2014 |
Hellal, Malik ; Falk, Florian C; Wolf, Elena ; Dryzhakov, Marian ; Moran, Joseph Breaking the dichotomy of reactivity vs. chemoselectivity in catalytic S(N)1 reactions of alcohols Journal Article In: ORGANIC & BIOMOLECULAR CHEMISTRY, 12 (31), pp. 5990–5994, 2014, ISSN: 1477-0520. @article{hellal_breaking_2014, title = {Breaking the dichotomy of reactivity vs. chemoselectivity in catalytic S(N)1 reactions of alcohols}, author = {Hellal, Malik and Falk, Florian C. and Wolf, Elena and Dryzhakov, Marian and Moran, Joseph}, doi = {10.1039/c4ob01265h}, issn = {1477-0520}, year = {2014}, date = {2014-08-01}, journal = {ORGANIC & BIOMOLECULAR CHEMISTRY}, volume = {12}, number = {31}, pages = {5990--5994}, abstract = {The inability to decouple Lewis acid catalysis from undesirable Bronsted acid catalysed side reactions when water or other protic functional groups are necessarily present has forced chemists to choose between powerful but harsh catalysts or poor but mild ones, a dichotomy that restricts the substrate scope of dehydrative transformations such as the direct S(N)1 reaction of alcohols. A systematic survey of Lewis and Bronsted acids reveals that the strong non-hydrolyzable Lewis acid B(C6F5)(3) leads to highly chemoselective alcohol substitution in the presence of acid-sensitive alkenes, protecting groups and other functional groups without the typical compromise in reaction rates, substrate scope and catalyst loading.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The inability to decouple Lewis acid catalysis from undesirable Bronsted acid catalysed side reactions when water or other protic functional groups are necessarily present has forced chemists to choose between powerful but harsh catalysts or poor but mild ones, a dichotomy that restricts the substrate scope of dehydrative transformations such as the direct S(N)1 reaction of alcohols. A systematic survey of Lewis and Bronsted acids reveals that the strong non-hydrolyzable Lewis acid B(C6F5)(3) leads to highly chemoselective alcohol substitution in the presence of acid-sensitive alkenes, protecting groups and other functional groups without the typical compromise in reaction rates, substrate scope and catalyst loading. |
Taly, Antoine ; Henin, Jerome ; Changeux, Jean-Pierre ; Cecchini, Marco Allosteric regulation of pentameric ligand-gated ion channels An emerging mechanistic perspective Journal Article In: CHANNELS, 8 (4), pp. 350–360, 2014, ISSN: 1933-6950. @article{taly_allosteric_2014, title = {Allosteric regulation of pentameric ligand-gated ion channels An emerging mechanistic perspective}, author = {Taly, Antoine and Henin, Jerome and Changeux, Jean-Pierre and Cecchini, Marco}, doi = {10.4161/chan.29444}, issn = {1933-6950}, year = {2014}, date = {2014-08-01}, journal = {CHANNELS}, volume = {8}, number = {4}, pages = {350--360}, abstract = {Pentameric ligand-gated ion channels (pLGICs) play a central role in intercellular communications in the nervous system by converting the binding of a chemical messenger-a neurotransmitter-into an ion flux through the postsynaptic membrane. They are oligomeric assemblies that provide prototypical examples of allosterically regulated integral membrane proteins. Here, we present an overview of the most recent advances on the signal transduction mechanism based on the X-ray structures of both prokaryotic and invertebrate eukaryotic pLGICs and atomistic Molecular Dynamics simulations. The present results suggest that ion gating involves a large structural reorganization of the molecule mediated by two distinct quaternary transitions, a global twisting and the blooming of the extracellular domain, which can be modulated by ligand binding at the topographically distinct orthosteric and allosteric sites. The emerging model of gating is consistent with a wealth of functional studies and will boost the development of novel pharmacological strategies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Pentameric ligand-gated ion channels (pLGICs) play a central role in intercellular communications in the nervous system by converting the binding of a chemical messenger-a neurotransmitter-into an ion flux through the postsynaptic membrane. They are oligomeric assemblies that provide prototypical examples of allosterically regulated integral membrane proteins. Here, we present an overview of the most recent advances on the signal transduction mechanism based on the X-ray structures of both prokaryotic and invertebrate eukaryotic pLGICs and atomistic Molecular Dynamics simulations. The present results suggest that ion gating involves a large structural reorganization of the molecule mediated by two distinct quaternary transitions, a global twisting and the blooming of the extracellular domain, which can be modulated by ligand binding at the topographically distinct orthosteric and allosteric sites. The emerging model of gating is consistent with a wealth of functional studies and will boost the development of novel pharmacological strategies. |
Luelf, Henning ; Bertucci, Alessandro ; Septiadi, Dedy ; Corradini, Roberto ; De Cola, Luisa Multifunctional Inorganic Nanocontainers for DNA and Drug Delivery into Living Cells Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (35, SI), pp. 10900–10904, 2014, ISSN: 0947-6539. @article{luelf_multifunctional_2014, title = {Multifunctional Inorganic Nanocontainers for DNA and Drug Delivery into Living Cells}, author = {Luelf, Henning and Bertucci, Alessandro and Septiadi, Dedy and Corradini, Roberto and De Cola, Luisa}, doi = {10.1002/chem.201403232}, issn = {0947-6539}, year = {2014}, date = {2014-08-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {20}, number = {35, SI}, pages = {10900--10904}, abstract = {The design and synthesis of multifunctional nanomaterials could lead to applications relevant for biomedicine. Manufacturing porous particles to make them able to carry bioactive molecules into living cells represents a substantial goal towards the development of powerful tools for nanomedicine. This work describes a first example of using zeolite-L crystals as multifunctional nanocontainers to simultaneously deliver DNA oligonucleotides and organic molecules into living cells. Multifunctional zeolite-L was prepared by filling the pore system with guest molecules, whilst DNA was adsorbed electrostatically on their surface. The release kinetics of DNA and of the guest molecules into living cells was studied to prove the multiple-drug-delivery ability of the system. The localization of all the components in different cellular compartments was followed. The presented system may be a prototype for the development of novel nanoparticles for drug delivery and gene therapy.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The design and synthesis of multifunctional nanomaterials could lead to applications relevant for biomedicine. Manufacturing porous particles to make them able to carry bioactive molecules into living cells represents a substantial goal towards the development of powerful tools for nanomedicine. This work describes a first example of using zeolite-L crystals as multifunctional nanocontainers to simultaneously deliver DNA oligonucleotides and organic molecules into living cells. Multifunctional zeolite-L was prepared by filling the pore system with guest molecules, whilst DNA was adsorbed electrostatically on their surface. The release kinetics of DNA and of the guest molecules into living cells was studied to prove the multiple-drug-delivery ability of the system. The localization of all the components in different cellular compartments was followed. The presented system may be a prototype for the development of novel nanoparticles for drug delivery and gene therapy. |
Wang, Chengliang ; Fang, Yaoguo ; Wen, Liaoyong ; Zhou, Min ; Xu, Yang ; Zhao, Huaping ; De Cola, Luisa ; Hu, Wenping ; Lei, Yong Vectorial Diffusion for Facile Solution-Processed Self-Assembly of Insoluble Semiconductors: A Case Study on Metal Phthalocyanines Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (35, SI), pp. 10990–10995, 2014, ISSN: 0947-6539. @article{wang_vectorial_2014, title = {Vectorial Diffusion for Facile Solution-Processed Self-Assembly of Insoluble Semiconductors: A Case Study on Metal Phthalocyanines}, author = {Wang, Chengliang and Fang, Yaoguo and Wen, Liaoyong and Zhou, Min and Xu, Yang and Zhao, Huaping and De Cola, Luisa and Hu, Wenping and Lei, Yong}, doi = {10.1002/chem.201403702}, issn = {0947-6539}, year = {2014}, date = {2014-08-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {20}, number = {35, SI}, pages = {10990--10995}, abstract = {Solution processibility is one of the most intriguing properties of organic semiconductors. However, it is difficult to find a suitable solvent and solution process for most semiconductors. For example, metal phthalocyanines (MPcs) are only soluble in non-volatile solvents, which prevent their applications from solution process. For the first time, vectorial diffusion is utilized for solution processing of MPcs. The obtained large F16CuPc and alpha-phase CuPc crystals and the efficient phase separation of them suggest the vectorial diffusion process is as slow as a self-assembly process, which is helpful to yield large crystals and purify the semiconductors. This method, which only uses common commercial solvents without any complex and expensive instruments and hightemperature operation, provides a facile approach for purification of organic semiconductors and growth of their crystals in large quantities.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Solution processibility is one of the most intriguing properties of organic semiconductors. However, it is difficult to find a suitable solvent and solution process for most semiconductors. For example, metal phthalocyanines (MPcs) are only soluble in non-volatile solvents, which prevent their applications from solution process. For the first time, vectorial diffusion is utilized for solution processing of MPcs. The obtained large F16CuPc and alpha-phase CuPc crystals and the efficient phase separation of them suggest the vectorial diffusion process is as slow as a self-assembly process, which is helpful to yield large crystals and purify the semiconductors. This method, which only uses common commercial solvents without any complex and expensive instruments and hightemperature operation, provides a facile approach for purification of organic semiconductors and growth of their crystals in large quantities. |
De Cola, Luisa ; Mauro, Matteo ; Aliprandi, Alessandro ; Septiadi, Dedy Assembling metal complexes for tuning their photophysical properties Journal Article In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 248 , 2014, ISSN: 0065-7727. @article{de_cola_assembling_2014, title = {Assembling metal complexes for tuning their photophysical properties}, author = {De Cola, Luisa and Mauro, Matteo and Aliprandi, Alessandro and Septiadi, Dedy}, issn = {0065-7727}, year = {2014}, date = {2014-08-01}, journal = {ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY}, volume = {248}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
