudden change in the Hamiltonian parameters. We find that the integrability of the system plays a crucial role in the validity of the fluctuation-dissipation theorem. Namely, the system thermalizes according to the eigenstate thermalization hypothesis and the theorem holds if the system is nonintegrable after the quench. However, it fails if the system is integrable, unless the initial state is an eigenstate of a nonintegrable Hamiltonian, in which case the system still thermalizes despite the eigenstate thermalization hypothesis failing to describe it. |
Durot, Stephanie ; Heitz, Valerie ; Sour, Angelique ; Sauvage, Jean-Pierre Transition-Metal-Complexed Catenanes and Rotaxanes: From Dynamic Systems to Functional Molecular Machines Incollection In: {Credi, A; Silvi, S; Venturi, M} (Ed.): MOLECULAR MACHINES AND MOTORS: RECENT ADVANCES AND PERSPECTIVES, 354 , pp. 35–70, 2014, ISBN: 978-3-319-08678-1 978-3-319-08677-4. @incollection{durot_transition-metal-complexed_2014, title = {Transition-Metal-Complexed Catenanes and Rotaxanes: From Dynamic Systems to Functional Molecular Machines}, author = {Durot, Stephanie and Heitz, Valerie and Sour, Angelique and Sauvage, Jean-Pierre}, editor = {{Credi, A and Silvi, S and Venturi, M}}, doi = {10.1007/128_2013_514}, isbn = {978-3-319-08678-1 978-3-319-08677-4}, year = {2014}, date = {2014-01-01}, booktitle = {MOLECULAR MACHINES AND MOTORS: RECENT ADVANCES AND PERSPECTIVES}, volume = {354}, pages = {35--70}, series = {Topics in Current Chemistry-Series}, abstract = {Transition metal-based catenanes and rotaxanes constitute a specific class of mechanically interlocked molecules whose metal centers are essential both as templates in the construction of the compounds and for their ability to induce large-amplitude motions. In the present chapter we will first present a historical perspective of the field of interlocking compounds in general, in relation to molecular machines, starting with old work dating back to the 1980s and 1990s. Copper was shown many years ago to be the metal of choice for synthesizing the compounds via a template approach and for setting the molecules in motion using a redox signal (Cu-II/Cu-I). In a second paragraph, we will discuss various rotaxanes able to undergo a pirouetting motion of the axis within the threaded ring. Two families of such molecules will be mentioned: (1) a porphyrin-containing [2] rotaxane whose pirouetting motion is induced by a chemical reaction and (2) electrochemically driven systems. In this second category of [2] rotaxanes, the rate of motion could be dramatically increased by gradually modifying structural parameters and, in particular, by making the metal center less and less hindered by its surrounding ligands. The third section will be devoted to molecular shuttles and muscles, both families of compounds being reminiscent of linear machines such as biological muscles. By replacing the classical 2,9-diaryl-1,10-phenanthroline chelate (highly shielding and hindering) used by our group since the 1980s by an endocyclic but non-sterically hindering 3,3'-biisoquinoline derivative, the shuttling rate was increased in spectacular fashion, demonstrating the importance of steric factors in transition metal-based molecular machines. The same 3,3'-biisoquinoline motif was also used in the elaboration of a three-station shuttle, leading to long-distance (textbackslashtextbackslashtextgreater20 angstrom) transport of a ring along the axis on which it is threaded. Finally, porphyrin-containing [3] rotaxanes and [4] rotaxanes, the latter displaying an overall cyclic structure, will be discussed and shown to behave as adjustable and switchable receptors. The synthesis of such compounds is a particularly challenging task in itself. In addition, the new receptors display fascinating properties such as, in particular, their ability to compress various guests and to expel them from their binding site using a chemical signal.}, keywords = {}, pubstate = {published}, tppubtype = {incollection} } Transition metal-based catenanes and rotaxanes constitute a specific class of mechanically interlocked molecules whose metal centers are essential both as templates in the construction of the compounds and for their ability to induce large-amplitude motions. In the present chapter we will first present a historical perspective of the field of interlocking compounds in general, in relation to molecular machines, starting with old work dating back to the 1980s and 1990s. Copper was shown many years ago to be the metal of choice for synthesizing the compounds via a template approach and for setting the molecules in motion using a redox signal (Cu-II/Cu-I). In a second paragraph, we will discuss various rotaxanes able to undergo a pirouetting motion of the axis within the threaded ring. Two families of such molecules will be mentioned: (1) a porphyrin-containing [2] rotaxane whose pirouetting motion is induced by a chemical reaction and (2) electrochemically driven systems. In this second category of [2] rotaxanes, the rate of motion could be dramatically increased by gradually modifying structural parameters and, in particular, by making the metal center less and less hindered by its surrounding ligands. The third section will be devoted to molecular shuttles and muscles, both families of compounds being reminiscent of linear machines such as biological muscles. By replacing the classical 2,9-diaryl-1,10-phenanthroline chelate (highly shielding and hindering) used by our group since the 1980s by an endocyclic but non-sterically hindering 3,3'-biisoquinoline derivative, the shuttling rate was increased in spectacular fashion, demonstrating the importance of steric factors in transition metal-based molecular machines. The same 3,3'-biisoquinoline motif was also used in the elaboration of a three-station shuttle, leading to long-distance (textbackslashtextbackslashtextgreater20 angstrom) transport of a ring along the axis on which it is threaded. Finally, porphyrin-containing [3] rotaxanes and [4] rotaxanes, the latter displaying an overall cyclic structure, will be discussed and shown to behave as adjustable and switchable receptors. The synthesis of such compounds is a particularly challenging task in itself. In addition, the new receptors display fascinating properties such as, in particular, their ability to compress various guests and to expel them from their binding site using a chemical signal. |
Huang, J; Mara, M W; Stickrath, A B; Kokhan, O; Harpham, M R; Haldrup, K; Shelby, M L; Zhang, X; Ruppert, R; Sauvage, J -P; Chen, L X A strong steric hindrance effect on ground state, excited state, and charge separated state properties of a Cu-I-diimine complex captured by X-ray transient absorption spectroscopy Journal Article In: DALTON TRANSACTIONS, 43 (47), pp. 17615–17623, 2014, ISSN: 1477-9226. @article{huang_strong_2014, title = {A strong steric hindrance effect on ground state, excited state, and charge separated state properties of a Cu-I-diimine complex captured by X-ray transient absorption spectroscopy}, author = {Huang, J. and Mara, M. W. and Stickrath, A. B. and Kokhan, O. and Harpham, M. R. and Haldrup, K. and Shelby, M. L. and Zhang, X. and Ruppert, R. and Sauvage, J. -P. and Chen, L. X.}, doi = {10.1039/c4dt02046d}, issn = {1477-9226}, year = {2014}, date = {2014-01-01}, journal = {DALTON TRANSACTIONS}, volume = {43}, number = {47}, pages = {17615--17623}, abstract = {Photophysical and structural properties of a Cu-I diimine complex with very strong steric hindrance, [Cu-I(dppS)(2)](+) (dppS = 2,9-diphenyl-1,10-phenanthroline disulfonic acid disodium salt), are investigated by optical and X-ray transient absorption (OTA and XTA) spectroscopy. The bulky phenylsulfonic acid groups at 2,9 positions of phenanthroline ligands force the ground state and the metal-to-ligand charge-transfer (MLCT) excited state to adopt a flattened pseudo-tetrahedral coordination geometry in which the solvent access to the copper center is completely blocked. We analyzed the MLCT state dynamics and structures as well as those of the charge separated state resulting from the interfacial electron injection from the MLCT state to TiO2 nanoparticles (NPs). The OTA results show the absence of the sub-picosecond component previously assigned as the time constant for flattening, while the two observed time constants are assigned to a relatively slow intersystem crossing (ISC) rate (similar to 13.8 ps) and a decay rate (100 ns) of the [Cu-I(dppS)(2)](+) MLCT state in water. These results correlate well with the XTA studies that resolved a flattened tetrahedral Cu(I) coordination geometry in the ground state. Probing the (MLCT)-M-3 state structure with XTA establishes that the (MLCT)-M-3 state has the same oxidation state as the copper center in [Cu-II(dppS)(2)](2+) and the Cu-N distance is reduced by 0.06 angstrom compared to that of the ground state, accompained by a rotation of phenyl rings located at 2,9 positions of phenanthroline. The structural dynamics of the photoinduced charge transfer process in the [Cu-I(dppS) (2)](+)/TiO2 hybrid is also investigated, which suggests a more restricted environment for the complex upon binding to TiO2 NPs. Moreover, the Cu-N bond length of the oxidized state of [ Cu-I(dppS)(2)](+) after electron injection to TiO2 NPs shortens by 0.05 angstrom compared to that in the ground state. The interpretation of these observed structural changes associated with excited and charge separated states will be discussed. These results not only set an example for applying XTA in capturing the intermediate structure of metal complex/semiconductor NP hybrids but also provide guidance for designing efficient CuI diimine complexes with optimized structures for application in solar-to-electricity conversion.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Photophysical and structural properties of a Cu-I diimine complex with very strong steric hindrance, [Cu-I(dppS)(2)](+) (dppS = 2,9-diphenyl-1,10-phenanthroline disulfonic acid disodium salt), are investigated by optical and X-ray transient absorption (OTA and XTA) spectroscopy. The bulky phenylsulfonic acid groups at 2,9 positions of phenanthroline ligands force the ground state and the metal-to-ligand charge-transfer (MLCT) excited state to adopt a flattened pseudo-tetrahedral coordination geometry in which the solvent access to the copper center is completely blocked. We analyzed the MLCT state dynamics and structures as well as those of the charge separated state resulting from the interfacial electron injection from the MLCT state to TiO2 nanoparticles (NPs). The OTA results show the absence of the sub-picosecond component previously assigned as the time constant for flattening, while the two observed time constants are assigned to a relatively slow intersystem crossing (ISC) rate (similar to 13.8 ps) and a decay rate (100 ns) of the [Cu-I(dppS)(2)](+) MLCT state in water. These results correlate well with the XTA studies that resolved a flattened tetrahedral Cu(I) coordination geometry in the ground state. Probing the (MLCT)-M-3 state structure with XTA establishes that the (MLCT)-M-3 state has the same oxidation state as the copper center in [Cu-II(dppS)(2)](2+) and the Cu-N distance is reduced by 0.06 angstrom compared to that of the ground state, accompained by a rotation of phenyl rings located at 2,9 positions of phenanthroline. The structural dynamics of the photoinduced charge transfer process in the [Cu-I(dppS) (2)](+)/TiO2 hybrid is also investigated, which suggests a more restricted environment for the complex upon binding to TiO2 NPs. Moreover, the Cu-N bond length of the oxidized state of [ Cu-I(dppS)(2)](+) after electron injection to TiO2 NPs shortens by 0.05 angstrom compared to that in the ground state. The interpretation of these observed structural changes associated with excited and charge separated states will be discussed. These results not only set an example for applying XTA in capturing the intermediate structure of metal complex/semiconductor NP hybrids but also provide guidance for designing efficient CuI diimine complexes with optimized structures for application in solar-to-electricity conversion. |
Septiadi, Dedy ; Aliprandi, Alessandro ; Mauro, Matteo ; De Cola, Luisa Bio-imaging with neutral luminescent Pt(II) complexes showing metal ... metal interactions Journal Article In: RSC ADVANCES, 4 (49), pp. 25709–25718, 2014, ISSN: 2046-2069. @article{septiadi_bio-imaging_2014, title = {Bio-imaging with neutral luminescent Pt(II) complexes showing metal ... metal interactions}, author = {Septiadi, Dedy and Aliprandi, Alessandro and Mauro, Matteo and De Cola, Luisa}, doi = {10.1039/c4ra02351j}, issn = {2046-2069}, year = {2014}, date = {2014-01-01}, journal = {RSC ADVANCES}, volume = {4}, number = {49}, pages = {25709--25718}, abstract = {Molecular bio-imaging based on optical detection is facing important challenges in the attempt to develop new materials and small molecules able to have better emission quantum yield, stability toward photobleaching and long excited-state lifetime. A strategy to achieve these properties is to use triplet emitters based on metal complexes and to protect them from dioxygen quenching. We report on an interesting approach based on the use of self-assembled platinum compounds in order to obtain stable, highly emissive and long-lived species. Cell internalization and localization experiments show that the assemblies possess a different selectivity towards cellular compartments dictated by the terdentate ligand coordinated to the platinum. Also, the conditions used for the incubation determine cell internalization of the platinum complexes or their expulsion in the media.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Molecular bio-imaging based on optical detection is facing important challenges in the attempt to develop new materials and small molecules able to have better emission quantum yield, stability toward photobleaching and long excited-state lifetime. A strategy to achieve these properties is to use triplet emitters based on metal complexes and to protect them from dioxygen quenching. We report on an interesting approach based on the use of self-assembled platinum compounds in order to obtain stable, highly emissive and long-lived species. Cell internalization and localization experiments show that the assemblies possess a different selectivity towards cellular compartments dictated by the terdentate ligand coordinated to the platinum. Also, the conditions used for the incubation determine cell internalization of the platinum complexes or their expulsion in the media. |
Mauro, Matteo ; Aliprandi, Alessandro ; Cebrian, Cristina ; Wang, Di ; Kuebel, Christian ; De Cola, Luisa Self-assembly of a neutral platinum(II) complex into highly emitting microcrystalline fibers through metallophilic interactions Journal Article In: CHEMICAL COMMUNICATIONS, 50 (55), pp. 7269–7272, 2014, ISSN: 1359-7345. @article{mauro_self-assembly_2014, title = {Self-assembly of a neutral platinum(II) complex into highly emitting microcrystalline fibers through metallophilic interactions}, author = {Mauro, Matteo and Aliprandi, Alessandro and Cebrian, Cristina and Wang, Di and Kuebel, Christian and De Cola, Luisa}, doi = {10.1039/c4cc01045k}, issn = {1359-7345}, year = {2014}, date = {2014-01-01}, journal = {CHEMICAL COMMUNICATIONS}, volume = {50}, number = {55}, pages = {7269--7272}, abstract = {The solvent-assisted self-assembly of a blue-emitting neutral platinum(II) complex into micrometer-long and highly crystalline fibers has been achieved. The aggregates show highly efficient (quantum yield up to 74%) polarized yellow-orange light emission, as a consequence of their high degree of supramolecular order imparted by weak non-covalent intermolecular (metal...metal and pi-pi) interactions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The solvent-assisted self-assembly of a blue-emitting neutral platinum(II) complex into micrometer-long and highly crystalline fibers has been achieved. The aggregates show highly efficient (quantum yield up to 74%) polarized yellow-orange light emission, as a consequence of their high degree of supramolecular order imparted by weak non-covalent intermolecular (metal...metal and pi-pi) interactions. |