De Cola, Luisa Porous (nano)materials: Properties, self-assembly, and applications Journal Article In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 248 , 2014, ISSN: 0065-7727. @article{de_cola_porous_2014, title = {Porous (nano)materials: Properties, self-assembly, and applications}, author = {De Cola, Luisa}, issn = {0065-7727}, year = {2014}, date = {2014-08-01}, journal = {ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY}, volume = {248}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Rosticher, Celine ; De Cola, Luisa ; Donato, Loic Design, synthesis and characterization luminescent new materials by self-assembly of copper nanoclusters/Cu(I) complexes in nanoporous materials Journal Article In: LUMINESCENCE, 29 (1, SI), pp. 43–44, 2014, ISSN: 1522-7235. @article{rosticher_design_2014, title = {Design, synthesis and characterization luminescent new materials by self-assembly of copper nanoclusters/Cu(I) complexes in nanoporous materials}, author = {Rosticher, Celine and De Cola, Luisa and Donato, Loic}, issn = {1522-7235}, year = {2014}, date = {2014-08-01}, journal = {LUMINESCENCE}, volume = {29}, number = {1, SI}, pages = {43--44}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Osella, Silvio ; Samori, Paolo ; Cornil, Jerome Photoswitching Azobenzene Derivatives in Single Molecule Junctions: A Theoretical Insight into the I/V Characteristics Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY C, 118 (32), pp. 18721–18729, 2014, ISSN: 1932-7447. @article{osella_photoswitching_2014, title = {Photoswitching Azobenzene Derivatives in Single Molecule Junctions: A Theoretical Insight into the I/V Characteristics}, author = {Osella, Silvio and Samori, Paolo and Cornil, Jerome}, doi = {10.1021/jp504582a}, issn = {1932-7447}, year = {2014}, date = {2014-08-01}, journal = {JOURNAL OF PHYSICAL CHEMISTRY C}, volume = {118}, number = {32}, pages = {18721--18729}, abstract = {The I/V characteristics of several photoswitching azobenzene derivatives connected to two gold electrodes to form single-molecule junctions are investigated within the nonequilibrium Green's function formalism coupled to density functional theory. We focus here on the changes in the I/V characteristics as a function of the length and degree of fluorination of the conjugated backbones as well as different coupling strength at the electrodes (chemisorption versus physisorption) upon trans/cis isomerization. The calculations illustrate that the conductance is larger for the trans isomer when the molecule is chemisorbed at both electrodes. However, a larger conduction for the cis isomer is found in the presence of a physisorbed contact at one electrode for specific geometries of the isomer in the junction, in full consistency with the apparent discrepancies observed among experimental measurements. The I/V curves are fully rationalized by analyzing the evolution under bias of the shape of the transmitting molecular orbitals.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The I/V characteristics of several photoswitching azobenzene derivatives connected to two gold electrodes to form single-molecule junctions are investigated within the nonequilibrium Green's function formalism coupled to density functional theory. We focus here on the changes in the I/V characteristics as a function of the length and degree of fluorination of the conjugated backbones as well as different coupling strength at the electrodes (chemisorption versus physisorption) upon trans/cis isomerization. The calculations illustrate that the conductance is larger for the trans isomer when the molecule is chemisorbed at both electrodes. However, a larger conduction for the cis isomer is found in the presence of a physisorbed contact at one electrode for specific geometries of the isomer in the junction, in full consistency with the apparent discrepancies observed among experimental measurements. The I/V curves are fully rationalized by analyzing the evolution under bias of the shape of the transmitting molecular orbitals. |
Masillamani, Appan Merari ; Osella, Silvio ; Liscio, Andrea ; Fenwick, Oliver ; Reinders, Federica ; Mayor, Marcel ; Palermo, Vincenzo ; Cornil, Jerome ; Samori, Paolo Light-induced reversible modification of the work function of a new perfluorinated biphenyl azobenzene chemisorbed on Au (111) Journal Article In: NANOSCALE, 6 (15), pp. 8969–8977, 2014, ISSN: 2040-3364. @article{masillamani_light-induced_2014, title = {Light-induced reversible modification of the work function of a new perfluorinated biphenyl azobenzene chemisorbed on Au (111)}, author = {Masillamani, Appan Merari and Osella, Silvio and Liscio, Andrea and Fenwick, Oliver and Reinders, Federica and Mayor, Marcel and Palermo, Vincenzo and Cornil, Jerome and Samori, Paolo}, doi = {10.1039/c4nr01880j}, issn = {2040-3364}, year = {2014}, date = {2014-08-01}, journal = {NANOSCALE}, volume = {6}, number = {15}, pages = {8969--8977}, abstract = {We describe the synthesis of a novel biphenyl azobenzene derivative exhibiting: (i) a protected thiol anchoring group in the a-position to readily form self-assembled monolayers (SAMs) on Au surfaces; and (ii) a terminal perfluorinated benzene ring in the a-position to modify the surface properties. The design of this molecule ensured both an efficient in situ photoswitching between the trans and cis isomers when chemisorbed on Au(111), due to the presence of a biphenyl bridge between the thiol protected anchoring group and the azo dye, and a significant variation of the work function of the SAM in the two isomeric states, induced by the perfluorinated phenyl head group. By exploiting the light responsive nature of the chemisorbed molecules, it is possible to dynamically modify in situ the work function of the SAM-covered electrode, as demonstrated both experimentally and by quantum-chemical calculations, revealing changes in work function up to 220 meV. These findings are relevant for tuning the work function of metallic electrodes, and hence to dynamically modulate charge injection at metal-semiconductor interfaces for organic opto-electronic applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We describe the synthesis of a novel biphenyl azobenzene derivative exhibiting: (i) a protected thiol anchoring group in the a-position to readily form self-assembled monolayers (SAMs) on Au surfaces; and (ii) a terminal perfluorinated benzene ring in the a-position to modify the surface properties. The design of this molecule ensured both an efficient in situ photoswitching between the trans and cis isomers when chemisorbed on Au(111), due to the presence of a biphenyl bridge between the thiol protected anchoring group and the azo dye, and a significant variation of the work function of the SAM in the two isomeric states, induced by the perfluorinated phenyl head group. By exploiting the light responsive nature of the chemisorbed molecules, it is possible to dynamically modify in situ the work function of the SAM-covered electrode, as demonstrated both experimentally and by quantum-chemical calculations, revealing changes in work function up to 220 meV. These findings are relevant for tuning the work function of metallic electrodes, and hence to dynamically modulate charge injection at metal-semiconductor interfaces for organic opto-electronic applications. |
Mifkova, Alzbeta ; Kodet, Ondrej ; Szabo, Pavol ; Kucera, Jan ; Dvorankova, Barbora ; Andre, Sabine ; Koripelly, Girish ; Gabius, Hans-Joachim ; Lehn, Jean-Marie ; Smetana Jr., Karel Synthetic Polyamine BPA-C8 Inhibits TGF-beta 1-Mediated Conversion of Human Dermal Fibroblast to Myofibroblasts and Establishment of Galectin-1-Rich Extracellular Matrix in Vitro Journal Article In: CHEMBIOCHEM, 15 (10), pp. 1465–1470, 2014, ISSN: 1439-4227. @article{mifkova_synthetic_2014, title = {Synthetic Polyamine BPA-C8 Inhibits TGF-beta 1-Mediated Conversion of Human Dermal Fibroblast to Myofibroblasts and Establishment of Galectin-1-Rich Extracellular Matrix in Vitro}, author = {Mifkova, Alzbeta and Kodet, Ondrej and Szabo, Pavol and Kucera, Jan and Dvorankova, Barbora and Andre, Sabine and Koripelly, Girish and Gabius, Hans-Joachim and Lehn, Jean-Marie and Smetana, Jr., Karel}, doi = {10.1002/cbic.201402087}, issn = {1439-4227}, year = {2014}, date = {2014-07-01}, journal = {CHEMBIOCHEM}, volume = {15}, number = {10}, pages = {1465--1470}, abstract = {Cancer-associated fibroblasts (CAFs) play a role in the progression of malignant tumors. They are formed by conversion of fibroblasts to smooth muscle alpha-actin-positive (SMA-positive) myofibroblasts. Polyamines are known to change the arrangement of the actin cytoskeleton by binding to the anionic actin. We tested the effect of the synthetic polyamine BPA-C8 on the transition of human dermal fibroblasts to myofibroblasts induced either by TGF-beta 1 alone or by TGF-beta 1 together with adhesion/growth-regulatory galectin-1. Pre-existing CAFs, myofi-broblasts from pancreatitis, and rat smooth muscle cells were also exposed to BPA-C8. BPA-C8 impaired myofibroblast formation from activated fibroblasts, but it had no effect on cells already expressing SMA. BPA-C8 also reduced the occurrence of an extracellular matrix around the activated fibroblasts. The reported data thus extend current insights into polyamine activity, adding interference with tumor progression to the tumor-promoting processes warranting study.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cancer-associated fibroblasts (CAFs) play a role in the progression of malignant tumors. They are formed by conversion of fibroblasts to smooth muscle alpha-actin-positive (SMA-positive) myofibroblasts. Polyamines are known to change the arrangement of the actin cytoskeleton by binding to the anionic actin. We tested the effect of the synthetic polyamine BPA-C8 on the transition of human dermal fibroblasts to myofibroblasts induced either by TGF-beta 1 alone or by TGF-beta 1 together with adhesion/growth-regulatory galectin-1. Pre-existing CAFs, myofi-broblasts from pancreatitis, and rat smooth muscle cells were also exposed to BPA-C8. BPA-C8 impaired myofibroblast formation from activated fibroblasts, but it had no effect on cells already expressing SMA. BPA-C8 also reduced the occurrence of an extracellular matrix around the activated fibroblasts. The reported data thus extend current insights into polyamine activity, adding interference with tumor progression to the tumor-promoting processes warranting study. |
Vantomme, Ghislaine ; Jiang, Shimei ; Lehn, Jean-Marie Adaptation in Constitutional Dynamic Libraries and Networks, Switching between Orthogonal Metalloselection and Photoselection Processes Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 136 (26), pp. 9509–9518, 2014, ISSN: 0002-7863. @article{vantomme_adaptation_2014, title = {Adaptation in Constitutional Dynamic Libraries and Networks, Switching between Orthogonal Metalloselection and Photoselection Processes}, author = {Vantomme, Ghislaine and Jiang, Shimei and Lehn, Jean-Marie}, doi = {10.1021/ja504813r}, issn = {0002-7863}, year = {2014}, date = {2014-07-01}, journal = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, volume = {136}, number = {26}, pages = {9509--9518}, abstract = {Constitutional dynamic libraries of hydrazones (a)A(b)B and acylhydrazones (a)A(c)C undergo reorganization and adaptation in response to a chemical effector (metal cations) or a physical stimulus (light). The set of hydrazones [(1)A(1)B, (1)A(2)B, (2)A(1)B, (2)A(2)B] undergoes metalloselection on addition of zinc cations which drive the amplification of Zn((1)A(2)B)(2) by selection of the fittest component (1)A(2)B. The set of acylhydrazones E-(1)A(1)C, (1)A(2)C, (2)A(1)C, (2)A(2)C] undergoes photoselection by irradiation of the system, which causes photoisomerization of E-(1)A(1)C into Z-(1)A(1)C with amplification of the latter. The set of acyl hydrazones [E-(1)A(1)C, (1)A(3)C, (2)A(1)C, (2)A(3)C] undergoes a dual adaptation via component exchange and selection in response to two orthogonal external agents: a chemical effector, metal cations, and a physical stimulus, light irradiation. Metalloselection takes place on addition of zinc amplification of Zn((1)A(3)C)(2) by selection of the fittest constituent (1)A(3)C. Photoselection is obtained on irradiation of the acylhydrazones that leads to photoisomerization from E-(1)A(1)C to Z-(1)A(1)C configuration with amplification of the latter. These changes may be represented by square constitutional dynamic networks that display up-regulation of the pairs of agonists ((1)A(2)B, (2)A(1)B), (Z-(1)A(1)C, (2)A(2)C), ((1)A(3)C, (2)A(1)C), (Z-(1)A(1)C, (2)A(3)C) and the simultaneous down-regulation of the pairs of antagonists ((1)A(1)B, (2)A(2)B), ((1)A(2)C, (2)A(1)C), (E-(1)A(1)C, (2)A(3)C), ((1)A(3)C, (2)A(1)C). The orthogonal dual adaptation undergone by the set of acylhydrazones amounts to a network switching process.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Constitutional dynamic libraries of hydrazones (a)A(b)B and acylhydrazones (a)A(c)C undergo reorganization and adaptation in response to a chemical effector (metal cations) or a physical stimulus (light). The set of hydrazones [(1)A(1)B, (1)A(2)B, (2)A(1)B, (2)A(2)B] undergoes metalloselection on addition of zinc cations which drive the amplification of Zn((1)A(2)B)(2) by selection of the fittest component (1)A(2)B. The set of acylhydrazones E-(1)A(1)C, (1)A(2)C, (2)A(1)C, (2)A(2)C] undergoes photoselection by irradiation of the system, which causes photoisomerization of E-(1)A(1)C into Z-(1)A(1)C with amplification of the latter. The set of acyl hydrazones [E-(1)A(1)C, (1)A(3)C, (2)A(1)C, (2)A(3)C] undergoes a dual adaptation via component exchange and selection in response to two orthogonal external agents: a chemical effector, metal cations, and a physical stimulus, light irradiation. Metalloselection takes place on addition of zinc amplification of Zn((1)A(3)C)(2) by selection of the fittest constituent (1)A(3)C. Photoselection is obtained on irradiation of the acylhydrazones that leads to photoisomerization from E-(1)A(1)C to Z-(1)A(1)C configuration with amplification of the latter. These changes may be represented by square constitutional dynamic networks that display up-regulation of the pairs of agonists ((1)A(2)B, (2)A(1)B), (Z-(1)A(1)C, (2)A(2)C), ((1)A(3)C, (2)A(1)C), (Z-(1)A(1)C, (2)A(3)C) and the simultaneous down-regulation of the pairs of antagonists ((1)A(1)B, (2)A(2)B), ((1)A(2)C, (2)A(1)C), (E-(1)A(1)C, (2)A(3)C), ((1)A(3)C, (2)A(1)C). The orthogonal dual adaptation undergone by the set of acylhydrazones amounts to a network switching process. |
Niess, Frederic ; Duplan, Vincent ; Sauvage, Jean-Pierre Molecular Muscles: From Species in Solution to Materials and Devices Journal Article In: CHEMISTRY LETTERS, 43 (7), pp. 964–974, 2014, ISSN: 0366-7022. @article{niess_molecular_2014, title = {Molecular Muscles: From Species in Solution to Materials and Devices}, author = {Niess, Frederic and Duplan, Vincent and Sauvage, Jean-Pierre}, doi = {10.1246/cl.140315}, issn = {0366-7022}, year = {2014}, date = {2014-07-01}, journal = {CHEMISTRY LETTERS}, volume = {43}, number = {7}, pages = {964--974}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Caballero, David ; Voituriez, Raphael ; Riveline, Daniel Protrusion Fluctuations Direct Cell Motion Journal Article In: BIOPHYSICAL JOURNAL, 107 (1), pp. 34–42, 2014, ISSN: 0006-3495. @article{caballero_protrusion_2014, title = {Protrusion Fluctuations Direct Cell Motion}, author = {Caballero, David and Voituriez, Raphael and Riveline, Daniel}, doi = {10.1016/j.bpj.2014.05.002}, issn = {0006-3495}, year = {2014}, date = {2014-07-01}, journal = {BIOPHYSICAL JOURNAL}, volume = {107}, number = {1}, pages = {34--42}, abstract = {Many physiological phenomena involve directional cell migration. It is usually attributed to chemical gradients in vivo. Recently, other cues have been shown to guide cells in vitro, including stiffness/adhesion gradients or micropatterned adhesive motifs. However, the cellular mechanism leading to these biased migrations remains unknown, and, often, even the direction of motion is unpredictable. In this study, we show the key role of fluctuating protrusions on ratchet-like structures in driving NIH3T3 cell migration. We identified the concept of efficient protrusion and an associated direction index. Our analysis of the protrusion statistics facilitated the quantitative prediction of cell trajectories in all investigated conditions. We varied the external cues by changing the adhesive patterns. We also modified the internal cues using drug treatments, which modified the protrusion activity. Stochasticity affects the short- and long-term steps. We developed a theoretical model showing that an asymmetry in the protrusion fluctuations is sufficient for predicting all measures associated with the long-term motion, which can be described as a biased persistent random walk.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Many physiological phenomena involve directional cell migration. It is usually attributed to chemical gradients in vivo. Recently, other cues have been shown to guide cells in vitro, including stiffness/adhesion gradients or micropatterned adhesive motifs. However, the cellular mechanism leading to these biased migrations remains unknown, and, often, even the direction of motion is unpredictable. In this study, we show the key role of fluctuating protrusions on ratchet-like structures in driving NIH3T3 cell migration. We identified the concept of efficient protrusion and an associated direction index. Our analysis of the protrusion statistics facilitated the quantitative prediction of cell trajectories in all investigated conditions. We varied the external cues by changing the adhesive patterns. We also modified the internal cues using drug treatments, which modified the protrusion activity. Stochasticity affects the short- and long-term steps. We developed a theoretical model showing that an asymmetry in the protrusion fluctuations is sufficient for predicting all measures associated with the long-term motion, which can be described as a biased persistent random walk. |
El Gemayel, Mirella ; Haar, Sebastien ; Liscio, Fabiola ; Schlierf, Andrea ; Melinte, Georgian ; Milita, Silvia ; Ersen, Ovidiu ; Ciesielski, Artur ; Palermo, Vincenzo ; Samori, Paolo Leveraging the Ambipolar Transport in Polymeric Field-Effect Transistors via Blending with Liquid-Phase Exfoliated Graphene Journal Article In: ADVANCED MATERIALS, 26 (28), pp. 4814+, 2014, ISSN: 0935-9648. @article{el_gemayel_leveraging_2014, title = {Leveraging the Ambipolar Transport in Polymeric Field-Effect Transistors via Blending with Liquid-Phase Exfoliated Graphene}, author = {El Gemayel, Mirella and Haar, Sebastien and Liscio, Fabiola and Schlierf, Andrea and Melinte, Georgian and Milita, Silvia and Ersen, Ovidiu and Ciesielski, Artur and Palermo, Vincenzo and Samori, Paolo}, doi = {10.1002/adma.201400895}, issn = {0935-9648}, year = {2014}, date = {2014-07-01}, journal = {ADVANCED MATERIALS}, volume = {26}, number = {28}, pages = {4814+}, abstract = {Enhancement in the ambipolar behavior of field-effect transistors based on an n-type polymer, P(NDI2OD-T2), is obtained by co-deposition with liquid-phase exfoliated graphene. This approach provides a prospective pathway for the application of graphene-based nanocomposites for logic circuits.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Enhancement in the ambipolar behavior of field-effect transistors based on an n-type polymer, P(NDI2OD-T2), is obtained by co-deposition with liquid-phase exfoliated graphene. This approach provides a prospective pathway for the application of graphene-based nanocomposites for logic circuits. |
Chmielewski, Michal J; Buhler, Eric ; Candau, Jean ; Lehn, Jean-Marie Multivalency by Self-Assembly: Binding of ConcanavalinA to Metallosupramolecular Architectures Decorated with Multiple Carbohydrate Groups Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (23), pp. 6960–6977, 2014, ISSN: 0947-6539. @article{chmielewski_multivalency_2014, title = {Multivalency by Self-Assembly: Binding of ConcanavalinA to Metallosupramolecular Architectures Decorated with Multiple Carbohydrate Groups}, author = {Chmielewski, Michal J. and Buhler, Eric and Candau, Jean and Lehn, Jean-Marie}, doi = {10.1002/chem.201304511}, issn = {0947-6539}, year = {2014}, date = {2014-06-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {20}, number = {23}, pages = {6960--6977}, abstract = {Multiplication of functional units through self-assembly is a powerful way to new properties and functions. In particular, self-organization of components decorated with recognition groups leads to multivalent entities, amenable to strong and selective binding with multivalent targets, such as protein receptors. Here we describe an efficient, supramolecular, one-pot valency multiplication process proceeding through self-organization of monovalent components into well-defined, grid-shaped [2x2] tetranuclear complexes bearing eight sugar residues for multivalent interaction with the tetrameric lectin, concanavalinA (ConA). The grids are stable in water under physiological pH at a relatively high concentration, but dissociate readily at slightly more acidic pH or upon dilution below a certain threshold, in a type of on-off behavior. The carbohydrate-decorated grids interact strongly and selectively with ConA forming triply supramolecular bio-hybrid polymeric networks, which lead to a highly specific phase-separation and quasi-quantitative precipitation of ConA out of solution. Dramatic effects of valency number on agglutination properties were demonstrated by comparison of grids with divalent carbohydrates of covalent and non-covalent (L-shaped, mononuclear zinc complex) scaffolds. The results presented here provide prototypical illustration of the power of multivalency generation by self-assembly leading to defined arrays of functional groups and binding patterns.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Multiplication of functional units through self-assembly is a powerful way to new properties and functions. In particular, self-organization of components decorated with recognition groups leads to multivalent entities, amenable to strong and selective binding with multivalent targets, such as protein receptors. Here we describe an efficient, supramolecular, one-pot valency multiplication process proceeding through self-organization of monovalent components into well-defined, grid-shaped [2x2] tetranuclear complexes bearing eight sugar residues for multivalent interaction with the tetrameric lectin, concanavalinA (ConA). The grids are stable in water under physiological pH at a relatively high concentration, but dissociate readily at slightly more acidic pH or upon dilution below a certain threshold, in a type of on-off behavior. The carbohydrate-decorated grids interact strongly and selectively with ConA forming triply supramolecular bio-hybrid polymeric networks, which lead to a highly specific phase-separation and quasi-quantitative precipitation of ConA out of solution. Dramatic effects of valency number on agglutination properties were demonstrated by comparison of grids with divalent carbohydrates of covalent and non-covalent (L-shaped, mononuclear zinc complex) scaffolds. The results presented here provide prototypical illustration of the power of multivalency generation by self-assembly leading to defined arrays of functional groups and binding patterns. |