Soman, Suraj ; Manton, Jennifer C; Inglis, Jane L; Halpin, Yvonne ; Twamley, Brendan ; Otten, Edwin ; Browne, Wesley R; De Cola, Luisa ; Vos, Johannes G; Pryce, Mary T New synthetic pathways to the preparation of near-blue emitting heteroleptic Ir(III) N-6 coordinated compounds with microsecond lifetimes Journal Article In: CHEMICAL COMMUNICATIONS, 50 (49), pp. 6461–6463, 2014, ISSN: 1359-7345. @article{soman_new_2014, title = {New synthetic pathways to the preparation of near-blue emitting heteroleptic Ir(III) N-6 coordinated compounds with microsecond lifetimes}, author = {Soman, Suraj and Manton, Jennifer C. and Inglis, Jane L. and Halpin, Yvonne and Twamley, Brendan and Otten, Edwin and Browne, Wesley R. and De Cola, Luisa and Vos, Johannes G. and Pryce, Mary T.}, doi = {10.1039/c4cc02249a}, issn = {1359-7345}, year = {2014}, date = {2014-01-01}, journal = {CHEMICAL COMMUNICATIONS}, volume = {50}, number = {49}, pages = {6461--6463}, abstract = {A high yield synthetic route for the preparation of N-6 coordinated heteroleptic Ir(III) complexes using bidentate polypyridyl type ligands is described. The complexes are near-blue emitters and showmicrosecond emission lifetimes, high emission quantum yields and have two quasi-reversible reduction processes between -1.0 and -1.3 V vs. Ag/AgCl.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A high yield synthetic route for the preparation of N-6 coordinated heteroleptic Ir(III) complexes using bidentate polypyridyl type ligands is described. The complexes are near-blue emitters and showmicrosecond emission lifetimes, high emission quantum yields and have two quasi-reversible reduction processes between -1.0 and -1.3 V vs. Ag/AgCl. |
Mauro, Matteo ; Aliprandi, Alessandro ; Septiadi, Dedy ; Kehra, Nermin Seda ; De Cola, Luisa When self-assembly meets biology: luminescent platinum complexes for imaging applications Journal Article In: CHEMICAL SOCIETY REVIEWS, 43 (12), pp. 4144–4166, 2014, ISSN: 0306-0012. @article{mauro_when_2014, title = {When self-assembly meets biology: luminescent platinum complexes for imaging applications}, author = {Mauro, Matteo and Aliprandi, Alessandro and Septiadi, Dedy and Kehra, Nermin Seda and De Cola, Luisa}, doi = {10.1039/c3cs60453e}, issn = {0306-0012}, year = {2014}, date = {2014-01-01}, journal = {CHEMICAL SOCIETY REVIEWS}, volume = {43}, number = {12}, pages = {4144--4166}, abstract = {Luminescent platinum complexes have attractive chemical and photophysical properties such as high stability, emission in the visible region, high emission quantum yields and long excited state lifetimes. However the absorption spectrum of the compounds in the UV region, preventing their excitation in the harmless visible/red region, as well as the strong quenching of the luminescent triplet state, caused by dioxygen in water and biological fluids, reduces their possible applications for imaging. Therefore a possible solution to these drawbacks is to take advantage of the high tendency of such square planar compounds to self-assemble in supramolecular structures. The assemblies can be considered new chemical species with enhanced and tunable properties. Furthermore the assembly and disassembly process can be explored as a tool to obtain dynamic labels that can be applied in biomedicine. The change in color, the turn on and off of luminescence but also of the reactivity, the protection from quenching and environmental degradation are some of the attractive properties connected to the aggregation of the complexes.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Luminescent platinum complexes have attractive chemical and photophysical properties such as high stability, emission in the visible region, high emission quantum yields and long excited state lifetimes. However the absorption spectrum of the compounds in the UV region, preventing their excitation in the harmless visible/red region, as well as the strong quenching of the luminescent triplet state, caused by dioxygen in water and biological fluids, reduces their possible applications for imaging. Therefore a possible solution to these drawbacks is to take advantage of the high tendency of such square planar compounds to self-assemble in supramolecular structures. The assemblies can be considered new chemical species with enhanced and tunable properties. Furthermore the assembly and disassembly process can be explored as a tool to obtain dynamic labels that can be applied in biomedicine. The change in color, the turn on and off of luminescence but also of the reactivity, the protection from quenching and environmental degradation are some of the attractive properties connected to the aggregation of the complexes. |
Darmawan, Noviyan ; Yang, Cheng-Han ; Mauro, Matteo ; Froehlich, Roland ; De Cola, Luisa ; Chang, Chih-Hao ; Wu, Zih-Jyun ; Tai, Cheng-Wei Highly efficient blue and deep-blue emitting zwitterionic iridium(III) complexes: synthesis, photophysics and electroluminescence Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 2 (14), pp. 2569–2582, 2014, ISSN: 2050-7526. @article{darmawan_highly_2014, title = {Highly efficient blue and deep-blue emitting zwitterionic iridium(III) complexes: synthesis, photophysics and electroluminescence}, author = {Darmawan, Noviyan and Yang, Cheng-Han and Mauro, Matteo and Froehlich, Roland and De Cola, Luisa and Chang, Chih-Hao and Wu, Zih-Jyun and Tai, Cheng-Wei}, doi = {10.1039/c3tc32181a}, issn = {2050-7526}, year = {2014}, date = {2014-01-01}, journal = {JOURNAL OF MATERIALS CHEMISTRY C}, volume = {2}, number = {14}, pages = {2569--2582}, abstract = {We report on a series of blue and deep-blue emitting zwitterionic iridium(III) complexes, consisting formally of a cationic Ir centre and a N,N'-heteroaromatic (N boolean AND N) ligand bearing negatively charged side groups, i.e. sulfonate and borate. The synthesis, photophysical and electrochemical properties of this series are described in detail together with their X-ray crystal structure determination. The reported complexes exhibit intense blue (lambda(max) at 450 nm) and deep blue (lambda(max) at 435 nm) emission in deaerated solution, similar to the related cationic complexes. The strategy employed, namely the internal salt formation, allows high solubility in many organic solvents as well as for some of the complexes a low sublimation temperature. For this reason, one of the complexes was further tested as an emitter in phosphorescent organic light emitting diodes (PhOLEDs). Despite the zwitterionic nature of the triplet emitter employed, the devices were fabricated by means of sublimation process. The devices showed a peak external quantum efficiency (EQE) as high as 11.0% and Commission Internationale d'Enclairage (CIE) coordinates x = 0.21 and y = 0.33.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report on a series of blue and deep-blue emitting zwitterionic iridium(III) complexes, consisting formally of a cationic Ir centre and a N,N'-heteroaromatic (N boolean AND N) ligand bearing negatively charged side groups, i.e. sulfonate and borate. The synthesis, photophysical and electrochemical properties of this series are described in detail together with their X-ray crystal structure determination. The reported complexes exhibit intense blue (lambda(max) at 450 nm) and deep blue (lambda(max) at 435 nm) emission in deaerated solution, similar to the related cationic complexes. The strategy employed, namely the internal salt formation, allows high solubility in many organic solvents as well as for some of the complexes a low sublimation temperature. For this reason, one of the complexes was further tested as an emitter in phosphorescent organic light emitting diodes (PhOLEDs). Despite the zwitterionic nature of the triplet emitter employed, the devices were fabricated by means of sublimation process. The devices showed a peak external quantum efficiency (EQE) as high as 11.0% and Commission Internationale d'Enclairage (CIE) coordinates x = 0.21 and y = 0.33. |
Wang, Shaojun ; Mika, Arkadiusz ; Hutchison, James A; Genet, Cyriaque ; Jouaiti, Abdelaziz ; Hosseini, Mir Wais ; Ebbesen, Thomas W Phase transition of a perovskite strongly coupled to the vacuum field Journal Article In: NANOSCALE, 6 (13), pp. 7243–7248, 2014, ISSN: 2040-3364. @article{wang_phase_2014, title = {Phase transition of a perovskite strongly coupled to the vacuum field}, author = {Wang, Shaojun and Mika, Arkadiusz and Hutchison, James A. and Genet, Cyriaque and Jouaiti, Abdelaziz and Hosseini, Mir Wais and Ebbesen, Thomas W.}, doi = {10.1039/c4nr01971g}, issn = {2040-3364}, year = {2014}, date = {2014-01-01}, journal = {NANOSCALE}, volume = {6}, number = {13}, pages = {7243--7248}, abstract = {The hysteresis and dynamics of the phase transition of the perovskite salt [Pb(II)I-4(2-),(C12H25NH3+)(2)] is shown to be significantly modified when strongly coupled to the vacuum field inside a micro-cavity. The transition barrier is increased and the hysteresis loop is enlarged, demonstrating the potential of controlling the electromagnetic environment of a material.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The hysteresis and dynamics of the phase transition of the perovskite salt [Pb(II)I-4(2-),(C12H25NH3+)(2)] is shown to be significantly modified when strongly coupled to the vacuum field inside a micro-cavity. The transition barrier is increased and the hysteresis loop is enlarged, demonstrating the potential of controlling the electromagnetic environment of a material. |
Mativetsky, Jeffrey M; Orgiu, Emanuele ; Lieberwirth, Ingo ; Pisula, Wojciech ; Samori, Paolo Charge Transport Over Multiple Length Scales in Supramolecular Fiber Transistors: Single Fiber Versus Ensemble Performance Journal Article In: ADVANCED MATERIALS, 26 (3), pp. 430–435, 2014, ISSN: 0935-9648. @article{mativetsky_charge_2014, title = {Charge Transport Over Multiple Length Scales in Supramolecular Fiber Transistors: Single Fiber Versus Ensemble Performance}, author = {Mativetsky, Jeffrey M. and Orgiu, Emanuele and Lieberwirth, Ingo and Pisula, Wojciech and Samori, Paolo}, doi = {10.1002/adma.201303419}, issn = {0935-9648}, year = {2014}, date = {2014-01-01}, journal = {ADVANCED MATERIALS}, volume = {26}, number = {3}, pages = {430--435}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2013 |
Ledoux, I; Zyss, J; Siegel, J S; Brienne, J; Lehn, J-M Historical perspective on: Second-harmonic generation from non-dipolar non-centrosymmetric aromatic charge-transfer molecules [Volume 172, Issue 6, 21 September 1990, Pages 440-444] Journal Article In: CHEMICAL PHYSICS LETTERS, 589 , pp. 46, 2013, ISSN: 0009-2614. @article{ledoux_historical_2013, title = {Historical perspective on: Second-harmonic generation from non-dipolar non-centrosymmetric aromatic charge-transfer molecules [Volume 172, Issue 6, 21 September 1990, Pages 440-444]}, author = {Ledoux, I. and Zyss, J. and Siegel, J. S. and Brienne, J. and Lehn, J-M}, doi = {10.1016/j.cplett.2013.08.046}, issn = {0009-2614}, year = {2013}, date = {2013-12-01}, journal = {CHEMICAL PHYSICS LETTERS}, volume = {589}, pages = {46}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Ledoux, I; Zyss, J; Siegel, J S; Brienne, J; Lehn, J-M Second-harmonic generation from non-dipolar non-centrosymmetric aromatic charge-transfer molecules (Reprinted from Chemical Physics Letters) Journal Article In: CHEMICAL PHYSICS LETTERS, 589 , pp. 47–50, 2013, ISSN: 0009-2614. @article{ledoux_second-harmonic_2013, title = {Second-harmonic generation from non-dipolar non-centrosymmetric aromatic charge-transfer molecules (Reprinted from Chemical Physics Letters)}, author = {Ledoux, I. and Zyss, J. and Siegel, J. S. and Brienne, J. and Lehn, J-M}, doi = {10.1016/j.cplett.2013.08.066}, issn = {0009-2614}, year = {2013}, date = {2013-12-01}, journal = {CHEMICAL PHYSICS LETTERS}, volume = {589}, pages = {47--50}, abstract = {Second-harmonic generation from powders of a series of three aromatic intramolecular charge-transfer moieties of D3h symmetry is reported. One compound is shown to be active while its symmetric structure. precludes any molecular non-linear contribution of a vectorial nature such as usually prevails in polar paranitroaniline-like systems. Similar non-dipolar non-centrosymmetric molecular moieties could serve as building blocks in new types of optically non-linear materials where the packing is not influenced by dipole-dipole interactions and the statistical occurrence of non-centrosymmetry would consequently increase. (C) 2013 Published by Elsevier B. V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Second-harmonic generation from powders of a series of three aromatic intramolecular charge-transfer moieties of D3h symmetry is reported. One compound is shown to be active while its symmetric structure. precludes any molecular non-linear contribution of a vectorial nature such as usually prevails in polar paranitroaniline-like systems. Similar non-dipolar non-centrosymmetric molecular moieties could serve as building blocks in new types of optically non-linear materials where the packing is not influenced by dipole-dipole interactions and the statistical occurrence of non-centrosymmetry would consequently increase. (C) 2013 Published by Elsevier B. V. |
Riveline, Daniel `Single molecule': theory and experiments, an introduction Journal Article In: JOURNAL OF NANOBIOTECHNOLOGY, 11 (1), 2013, ISSN: 1477-3155. @article{riveline_`single_2013, title = {`Single molecule': theory and experiments, an introduction}, author = {Riveline, Daniel}, doi = {10.1186/1477-3155-11-S1-S1}, issn = {1477-3155}, year = {2013}, date = {2013-12-01}, journal = {JOURNAL OF NANOBIOTECHNOLOGY}, volume = {11}, number = {1}, abstract = {At scales below micrometers, Brownian motion dictates most of the behaviors. The simple observation of a colloid is striking: a permanent and random motion is seen, whereas inertial forces play a negligible role. This Physics, where velocity is proportional to force, has opened new horizons in biology. The random feature is challenged in living systems where some proteins - molecular motors - have a directed motion whereas their passive behaviors of colloid should lead to a Brownian motion. Individual proteins, polymers of living matter such as DNA, RNA, actin or microtubules, molecular motors, all these objects can be viewed as chains of colloids. They are submitted to shocks from molecules of the solvent. Shapes taken by these biopolymers or dynamics imposed by motors can be measured and modeled from single molecules to their collective effects. Thanks to the development of experimental methods such as optical tweezers, Atomic Force Microscope (AFM), micropipettes, and quantitative fluorescence (such as Forster Resonance Energy Transfer, FRET), it is possible to manipulate these individual biomolecules in an unprecedented manner: experiments allow to probe the validity of models; and a new Physics has thereby emerged with original biological insights. Theories based on statistical mechanics are needed to explain behaviors of these systems. When force-extension curves of these molecules are extracted, the curves need to be fitted with models that predict the deformation of free objects or submitted to a force. When velocity of motors is altered, a quantitative analysis is required to explain the motions of individual molecules under external forces. This lecture will give some elements of introduction to the lectures of the session `Nanophysics for Molecular Biology'.}, keywords = {}, pubstate = {published}, tppubtype = {article} } At scales below micrometers, Brownian motion dictates most of the behaviors. The simple observation of a colloid is striking: a permanent and random motion is seen, whereas inertial forces play a negligible role. This Physics, where velocity is proportional to force, has opened new horizons in biology. The random feature is challenged in living systems where some proteins - molecular motors - have a directed motion whereas their passive behaviors of colloid should lead to a Brownian motion. Individual proteins, polymers of living matter such as DNA, RNA, actin or microtubules, molecular motors, all these objects can be viewed as chains of colloids. They are submitted to shocks from molecules of the solvent. Shapes taken by these biopolymers or dynamics imposed by motors can be measured and modeled from single molecules to their collective effects. Thanks to the development of experimental methods such as optical tweezers, Atomic Force Microscope (AFM), micropipettes, and quantitative fluorescence (such as Forster Resonance Energy Transfer, FRET), it is possible to manipulate these individual biomolecules in an unprecedented manner: experiments allow to probe the validity of models; and a new Physics has thereby emerged with original biological insights. Theories based on statistical mechanics are needed to explain behaviors of these systems. When force-extension curves of these molecules are extracted, the curves need to be fitted with models that predict the deformation of free objects or submitted to a force. When velocity of motors is altered, a quantitative analysis is required to explain the motions of individual molecules under external forces. This lecture will give some elements of introduction to the lectures of the session `Nanophysics for Molecular Biology'. |