Raykov, Zahary ; Grekova, Svitlana P; Bour, Gaetan ; Lehn, Jean Marie ; Giese, N A; Nicolau, Claude ; Aprahamian, Marc Myo- inositol trispyrophosphate- mediated hypoxia reversion controls pancreatic cancer in rodents and enhances gemcitabine efficacy Journal Article In: INTERNATIONAL JOURNAL OF CANCER, 134 (11), pp. 2572–2582, 2014, ISSN: 0020-7136. @article{raykov_myo-_2014, title = {Myo- inositol trispyrophosphate- mediated hypoxia reversion controls pancreatic cancer in rodents and enhances gemcitabine efficacy}, author = {Raykov, Zahary and Grekova, Svitlana P. and Bour, Gaetan and Lehn, Jean Marie and Giese, N. A. and Nicolau, Claude and Aprahamian, Marc}, doi = {10.1002/ijc.28597}, issn = {0020-7136}, year = {2014}, date = {2014-06-01}, journal = {INTERNATIONAL JOURNAL OF CANCER}, volume = {134}, number = {11}, pages = {2572--2582}, abstract = {Hypoxia and dysfunctional tumor vessels represent a prominent feature of pancreatic cancer, being, at least in part, responsible for chemotherapy resistance and immune suppression in these tumors. We tested whether the increase of oxygen delivery induced in vivo by myo-inositol trispyrophosphate (ITPP) can reverse hypoxia, control tumor growth and improve chemotherapy response. Tumor size, metastatic development (microcomputed tomography scan follow-up) and the survival of rats and nude or NOD.SCID mice, (bearing syngenic rat and MiaPaCa2- or patient-derived pancreatic tumors), were determined on ITPP and/or gemcitabine treatment. Partial oxygen pressure, expression of angiogenic factors and tumor histology were evaluated. Infiltration and oxidative status of immune cells, as well as chemotherapy penetration in tumors, were determined by fluorescence-activated cell sorting, fluorometry, nitric oxide release assays, Western blot and confocal microscopy. Weekly intravenous ITPP application resulted in the inhibition of metastasis development and restricted primary tumor growth, showing a superior effect on the rats' survival compared with gemcitabine. ITPP treatment restored tumor normoxia and caused a reduction in hypoxia inducible factor-1 levels, with subsequent VEGF and Lox downregulation, resulting in improved vessel structure and decreased desmoplasia. The latter effects translated into elevated immune cells influx and improved susceptibility to gemcitabine treatment. Growth of human pancreatic tumor xenografts was strongly inhibited by administration of ITPP. ITPP exploits a two-stage mechanism causing rapid, early and sustainable late stage normoxia. This is due to the angiogenic factor modulation and vascular normalization, leading to enhanced chemotherapy delivery and synergistic life prolongation, on combination with low doses of gemcitabine. Pancreatic tumors are highly hypoxic, owing to extensive stromal reaction and disturbed angioarchitecture, features that also reduce the uptake of chemotherapeutics and hinder the flow of immune cells into tumors. In this study, treatment with myo-inositol trispyrophosphate (ITPP), a novel investigational drug (approved for Phase I and II clinical use in humans), was found to reverse hypoxia in rodents with pancreatic tumors. Therapy-induced reduction of HIF-1 and VEGF levels resulted in improved vessel structure. ITPP was active especially upon combination with standard gemcitabine chemotherapy. The latter protocol resulted in significant control of metastatic growth, life prolongation, and improved penetration of chemotherapy in tested animals.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hypoxia and dysfunctional tumor vessels represent a prominent feature of pancreatic cancer, being, at least in part, responsible for chemotherapy resistance and immune suppression in these tumors. We tested whether the increase of oxygen delivery induced in vivo by myo-inositol trispyrophosphate (ITPP) can reverse hypoxia, control tumor growth and improve chemotherapy response. Tumor size, metastatic development (microcomputed tomography scan follow-up) and the survival of rats and nude or NOD.SCID mice, (bearing syngenic rat and MiaPaCa2- or patient-derived pancreatic tumors), were determined on ITPP and/or gemcitabine treatment. Partial oxygen pressure, expression of angiogenic factors and tumor histology were evaluated. Infiltration and oxidative status of immune cells, as well as chemotherapy penetration in tumors, were determined by fluorescence-activated cell sorting, fluorometry, nitric oxide release assays, Western blot and confocal microscopy. Weekly intravenous ITPP application resulted in the inhibition of metastasis development and restricted primary tumor growth, showing a superior effect on the rats' survival compared with gemcitabine. ITPP treatment restored tumor normoxia and caused a reduction in hypoxia inducible factor-1 levels, with subsequent VEGF and Lox downregulation, resulting in improved vessel structure and decreased desmoplasia. The latter effects translated into elevated immune cells influx and improved susceptibility to gemcitabine treatment. Growth of human pancreatic tumor xenografts was strongly inhibited by administration of ITPP. ITPP exploits a two-stage mechanism causing rapid, early and sustainable late stage normoxia. This is due to the angiogenic factor modulation and vascular normalization, leading to enhanced chemotherapy delivery and synergistic life prolongation, on combination with low doses of gemcitabine. Pancreatic tumors are highly hypoxic, owing to extensive stromal reaction and disturbed angioarchitecture, features that also reduce the uptake of chemotherapeutics and hinder the flow of immune cells into tumors. In this study, treatment with myo-inositol trispyrophosphate (ITPP), a novel investigational drug (approved for Phase I and II clinical use in humans), was found to reverse hypoxia in rodents with pancreatic tumors. Therapy-induced reduction of HIF-1 and VEGF levels resulted in improved vessel structure. ITPP was active especially upon combination with standard gemcitabine chemotherapy. The latter protocol resulted in significant control of metastatic growth, life prolongation, and improved penetration of chemotherapy in tested animals. |
Heitz, Valerie ; Sauvage, Jean-Pierre ; Trolez, Yann Cu(I)/Zn2+ exchange has no geometrical effect in a cyclic [4]rotaxane whereas it induces rearrangement in a simpler [3]rotaxane Journal Article In: INORGANICA CHIMICA ACTA, 417 , pp. 186–191, 2014, ISSN: 0020-1693. @article{heitz_cui/zn2+_2014, title = {Cu(I)/Zn2+ exchange has no geometrical effect in a cyclic [4]rotaxane whereas it induces rearrangement in a simpler [3]rotaxane}, author = {Heitz, Valerie and Sauvage, Jean-Pierre and Trolez, Yann}, doi = {10.1016/j.ica.2013.12.010}, issn = {0020-1693}, year = {2014}, date = {2014-06-01}, journal = {INORGANICA CHIMICA ACTA}, volume = {417}, pages = {186--191}, abstract = {The dynamic behaviour of a [4]rotaxane consisting of two rigid bis-macrocycles and two linear fragments threading the rings, was compared to that of a simple model, namely a [3]rotaxane, consisting of roughly one half of the full [4]rotaxane molecule. Although the coordination sites are strictly identical in both compounds, it was observed that demetalation or metal exchange (Cu-I/Zn2+) has very limited effect on the [4]rotaxane geometry whereas the same reactions have a profound effect on the geometrical arrangement of the [3] rotaxane. This observation is a clear demonstration that the number of mechanical bonds is determining in terms of flexibility and rigidity, the more constrained [4] rotaxane being more difficult to distort than its smaller congener. (C) 2013 Elsevier B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The dynamic behaviour of a [4]rotaxane consisting of two rigid bis-macrocycles and two linear fragments threading the rings, was compared to that of a simple model, namely a [3]rotaxane, consisting of roughly one half of the full [4]rotaxane molecule. Although the coordination sites are strictly identical in both compounds, it was observed that demetalation or metal exchange (Cu-I/Zn2+) has very limited effect on the [4]rotaxane geometry whereas the same reactions have a profound effect on the geometrical arrangement of the [3] rotaxane. This observation is a clear demonstration that the number of mechanical bonds is determining in terms of flexibility and rigidity, the more constrained [4] rotaxane being more difficult to distort than its smaller congener. (C) 2013 Elsevier B.V. All rights reserved. |
Stein, Benedikt ; Devaux, Eloise ; Genet, Cyriaque ; Ebbesen, Thomas W Plasmonic crystal enhanced refractive index sensing Journal Article In: APPLIED PHYSICS LETTERS, 104 (25), 2014, ISSN: 0003-6951. @article{stein_plasmonic_2014, title = {Plasmonic crystal enhanced refractive index sensing}, author = {Stein, Benedikt and Devaux, Eloise and Genet, Cyriaque and Ebbesen, Thomas W.}, doi = {10.1063/1.4885120}, issn = {0003-6951}, year = {2014}, date = {2014-06-01}, journal = {APPLIED PHYSICS LETTERS}, volume = {104}, number = {25}, abstract = {We demonstrate experimentally how the local anisotropy of the dispersion relation of surface plasmon modes propagating over periodic metal gratings can lead to an enhancement of the figure of merit of refractive index sensors. Exploiting the possibility to acquire defocused images of the Fourier space of a highly stable leakage radiation microscope, we report a twofold increase in sensing sensitivity close to the band gap of a one-dimensional plasmonic crystal where the anisotropy of the band structure is the most important. A practical sensing resolution of O(10(-6)) refractive index units is demonstrated. (C) 2014 AIP Publishing LLC.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We demonstrate experimentally how the local anisotropy of the dispersion relation of surface plasmon modes propagating over periodic metal gratings can lead to an enhancement of the figure of merit of refractive index sensors. Exploiting the possibility to acquire defocused images of the Fourier space of a highly stable leakage radiation microscope, we report a twofold increase in sensing sensitivity close to the band gap of a one-dimensional plasmonic crystal where the anisotropy of the band structure is the most important. A practical sensing resolution of O(10(-6)) refractive index units is demonstrated. (C) 2014 AIP Publishing LLC. |
Colella, Silvia ; Orgiu, Emanuele ; Bruder, Ingmar ; Liscio, Andrea ; Palermo, Vincenzo ; Bruchmann, Bernd ; Samori, Paolo ; Erk, Peter Titanium Dioxide Mesoporous Electrodes for Solid-State Dye-Sensitized Solar Cells: Cross-Analysis of the Critical Parameters Journal Article In: ADVANCED ENERGY MATERIALS, 4 (9), 2014, ISSN: 1614-6832. @article{colella_titanium_2014, title = {Titanium Dioxide Mesoporous Electrodes for Solid-State Dye-Sensitized Solar Cells: Cross-Analysis of the Critical Parameters}, author = {Colella, Silvia and Orgiu, Emanuele and Bruder, Ingmar and Liscio, Andrea and Palermo, Vincenzo and Bruchmann, Bernd and Samori, Paolo and Erk, Peter}, doi = {10.1002/aenm.201301362}, issn = {1614-6832}, year = {2014}, date = {2014-06-01}, journal = {ADVANCED ENERGY MATERIALS}, volume = {4}, number = {9}, abstract = {We report a comparative study on the use of four different mesoporous titanium dioxide (TiO2) photo-electrodes for the fabrication of solid-state dye-sensitized solar cells (sDSSCs). The photovoltaic parameters of the device correlate with several intrinsic properties of the film, based not only on its morphological features, as commonly considered in standard characterizations, but also on the transport and the electronic properties of the photo-electrode. These properties differ significantly for TiO2 electrodes processed using different colloidal pastes, and are decisive for the photovoltaic efficiency, ranging from 3.7% up to 5.1%. In particular, the dielectric permittivity of each mesoporous layer (epsilon(eff)) and the number of traps (N-t) determined by the space-charge-limited current (SCLC) theory are found to be a bottle-neck for the charge transport, greatly influencing the fill factor (FF) and open circuit voltage (V-oc) of the cells. In addition, a direct correlation between TiO2 surface potential with the V-oc was established. Cross-analysis of key macroscopic parameters of the films prior to integration in the devices, in particular focusing on the determination of the capacitance and surface potential shift of the TiO2 mesoporous anode, represents a straightforward yet powerful method to screen and select the most suitable TiO2 for applications in sDSSCs.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report a comparative study on the use of four different mesoporous titanium dioxide (TiO2) photo-electrodes for the fabrication of solid-state dye-sensitized solar cells (sDSSCs). The photovoltaic parameters of the device correlate with several intrinsic properties of the film, based not only on its morphological features, as commonly considered in standard characterizations, but also on the transport and the electronic properties of the photo-electrode. These properties differ significantly for TiO2 electrodes processed using different colloidal pastes, and are decisive for the photovoltaic efficiency, ranging from 3.7% up to 5.1%. In particular, the dielectric permittivity of each mesoporous layer (epsilon(eff)) and the number of traps (N-t) determined by the space-charge-limited current (SCLC) theory are found to be a bottle-neck for the charge transport, greatly influencing the fill factor (FF) and open circuit voltage (V-oc) of the cells. In addition, a direct correlation between TiO2 surface potential with the V-oc was established. Cross-analysis of key macroscopic parameters of the films prior to integration in the devices, in particular focusing on the determination of the capacitance and surface potential shift of the TiO2 mesoporous anode, represents a straightforward yet powerful method to screen and select the most suitable TiO2 for applications in sDSSCs. |
Madalan, Augustin M; Cao, Xiao-Yu ; Rogez, Guillaume ; Lehn, Jean-Marie Ferromagnetic Coupling in Copper(II) [2 x 2] Grid-like Complexes Journal Article In: INORGANIC CHEMISTRY, 53 (9), pp. 4275–4277, 2014, ISSN: 0020-1669. @article{madalan_ferromagnetic_2014, title = {Ferromagnetic Coupling in Copper(II) [2 x 2] Grid-like Complexes}, author = {Madalan, Augustin M. and Cao, Xiao-Yu and Rogez, Guillaume and Lehn, Jean-Marie}, doi = {10.1021/ic500285m}, issn = {0020-1669}, year = {2014}, date = {2014-05-01}, journal = {INORGANIC CHEMISTRY}, volume = {53}, number = {9}, pages = {4275--4277}, abstract = {Two copper(II) [2 x 2] grid-like complexes were synthesized and structurally characterized. Investigation of the magnetic properties showed for both the occurrence of intramolecular ferromagnetic interactions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two copper(II) [2 x 2] grid-like complexes were synthesized and structurally characterized. Investigation of the magnetic properties showed for both the occurrence of intramolecular ferromagnetic interactions. |
Ovchinnikov, Victor ; Karplus, Martin Investigations of alpha-helix textbackslashtextbackslashtextless-textbackslashtextbackslashtextgreaterbeta-sheet transition pathways in a miniprotein using the finite-temperature string method Journal Article In: JOURNAL OF CHEMICAL PHYSICS, 140 (17), 2014, ISSN: 0021-9606. @article{ovchinnikov_investigations_2014, title = {Investigations of alpha-helix textbackslashtextbackslashtextless-textbackslashtextbackslashtextgreaterbeta-sheet transition pathways in a miniprotein using the finite-temperature string method}, author = {Ovchinnikov, Victor and Karplus, Martin}, doi = {10.1063/1.4871685}, issn = {0021-9606}, year = {2014}, date = {2014-05-01}, journal = {JOURNAL OF CHEMICAL PHYSICS}, volume = {140}, number = {17}, abstract = {A parallel implementation of the finite-temperature string method is described, which takes into account the invariance of coordinates with respect to rigid-body motions. The method is applied to the complex alpha-helix textbackslashtextbackslashtextless-textbackslashtextbackslashtextgreaterbeta-sheet transition in a beta-hairpin miniprotein in implicit solvent, which exhibits much of the complexity of conformational changes in proteins. Two transition paths are considered, one derived from a linear interpolant between the endpoint structures and the other derived from a targeted dynamics simulation. Two methods for computing the conformational free energy (FE) along the string are compared, a restrained method, and a tessellation method introduced by E. Vanden-Eijnden and M. Venturoli [J. Chem. Phys. 130, 194103 (2009)]. It is found that obtaining meaningful free energy profiles using the present atom-based coordinates requires restricting sampling to a vicinity of the converged path, where the hyperplanar approximation to the isocommittor surface is sufficiently accurate. This sampling restriction can be easily achieved using restraints or constraints. The endpoint FE differences computed from the FE profiles are validated by comparison with previous calculations using a path-independent confinement method. The FE profiles are decomposed into the enthalpic and entropic contributions, and it is shown that the entropy difference contribution can be as large as 10 kcal/mol for intermediate regions along the path, compared to 15-20 kcal/mol for the enthalpy contribution. This result demonstrates that enthalpic barriers for transitions are offset by entropic contributions arising from the existence of different paths across a barrier. The possibility of using systematically coarse-grained representations of amino acids, in the spirit of multiple interaction site residue models, is proposed as a means to avoid ad hoc sampling restrictions to narrow transition tubes. (C) 2014 AIP Publishing LLC.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A parallel implementation of the finite-temperature string method is described, which takes into account the invariance of coordinates with respect to rigid-body motions. The method is applied to the complex alpha-helix textbackslashtextbackslashtextless-textbackslashtextbackslashtextgreaterbeta-sheet transition in a beta-hairpin miniprotein in implicit solvent, which exhibits much of the complexity of conformational changes in proteins. Two transition paths are considered, one derived from a linear interpolant between the endpoint structures and the other derived from a targeted dynamics simulation. Two methods for computing the conformational free energy (FE) along the string are compared, a restrained method, and a tessellation method introduced by E. Vanden-Eijnden and M. Venturoli [J. Chem. Phys. 130, 194103 (2009)]. It is found that obtaining meaningful free energy profiles using the present atom-based coordinates requires restricting sampling to a vicinity of the converged path, where the hyperplanar approximation to the isocommittor surface is sufficiently accurate. This sampling restriction can be easily achieved using restraints or constraints. The endpoint FE differences computed from the FE profiles are validated by comparison with previous calculations using a path-independent confinement method. The FE profiles are decomposed into the enthalpic and entropic contributions, and it is shown that the entropy difference contribution can be as large as 10 kcal/mol for intermediate regions along the path, compared to 15-20 kcal/mol for the enthalpy contribution. This result demonstrates that enthalpic barriers for transitions are offset by entropic contributions arising from the existence of different paths across a barrier. The possibility of using systematically coarse-grained representations of amino acids, in the spirit of multiple interaction site residue models, is proposed as a means to avoid ad hoc sampling restrictions to narrow transition tubes. (C) 2014 AIP Publishing LLC. |
Gourlaouen, Christophe ; Daniel, Chantal ; Durola, Fabien ; Frey, Julien ; Heitz, Valerie ; Sauvage, Jean-Pierre ; Ventura, Barbara ; Flamigni, Lucia NIR Dual Luminescence from an Extended Porphyrin. Spectroscopy, Photophysics and Theory Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY A, 118 (20), pp. 3616–3624, 2014, ISSN: 1089-5639. @article{gourlaouen_nir_2014, title = {NIR Dual Luminescence from an Extended Porphyrin. Spectroscopy, Photophysics and Theory}, author = {Gourlaouen, Christophe and Daniel, Chantal and Durola, Fabien and Frey, Julien and Heitz, Valerie and Sauvage, Jean-Pierre and Ventura, Barbara and Flamigni, Lucia}, doi = {10.1021/jp5033383}, issn = {1089-5639}, year = {2014}, date = {2014-05-01}, journal = {JOURNAL OF PHYSICAL CHEMISTRY A}, volume = {118}, number = {20}, pages = {3616--3624}, abstract = {Spectroscopic and photophysical properties of an extended Zn porphyrin with fused bis(tetraazaanthracene) arms including a 2,9-diphenyl-1,10-phenanthroline incorporated in a polyether macrocycle are investigated in solvents of different polarity pointing to the presence of two emitting singlet excited states. The absorption and emission features are identified and ascribed, on the basis of solvent polarity dependence, to a pi-pi* and to a charge transfer (CT) state, respectively. Whereas the intraligand pi-pi* transition is assigned to the intense absorption observed at 442-455 nm, the CT states contribute to the bands at 521-525 nm and 472-481 nm. The theoretical analysis of the absorption spectrum confirms the presence of two strong bands centered at 536 and 437 nm corresponding to CT and pi-pi* states, respectively. Weak CT transitions are calculated at 657 and 486 nm. Two emission maxima are observed in toluene at 724 nm from a (1)pi-pi* state and at 800 nm from a (CT)-C-1 state, respectively. (CT)-C-1 bands shift bathochromically by increasing the solvent polarity whereas the energy of the (1)pi-pi band is less affected. Likewise, the emission yield and lifetime energy (CT)-C-1 band are strongly affected by solvent polarity. This is rationalized by a (1)pi-pi* -textbackslashtextbackslashtextgreater (CT)-C-1 internal conversion driven by solvent polarity, this process being competitive with the (1)pi-pi* to ground state deactivation channel. Time resolved absorption spectra indicate the presence of two triplet states, a short-lived one (nanoseconds range) and a longer lived one (hundreds of microsecond range) ascribed to a (3)pi-pi* and a (CT)-C-3, respectively. For them, a conversion mechanism similar to that of the singlet excited states is suggested.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Spectroscopic and photophysical properties of an extended Zn porphyrin with fused bis(tetraazaanthracene) arms including a 2,9-diphenyl-1,10-phenanthroline incorporated in a polyether macrocycle are investigated in solvents of different polarity pointing to the presence of two emitting singlet excited states. The absorption and emission features are identified and ascribed, on the basis of solvent polarity dependence, to a pi-pi* and to a charge transfer (CT) state, respectively. Whereas the intraligand pi-pi* transition is assigned to the intense absorption observed at 442-455 nm, the CT states contribute to the bands at 521-525 nm and 472-481 nm. The theoretical analysis of the absorption spectrum confirms the presence of two strong bands centered at 536 and 437 nm corresponding to CT and pi-pi* states, respectively. Weak CT transitions are calculated at 657 and 486 nm. Two emission maxima are observed in toluene at 724 nm from a (1)pi-pi* state and at 800 nm from a (CT)-C-1 state, respectively. (CT)-C-1 bands shift bathochromically by increasing the solvent polarity whereas the energy of the (1)pi-pi band is less affected. Likewise, the emission yield and lifetime energy (CT)-C-1 band are strongly affected by solvent polarity. This is rationalized by a (1)pi-pi* -textbackslashtextbackslashtextgreater (CT)-C-1 internal conversion driven by solvent polarity, this process being competitive with the (1)pi-pi* to ground state deactivation channel. Time resolved absorption spectra indicate the presence of two triplet states, a short-lived one (nanoseconds range) and a longer lived one (hundreds of microsecond range) ascribed to a (3)pi-pi* and a (CT)-C-3, respectively. For them, a conversion mechanism similar to that of the singlet excited states is suggested. |