Canaguier-Durand, Antoine ; Hutchison, James A; Genet, Cyriaque ; Ebbesen, Thomas W Mechanical separation of chiral dipoles by chiral light Journal Article In: NEW JOURNAL OF PHYSICS, 15 , 2013, ISSN: 1367-2630. @article{canaguier-durand_mechanical_2013, title = {Mechanical separation of chiral dipoles by chiral light}, author = {Canaguier-Durand, Antoine and Hutchison, James A. and Genet, Cyriaque and Ebbesen, Thomas W.}, doi = {10.1088/1367-2630/15/12/123037}, issn = {1367-2630}, year = {2013}, date = {2013-12-01}, journal = {NEW JOURNAL OF PHYSICS}, volume = {15}, abstract = {We calculate optical forces and torques exerted on a chiral dipole by chiral light fields and reveal genuine chiral forces in combining the chiral contents of both light field and dipolar matter. Here, the optical chirality is characterized in a general way through the definition of optical chirality density and chirality flow. We show, in particular, that both terms have mechanical effects associated, respectively, with reactive and dissipative components of the chiral forces. Remarkably, these chiral force components are directly related to standard observables: optical rotation for the reactive component and circular dichroism for the dissipative one. As a consequence, the resulting forces and torques are dependent on the enantiomeric form of the chiral dipole. This suggests promising strategies for using chiral light forces to mechanically separate chiral objects according to their enantiomeric form.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We calculate optical forces and torques exerted on a chiral dipole by chiral light fields and reveal genuine chiral forces in combining the chiral contents of both light field and dipolar matter. Here, the optical chirality is characterized in a general way through the definition of optical chirality density and chirality flow. We show, in particular, that both terms have mechanical effects associated, respectively, with reactive and dissipative components of the chiral forces. Remarkably, these chiral force components are directly related to standard observables: optical rotation for the reactive component and circular dichroism for the dissipative one. As a consequence, the resulting forces and torques are dependent on the enantiomeric form of the chiral dipole. This suggests promising strategies for using chiral light forces to mechanically separate chiral objects according to their enantiomeric form. |
Biscarini, Fabio ; Ong, Quy Khac ; Albonetti, Cristiano ; Liscio, Fabiola ; Longobardi, Maria ; Mali, Kunal S; Ciesielski, Artur ; Reguera, Javier ; Renner, Christoph ; De Feyter, Steven ; Samori, Paolo ; Stellacci, Francesco Quantitative Analysis of Scanning Tunneling Microscopy Images of Mixed-Ligand-Functionalized Nanoparticles Journal Article In: LANGMUIR, 29 (45), pp. 13723–13734, 2013, ISSN: 0743-7463. @article{biscarini_quantitative_2013, title = {Quantitative Analysis of Scanning Tunneling Microscopy Images of Mixed-Ligand-Functionalized Nanoparticles}, author = {Biscarini, Fabio and Ong, Quy Khac and Albonetti, Cristiano and Liscio, Fabiola and Longobardi, Maria and Mali, Kunal S. and Ciesielski, Artur and Reguera, Javier and Renner, Christoph and De Feyter, Steven and Samori, Paolo and Stellacci, Francesco}, doi = {10.1021/la403546c}, issn = {0743-7463}, year = {2013}, date = {2013-11-01}, journal = {LANGMUIR}, volume = {29}, number = {45}, pages = {13723--13734}, abstract = {Ligand-protected gold nanoparticles exhibit large local curvatures, features rapidly varying over small scales, and chemical heterogeneity. Their imaging by scanning tunneling microscopy (STM) can, in principle, provide direct information on the architecture of their ligand shell, yet STM images require laborious analysis and are challenging to interpret. Here, we report a straightforward, robust, and rigorous method for the quantitative analysis of the multiscale features contained in STM images of samples consisting of functionalized Au nanoparticles deposited onto Au/mica. The method relies on the analysis of the topographical power spectral density (PSD) and allows us to extract the characteristic length scales of the features exhibited by nanoparticles in STM images. For the mixed-ligand-protected Au nanoparticles analyzed here, the characteristic length scale is 1.2 +/- 0.1 nm, whereas for the homoligand Au NPs this scale is 0.75 +/- 0.05 nm. These length scales represent spatial correlations independent of scanning parameters, and hence the features in the PSD can be ascribed to a fingerprint of the STM contrast of ligand-protected nanoparticles. PSD spectra from images recorded at different laboratories using different microscopes and operators can be overlapped across most of the frequency range, proving that the features in the STM images of nanoparticles can be compared and reproduced.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ligand-protected gold nanoparticles exhibit large local curvatures, features rapidly varying over small scales, and chemical heterogeneity. Their imaging by scanning tunneling microscopy (STM) can, in principle, provide direct information on the architecture of their ligand shell, yet STM images require laborious analysis and are challenging to interpret. Here, we report a straightforward, robust, and rigorous method for the quantitative analysis of the multiscale features contained in STM images of samples consisting of functionalized Au nanoparticles deposited onto Au/mica. The method relies on the analysis of the topographical power spectral density (PSD) and allows us to extract the characteristic length scales of the features exhibited by nanoparticles in STM images. For the mixed-ligand-protected Au nanoparticles analyzed here, the characteristic length scale is 1.2 +/- 0.1 nm, whereas for the homoligand Au NPs this scale is 0.75 +/- 0.05 nm. These length scales represent spatial correlations independent of scanning parameters, and hence the features in the PSD can be ascribed to a fingerprint of the STM contrast of ligand-protected nanoparticles. PSD spectra from images recorded at different laboratories using different microscopes and operators can be overlapped across most of the frequency range, proving that the features in the STM images of nanoparticles can be compared and reproduced. |
Calimet, Nicolas ; Simoes, Manuel ; Changeux, Jean-Pierre ; Karplus, Martin ; Taly, Antoine ; Cecchini, Marco A gating mechanism of pentameric ligand-gated ion channels Journal Article In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 110 (42), pp. E3987–E3996, 2013, ISSN: 0027-8424. @article{calimet_gating_2013, title = {A gating mechanism of pentameric ligand-gated ion channels}, author = {Calimet, Nicolas and Simoes, Manuel and Changeux, Jean-Pierre and Karplus, Martin and Taly, Antoine and Cecchini, Marco}, doi = {10.1073/pnas.1313785110}, issn = {0027-8424}, year = {2013}, date = {2013-10-01}, journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, volume = {110}, number = {42}, pages = {E3987--E3996}, abstract = {Pentameric ligand-gated ion channels (pLGICs) play a central role in intercellular communication in the nervous system and are involved in fundamental processes such as attention, learning, and memory. They are oligomeric protein assemblies that convert a chemical signal into an ion flux through the postsynaptic membrane, but the molecular mechanism of gating ions has remained elusive. Here, we present atomistic molecular dynamics simulations of the prokaryotic channels from Gloeobacter violaceus (GLIC) and Erwinia chrysanthemi (ELIC), whose crystal structures are thought to represent the active and the resting states of pLGICs, respectively, and of the eukaryotic glutamate-gated chloride channel from Caenorhabditis elegans (GluCl), whose open-channel structure was determined complexed with the positive allosteric modulator ivermectin. Structural observables extracted from the trajectories of GLIC and ELIC are used as progress variables to analyze the time evolution of GluCl, which was simulated in the absence of ivermectin starting from the structure with bound ivermectin. The trajectory of GluCl with ivermectin removed shows a sequence of structural events that couple agonist unbinding from the extracellular domain to ion-pore closing in the transmembrane domain. Based on these results, we propose a structural mechanism for the allosteric communication leading to deactivation/activation of the GluCl channel. This model of gating emphasizes the coupling between the quaternary twisting and the opening/closing of the ion pore and is likely to apply to other members of the pLGIC family.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Pentameric ligand-gated ion channels (pLGICs) play a central role in intercellular communication in the nervous system and are involved in fundamental processes such as attention, learning, and memory. They are oligomeric protein assemblies that convert a chemical signal into an ion flux through the postsynaptic membrane, but the molecular mechanism of gating ions has remained elusive. Here, we present atomistic molecular dynamics simulations of the prokaryotic channels from Gloeobacter violaceus (GLIC) and Erwinia chrysanthemi (ELIC), whose crystal structures are thought to represent the active and the resting states of pLGICs, respectively, and of the eukaryotic glutamate-gated chloride channel from Caenorhabditis elegans (GluCl), whose open-channel structure was determined complexed with the positive allosteric modulator ivermectin. Structural observables extracted from the trajectories of GLIC and ELIC are used as progress variables to analyze the time evolution of GluCl, which was simulated in the absence of ivermectin starting from the structure with bound ivermectin. The trajectory of GluCl with ivermectin removed shows a sequence of structural events that couple agonist unbinding from the extracellular domain to ion-pore closing in the transmembrane domain. Based on these results, we propose a structural mechanism for the allosteric communication leading to deactivation/activation of the GluCl channel. This model of gating emphasizes the coupling between the quaternary twisting and the opening/closing of the ion pore and is likely to apply to other members of the pLGIC family. |
Mattioli, Marco ; Dalmonte, Marcello ; Lechner, Wolfgang ; Pupillo, Guido Cluster Luttinger Liquids of Rydberg-Dressed Atoms in Optical Lattices Journal Article In: PHYSICAL REVIEW LETTERS, 111 (16), 2013, ISSN: 0031-9007. @article{mattioli_cluster_2013, title = {Cluster Luttinger Liquids of Rydberg-Dressed Atoms in Optical Lattices}, author = {Mattioli, Marco and Dalmonte, Marcello and Lechner, Wolfgang and Pupillo, Guido}, doi = {10.1103/PhysRevLett.111.165302}, issn = {0031-9007}, year = {2013}, date = {2013-10-01}, journal = {PHYSICAL REVIEW LETTERS}, volume = {111}, number = {16}, abstract = {We investigate the zero-temperature phases of bosonic and fermionic gases confined to one dimension and interacting via a class of finite-range soft-shoulder potentials (i.e., soft-core potentials with an additional hard-core onsite interaction). Using a combination of analytical and numerical methods, we demonstrate the stabilization of critical quantum liquids with qualitatively new features with respect to the Tomonaga-Luttinger liquid paradigm. These features result from frustration and cluster formation in the corresponding classical ground state. Characteristic signatures of these liquids are accessible in state-of-the-art experimental setups with Rydberg-dressed ground-state atoms trapped in optical lattices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We investigate the zero-temperature phases of bosonic and fermionic gases confined to one dimension and interacting via a class of finite-range soft-shoulder potentials (i.e., soft-core potentials with an additional hard-core onsite interaction). Using a combination of analytical and numerical methods, we demonstrate the stabilization of critical quantum liquids with qualitatively new features with respect to the Tomonaga-Luttinger liquid paradigm. These features result from frustration and cluster formation in the corresponding classical ground state. Characteristic signatures of these liquids are accessible in state-of-the-art experimental setups with Rydberg-dressed ground-state atoms trapped in optical lattices. |
Szarpak-Jankowska, Anna ; Burgess, Christine ; De Cola, Luisa ; Huskens, Jurriaan Cyclodextrin-Modified Zeolites: Host-Guest Surface Chemistry for the Construction of Multifunctional Nanocontainers Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 19 (44), pp. 14925–14930, 2013, ISSN: 0947-6539. @article{szarpak-jankowska_cyclodextrin-modified_2013, title = {Cyclodextrin-Modified Zeolites: Host-Guest Surface Chemistry for the Construction of Multifunctional Nanocontainers}, author = {Szarpak-Jankowska, Anna and Burgess, Christine and De Cola, Luisa and Huskens, Jurriaan}, doi = {10.1002/chem.201302153}, issn = {0947-6539}, year = {2013}, date = {2013-10-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {19}, number = {44}, pages = {14925--14930}, abstract = {The functionalization of nanoporous zeolite L crystals with beta-cyclodextrin (CD) has been demonstrated. The zeolite surface was first modified with amino groups by using two different aminoalkoxysilanes. Then, 1,4-phenylene diisothiocyanate was reacted with the amino monolayer and used to bind CD heptamine by using its remaining isothiocyanate groups. The use of the different aminoalkoxysilanes, 3-aminopropyl dimethylethoxysilane (APDMES) and 3-aminopropyl triethoxysilane (APTES), led to drastic differences in uptake and release properties. Thionine was found to be absorbed and released from amino- and CD-functionalized zeolites when APDMES was used, whereas functionalization by APTES led to complete blockage of the zeolite channels. Fluorescence microscopy showed that the CD groups covalently attached to the zeolite crystals could bind adamantyl-modified dyes in a specific and reversible manner. This strategy allowed the specific immobilization of His-tagged proteins by using combined host-guest and His-tag-Ni-nitrilotriacetic acid (NTA) coordination chemistry. Such multifunctional systems have the potential for encapsulation of drug molecules inside the zeolite pores and noncovalent attachment of other (for example, targeting) ligand molecules on its surface.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The functionalization of nanoporous zeolite L crystals with beta-cyclodextrin (CD) has been demonstrated. The zeolite surface was first modified with amino groups by using two different aminoalkoxysilanes. Then, 1,4-phenylene diisothiocyanate was reacted with the amino monolayer and used to bind CD heptamine by using its remaining isothiocyanate groups. The use of the different aminoalkoxysilanes, 3-aminopropyl dimethylethoxysilane (APDMES) and 3-aminopropyl triethoxysilane (APTES), led to drastic differences in uptake and release properties. Thionine was found to be absorbed and released from amino- and CD-functionalized zeolites when APDMES was used, whereas functionalization by APTES led to complete blockage of the zeolite channels. Fluorescence microscopy showed that the CD groups covalently attached to the zeolite crystals could bind adamantyl-modified dyes in a specific and reversible manner. This strategy allowed the specific immobilization of His-tagged proteins by using combined host-guest and His-tag-Ni-nitrilotriacetic acid (NTA) coordination chemistry. Such multifunctional systems have the potential for encapsulation of drug molecules inside the zeolite pores and noncovalent attachment of other (for example, targeting) ligand molecules on its surface. |