Weber, Dennis ; Botnaras, Silviu ; Pham, Duy Vu ; Merkulov, Alexey ; Steiger, Juergen ; Schmechel, Roland ; De Cola, Luisa A Facile Solution-Doping Method to Improve a LowTemperature Zinc Oxide Precursor: Towards Low-Cost Electronics on Plastic Foil Journal Article In: ADVANCED FUNCTIONAL MATERIALS, 24 (17), pp. 2537–2543, 2014, ISSN: 1616-301X. @article{weber_facile_2014, title = {A Facile Solution-Doping Method to Improve a LowTemperature Zinc Oxide Precursor: Towards Low-Cost Electronics on Plastic Foil}, author = {Weber, Dennis and Botnaras, Silviu and Pham, Duy Vu and Merkulov, Alexey and Steiger, Juergen and Schmechel, Roland and De Cola, Luisa}, doi = {10.1002/adfm.201303461}, issn = {1616-301X}, year = {2014}, date = {2014-05-01}, journal = {ADVANCED FUNCTIONAL MATERIALS}, volume = {24}, number = {17}, pages = {2537--2543}, abstract = {Optimization of thin-film transistors performance is usually accompanied by an increase of the process temperature. This work presents a method to raise the field effect mobility by a factor of 3 without a change of the process parameters. The modification involves a solution doping process where an ammine zinc complex is formed in the presence of metal ions of the 13(th) group, namely gallium and indium. Morphological studies, including scanning electron microscopy and atomic force microscopy, reveal the difference among the resulting films. Moreover, X-ray diffraction results show that the doping affects the preferred orientation of the zinc oxide crystals in the resulting film. The electrical properties vary distinctly and are best for a solution doped with both gallium and indium. With a double-layer system the performance of this new precursor exceeds field effect mobility values of 1 cm(2) V-1 s(-1) after a maximum process temperature of 160 degrees C.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Optimization of thin-film transistors performance is usually accompanied by an increase of the process temperature. This work presents a method to raise the field effect mobility by a factor of 3 without a change of the process parameters. The modification involves a solution doping process where an ammine zinc complex is formed in the presence of metal ions of the 13(th) group, namely gallium and indium. Morphological studies, including scanning electron microscopy and atomic force microscopy, reveal the difference among the resulting films. Moreover, X-ray diffraction results show that the doping affects the preferred orientation of the zinc oxide crystals in the resulting film. The electrical properties vary distinctly and are best for a solution doped with both gallium and indium. With a double-layer system the performance of this new precursor exceeds field effect mobility values of 1 cm(2) V-1 s(-1) after a maximum process temperature of 160 degrees C. |
Yang, Qing-Yuan ; Lehn, Jean-Marie Bright White- Light Emission from a Single Organic Compound in the Solid State Journal Article In: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 53 (18), pp. 4572–4577, 2014, ISSN: 1433-7851. @article{yang_bright_2014, title = {Bright White- Light Emission from a Single Organic Compound in the Solid State}, author = {Yang, Qing-Yuan and Lehn, Jean-Marie}, doi = {10.1002/anie.201400155}, issn = {1433-7851}, year = {2014}, date = {2014-04-01}, journal = {ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, volume = {53}, number = {18}, pages = {4572--4577}, abstract = {White-light-emitting materials and devices have attracted enormous interest because of their great potential for various lighting applications. We herein describe the light-emitting properties of a series of new difunctional organic molecules of remarkably simple structure consisting of two terminal 4-pyridone push-pull subunits separated by a polymethylene chain. They were found to emit almost pure white light as a single organic compound in the solid state, as well as when incorporated in a polymer film. To the best of our knowledge, they are the simplest white-light-emitting organic molecules reported to date.}, keywords = {}, pubstate = {published}, tppubtype = {article} } White-light-emitting materials and devices have attracted enormous interest because of their great potential for various lighting applications. We herein describe the light-emitting properties of a series of new difunctional organic molecules of remarkably simple structure consisting of two terminal 4-pyridone push-pull subunits separated by a polymethylene chain. They were found to emit almost pure white light as a single organic compound in the solid state, as well as when incorporated in a polymer film. To the best of our knowledge, they are the simplest white-light-emitting organic molecules reported to date. |
Kalgin, Igor V; Chekmarev, Sergei F; Karplus, Martin First Passage Analysis of the Folding of a beta-Sheet Miniprotein: Is it More Realistic Than the Standard Equilibrium Approach? Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY B, 118 (16), pp. 4287–4299, 2014, ISSN: 1520-6106. @article{kalgin_first_2014, title = {First Passage Analysis of the Folding of a beta-Sheet Miniprotein: Is it More Realistic Than the Standard Equilibrium Approach?}, author = {Kalgin, Igor V. and Chekmarev, Sergei F. and Karplus, Martin}, doi = {10.1021/jp412729r}, issn = {1520-6106}, year = {2014}, date = {2014-04-01}, journal = {JOURNAL OF PHYSICAL CHEMISTRY B}, volume = {118}, number = {16}, pages = {4287--4299}, abstract = {Simulations of first-passage folding of the antiparallel beta-sheet miniprotein beta3s, which has been intensively studied under equilibrium conditions by A. Caflisch and co-workers, show that the kinetics and dynamics are significantly different from those for equilibrium folding. Because the folding of a protein in a living system generally corresponds to the former (i.e., the folded protein is stable and unfolding is a rare event), the difference is of interest. In contrast to equilibrium folding, the Ch-curl conformations become very rare because they contain unfavorable parallel beta-strand arrangements, which are difficult to form dynamically due to the distant N- and C-terminal strands. At the same time, the formation of helical conformations becomes much easier (particularly in the early stage of folding) due to short-range contacts. The hydrodynamic descriptions of the folding reaction have also revealed that while the equilibrium flow field presented a collection of local vortices with closed “streamlines”, the first-passage folding is characterized by a pronounced overall flow from the unfolded states to the native state. The flows through the locally stable structures Cs-or and Ns-or, which are conformationally close to the native state, are negligible due to detailed balance established between these structures and the native state. Although there are significant differences in the general picture of the folding process from the equilibrium and first-passage folding simulations, some aspects of the two are in agreement. The rate of transitions between the clusters of characteristic protein conformations in both cases decreases approximately exponentially with the distance between the clusters in the hydrogen bond distance space of collective variables, and the folding time distribution in the first-passage segments of the equilibrium trajectory is in good agreement with that for the first-passage folding simulations.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Simulations of first-passage folding of the antiparallel beta-sheet miniprotein beta3s, which has been intensively studied under equilibrium conditions by A. Caflisch and co-workers, show that the kinetics and dynamics are significantly different from those for equilibrium folding. Because the folding of a protein in a living system generally corresponds to the former (i.e., the folded protein is stable and unfolding is a rare event), the difference is of interest. In contrast to equilibrium folding, the Ch-curl conformations become very rare because they contain unfavorable parallel beta-strand arrangements, which are difficult to form dynamically due to the distant N- and C-terminal strands. At the same time, the formation of helical conformations becomes much easier (particularly in the early stage of folding) due to short-range contacts. The hydrodynamic descriptions of the folding reaction have also revealed that while the equilibrium flow field presented a collection of local vortices with closed “streamlines”, the first-passage folding is characterized by a pronounced overall flow from the unfolded states to the native state. The flows through the locally stable structures Cs-or and Ns-or, which are conformationally close to the native state, are negligible due to detailed balance established between these structures and the native state. Although there are significant differences in the general picture of the folding process from the equilibrium and first-passage folding simulations, some aspects of the two are in agreement. The rate of transitions between the clusters of characteristic protein conformations in both cases decreases approximately exponentially with the distance between the clusters in the hydrogen bond distance space of collective variables, and the folding time distribution in the first-passage segments of the equilibrium trajectory is in good agreement with that for the first-passage folding simulations. |