Darmawan, Noviyan ; Yang, Cheng-Han ; Mauro, Matteo ; Raynal, Matthieu ; Heun, Susanne ; Pan, Junyou ; Buchholz, Herwig ; Braunstein, Pierre ; De Cola, Luisa Efficient Near-UV Emitters Based on Cationic Bis-Pincer Iridium(III) Carbene Complexes Journal Article In: INORGANIC CHEMISTRY, 52 (19), pp. 10756–10765, 2013, ISSN: 0020-1669. @article{darmawan_efficient_2013, title = {Efficient Near-UV Emitters Based on Cationic Bis-Pincer Iridium(III) Carbene Complexes}, author = {Darmawan, Noviyan and Yang, Cheng-Han and Mauro, Matteo and Raynal, Matthieu and Heun, Susanne and Pan, Junyou and Buchholz, Herwig and Braunstein, Pierre and De Cola, Luisa}, doi = {10.1021/ic302695q}, issn = {0020-1669}, year = {2013}, date = {2013-10-01}, journal = {INORGANIC CHEMISTRY}, volume = {52}, number = {19}, pages = {10756--10765}, abstract = {We report on the photophysical studies of two cationic near-UV emitters based on bis-pincer Ir(III) carbene complexes: [Ir-nBu((CNHCCCNHC)-C-Me)(2)]X, where Ir-nBu((CNHCCCNHC)-C-Me) is (4,6-dimethyl-1,3-phenylene-kappa C-2)bis(1-butylimidazol-2-ylidene) and X = I- or PF6-). The compounds are highly emitting in deaerated CH3CN solution with emission maxima at 384 and 406 nm, and photoluminescence quantum yields of 0.41 and 0.38, for [Ir-nbu((CNHCCCNHC)-C-Me)(2)]I and Ir-nBu((CNHCCCNHC)-C-Me)(2)]PF6, respectively. In order to gain deeper understandings into their structural and electronic features, as well as to ascertain the nature of the excited states involved into the electronic absorption processes, density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations have been performed on the ground and excited states of the closely related complex [Ir-Me((CNHCCCNHC)-C-Me)(2)](+). In the solid state, an emission at low energy is observed (lambda(max) = 500 nm) for both complexes. However, the intensity of the emission at high energy versus the intensity of the new emission at low energy is dependent on the nature of counterions. The origin of this emission is not completely clear, but the experimental data point to the formation of trapping sites induced by aggregation processes involving the interaction between the cationic emitter and the counterion.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report on the photophysical studies of two cationic near-UV emitters based on bis-pincer Ir(III) carbene complexes: [Ir-nBu((CNHCCCNHC)-C-Me)(2)]X, where Ir-nBu((CNHCCCNHC)-C-Me) is (4,6-dimethyl-1,3-phenylene-kappa C-2)bis(1-butylimidazol-2-ylidene) and X = I- or PF6-). The compounds are highly emitting in deaerated CH3CN solution with emission maxima at 384 and 406 nm, and photoluminescence quantum yields of 0.41 and 0.38, for [Ir-nbu((CNHCCCNHC)-C-Me)(2)]I and Ir-nBu((CNHCCCNHC)-C-Me)(2)]PF6, respectively. In order to gain deeper understandings into their structural and electronic features, as well as to ascertain the nature of the excited states involved into the electronic absorption processes, density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations have been performed on the ground and excited states of the closely related complex [Ir-Me((CNHCCCNHC)-C-Me)(2)](+). In the solid state, an emission at low energy is observed (lambda(max) = 500 nm) for both complexes. However, the intensity of the emission at high energy versus the intensity of the new emission at low energy is dependent on the nature of counterions. The origin of this emission is not completely clear, but the experimental data point to the formation of trapping sites induced by aggregation processes involving the interaction between the cationic emitter and the counterion. |
Derbal-Wolfrom, L; Pencreach, E; Saandi, T; Aprahamian, M; Martin, E; Greferath, R; Tufa, E; Choquet, P; Lehn, J-M; Nicolau, C; Duluc, I; Freund, J-N Increasing the oxygen load by treatment with myo-inositol trispyrophosphate reduces growth of colon cancer and modulates the intestine homeobox gene Cdx2 Journal Article In: ONCOGENE, 32 (36), pp. 4313–4318, 2013, ISSN: 0950-9232. @article{derbal-wolfrom_increasing_2013, title = {Increasing the oxygen load by treatment with myo-inositol trispyrophosphate reduces growth of colon cancer and modulates the intestine homeobox gene Cdx2}, author = {Derbal-Wolfrom, L. and Pencreach, E. and Saandi, T. and Aprahamian, M. and Martin, E. and Greferath, R. and Tufa, E. and Choquet, P. and Lehn, J-M and Nicolau, C. and Duluc, I. and Freund, J-N}, doi = {10.1038/onc.2012.445}, issn = {0950-9232}, year = {2013}, date = {2013-09-01}, journal = {ONCOGENE}, volume = {32}, number = {36}, pages = {4313--4318}, abstract = {Preventing tumor neovascularisation is one of the strategies recently developed to limit the dissemination of cancer cells and apparition of metastases. Although these approaches could improve the existing treatments, a number of unexpected negative effects have been reported, mainly linked to the hypoxic condition and the subsequent induction of the pro-oncogenic hypoxia inducible factor(s) resulting from cancer cells' oxygen starvation. Here, we checked in vivo on colon cancer cells an alternative approach. It is based on treatment with myo-inositol trispyrophosphate (ITPP), a molecule that leads to increased oxygenation of tumors. We provide evidence that ITPP increases the survival of mice in a model of carcinomatosis of human colon cancer cells implanted into the peritoneal cavity. ITPP also reduced the growth of subcutaneous colon cancer cells xenografted in nu/nu mice. In the subcutaneous tumors, ITPP stimulated the expression of the homeobox gene Cdx2 that is crucial for intestinal differentiation and that also has an anti-tumoral function. On this basis, human colon cancer cells were cultured in vitro in hypoxic conditions. Hypoxia was shown to decrease the level of Cdx2 protein, mRNA and the activity of the Cdx2 promoter. This decline was unrelated to the activation of HIF1 alpha and HIF2 alpha by hypoxia. However, it resulted from the activation of a phosphatidylinositol 3-kinases-like mitogen-activated protein kinase pathway, as assessed by the fact that LY294002 and U0126 restored high Cdx2 expression in hypoxia. Corroborating these results, U0126 recapitulated the increase of Cdx2 triggered by ITPP in subcutaneous colon tumor xenografts. The present study provides evidence that a chemical compound that increases oxygen pressure can antagonize the hypoxic setting and reduce the growth of human colon tumors implanted in nu/nu mice.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Preventing tumor neovascularisation is one of the strategies recently developed to limit the dissemination of cancer cells and apparition of metastases. Although these approaches could improve the existing treatments, a number of unexpected negative effects have been reported, mainly linked to the hypoxic condition and the subsequent induction of the pro-oncogenic hypoxia inducible factor(s) resulting from cancer cells' oxygen starvation. Here, we checked in vivo on colon cancer cells an alternative approach. It is based on treatment with myo-inositol trispyrophosphate (ITPP), a molecule that leads to increased oxygenation of tumors. We provide evidence that ITPP increases the survival of mice in a model of carcinomatosis of human colon cancer cells implanted into the peritoneal cavity. ITPP also reduced the growth of subcutaneous colon cancer cells xenografted in nu/nu mice. In the subcutaneous tumors, ITPP stimulated the expression of the homeobox gene Cdx2 that is crucial for intestinal differentiation and that also has an anti-tumoral function. On this basis, human colon cancer cells were cultured in vitro in hypoxic conditions. Hypoxia was shown to decrease the level of Cdx2 protein, mRNA and the activity of the Cdx2 promoter. This decline was unrelated to the activation of HIF1 alpha and HIF2 alpha by hypoxia. However, it resulted from the activation of a phosphatidylinositol 3-kinases-like mitogen-activated protein kinase pathway, as assessed by the fact that LY294002 and U0126 restored high Cdx2 expression in hypoxia. Corroborating these results, U0126 recapitulated the increase of Cdx2 triggered by ITPP in subcutaneous colon tumor xenografts. The present study provides evidence that a chemical compound that increases oxygen pressure can antagonize the hypoxic setting and reduce the growth of human colon tumors implanted in nu/nu mice. |
Genes, Claudiu ; Xuereb, Andre ; Pupillo, Guido ; Dantan, Aurelien Enhanced optomechanical readout using optical coalescence Journal Article In: PHYSICAL REVIEW A, 88 (3), 2013, ISSN: 1050-2947. @article{genes_enhanced_2013, title = {Enhanced optomechanical readout using optical coalescence}, author = {Genes, Claudiu and Xuereb, Andre and Pupillo, Guido and Dantan, Aurelien}, doi = {10.1103/PhysRevA.88.033855}, issn = {1050-2947}, year = {2013}, date = {2013-09-01}, journal = {PHYSICAL REVIEW A}, volume = {88}, number = {3}, abstract = {We present a scheme to strongly enhance the readout sensitivity of the squared displacement of a mobile scatterer placed in a Fabry-Perot cavity. We investigate the largely unexplored regime of cavity electrodynamics in which a highly reflective element positioned between the end mirrors of a symmetric Fabry-Perot resonator strongly modifies the cavity response function, such that two longitudinal modes with different spatial parity are brought close to frequency degeneracy and interfere in the cavity output field. In the case of a movable middle reflector we show that the interference in this generic “optical coalescence” phenomenon gives rise to an enhanced frequency shift of the peaks of the cavity transmission that can be exploited in optomechanics.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present a scheme to strongly enhance the readout sensitivity of the squared displacement of a mobile scatterer placed in a Fabry-Perot cavity. We investigate the largely unexplored regime of cavity electrodynamics in which a highly reflective element positioned between the end mirrors of a symmetric Fabry-Perot resonator strongly modifies the cavity response function, such that two longitudinal modes with different spatial parity are brought close to frequency degeneracy and interfere in the cavity output field. In the case of a movable middle reflector we show that the interference in this generic “optical coalescence” phenomenon gives rise to an enhanced frequency shift of the peaks of the cavity transmission that can be exploited in optomechanics. |
Baytekin, Tarik H; Baytekin, Bilge ; Hermans, Thomas M; Kowalczyk, Bartlomiej ; Grzybowski, Bartosz A Control of Surface Charges by Radicals as a Principle of Antistatic Polymers Protecting Electronic Circuitry Journal Article In: SCIENCE, 341 (6152), pp. 1368–1371, 2013, ISSN: 0036-8075. @article{baytekin_control_2013, title = {Control of Surface Charges by Radicals as a Principle of Antistatic Polymers Protecting Electronic Circuitry}, author = {Baytekin, H. Tarik and Baytekin, Bilge and Hermans, Thomas M. and Kowalczyk, Bartlomiej and Grzybowski, Bartosz A.}, doi = {10.1126/science.1241326}, issn = {0036-8075}, year = {2013}, date = {2013-09-01}, journal = {SCIENCE}, volume = {341}, number = {6152}, pages = {1368--1371}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Joosten, Antoine ; Trolez, Yann ; Heitz, Valerie ; Sauvage, Jean-Pierre Use of Cleavable Coordinating Rings as Protective Groups in the Synthesis of a Rotaxane with an Axis that Incorporates More Chelating Groups Than Threaded Macrocycles Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 19 (38), pp. 12815–12823, 2013, ISSN: 0947-6539. @article{joosten_use_2013, title = {Use of Cleavable Coordinating Rings as Protective Groups in the Synthesis of a Rotaxane with an Axis that Incorporates More Chelating Groups Than Threaded Macrocycles}, author = {Joosten, Antoine and Trolez, Yann and Heitz, Valerie and Sauvage, Jean-Pierre}, doi = {10.1002/chem.201301717}, issn = {0947-6539}, year = {2013}, date = {2013-09-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {19}, number = {38}, pages = {12815--12823}, abstract = {A new methodology allowing preparation of a linear unsaturated [3]rotaxane consisting of an axis incorporating more coordination sites than threaded rings was developed. It was based on the preliminary synthesis of a saturated [5]rotaxane consisting of a four-chelating site axis threaded through four macrocyclic components, two of them being cleavable rings incorporating a lactone function and the two others being secure non-cleavable rings. The stoppering reaction was based on click chemistry. Subsequently, cleavage and removal of the two lactone-containing macrocycles from the [5]rotaxane in basic medium afforded the desired unsaturated [3]rotaxane in quantitative yield.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new methodology allowing preparation of a linear unsaturated [3]rotaxane consisting of an axis incorporating more coordination sites than threaded rings was developed. It was based on the preliminary synthesis of a saturated [5]rotaxane consisting of a four-chelating site axis threaded through four macrocyclic components, two of them being cleavable rings incorporating a lactone function and the two others being secure non-cleavable rings. The stoppering reaction was based on click chemistry. Subsequently, cleavage and removal of the two lactone-containing macrocycles from the [5]rotaxane in basic medium afforded the desired unsaturated [3]rotaxane in quantitative yield. |
Canaguier-Durand, Antoine ; Cuche, Aurelien ; Genet, Cyriaque ; Ebbesen, Thomas W Force and torque on an electric dipole by spinning light fields Journal Article In: PHYSICAL REVIEW A, 88 (3), 2013, ISSN: 1050-2947. @article{canaguier-durand_force_2013, title = {Force and torque on an electric dipole by spinning light fields}, author = {Canaguier-Durand, Antoine and Cuche, Aurelien and Genet, Cyriaque and Ebbesen, Thomas W.}, doi = {10.1103/PhysRevA.88.033831}, issn = {1050-2947}, year = {2013}, date = {2013-09-01}, journal = {PHYSICAL REVIEW A}, volume = {88}, number = {3}, abstract = {We calculate the optical force and torque applied to an electric dipole by a spinning light field. We find that the dissipative part of the force depends on the orbital energy flow of the field only, because the latter is related to the phase gradient generalized for such a light field. As for the remaining spin energy flow, it gives rise to an optical torque. The resulting change in the optical force is detailed for different experimentally relevant configurations, and we show in particular how this change is critical when surface plasmon modes are involved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We calculate the optical force and torque applied to an electric dipole by a spinning light field. We find that the dissipative part of the force depends on the orbital energy flow of the field only, because the latter is related to the phase gradient generalized for such a light field. As for the remaining spin energy flow, it gives rise to an optical torque. The resulting change in the optical force is detailed for different experimentally relevant configurations, and we show in particular how this change is critical when surface plasmon modes are involved. |
Cuche, A; Canaguier-Durand, A; Devaux, E; Hutchison, J A; Genet, C; Ebbesen, T W Sorting Nanoparticles with Intertwined Plasmonic and Thermo-Hydrodynamical Forces Journal Article In: NANO LETTERS, 13 (9), pp. 4230–4235, 2013, ISSN: 1530-6984. @article{cuche_sorting_2013, title = {Sorting Nanoparticles with Intertwined Plasmonic and Thermo-Hydrodynamical Forces}, author = {Cuche, A. and Canaguier-Durand, A. and Devaux, E. and Hutchison, J. A. and Genet, C. and Ebbesen, T. W.}, doi = {10.1021/nl401922p}, issn = {1530-6984}, year = {2013}, date = {2013-09-01}, journal = {NANO LETTERS}, volume = {13}, number = {9}, pages = {4230--4235}, abstract = {We exploit plasmonic and thermo-hydrodynamical forces to sort gold nanoparticles in a microfluidic environment. In the appropriate regime, the experimental data extracted from a Brownian statistical analysis of the kinetic motions are in good agreement with Mie-type theoretical evaluations of the optical forces acting on the nanoparticles in the plasmonic near field. This analysis enables us to demonstrate the importance of thermal and hydrodynamical effects in a sorting perspective.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We exploit plasmonic and thermo-hydrodynamical forces to sort gold nanoparticles in a microfluidic environment. In the appropriate regime, the experimental data extracted from a Brownian statistical analysis of the kinetic motions are in good agreement with Mie-type theoretical evaluations of the optical forces acting on the nanoparticles in the plasmonic near field. This analysis enables us to demonstrate the importance of thermal and hydrodynamical effects in a sorting perspective. |
Frasconi, Marco ; Liu, Zhichang ; Lei, Juying ; Wu, Yilei ; Strekalova, Elena ; Malin, Dmitry ; Ambrogio, Michael W; Chen, Xinqi ; Botros, Youssry Y; Cryns, Vincent L; Sauvage, Jean-Pierre ; Stoddart, Fraser J Photoexpulsion of Surface-Grafted Ruthenium Complexes and Subsequent Release of Cytotoxic Cargos to Cancer Cells from Mesoporous Silica Nanoparticles Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 135 (31), pp. 11603–11613, 2013, ISSN: 0002-7863. @article{frasconi_photoexpulsion_2013, title = {Photoexpulsion of Surface-Grafted Ruthenium Complexes and Subsequent Release of Cytotoxic Cargos to Cancer Cells from Mesoporous Silica Nanoparticles}, author = {Frasconi, Marco and Liu, Zhichang and Lei, Juying and Wu, Yilei and Strekalova, Elena and Malin, Dmitry and Ambrogio, Michael W. and Chen, Xinqi and Botros, Youssry Y. and Cryns, Vincent L. and Sauvage, Jean-Pierre and Stoddart, J. Fraser}, doi = {10.1021/ja405058y}, issn = {0002-7863}, year = {2013}, date = {2013-08-01}, journal = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, volume = {135}, number = {31}, pages = {11603--11613}, abstract = {Ruthenium(II) polypyridyl complexes have emerged both as promising probes of DNA structure and as anticancer agents because of their unique photophysical and c-ytotoxic properties. A key consideration in the administration of those therapeutic agents is the optimization of their chemical reactivities to allow facile attack on the target sites, yet avoid unwanted side effects. Here, we present a drug delivery platform technology, obtained by grafting the surface of mesoporous silica nanoparticles (MSNPs) with ruthenium(II) dipyridophenazine (dppz) complexes. This hybrid nanomaterial displays enhanced luminescent properties relative to that of the ruthenium(II) dppz complex in a homogeneous phase. Since the coordination between the ruthenium(II) complex and a monodentate ligand linked covalently to the nanoparticles can be cleaved under irradiation with visible light, the ruthenium complex can be released from the surface of the nanoparticles by selective substitution of this ligand with a water molecule. Indeed, the modified MSNPs undergo rapid cellular uptake, and after activation with light, the release of an aqua ruthenium(II) complex is observed. We have delivered, in combination, the ruthenium(H) complex and paclitaxel, loaded in the mesoporous structure, to breast cancer cells. This hybrid material represents a promising candidate as one of the so-called theranostic agents that possess both diagnostic and therapeutic functions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ruthenium(II) polypyridyl complexes have emerged both as promising probes of DNA structure and as anticancer agents because of their unique photophysical and c-ytotoxic properties. A key consideration in the administration of those therapeutic agents is the optimization of their chemical reactivities to allow facile attack on the target sites, yet avoid unwanted side effects. Here, we present a drug delivery platform technology, obtained by grafting the surface of mesoporous silica nanoparticles (MSNPs) with ruthenium(II) dipyridophenazine (dppz) complexes. This hybrid nanomaterial displays enhanced luminescent properties relative to that of the ruthenium(II) dppz complex in a homogeneous phase. Since the coordination between the ruthenium(II) complex and a monodentate ligand linked covalently to the nanoparticles can be cleaved under irradiation with visible light, the ruthenium complex can be released from the surface of the nanoparticles by selective substitution of this ligand with a water molecule. Indeed, the modified MSNPs undergo rapid cellular uptake, and after activation with light, the release of an aqua ruthenium(II) complex is observed. We have delivered, in combination, the ruthenium(H) complex and paclitaxel, loaded in the mesoporous structure, to breast cancer cells. This hybrid material represents a promising candidate as one of the so-called theranostic agents that possess both diagnostic and therapeutic functions. |
Schaeffer, Gael ; Buhler, Eric ; Candau, Sauveur J; Lehn, Jean-Marie Double Dynamic Supramolecular Polymers of Covalent Oligo-Dynamers Journal Article In: MACROMOLECULES, 46 (14), pp. 5664–5671, 2013, ISSN: 0024-9297. @article{schaeffer_double_2013, title = {Double Dynamic Supramolecular Polymers of Covalent Oligo-Dynamers}, author = {Schaeffer, Gael and Buhler, Eric and Candau, Sauveur J. and Lehn, Jean-Marie}, doi = {10.1021/ma400449u}, issn = {0024-9297}, year = {2013}, date = {2013-07-01}, journal = {MACROMOLECULES}, volume = {46}, number = {14}, pages = {5664--5671}, abstract = {Double-dynamic polymers, incorporating both molecular and supramolecular dynamic features (”double dynamers”) have been generated, where these functions are present in a nonstoichiometric ratio in the main chain of the polymer. It has been achieved by (1) the formation of covalent oligo-dynamers in which the monomers are connected by reversible covalent interactions and (2) the association of these oligomers through supramolecular interactions (hydrogen bonding). This procedure leads to the formation of an entity that can be seen as a supramolecular polymer of molecular oligo-dynamers. It thus combines two types of dynamic processes that do not simply alternate in the polymeric chain but may be incorporated in various ratios. These non-alternating double dynamic polymers have been generated by sequential construction and the different steps have been characterized by NMR spectroscopy, mass spectrometry and light scattering.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Double-dynamic polymers, incorporating both molecular and supramolecular dynamic features (”double dynamers”) have been generated, where these functions are present in a nonstoichiometric ratio in the main chain of the polymer. It has been achieved by (1) the formation of covalent oligo-dynamers in which the monomers are connected by reversible covalent interactions and (2) the association of these oligomers through supramolecular interactions (hydrogen bonding). This procedure leads to the formation of an entity that can be seen as a supramolecular polymer of molecular oligo-dynamers. It thus combines two types of dynamic processes that do not simply alternate in the polymeric chain but may be incorporated in various ratios. These non-alternating double dynamic polymers have been generated by sequential construction and the different steps have been characterized by NMR spectroscopy, mass spectrometry and light scattering. |
Lehn, J -M Perspectives in chemistry: from supramolecular chemistry towards adaptive chemistry Journal Article In: FEBS JOURNAL, 280 (1, SI), pp. 1–2, 2013, ISSN: 1742-464X. @article{lehn_perspectives_2013, title = {Perspectives in chemistry: from supramolecular chemistry towards adaptive chemistry}, author = {Lehn, J. -M.}, issn = {1742-464X}, year = {2013}, date = {2013-07-01}, journal = {FEBS JOURNAL}, volume = {280}, number = {1, SI}, pages = {1--2}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Nedeva, Iliana ; Koripelly, Girish ; Caballero, David ; Chieze, Lionel ; Guichard, Berangere ; Romain, Benoit ; Pencreach, Erwan ; Lehn, Jean-Marie ; Carlier, Marie-France ; Riveline, Daniel Synthetic polyamines promote rapid lamellipodial growth by regulating actin dynamics Journal Article In: NATURE COMMUNICATIONS, 4 , 2013, ISSN: 2041-1723. @article{nedeva_synthetic_2013, title = {Synthetic polyamines promote rapid lamellipodial growth by regulating actin dynamics}, author = {Nedeva, Iliana and Koripelly, Girish and Caballero, David and Chieze, Lionel and Guichard, Berangere and Romain, Benoit and Pencreach, Erwan and Lehn, Jean-Marie and Carlier, Marie-France and Riveline, Daniel}, doi = {10.1038/ncomms3165}, issn = {2041-1723}, year = {2013}, date = {2013-07-01}, journal = {NATURE COMMUNICATIONS}, volume = {4}, abstract = {Cellular protrusions involved in motile processes are driven by site-directed assembly of actin filaments in response to Rho-GTPase signalling. So far, only chemical compounds depolymerizing actin or stabilizing filaments, inhibiting N-WASP, Arp2/3 or formins, have been used to eliminate the formation of protrusions, while Rho-GTPase-dominant positive strategies have been designed to stimulate protrusions. Here we describe the design of four polyamines (macrocyclic and branched acyclic), and show that they enter the cell and induce specific growth of actin-enriched lamellipodia within minutes. The largest increase in cell area is obtained with micromolar amounts of a branched polyamine harbouring an 8-carbon chain. These polyamines specifically target actin both in vitro and in vivo. Analysis of their effects on filament assembly dynamics and its regulation indicates that the polyamines act by slowing down filament dynamics and by enhancing actin nucleation. These compounds provide new opportunities to study the actin cytoskeleton in motile and morphogenetic processes.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cellular protrusions involved in motile processes are driven by site-directed assembly of actin filaments in response to Rho-GTPase signalling. So far, only chemical compounds depolymerizing actin or stabilizing filaments, inhibiting N-WASP, Arp2/3 or formins, have been used to eliminate the formation of protrusions, while Rho-GTPase-dominant positive strategies have been designed to stimulate protrusions. Here we describe the design of four polyamines (macrocyclic and branched acyclic), and show that they enter the cell and induce specific growth of actin-enriched lamellipodia within minutes. The largest increase in cell area is obtained with micromolar amounts of a branched polyamine harbouring an 8-carbon chain. These polyamines specifically target actin both in vitro and in vivo. Analysis of their effects on filament assembly dynamics and its regulation indicates that the polyamines act by slowing down filament dynamics and by enhancing actin nucleation. These compounds provide new opportunities to study the actin cytoskeleton in motile and morphogenetic processes. |
Roy, Nabarun ; Buhler, Eric ; Lehn, Jean-Marie The Tris-Urea Motif and Its Incorporation into Polydimethylsiloxane-Based Supramolecular Materials Presenting Self-Healing Features Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 19 (27), pp. 8814–8820, 2013, ISSN: 0947-6539. @article{roy_tris-urea_2013, title = {The Tris-Urea Motif and Its Incorporation into Polydimethylsiloxane-Based Supramolecular Materials Presenting Self-Healing Features}, author = {Roy, Nabarun and Buhler, Eric and Lehn, Jean-Marie}, doi = {10.1002/chem.201203518}, issn = {0947-6539}, year = {2013}, date = {2013-07-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {19}, number = {27}, pages = {8814--8820}, abstract = {Materials of supramolecular nature have attracted much attention owing to their interesting features, such as self-reparability and material robustness, that are imparted by noncovalent interactions to synthetic materials. Among the various structures and synthetic methodologies that may be considered for this purpose, the introduction of extensive arrays of multiple hydrogen bonds allows for the formation of supramolecular materials that may, in principle, present self-healing behavior. Hydrogen bonded networks implement dynamic noncovalent interactions. Suitable selection of structural units gives access to novel dynamic self-repairing materials by incrementing the number of hydrogen-bonding sites present within a molecular framework. Herein, we describe the formation of a tris-urea based motif giving access to six hydrogen-bonding sites, easily accessible through reaction of carbohydrazide with an isocyanate derivative. Extension towards the synthesis of multiply hydrogen-bonded supramolecular materials has been achieved by polycondensation of carbohydrazide with a bis-isocyanate component derived from poly-dimethylsiloxane chains. Such materials underwent self-repair at a mechanically cut surface. This approach gives access to a broad spectrum of materials of varying flexibility by appropriate selection of the bis-isocyanate component that forms the polymer backbone.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Materials of supramolecular nature have attracted much attention owing to their interesting features, such as self-reparability and material robustness, that are imparted by noncovalent interactions to synthetic materials. Among the various structures and synthetic methodologies that may be considered for this purpose, the introduction of extensive arrays of multiple hydrogen bonds allows for the formation of supramolecular materials that may, in principle, present self-healing behavior. Hydrogen bonded networks implement dynamic noncovalent interactions. Suitable selection of structural units gives access to novel dynamic self-repairing materials by incrementing the number of hydrogen-bonding sites present within a molecular framework. Herein, we describe the formation of a tris-urea based motif giving access to six hydrogen-bonding sites, easily accessible through reaction of carbohydrazide with an isocyanate derivative. Extension towards the synthesis of multiply hydrogen-bonded supramolecular materials has been achieved by polycondensation of carbohydrazide with a bis-isocyanate component derived from poly-dimethylsiloxane chains. Such materials underwent self-repair at a mechanically cut surface. This approach gives access to a broad spectrum of materials of varying flexibility by appropriate selection of the bis-isocyanate component that forms the polymer backbone. |