Xuereb, Andre ; Genes, Claudiu ; Pupillo, Guido ; Paternostro, Mauro ; Dantan, Aurelien Reconfigurable Long-Range Phonon Dynamics in Optomechanical Arrays Journal Article In: PHYSICAL REVIEW LETTERS, 112 (13), 2014, ISSN: 0031-9007. @article{xuereb_reconfigurable_2014, title = {Reconfigurable Long-Range Phonon Dynamics in Optomechanical Arrays}, author = {Xuereb, Andre and Genes, Claudiu and Pupillo, Guido and Paternostro, Mauro and Dantan, Aurelien}, doi = {10.1103/PhysRevLett.112.133604}, issn = {0031-9007}, year = {2014}, date = {2014-04-01}, journal = {PHYSICAL REVIEW LETTERS}, volume = {112}, number = {13}, abstract = {We investigate periodic optomechanical arrays as reconfigurable platforms for engineering the coupling between multiple mechanical and electromagnetic modes and for exploring many-body phonon dynamics. Exploiting structural resonances in the coupling between light fields and collective motional modes of the array, we show that tunable effective long-range interactions between mechanical modes can be achieved. This paves the way towards the implementation of controlled phononic walks and heat transfer on densely connected graphs as well as the coherent transfer of excitations between distant elements of optomechanical arrays.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We investigate periodic optomechanical arrays as reconfigurable platforms for engineering the coupling between multiple mechanical and electromagnetic modes and for exploring many-body phonon dynamics. Exploiting structural resonances in the coupling between light fields and collective motional modes of the array, we show that tunable effective long-range interactions between mechanical modes can be achieved. This paves the way towards the implementation of controlled phononic walks and heat transfer on densely connected graphs as well as the coherent transfer of excitations between distant elements of optomechanical arrays. |
Niess, Frederic ; Duplan, Vincent ; Sauvage, Jean-Pierre Interconversion between a Vertically Oriented Transition Metal-Complexed Figure-of-Eight and a Horizontally Disposed One Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 136 (16), pp. 5876–5879, 2014, ISSN: 0002-7863. @article{niess_interconversion_2014, title = {Interconversion between a Vertically Oriented Transition Metal-Complexed Figure-of-Eight and a Horizontally Disposed One}, author = {Niess, Frederic and Duplan, Vincent and Sauvage, Jean-Pierre}, doi = {10.1021/ja501765y}, issn = {0002-7863}, year = {2014}, date = {2014-04-01}, journal = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, volume = {136}, number = {16}, pages = {5876--5879}, abstract = {A large ring containing two pairs of transition metal-complexing fragments with alternating bi- and tridentate chelates has been shown to behave as a bimodal figure-of-eight. When coordinated to a preferentially octahedrally coordinated Fe(II) or Cu(II) center, the height of the molecule along the coordinating axis of the tridentate ligands (vertical on the drawing) is only similar to 11 angstrom, whereas the height of the molecule along the same vertical axis is several times as large for the complex of the tetrahedrally coordinated copper(I) center. This new type of molecular machine-prototype could be used as constitutive element in muscle-like dynamic systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A large ring containing two pairs of transition metal-complexing fragments with alternating bi- and tridentate chelates has been shown to behave as a bimodal figure-of-eight. When coordinated to a preferentially octahedrally coordinated Fe(II) or Cu(II) center, the height of the molecule along the coordinating axis of the tridentate ligands (vertical on the drawing) is only similar to 11 angstrom, whereas the height of the molecule along the same vertical axis is several times as large for the complex of the tetrahedrally coordinated copper(I) center. This new type of molecular machine-prototype could be used as constitutive element in muscle-like dynamic systems. |
Wang, Shaojun ; Chervy, Thibault ; George, Jino ; Hutchison, James A; Genet, Cyriaque ; Ebbesen, Thomas W Quantum Yield of Polariton Emission from Hybrid Light-Matter States Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 5 (8), pp. 1433–1439, 2014, ISSN: 1948-7185. @article{wang_quantum_2014, title = {Quantum Yield of Polariton Emission from Hybrid Light-Matter States}, author = {Wang, Shaojun and Chervy, Thibault and George, Jino and Hutchison, James A. and Genet, Cyriaque and Ebbesen, Thomas W.}, doi = {10.1021/jz5004439}, issn = {1948-7185}, year = {2014}, date = {2014-04-01}, journal = {JOURNAL OF PHYSICAL CHEMISTRY LETTERS}, volume = {5}, number = {8}, pages = {1433--1439}, abstract = {The efficiency of light-matter strong coupling is tuned by precisely varying the spatial position of a thin layer of cyanine dye J-aggregates in Fabry-Perot microcavities, and their photophysical properties are determined. Placing the layer at the cavity field maximum affords an interaction energy (Rabi splitting) of 503 meV, a 62% increase over that observed if the aggregates are simply spread evenly through the cavity, placing the system in the ultrastrong coupling regime. The fluorescence quantum yield of the lowest polaritonic state P- integrated over k-space is found to be similar to 10(-2). The same value can be deduced from the 1.4 ps lifetime of P- measured by femtosecond transient absorption spectroscopy and the calculated radiative decay rate constant. Thus, the polariton decay is dominated by nonradiative processes, in contrast with what might be expected from the small effective mass of the polaritons. These findings provide a deeper understanding of hybrid light-molecule states and have implications for the modification of molecular and material properties by strong coupling.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The efficiency of light-matter strong coupling is tuned by precisely varying the spatial position of a thin layer of cyanine dye J-aggregates in Fabry-Perot microcavities, and their photophysical properties are determined. Placing the layer at the cavity field maximum affords an interaction energy (Rabi splitting) of 503 meV, a 62% increase over that observed if the aggregates are simply spread evenly through the cavity, placing the system in the ultrastrong coupling regime. The fluorescence quantum yield of the lowest polaritonic state P- integrated over k-space is found to be similar to 10(-2). The same value can be deduced from the 1.4 ps lifetime of P- measured by femtosecond transient absorption spectroscopy and the calculated radiative decay rate constant. Thus, the polariton decay is dominated by nonradiative processes, in contrast with what might be expected from the small effective mass of the polaritons. These findings provide a deeper understanding of hybrid light-molecule states and have implications for the modification of molecular and material properties by strong coupling. |
Yi, Jue-Min ; Cuche, Aurelien ; Devaux, Eloise ; Genet, Cyriaque ; Ebbesen, Thomas W Beaming Visible Light with a Plasmonic Aperture Antenna Journal Article In: ACS PHOTONICS, 1 (4), pp. 365–370, 2014, ISSN: 2330-4022. @article{yi_beaming_2014, title = {Beaming Visible Light with a Plasmonic Aperture Antenna}, author = {Yi, Jue-Min and Cuche, Aurelien and Devaux, Eloise and Genet, Cyriaque and Ebbesen, Thomas W.}, doi = {10.1021/ph400146n}, issn = {2330-4022}, year = {2014}, date = {2014-04-01}, journal = {ACS PHOTONICS}, volume = {1}, number = {4}, pages = {365--370}, abstract = {We investigate experimentally the parameter space defining, in the visible range, the far-field diffraction properties of a single circular subwavelength aperture surrounded by periodic circular grooves milled on a metallic film. Diffraction patterns emerging from such an antenna are recorded under parallel- and perpendicular-polarized illumination at a given illumination wavelength. By monitoring the directivity and the gain of the antenna with respect to a single aperture, we point out the role played by the near-field surface plasmon excitations. The results can be analyzed through a Huygens-Fresnel model, accounting for the coherent interaction between the field radiated by the hole and the plasmonic field, propagating along the antenna surface and diffracted away in free space.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We investigate experimentally the parameter space defining, in the visible range, the far-field diffraction properties of a single circular subwavelength aperture surrounded by periodic circular grooves milled on a metallic film. Diffraction patterns emerging from such an antenna are recorded under parallel- and perpendicular-polarized illumination at a given illumination wavelength. By monitoring the directivity and the gain of the antenna with respect to a single aperture, we point out the role played by the near-field surface plasmon excitations. The results can be analyzed through a Huygens-Fresnel model, accounting for the coherent interaction between the field radiated by the hole and the plasmonic field, propagating along the antenna surface and diffracted away in free space. |
Stadler, Adrian-Mihail ; Lehn, Jean-Marie P Coupled Nanomechanical Motions: Metal-Ion-Effected, pH-Modulated, Simultaneous Extension/Contraction Motions of Double-Domain Helical/Linear Molecular Strands Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 136 (9), pp. 3400–3409, 2014, ISSN: 0002-7863. @article{stadler_coupled_2014, title = {Coupled Nanomechanical Motions: Metal-Ion-Effected, pH-Modulated, Simultaneous Extension/Contraction Motions of Double-Domain Helical/Linear Molecular Strands}, author = {Stadler, Adrian-Mihail and Lehn, Jean-Marie P.}, doi = {10.1021/ja408752m}, issn = {0002-7863}, year = {2014}, date = {2014-03-01}, journal = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, volume = {136}, number = {9}, pages = {3400--3409}, abstract = {A new class of shape-enforced synthetic polyheterocyclic molecular strands, containing both a helical and a linear domain, has been designed and synthesized. On reaction with Pb(II), under the effect of cation binding to the coordination subunits, the helical section unfolds into a linear shape in the complex and the linear domain folds into a helical ligand wrapped around the bound cations. Such double-domain ligand strands are thus able to undergo a combined unfolding-folding interconversion on binding and release of metal cations. These changes can be modulated through coupling to a competing ligand that reversibly binds and releases metal cations, when respectively unprotonated and protonated, on effecting alternate pH changes. The resulting process thus performs nanomechanical extension/contraction molecular motions of a linear motor type, which is fueled by acid-base neutralization.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new class of shape-enforced synthetic polyheterocyclic molecular strands, containing both a helical and a linear domain, has been designed and synthesized. On reaction with Pb(II), under the effect of cation binding to the coordination subunits, the helical section unfolds into a linear shape in the complex and the linear domain folds into a helical ligand wrapped around the bound cations. Such double-domain ligand strands are thus able to undergo a combined unfolding-folding interconversion on binding and release of metal cations. These changes can be modulated through coupling to a competing ligand that reversibly binds and releases metal cations, when respectively unprotonated and protonated, on effecting alternate pH changes. The resulting process thus performs nanomechanical extension/contraction molecular motions of a linear motor type, which is fueled by acid-base neutralization. |