Kieda, Claudine ; El Hafny-Rahbi, Bouchra ; Collet, Guillaume ; Lamerant-Fayel, Nathalie ; Grillon, Catherine ; Guichard, Alan ; Dulak, Jozef ; Jozkowicz, Alicja ; Kotlinowski, Jerzy ; Fylaktakidou, Konstantina C; Vidal, Aurelien ; Auzeloux, Philippe ; Miot-Noirault, Elisabeth ; Beloeil, Jean-Claude ; Lehn, Jean-Marie ; Nicolau, Claude Stable tumor vessel normalization with pO(2) increase and endothelial PTEN activation by inositol trispyrophosphate brings novel tumor treatment Journal Article In: JOURNAL OF MOLECULAR MEDICINE-JMM, 91 (7), pp. 883–899, 2013, ISSN: 0946-2716. @article{kieda_stable_2013, title = {Stable tumor vessel normalization with pO(2) increase and endothelial PTEN activation by inositol trispyrophosphate brings novel tumor treatment}, author = {Kieda, Claudine and El Hafny-Rahbi, Bouchra and Collet, Guillaume and Lamerant-Fayel, Nathalie and Grillon, Catherine and Guichard, Alan and Dulak, Jozef and Jozkowicz, Alicja and Kotlinowski, Jerzy and Fylaktakidou, Konstantina C. and Vidal, Aurelien and Auzeloux, Philippe and Miot-Noirault, Elisabeth and Beloeil, Jean-Claude and Lehn, Jean-Marie and Nicolau, Claude}, doi = {10.1007/s00109-013-0992-6}, issn = {0946-2716}, year = {2013}, date = {2013-07-01}, journal = {JOURNAL OF MOLECULAR MEDICINE-JMM}, volume = {91}, number = {7}, pages = {883--899}, abstract = {Tumor hypoxia is a characteristic of cancer cell growth and invasion, promoting angiogenesis, which facilitates metastasis. Oxygen delivery remains impaired because tumor vessels are anarchic and leaky, contributing to tumor cell dissemination. Counteracting hypoxia by normalizing tumor vessels in order to improve drug and radio therapy efficacy and avoid cancer stem-like cell selection is a highly challenging issue. We show here that inositol trispyrophosphate (ITPP) treatment stably increases oxygen tension and blood flow in melanoma and breast cancer syngeneic models. It suppresses hypoxia-inducible factors (HIFs) and proangiogenic/glycolysis genes and proteins cascade. It selectively activates the tumor suppressor phosphatase and tensin homolog (PTEN) in vitro and in vivo at the endothelial cell (EC) level thus inhibiting PI3K and reducing tumor AKT phosphorylation. These mechanisms normalize tumor vessels by EC reorganization, maturation, pericytes attraction, and lowering progenitor cells recruitment in the tumor. It strongly reduces vascular leakage, tumor growth, drug resistance, and metastasis. ITPP treatment avoids cancer stem-like cell selection, multidrug resistance (MDR) activation and efficiently enhances chemotherapeutic drugs activity. These data show that counteracting tumor hypoxia by stably restoring healthy vasculature is achieved by ITPP treatment, which opens new therapeutic options overcoming hypoxia-related limitations of antiangiogenesis-restricted therapies. By achieving long-term vessels normalization, ITPP should provide the adjuvant treatment required in order to overcome the subtle definition of therapeutic windows for in vivo treatments aimed by the current strategies against angiogenesis-dependent tumors.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Tumor hypoxia is a characteristic of cancer cell growth and invasion, promoting angiogenesis, which facilitates metastasis. Oxygen delivery remains impaired because tumor vessels are anarchic and leaky, contributing to tumor cell dissemination. Counteracting hypoxia by normalizing tumor vessels in order to improve drug and radio therapy efficacy and avoid cancer stem-like cell selection is a highly challenging issue. We show here that inositol trispyrophosphate (ITPP) treatment stably increases oxygen tension and blood flow in melanoma and breast cancer syngeneic models. It suppresses hypoxia-inducible factors (HIFs) and proangiogenic/glycolysis genes and proteins cascade. It selectively activates the tumor suppressor phosphatase and tensin homolog (PTEN) in vitro and in vivo at the endothelial cell (EC) level thus inhibiting PI3K and reducing tumor AKT phosphorylation. These mechanisms normalize tumor vessels by EC reorganization, maturation, pericytes attraction, and lowering progenitor cells recruitment in the tumor. It strongly reduces vascular leakage, tumor growth, drug resistance, and metastasis. ITPP treatment avoids cancer stem-like cell selection, multidrug resistance (MDR) activation and efficiently enhances chemotherapeutic drugs activity. These data show that counteracting tumor hypoxia by stably restoring healthy vasculature is achieved by ITPP treatment, which opens new therapeutic options overcoming hypoxia-related limitations of antiangiogenesis-restricted therapies. By achieving long-term vessels normalization, ITPP should provide the adjuvant treatment required in order to overcome the subtle definition of therapeutic windows for in vivo treatments aimed by the current strategies against angiogenesis-dependent tumors. |
Hermans, Thomas M; Frauenrath, Holger ; Stellacci, Francesco Droplets Out of Equilibrium Journal Article In: SCIENCE, 341 (6143), pp. 243–244, 2013, ISSN: 0036-8075. @article{hermans_droplets_2013, title = {Droplets Out of Equilibrium}, author = {Hermans, Thomas M. and Frauenrath, Holger and Stellacci, Francesco}, doi = {10.1126/science.1241793}, issn = {0036-8075}, year = {2013}, date = {2013-07-01}, journal = {SCIENCE}, volume = {341}, number = {6143}, pages = {243--244}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Khatami, Ehsan ; Pupillo, Guido ; Srednicki, Mark ; Rigol, Marcos Fluctuation-Dissipation Theorem in an Isolated System of Quantum Dipolar Bosons after a Quench Journal Article In: PHYSICAL REVIEW LETTERS, 111 (5), 2013, ISSN: 0031-9007. @article{khatami_fluctuation-dissipation_2013, title = {Fluctuation-Dissipation Theorem in an Isolated System of Quantum Dipolar Bosons after a Quench}, author = {Khatami, Ehsan and Pupillo, Guido and Srednicki, Mark and Rigol, Marcos}, doi = {10.1103/PhysRevLett.111.050403}, issn = {0031-9007}, year = {2013}, date = {2013-07-01}, journal = {PHYSICAL REVIEW LETTERS}, volume = {111}, number = {5}, abstract = {We examine the validity of fluctuation-dissipation relations in isolated quantum systems taken out of equilibrium by a sudden quench. We focus on the dynamics of trapped hard-core bosons in one-dimensional lattices with dipolar interactions whose strength is changed during the quench. We find indications that fluctuation-dissipation relations hold if the system is nonintegrable after the quench, as well as if it is integrable after the quench if the initial state is an equilibrium state of a nonintegrable Hamiltonian. On the other hand, we find indications that they fail if the system is integrable both before and after quenching.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We examine the validity of fluctuation-dissipation relations in isolated quantum systems taken out of equilibrium by a sudden quench. We focus on the dynamics of trapped hard-core bosons in one-dimensional lattices with dipolar interactions whose strength is changed during the quench. We find indications that fluctuation-dissipation relations hold if the system is nonintegrable after the quench, as well as if it is integrable after the quench if the initial state is an equilibrium state of a nonintegrable Hamiltonian. On the other hand, we find indications that they fail if the system is integrable both before and after quenching. |
Mahato, R N; Luelf, H; Siekman, M H; Kersten, S P; Bobbert, P A; de Jong, M P; De Cola, L; van der Wiel, W G Ultrahigh Magnetoresistance at Room Temperature in Molecular Wires Journal Article In: SCIENCE, 341 (6143), pp. 257–260, 2013, ISSN: 0036-8075. @article{mahato_ultrahigh_2013, title = {Ultrahigh Magnetoresistance at Room Temperature in Molecular Wires}, author = {Mahato, R. N. and Luelf, H. and Siekman, M. H. and Kersten, S. P. and Bobbert, P. A. and de Jong, M. P. and De Cola, L. and van der Wiel, W. G.}, doi = {10.1126/science.1237242}, issn = {0036-8075}, year = {2013}, date = {2013-07-01}, journal = {SCIENCE}, volume = {341}, number = {6143}, pages = {257--260}, abstract = {Systems featuring large magnetoresistance (MR) at room temperature and in small magnetic fields are attractive owing to their potential for applications in magnetic field sensing and data storage. Usually, the magnetic properties of materials are exploited to achieve large MR effects. Here, we report on an exceptionally large (textbackslashtextbackslashtextgreater2000%), room-temperature, small-field (a few millitesla) MR effect in one-dimensional, nonmagnetic systems formed by molecular wires embedded in a zeolite host crystal. This ultrahigh MR effect is ascribed to spin blockade in one-dimensional electron transport. Its generic nature offers very good perspectives to exploit the effect in a wide range of low-dimensional systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Systems featuring large magnetoresistance (MR) at room temperature and in small magnetic fields are attractive owing to their potential for applications in magnetic field sensing and data storage. Usually, the magnetic properties of materials are exploited to achieve large MR effects. Here, we report on an exceptionally large (textbackslashtextbackslashtextgreater2000%), room-temperature, small-field (a few millitesla) MR effect in one-dimensional, nonmagnetic systems formed by molecular wires embedded in a zeolite host crystal. This ultrahigh MR effect is ascribed to spin blockade in one-dimensional electron transport. Its generic nature offers very good perspectives to exploit the effect in a wide range of low-dimensional systems. |
Ciesielski, Artur ; Haar, Sebastien ; Benyei, Attila ; Paragi, Gabor ; Guerra, Celia Fonseca ; Bickelhaupt, Matthias F; Masiero, Stefano ; Szolomajer, Janos ; Samori, Paolo ; Spada, Gian Piero ; Kovacs, Lajos Self-Assembly of N-3-Substituted Xanthines in the Solid State and at the Solid-Liquid Interface Journal Article In: LANGMUIR, 29 (24), pp. 7283–7290, 2013, ISSN: 0743-7463. @article{ciesielski_self-assembly_2013, title = {Self-Assembly of N-3-Substituted Xanthines in the Solid State and at the Solid-Liquid Interface}, author = {Ciesielski, Artur and Haar, Sebastien and Benyei, Attila and Paragi, Gabor and Guerra, Celia Fonseca and Bickelhaupt, F. Matthias and Masiero, Stefano and Szolomajer, Janos and Samori, Paolo and Spada, Gian Piero and Kovacs, Lajos}, doi = {10.1021/la304540b}, issn = {0743-7463}, year = {2013}, date = {2013-06-01}, journal = {LANGMUIR}, volume = {29}, number = {24}, pages = {7283--7290}, abstract = {The self-assembly of small molecular modules interacting through noncovalent forces is increasingly being used to generate functional. structures and materials for electronic, catalytic, and biomedical applications. The greatest control over the geometry in H-bond supramolecular architectures, especially in H-bonded supramolecular polymers, can be achieved by exploiting the rich programmability of artificial nucleobases undergoing self-assembly through strong H bonds. Here N-3-functionalized xanthine modules are described, which are capable of self-associating through self-complementary H-bonding patterns to form H-bonded supramolecular ribbons. The self-association of xanthines through directional H bonding between neighboring molecules allows the controlled generation of highly compact ID supramolecular polymeric ribbons on graphite. These architectures have been characterized by scanning tunneling microscopy at the solid liquid interface, corroborated by dispersion-corrected density functional theory (DFT) studies and X-ray diffraction.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The self-assembly of small molecular modules interacting through noncovalent forces is increasingly being used to generate functional. structures and materials for electronic, catalytic, and biomedical applications. The greatest control over the geometry in H-bond supramolecular architectures, especially in H-bonded supramolecular polymers, can be achieved by exploiting the rich programmability of artificial nucleobases undergoing self-assembly through strong H bonds. Here N-3-functionalized xanthine modules are described, which are capable of self-associating through self-complementary H-bonding patterns to form H-bonded supramolecular ribbons. The self-association of xanthines through directional H bonding between neighboring molecules allows the controlled generation of highly compact ID supramolecular polymeric ribbons on graphite. These architectures have been characterized by scanning tunneling microscopy at the solid liquid interface, corroborated by dispersion-corrected density functional theory (DFT) studies and X-ray diffraction. |
Greb, Daniel ; Lehn, Christian ; Rollenske, Soenke LAGRANGIAN FIBRATIONS ON HYPERKAHLER MANIFOLDS - ON A QUESTION OF BEAUVILLE Journal Article In: ANNALES SCIENTIFIQUES DE L ECOLE NORMALE SUPERIEURE, 46 (3), pp. 375–403, 2013, ISSN: 0012-9593. @article{greb_lagrangian_2013, title = {LAGRANGIAN FIBRATIONS ON HYPERKAHLER MANIFOLDS - ON A QUESTION OF BEAUVILLE}, author = {Greb, Daniel and Lehn, Christian and Rollenske, Soenke}, issn = {0012-9593}, year = {2013}, date = {2013-06-01}, journal = {ANNALES SCIENTIFIQUES DE L ECOLE NORMALE SUPERIEURE}, volume = {46}, number = {3}, pages = {375--403}, abstract = {Let X be a compact hyperkahler manifold containing a complex torus L as a Lagrangian subvariety. Beauville posed the question whether X admits a Lagrangian fibration with fibre L. We show that this is indeed the case if X is not projective. If X is projective we find an almost holomorphic Lagrangian fibration with fibre L under additional assumptions on the pair (X, L), which can be formulated in topological or deformation-theoretic terms. Moreover, we show that for any such almost holomorphic Lagrangian fibration there exists a smooth good minimal model, i.e., a hyperkahler manifold birational to X on which the fibration is holomorphic.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Let X be a compact hyperkahler manifold containing a complex torus L as a Lagrangian subvariety. Beauville posed the question whether X admits a Lagrangian fibration with fibre L. We show that this is indeed the case if X is not projective. If X is projective we find an almost holomorphic Lagrangian fibration with fibre L under additional assumptions on the pair (X, L), which can be formulated in topological or deformation-theoretic terms. Moreover, we show that for any such almost holomorphic Lagrangian fibration there exists a smooth good minimal model, i.e., a hyperkahler manifold birational to X on which the fibration is holomorphic. |
Salomon, Adi ; Wang, Shaojun ; Hutchison, James A; Genet, Cyriaque ; Ebbesen, Thomas W Strong Light-Molecule Coupling on Plasmonic Arrays of Different Symmetry Journal Article In: CHEMPHYSCHEM, 14 (9), pp. 1882–1886, 2013, ISSN: 1439-4235. @article{salomon_strong_2013, title = {Strong Light-Molecule Coupling on Plasmonic Arrays of Different Symmetry}, author = {Salomon, Adi and Wang, Shaojun and Hutchison, James A. and Genet, Cyriaque and Ebbesen, Thomas W.}, doi = {10.1002/cphc.201200914}, issn = {1439-4235}, year = {2013}, date = {2013-06-01}, journal = {CHEMPHYSCHEM}, volume = {14}, number = {9}, pages = {1882--1886}, abstract = {The strong coupling of porphyrin J-aggregates to plasmonic nanostructures of different symmetry is investigated. The nanostructures of higher symmetry show the strongest interaction with the molecular layer, suggesting that surface plasmon mode degeneracy plays an important role in the coupling efficiency. At high coupling strengths a new, weakly dispersive mode appears which has recently been predicted theoretically to be due to long-range energy transfer between molecules mediated by surface plasmons. These findings point to new ways for optimizing strong coupling and thereby realize its full potential for molecular and material science.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The strong coupling of porphyrin J-aggregates to plasmonic nanostructures of different symmetry is investigated. The nanostructures of higher symmetry show the strongest interaction with the molecular layer, suggesting that surface plasmon mode degeneracy plays an important role in the coupling efficiency. At high coupling strengths a new, weakly dispersive mode appears which has recently been predicted theoretically to be due to long-range energy transfer between molecules mediated by surface plasmons. These findings point to new ways for optimizing strong coupling and thereby realize its full potential for molecular and material science. |
Ciesielski, Artur ; Szabelski, Pawel J; Rzysko, Wojciech ; Cadeddu, Andrea ; Cook, Timothy R; Stang, Peter J; Samori, Paolo Concentration-Dependent Supramolecular Engineering of Hydrogen-Bonded Nanostructures at Surfaces: Predicting Self-Assembly in 2D Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 135 (18), pp. 6942–6950, 2013, ISSN: 0002-7863. @article{ciesielski_concentration-dependent_2013, title = {Concentration-Dependent Supramolecular Engineering of Hydrogen-Bonded Nanostructures at Surfaces: Predicting Self-Assembly in 2D}, author = {Ciesielski, Artur and Szabelski, Pawel J. and Rzysko, Wojciech and Cadeddu, Andrea and Cook, Timothy R. and Stang, Peter J. and Samori, Paolo}, doi = {10.1021/ja4002025}, issn = {0002-7863}, year = {2013}, date = {2013-05-01}, journal = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, volume = {135}, number = {18}, pages = {6942--6950}, abstract = {We report a joint computational and experimental study on the concentration-dependent self-assembly of a flat C-3-symmetric molecule at surfaces. As a model system we have chosen a rigid molecular module, 1,3,5-tris(pyridine-4-ylethynyl)benzene, which can undergo self-association via hydrogen bonding (H-bonding) to form ordered 2D nanostructures. In particular, the lattice Monte Carlo method, combined with density functional calculations, was employed to explore the spontaneous supramolecular organization of this tripod-shaped molecule under surface confinement. We analyzed the stability of different weak H-bonded patterns and the influence of the concentration of the starting molecule on the 2D supramolecular packing. We found that ordered, densely packed monolayers and 2D porous networks are obtained at high and low concentrations, respectively. A concentration-dependent scanning tunneling microscopy investigation of the molecular self-assembly at a graphite-solution interface revealed supramolecular motifs, which are in perfect agreement with those obtained by simulations. Therefore, our computational approach represents a step forward toward the deterministic prediction of molecular self-assembly at surfaces and interfaces.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report a joint computational and experimental study on the concentration-dependent self-assembly of a flat C-3-symmetric molecule at surfaces. As a model system we have chosen a rigid molecular module, 1,3,5-tris(pyridine-4-ylethynyl)benzene, which can undergo self-association via hydrogen bonding (H-bonding) to form ordered 2D nanostructures. In particular, the lattice Monte Carlo method, combined with density functional calculations, was employed to explore the spontaneous supramolecular organization of this tripod-shaped molecule under surface confinement. We analyzed the stability of different weak H-bonded patterns and the influence of the concentration of the starting molecule on the 2D supramolecular packing. We found that ordered, densely packed monolayers and 2D porous networks are obtained at high and low concentrations, respectively. A concentration-dependent scanning tunneling microscopy investigation of the molecular self-assembly at a graphite-solution interface revealed supramolecular motifs, which are in perfect agreement with those obtained by simulations. Therefore, our computational approach represents a step forward toward the deterministic prediction of molecular self-assembly at surfaces and interfaces. |
Hutchison, James A; Liscio, Andrea ; Schwartz, Tal ; Canaguier-Durand, Antoine ; Genet, Cyriaque ; Palermo, Vincenzo ; Samori, Paolo ; Ebbesen, Thomas W Tuning the Work-Function Via Strong Coupling Journal Article In: ADVANCED MATERIALS, 25 (17), pp. 2481–2485, 2013, ISSN: 0935-9648. @article{hutchison_tuning_2013, title = {Tuning the Work-Function Via Strong Coupling}, author = {Hutchison, James A. and Liscio, Andrea and Schwartz, Tal and Canaguier-Durand, Antoine and Genet, Cyriaque and Palermo, Vincenzo and Samori, Paolo and Ebbesen, Thomas W.}, doi = {10.1002/adma.201203682}, issn = {0935-9648}, year = {2013}, date = {2013-05-01}, journal = {ADVANCED MATERIALS}, volume = {25}, number = {17}, pages = {2481--2485}, abstract = {The tuning of the molecular material work-function via strong coupling with vacuum electromagnetic fields is demonstrated. Kelvin probe microscopy extracts the surface potential (SP) changes of a photochromic molecular film on plasmonic hole arrays and inside Fabry-Perot cavities. Modulating the optical cavity resonance or the photochromic film effectively tunes the work-function, suggesting a new tool for tailoring material properties.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The tuning of the molecular material work-function via strong coupling with vacuum electromagnetic fields is demonstrated. Kelvin probe microscopy extracts the surface potential (SP) changes of a photochromic molecular film on plasmonic hole arrays and inside Fabry-Perot cavities. Modulating the optical cavity resonance or the photochromic film effectively tunes the work-function, suggesting a new tool for tailoring material properties. |
Kalgin, Igor V; Caflisch, Amedeo ; Chekmarev, Sergei F; Karplus, Martin New Insights into the Folding of a beta-Sheet Miniprotein in a Reduced Space of Collective Hydrogen Bond Variables: Application to a Hydrodynamic Analysis of the Folding Flow Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY B, 117 (20), pp. 6092–6105, 2013, ISSN: 1520-6106. @article{kalgin_new_2013, title = {New Insights into the Folding of a beta-Sheet Miniprotein in a Reduced Space of Collective Hydrogen Bond Variables: Application to a Hydrodynamic Analysis of the Folding Flow}, author = {Kalgin, Igor V. and Caflisch, Amedeo and Chekmarev, Sergei F. and Karplus, Martin}, doi = {10.1021/jp401742y}, issn = {1520-6106}, year = {2013}, date = {2013-05-01}, journal = {JOURNAL OF PHYSICAL CHEMISTRY B}, volume = {117}, number = {20}, pages = {6092--6105}, abstract = {A new analysis of the 20 mu s equilibrium folding/unfolding molecular dynamics simulations of the three-stranded antiparallel beta-sheet miniprotein (beta3s) in implicit solvent is presented. The conformation space is reduced in dimensionality by introduction of linear combinations of hydrogen bond distances as the collective variables making use of a specially adapted principal component analysis (PCA); i.e., to make structured conformations more pronounced, only the formed bonds are included in determining the principal components. It is shown that a three-dimensional (3D) subspace gives a meaningful representation of the folding behavior. The first component, to which eight native hydrogen bonds make the major contribution (four in each beta hairpin), is found to play the role of the reaction coordinate for the overall folding process, while the second and third components distinguish the structured conformations. The representative points of the trajectory in the 3D space are grouped into conformational clusters that correspond to locally stable conformations of beta3s identified in earlier work. A simplified kinetic network based on the three components is constructed, and it is complemented by a hydrodynamic analysis. The latter, making use of “passive tracers” in 3D space, indicates that the folding flow is much more complex than suggested by the kinetic network. A 2D representation of streamlines shows there are vortices which correspond to repeated local rearrangement, not only around minima of the free energy surface but also in flat regions between minima. The vortices revealed by the hydrodynamic analysis are apparently not evident in folding pathways generated by transition-path sampling. Making use of the fact that the values of the collective hydrogen bond variables are linearly related to the Cartesian coordinate space, the RMSD between clusters is determined. Interestingly, the transition rates show an approximate exponential correlation with distance in the hydrogen bond subspace. Comparison with the many published studies shows good agreement with the present analysis for the parts that can be compared, supporting the robust character of our understanding of this “hydrogen atom” of protein folding.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new analysis of the 20 mu s equilibrium folding/unfolding molecular dynamics simulations of the three-stranded antiparallel beta-sheet miniprotein (beta3s) in implicit solvent is presented. The conformation space is reduced in dimensionality by introduction of linear combinations of hydrogen bond distances as the collective variables making use of a specially adapted principal component analysis (PCA); i.e., to make structured conformations more pronounced, only the formed bonds are included in determining the principal components. It is shown that a three-dimensional (3D) subspace gives a meaningful representation of the folding behavior. The first component, to which eight native hydrogen bonds make the major contribution (four in each beta hairpin), is found to play the role of the reaction coordinate for the overall folding process, while the second and third components distinguish the structured conformations. The representative points of the trajectory in the 3D space are grouped into conformational clusters that correspond to locally stable conformations of beta3s identified in earlier work. A simplified kinetic network based on the three components is constructed, and it is complemented by a hydrodynamic analysis. The latter, making use of “passive tracers” in 3D space, indicates that the folding flow is much more complex than suggested by the kinetic network. A 2D representation of streamlines shows there are vortices which correspond to repeated local rearrangement, not only around minima of the free energy surface but also in flat regions between minima. The vortices revealed by the hydrodynamic analysis are apparently not evident in folding pathways generated by transition-path sampling. Making use of the fact that the values of the collective hydrogen bond variables are linearly related to the Cartesian coordinate space, the RMSD between clusters is determined. Interestingly, the transition rates show an approximate exponential correlation with distance in the hydrogen bond subspace. Comparison with the many published studies shows good agreement with the present analysis for the parts that can be compared, supporting the robust character of our understanding of this “hydrogen atom” of protein folding. |
Mesto, Ernesto ; Scordari, Fernando ; Lacalamita, Maria ; De Cola, Luisa ; Ragni, Roberta ; Farinola, Gianluca Maria The correct assignment of stereochemistry in di–dichlorido-bisbis[2-(5-benzylsulfonyl)-3-fluoro-2-(pyridin-2-yl) phenyl-2N,C1]iridium(III) toluene monosolvate Journal Article In: ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, 69 (5), pp. 480+, 2013, ISSN: 0108-2701. @article{mesto_correct_2013, title = {The correct assignment of stereochemistry in di–dichlorido-bisbis[2-(5-benzylsulfonyl)-3-fluoro-2-(pyridin-2-yl) phenyl-2N,C1]iridium(III) toluene monosolvate}, author = {Mesto, Ernesto and Scordari, Fernando and Lacalamita, Maria and De Cola, Luisa and Ragni, Roberta and Farinola, Gianluca Maria}, doi = {10.1107/S010827011300663X}, issn = {0108-2701}, year = {2013}, date = {2013-05-01}, journal = {ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS}, volume = {69}, number = {5}, pages = {480+}, abstract = {The title complex, [Ir2(C18H13FNO2S)4Cl2]C7H8, was crystallized from dichloromethane solution under a toluene atmosphere. It is a dimeric complex in which each of the two IrIII centres is octahedrally coordinated by two bridging chloride ligands and by two chelating cyclometalated 2-(4-benzylsulfonyl-2-fluorophenyl)pyridine ligands. The crystal structure analysis unequivocally establishes the trans disposition of the two cyclometalated ligands bound to each IrIII centre, contrary to our previous hypothesis of a cis disposition. The latter was based on the 1HNMR spectra of a series of dimeric benzylsulfonyl-functionalized dichloride-bridged iridium complexes, including the compound described in the present work [Ragni et al. (2009). Chem. Eur. J.15, 136148]. The toluene solvent molecules, embedded in cavities in the crystal structure, are highly disordered and could not be modelled successfully; their contribution was removed from the refinement using the SQUEEZE routine in the program PLATON [Spek (2009). Acta Cryst. D65, 148155].}, keywords = {}, pubstate = {published}, tppubtype = {article} } The title complex, [Ir2(C18H13FNO2S)4Cl2]C7H8, was crystallized from dichloromethane solution under a toluene atmosphere. It is a dimeric complex in which each of the two IrIII centres is octahedrally coordinated by two bridging chloride ligands and by two chelating cyclometalated 2-(4-benzylsulfonyl-2-fluorophenyl)pyridine ligands. The crystal structure analysis unequivocally establishes the trans disposition of the two cyclometalated ligands bound to each IrIII centre, contrary to our previous hypothesis of a cis disposition. The latter was based on the 1HNMR spectra of a series of dimeric benzylsulfonyl-functionalized dichloride-bridged iridium complexes, including the compound described in the present work [Ragni et al. (2009). Chem. Eur. J.15, 136148]. The toluene solvent molecules, embedded in cavities in the crystal structure, are highly disordered and could not be modelled successfully; their contribution was removed from the refinement using the SQUEEZE routine in the program PLATON [Spek (2009). Acta Cryst. D65, 148155]. |
Gorodetski, Yuri ; Drezet, Aurelien ; Genet, Cyriaque ; Ebbesen, Thomas W Generating Far-Field Orbital Angular Momenta from Near-Field Optical Chirality Journal Article In: PHYSICAL REVIEW LETTERS, 110 (20), 2013, ISSN: 0031-9007. @article{gorodetski_generating_2013, title = {Generating Far-Field Orbital Angular Momenta from Near-Field Optical Chirality}, author = {Gorodetski, Yuri and Drezet, Aurelien and Genet, Cyriaque and Ebbesen, Thomas W.}, doi = {10.1103/PhysRevLett.110.203906}, issn = {0031-9007}, year = {2013}, date = {2013-05-01}, journal = {PHYSICAL REVIEW LETTERS}, volume = {110}, number = {20}, abstract = {We demonstrate orbital angular momentum (OAM) transfer by chiral plasmonic nanostructures designed on both sides of a thin suspended metallic membrane. We show how far-field vortex beams with tunable OAM indices can be tailored through nanostructure designs. We reveal the crucial role played by the central aperture that connects the two sides of the membrane from which OAM selection rules are derived in perfect agreement with experimental data.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We demonstrate orbital angular momentum (OAM) transfer by chiral plasmonic nanostructures designed on both sides of a thin suspended metallic membrane. We show how far-field vortex beams with tunable OAM indices can be tailored through nanostructure designs. We reveal the crucial role played by the central aperture that connects the two sides of the membrane from which OAM selection rules are derived in perfect agreement with experimental data. |
Briani, G; Pace, E; Shore, S N; Pupillo, G; Passaro, A; Aiello, S Simulations of micrometeoroid interactions with the Earth atmosphere Journal Article In: ASTRONOMY & ASTROPHYSICS, 552 , 2013, ISSN: 0004-6361. @article{briani_simulations_2013, title = {Simulations of micrometeoroid interactions with the Earth atmosphere}, author = {Briani, G. and Pace, E. and Shore, S. N. and Pupillo, G. and Passaro, A. and Aiello, S.}, doi = {10.1051/0004-6361/201219658}, issn = {0004-6361}, year = {2013}, date = {2013-04-01}, journal = {ASTRONOMY & ASTROPHYSICS}, volume = {552}, abstract = {Aims. Micrometeoroids (cosmic dust with size between a few mu m and similar to 1 mm) dominate the annual extraterrestrial mass flux to the Earth. We investigate the range of physical processes occurring when micrometeoroids traverse the atmosphere. We compute the time (and altitude) dependent mass loss, energy balance, and dynamics to identify which processes determine their survival for a range of entry conditions. Methods. We develop a general numerical model for the micrometeoroid-atmosphere interaction. The equations of motion, energy, and mass balance are simultaneously solved for different entry conditions (e. g. initial radii, incident speeds and angles). Several different physical processes are taken into account in the equation of energy and in the mass balance, in order to understand their relative roles and evolution during the micrometeoroid-atmosphere interaction. In particular, to analyze the micrometeoroid thermal history we include in the energy balance: collisions with atmospheric particles, micrometeoroid radiation emission, evaporation, melting, sputtering and kinetic energy of the ablated mass. Results. Low entry velocities and grazing incidence angles favor micrometeoroid survival. Among those that survive, our model distinguishes (1) micrometeoroids who reach the melting temperature and for which melting is the most effective mass loss mechanism, and (2) micrometeoroids for which ablation due to evaporation causes most of the the mass loss. Melting is the most effective cooling mechanism. Sputtering-induced mass loss is negligible.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Aims. Micrometeoroids (cosmic dust with size between a few mu m and similar to 1 mm) dominate the annual extraterrestrial mass flux to the Earth. We investigate the range of physical processes occurring when micrometeoroids traverse the atmosphere. We compute the time (and altitude) dependent mass loss, energy balance, and dynamics to identify which processes determine their survival for a range of entry conditions. Methods. We develop a general numerical model for the micrometeoroid-atmosphere interaction. The equations of motion, energy, and mass balance are simultaneously solved for different entry conditions (e. g. initial radii, incident speeds and angles). Several different physical processes are taken into account in the equation of energy and in the mass balance, in order to understand their relative roles and evolution during the micrometeoroid-atmosphere interaction. In particular, to analyze the micrometeoroid thermal history we include in the energy balance: collisions with atmospheric particles, micrometeoroid radiation emission, evaporation, melting, sputtering and kinetic energy of the ablated mass. Results. Low entry velocities and grazing incidence angles favor micrometeoroid survival. Among those that survive, our model distinguishes (1) micrometeoroids who reach the melting temperature and for which melting is the most effective mass loss mechanism, and (2) micrometeoroids for which ablation due to evaporation causes most of the the mass loss. Melting is the most effective cooling mechanism. Sputtering-induced mass loss is negligible. |
Szewczyk, Dawid ; Yamamoto, Tetsuya ; Riveline, Daniel Non-monotonic relationships between cell adhesion and protrusions Journal Article In: NEW JOURNAL OF PHYSICS, 15 , 2013, ISSN: 1367-2630. @article{szewczyk_non-monotonic_2013, title = {Non-monotonic relationships between cell adhesion and protrusions}, author = {Szewczyk, Dawid and Yamamoto, Tetsuya and Riveline, Daniel}, doi = {10.1088/1367-2630/15/3/035031}, issn = {1367-2630}, year = {2013}, date = {2013-03-01}, journal = {NEW JOURNAL OF PHYSICS}, volume = {15}, abstract = {Cells probe their environments by extending protrusions: this process is mediated by the polymerization of actin gels at the edge of cells. Although their molecular components have been widely studied, their mesoscopic properties remain to be characterized. In this paper, we show that cell adhesion modulates actin gel dynamics. By changing the grafting density of fibronectin on a surface, we changed the adhesion strength of a cell on this surface. We found that the length of filopodia, the speeds of their growth and the speeds of retrograde flows were non-monotonic functions of the grafting density of fibronectin. The minima of the length and speeds of filopodia and the maximum of the speeds of retrograde flows are found at the same fibronectin density; this implies that there are strong correlations between these parameters. We used a simple model to predict that retrograde flows show non-monotonic behaviors because integrin-fibronectin binding mediates actomyosin and friction forces applied to actin gels. This model also predicts that connectivity of actin gels is responsible for the strong correlations between retrograde flows and filopodial growth. Altogether, our study investigates how actomyosin forces and friction with the substrate influence actin gel dynamics in living cells.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cells probe their environments by extending protrusions: this process is mediated by the polymerization of actin gels at the edge of cells. Although their molecular components have been widely studied, their mesoscopic properties remain to be characterized. In this paper, we show that cell adhesion modulates actin gel dynamics. By changing the grafting density of fibronectin on a surface, we changed the adhesion strength of a cell on this surface. We found that the length of filopodia, the speeds of their growth and the speeds of retrograde flows were non-monotonic functions of the grafting density of fibronectin. The minima of the length and speeds of filopodia and the maximum of the speeds of retrograde flows are found at the same fibronectin density; this implies that there are strong correlations between these parameters. We used a simple model to predict that retrograde flows show non-monotonic behaviors because integrin-fibronectin binding mediates actomyosin and friction forces applied to actin gels. This model also predicts that connectivity of actin gels is responsible for the strong correlations between retrograde flows and filopodial growth. Altogether, our study investigates how actomyosin forces and friction with the substrate influence actin gel dynamics in living cells. |
Barboiu, Mihail ; Lehn, Jean-Marie Constitutional Dynamic Systems Journal Article In: ISRAEL JOURNAL OF CHEMISTRY, 53 (1-2), pp. 9–10, 2013, ISSN: 0021-2148. @article{barboiu_constitutional_2013, title = {Constitutional Dynamic Systems}, author = {Barboiu, Mihail and Lehn, Jean-Marie}, doi = {10.1002/ijch.201310003}, issn = {0021-2148}, year = {2013}, date = {2013-02-01}, journal = {ISRAEL JOURNAL OF CHEMISTRY}, volume = {53}, number = {1-2}, pages = {9--10}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Samori, Paolo ; Hecht, Stefan Gated Systems for Multifunctional Optoelectronic Devices Journal Article In: ADVANCED MATERIALS, 25 (3, SI), pp. 301, 2013, ISSN: 0935-9648. @article{samori_gated_2013, title = {Gated Systems for Multifunctional Optoelectronic Devices}, author = {Samori, Paolo and Hecht, Stefan}, doi = {10.1002/adma.201205030}, issn = {0935-9648}, year = {2013}, date = {2013-01-01}, journal = {ADVANCED MATERIALS}, volume = {25}, number = {3, SI}, pages = {301}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Publications
2014 |
Photoluminescent 3D lanthanide MOFs with a rare (10,3)-d net based on a new tripodal organic linker Journal Article In: CRYSTENGCOMM, 16 (28), pp. 6469–6475, 2014, ISSN: 1466-8033. |
A doubly hermaphroditic chiral crown ether Journal Article In: CRYSTENGCOMM, 16 (27), pp. 5984–5988, 2014, ISSN: 1466-8033. |
A light-induced reversible phase separation and its coupling to a dynamic library of imines Journal Article In: CHEMICAL SCIENCE, 5 (4), pp. 1475–1483, 2014, ISSN: 2041-6520. |
Enhanced Chemical Synthesis at Soft Interfaces: A Universal Reaction-Adsorption Mechanism in Microcompartments Journal Article In: PHYSICAL REVIEW LETTERS, 112 (2), 2014, ISSN: 0031-9007. |
Fluctuation-dissipation theorem in isolated quantum systems out of equilibrium Inproceedings In: 25TH IUPAP CONFERENCE ON COMPUTATIONAL PHYSICS (CCP2013), Russian Acad Sci, Landau Inst Theoret Phys; Int Union Pure & Appl Phys; European Phys Soc; Div Computat Phys American Phys Soc; Russian Fnd Basic Res; Russian Acad Sci, Dept Phys Sci; RSC Grp Co, 2014. |
Transition-Metal-Complexed Catenanes and Rotaxanes: From Dynamic Systems to Functional Molecular Machines Incollection In: {Credi, A; Silvi, S; Venturi, M} (Ed.): MOLECULAR MACHINES AND MOTORS: RECENT ADVANCES AND PERSPECTIVES, 354 , pp. 35–70, 2014, ISBN: 978-3-319-08678-1 978-3-319-08677-4. |
A strong steric hindrance effect on ground state, excited state, and charge separated state properties of a Cu-I-diimine complex captured by X-ray transient absorption spectroscopy Journal Article In: DALTON TRANSACTIONS, 43 (47), pp. 17615–17623, 2014, ISSN: 1477-9226. |
Bio-imaging with neutral luminescent Pt(II) complexes showing metal ... metal interactions Journal Article In: RSC ADVANCES, 4 (49), pp. 25709–25718, 2014, ISSN: 2046-2069. |
Self-assembly of a neutral platinum(II) complex into highly emitting microcrystalline fibers through metallophilic interactions Journal Article In: CHEMICAL COMMUNICATIONS, 50 (55), pp. 7269–7272, 2014, ISSN: 1359-7345. |
New synthetic pathways to the preparation of near-blue emitting heteroleptic Ir(III) N-6 coordinated compounds with microsecond lifetimes Journal Article In: CHEMICAL COMMUNICATIONS, 50 (49), pp. 6461–6463, 2014, ISSN: 1359-7345. |
When self-assembly meets biology: luminescent platinum complexes for imaging applications Journal Article In: CHEMICAL SOCIETY REVIEWS, 43 (12), pp. 4144–4166, 2014, ISSN: 0306-0012. |
Highly efficient blue and deep-blue emitting zwitterionic iridium(III) complexes: synthesis, photophysics and electroluminescence Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 2 (14), pp. 2569–2582, 2014, ISSN: 2050-7526. |
Phase transition of a perovskite strongly coupled to the vacuum field Journal Article In: NANOSCALE, 6 (13), pp. 7243–7248, 2014, ISSN: 2040-3364. |
Charge Transport Over Multiple Length Scales in Supramolecular Fiber Transistors: Single Fiber Versus Ensemble Performance Journal Article In: ADVANCED MATERIALS, 26 (3), pp. 430–435, 2014, ISSN: 0935-9648. |
2013 |
Historical perspective on: Second-harmonic generation from non-dipolar non-centrosymmetric aromatic charge-transfer molecules [Volume 172, Issue 6, 21 September 1990, Pages 440-444] Journal Article In: CHEMICAL PHYSICS LETTERS, 589 , pp. 46, 2013, ISSN: 0009-2614. |
Second-harmonic generation from non-dipolar non-centrosymmetric aromatic charge-transfer molecules (Reprinted from Chemical Physics Letters) Journal Article In: CHEMICAL PHYSICS LETTERS, 589 , pp. 47–50, 2013, ISSN: 0009-2614. |
`Single molecule': theory and experiments, an introduction Journal Article In: JOURNAL OF NANOBIOTECHNOLOGY, 11 (1), 2013, ISSN: 1477-3155. |
Mechanical separation of chiral dipoles by chiral light Journal Article In: NEW JOURNAL OF PHYSICS, 15 , 2013, ISSN: 1367-2630. |
Quantitative Analysis of Scanning Tunneling Microscopy Images of Mixed-Ligand-Functionalized Nanoparticles Journal Article In: LANGMUIR, 29 (45), pp. 13723–13734, 2013, ISSN: 0743-7463. |
A gating mechanism of pentameric ligand-gated ion channels Journal Article In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 110 (42), pp. E3987–E3996, 2013, ISSN: 0027-8424. |
Cluster Luttinger Liquids of Rydberg-Dressed Atoms in Optical Lattices Journal Article In: PHYSICAL REVIEW LETTERS, 111 (16), 2013, ISSN: 0031-9007. |
Cyclodextrin-Modified Zeolites: Host-Guest Surface Chemistry for the Construction of Multifunctional Nanocontainers Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 19 (44), pp. 14925–14930, 2013, ISSN: 0947-6539. |
Efficient Near-UV Emitters Based on Cationic Bis-Pincer Iridium(III) Carbene Complexes Journal Article In: INORGANIC CHEMISTRY, 52 (19), pp. 10756–10765, 2013, ISSN: 0020-1669. |
Increasing the oxygen load by treatment with myo-inositol trispyrophosphate reduces growth of colon cancer and modulates the intestine homeobox gene Cdx2 Journal Article In: ONCOGENE, 32 (36), pp. 4313–4318, 2013, ISSN: 0950-9232. |
Enhanced optomechanical readout using optical coalescence Journal Article In: PHYSICAL REVIEW A, 88 (3), 2013, ISSN: 1050-2947. |
Control of Surface Charges by Radicals as a Principle of Antistatic Polymers Protecting Electronic Circuitry Journal Article In: SCIENCE, 341 (6152), pp. 1368–1371, 2013, ISSN: 0036-8075. |
Use of Cleavable Coordinating Rings as Protective Groups in the Synthesis of a Rotaxane with an Axis that Incorporates More Chelating Groups Than Threaded Macrocycles Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 19 (38), pp. 12815–12823, 2013, ISSN: 0947-6539. |
Force and torque on an electric dipole by spinning light fields Journal Article In: PHYSICAL REVIEW A, 88 (3), 2013, ISSN: 1050-2947. |
Sorting Nanoparticles with Intertwined Plasmonic and Thermo-Hydrodynamical Forces Journal Article In: NANO LETTERS, 13 (9), pp. 4230–4235, 2013, ISSN: 1530-6984. |
Photoexpulsion of Surface-Grafted Ruthenium Complexes and Subsequent Release of Cytotoxic Cargos to Cancer Cells from Mesoporous Silica Nanoparticles Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 135 (31), pp. 11603–11613, 2013, ISSN: 0002-7863. |
Double Dynamic Supramolecular Polymers of Covalent Oligo-Dynamers Journal Article In: MACROMOLECULES, 46 (14), pp. 5664–5671, 2013, ISSN: 0024-9297. |
Perspectives in chemistry: from supramolecular chemistry towards adaptive chemistry Journal Article In: FEBS JOURNAL, 280 (1, SI), pp. 1–2, 2013, ISSN: 1742-464X. |
Synthetic polyamines promote rapid lamellipodial growth by regulating actin dynamics Journal Article In: NATURE COMMUNICATIONS, 4 , 2013, ISSN: 2041-1723. |
The Tris-Urea Motif and Its Incorporation into Polydimethylsiloxane-Based Supramolecular Materials Presenting Self-Healing Features Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 19 (27), pp. 8814–8820, 2013, ISSN: 0947-6539. |
Stable tumor vessel normalization with pO(2) increase and endothelial PTEN activation by inositol trispyrophosphate brings novel tumor treatment Journal Article In: JOURNAL OF MOLECULAR MEDICINE-JMM, 91 (7), pp. 883–899, 2013, ISSN: 0946-2716. |
Droplets Out of Equilibrium Journal Article In: SCIENCE, 341 (6143), pp. 243–244, 2013, ISSN: 0036-8075. |
Fluctuation-Dissipation Theorem in an Isolated System of Quantum Dipolar Bosons after a Quench Journal Article In: PHYSICAL REVIEW LETTERS, 111 (5), 2013, ISSN: 0031-9007. |
Ultrahigh Magnetoresistance at Room Temperature in Molecular Wires Journal Article In: SCIENCE, 341 (6143), pp. 257–260, 2013, ISSN: 0036-8075. |
Self-Assembly of N-3-Substituted Xanthines in the Solid State and at the Solid-Liquid Interface Journal Article In: LANGMUIR, 29 (24), pp. 7283–7290, 2013, ISSN: 0743-7463. |
LAGRANGIAN FIBRATIONS ON HYPERKAHLER MANIFOLDS - ON A QUESTION OF BEAUVILLE Journal Article In: ANNALES SCIENTIFIQUES DE L ECOLE NORMALE SUPERIEURE, 46 (3), pp. 375–403, 2013, ISSN: 0012-9593. |
Strong Light-Molecule Coupling on Plasmonic Arrays of Different Symmetry Journal Article In: CHEMPHYSCHEM, 14 (9), pp. 1882–1886, 2013, ISSN: 1439-4235. |
Concentration-Dependent Supramolecular Engineering of Hydrogen-Bonded Nanostructures at Surfaces: Predicting Self-Assembly in 2D Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 135 (18), pp. 6942–6950, 2013, ISSN: 0002-7863. |
Tuning the Work-Function Via Strong Coupling Journal Article In: ADVANCED MATERIALS, 25 (17), pp. 2481–2485, 2013, ISSN: 0935-9648. |
New Insights into the Folding of a beta-Sheet Miniprotein in a Reduced Space of Collective Hydrogen Bond Variables: Application to a Hydrodynamic Analysis of the Folding Flow Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY B, 117 (20), pp. 6092–6105, 2013, ISSN: 1520-6106. |
The correct assignment of stereochemistry in di–dichlorido-bisbis[2-(5-benzylsulfonyl)-3-fluoro-2-(pyridin-2-yl) phenyl-2N,C1]iridium(III) toluene monosolvate Journal Article In: ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, 69 (5), pp. 480+, 2013, ISSN: 0108-2701. |
Generating Far-Field Orbital Angular Momenta from Near-Field Optical Chirality Journal Article In: PHYSICAL REVIEW LETTERS, 110 (20), 2013, ISSN: 0031-9007. |
Simulations of micrometeoroid interactions with the Earth atmosphere Journal Article In: ASTRONOMY & ASTROPHYSICS, 552 , 2013, ISSN: 0004-6361. |
Non-monotonic relationships between cell adhesion and protrusions Journal Article In: NEW JOURNAL OF PHYSICS, 15 , 2013, ISSN: 1367-2630. |
Constitutional Dynamic Systems Journal Article In: ISRAEL JOURNAL OF CHEMISTRY, 53 (1-2), pp. 9–10, 2013, ISSN: 0021-2148. |
Gated Systems for Multifunctional Optoelectronic Devices Journal Article In: ADVANCED MATERIALS, 25 (3, SI), pp. 301, 2013, ISSN: 0935-9648. |