Beyler, Maryline ; Flamigni, Lucia ; Heitz, Valerie ; Sauvage, Jean-Pierre ; Ventura, Barbara Coordination Chemistry-Assembled Multicomponent Systems Built from a Gable-Like Bis-Porphyrin: Synthesis and Photophysical Properties Journal Article In: PHOTOCHEMISTRY AND PHOTOBIOLOGY, 90 (2), pp. 275–286, 2014, ISSN: 0031-8655. @article{beyler_coordination_2014, title = {Coordination Chemistry-Assembled Multicomponent Systems Built from a Gable-Like Bis-Porphyrin: Synthesis and Photophysical Properties}, author = {Beyler, Maryline and Flamigni, Lucia and Heitz, Valerie and Sauvage, Jean-Pierre and Ventura, Barbara}, doi = {10.1111/php.12177}, issn = {0031-8655}, year = {2014}, date = {2014-03-01}, journal = {PHOTOCHEMISTRY AND PHOTOBIOLOGY}, volume = {90}, number = {2}, pages = {275--286}, abstract = {Multiporphyrinic assemblies were quantitatively formed, in one step, from a gable-like zinc(II) bis-porphyrin ZnP2 and free-base porphyrins bearing pyridyl groups. The different fragments are held together by axial 4 `-N(pyridyl)-Zn interactions. Formation of a macrocycle ZnP2 center dot(4 `-cisDPyP) and a bis-macrocycle (ZnP2)(2)center dot(TPyP) is discussed. The macrocycle and the bis-macrocycle were crystallized and studied by X-ray diffraction, which confirmed the excellent complementarity between the various components. Spectrophotometric and spectrofluorimetric titrations and studies reveal high association constants for both multiporphyrinic assemblies due to the almost perfect geometrical match between the interacting units. As expected, energy transfer from the zinc porphyrin component to the free-base porphyrin quenches the fluorescence of the zinc porphyrin components in both compounds. But while in ZnP2 center dot(4 `-cis DPyP) sensitization of the emission of the free-base porphyrin was observed, in (ZnP2)(2)center dot(TPyP) excitation of the peripheral Zn porphyrin units does not lead to quantitative sensitization of the luminescence of the free-base porphyrin acceptor. An unusual HOMO-HOMO electron transfer reaction from ZnP2 to the excited TPyP unit was detected and studied.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Multiporphyrinic assemblies were quantitatively formed, in one step, from a gable-like zinc(II) bis-porphyrin ZnP2 and free-base porphyrins bearing pyridyl groups. The different fragments are held together by axial 4 `-N(pyridyl)-Zn interactions. Formation of a macrocycle ZnP2 center dot(4 `-cisDPyP) and a bis-macrocycle (ZnP2)(2)center dot(TPyP) is discussed. The macrocycle and the bis-macrocycle were crystallized and studied by X-ray diffraction, which confirmed the excellent complementarity between the various components. Spectrophotometric and spectrofluorimetric titrations and studies reveal high association constants for both multiporphyrinic assemblies due to the almost perfect geometrical match between the interacting units. As expected, energy transfer from the zinc porphyrin component to the free-base porphyrin quenches the fluorescence of the zinc porphyrin components in both compounds. But while in ZnP2 center dot(4 `-cis DPyP) sensitization of the emission of the free-base porphyrin was observed, in (ZnP2)(2)center dot(TPyP) excitation of the peripheral Zn porphyrin units does not lead to quantitative sensitization of the luminescence of the free-base porphyrin acceptor. An unusual HOMO-HOMO electron transfer reaction from ZnP2 to the excited TPyP unit was detected and studied. |
Stengel, Ilona ; Strassert, Cristian A; De Cola, Luisa ; Baeuerle, Peter Tracking Intramolecular Interactions in Flexibly Linked Binuclear Platinum(II) Complexes Journal Article In: ORGANOMETALLICS, 33 (6), pp. 1345–1355, 2014, ISSN: 0276-7333. @article{stengel_tracking_2014, title = {Tracking Intramolecular Interactions in Flexibly Linked Binuclear Platinum(II) Complexes}, author = {Stengel, Ilona and Strassert, Cristian A. and De Cola, Luisa and Baeuerle, Peter}, doi = {10.1021/om4004237}, issn = {0276-7333}, year = {2014}, date = {2014-03-01}, journal = {ORGANOMETALLICS}, volume = {33}, number = {6}, pages = {1345--1355}, abstract = {In this work we describe the synthesis and the photophysical and electrochemical characterization of binuclear Pt-11 complexes. Using a modular click chemistry approach, we decorated different flexible bridging units with (bpy)Pt-II bisacetylides (bpy = 2,2'-bipyridine). Intramolecular excimer formation originating from Pt-II-Pt-II and pi-pi interactions was investigated by steady-state and time-resolved emission spectroscopy in dilute solution. We observed that linkers bringing the metallic centers in close proximity favor both ground-state coupling and excimer formation. These interactions lead to changes in the photophysical and electrochemical properties, which can be tuned by the choice of solvent.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this work we describe the synthesis and the photophysical and electrochemical characterization of binuclear Pt-11 complexes. Using a modular click chemistry approach, we decorated different flexible bridging units with (bpy)Pt-II bisacetylides (bpy = 2,2'-bipyridine). Intramolecular excimer formation originating from Pt-II-Pt-II and pi-pi interactions was investigated by steady-state and time-resolved emission spectroscopy in dilute solution. We observed that linkers bringing the metallic centers in close proximity favor both ground-state coupling and excimer formation. These interactions lead to changes in the photophysical and electrochemical properties, which can be tuned by the choice of solvent. |
De Cola, Luisa ; van der Wiel, Wilfred G; Luelf, Henning ; Mahato, Robin N Light and electrical responsive porous materials Journal Article In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 247 , 2014, ISSN: 0065-7727. @article{de_cola_light_2014, title = {Light and electrical responsive porous materials}, author = {De Cola, Luisa and van der Wiel, Wilfred G. and Luelf, Henning and Mahato, Robin N.}, issn = {0065-7727}, year = {2014}, date = {2014-03-01}, journal = {ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY}, volume = {247}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
De Cola, Luisa ; Mauro, Matteo ; Aliprandi, Alessandro Luminescent metal complexes and their assemblies Journal Article In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 247 , 2014, ISSN: 0065-7727. @article{de_cola_luminescent_2014, title = {Luminescent metal complexes and their assemblies}, author = {De Cola, Luisa and Mauro, Matteo and Aliprandi, Alessandro}, issn = {0065-7727}, year = {2014}, date = {2014-03-01}, journal = {ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY}, volume = {247}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Samori, Paolo Scanning probe microscopies beyond imaging: Unraveling the dynamic properties of the supramolecular world Journal Article In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 247 , 2014, ISSN: 0065-7727. @article{samori_scanning_2014, title = {Scanning probe microscopies beyond imaging: Unraveling the dynamic properties of the supramolecular world}, author = {Samori, Paolo}, issn = {0065-7727}, year = {2014}, date = {2014-03-01}, journal = {ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY}, volume = {247}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Musumeci, Chiara ; Zappala, Gabriella ; Martsinovich, Natalia ; Orgiu, Emanuele ; Schuster, Swen ; Quici, Silvio ; Zharnikov, Michael ; Troisi, Alessandro ; Licciardello, Antonino ; Samori, Paolo Nanoscale Electrical Investigation of Layer-by-Layer Grown Molecular Wires Journal Article In: ADVANCED MATERIALS, 26 (11), pp. 1688–1693, 2014, ISSN: 0935-9648. @article{musumeci_nanoscale_2014, title = {Nanoscale Electrical Investigation of Layer-by-Layer Grown Molecular Wires}, author = {Musumeci, Chiara and Zappala, Gabriella and Martsinovich, Natalia and Orgiu, Emanuele and Schuster, Swen and Quici, Silvio and Zharnikov, Michael and Troisi, Alessandro and Licciardello, Antonino and Samori, Paolo}, doi = {10.1002/adma.201304848}, issn = {0935-9648}, year = {2014}, date = {2014-03-01}, journal = {ADVANCED MATERIALS}, volume = {26}, number = {11}, pages = {1688--1693}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Orgiu, Emanuele ; Samori, Paolo 25th Anniversary Article: Organic Electronics Marries Photochromism: Generation of Multifunctional Interfaces, Materials, and Devices Journal Article In: ADVANCED MATERIALS, 26 (12), pp. 1827–1845, 2014, ISSN: 0935-9648. @article{orgiu_25th_2014, title = {25th Anniversary Article: Organic Electronics Marries Photochromism: Generation of Multifunctional Interfaces, Materials, and Devices}, author = {Orgiu, Emanuele and Samori, Paolo}, doi = {10.1002/adma.201304695}, issn = {0935-9648}, year = {2014}, date = {2014-03-01}, journal = {ADVANCED MATERIALS}, volume = {26}, number = {12}, pages = {1827--1845}, abstract = {Organic semiconductors have garnered significant interest as key components for flexible, low-cost, and large-area electronics. Hitherto, both materials and processing thereof seems to head towards a mature technology which shall ultimately meet expectations and efforts built up over the past years. However, by its own organic electronics cannot compete or complement the silicon-based electronics in integrating multiple functions in a small area unless novel solutions are brought into play. Photochromic molecules are small organic molecules able to undergo reversible photochemical isomerization between (at least) two (meta)stable states which exhibit markedly different properties. They can be embedded as additional component in organic-based materials ready to be exploited in devices such as OLEDs, OFETs, and OLETs. The structurally controlled incorporation of photochromic molecules can be done at various interfaces of a device, including the electrode/semiconductor or dielectric/semiconductor interface, or even as a binary mixture in the active layer, in order to impart a light responsive nature to the device. This can be accomplished by modulating via a light stimulus fundamental physico-chemical properties such as charge injection and transport in the device.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Organic semiconductors have garnered significant interest as key components for flexible, low-cost, and large-area electronics. Hitherto, both materials and processing thereof seems to head towards a mature technology which shall ultimately meet expectations and efforts built up over the past years. However, by its own organic electronics cannot compete or complement the silicon-based electronics in integrating multiple functions in a small area unless novel solutions are brought into play. Photochromic molecules are small organic molecules able to undergo reversible photochemical isomerization between (at least) two (meta)stable states which exhibit markedly different properties. They can be embedded as additional component in organic-based materials ready to be exploited in devices such as OLEDs, OFETs, and OLETs. The structurally controlled incorporation of photochromic molecules can be done at various interfaces of a device, including the electrode/semiconductor or dielectric/semiconductor interface, or even as a binary mixture in the active layer, in order to impart a light responsive nature to the device. This can be accomplished by modulating via a light stimulus fundamental physico-chemical properties such as charge injection and transport in the device. |
Colella, Silvia ; Ruzie, Christian ; Schweicher, Guillaume ; Arlin, Jean-Baptiste ; Karpinska, Jolanta ; Geerts, Yves ; Samori, Paolo High Mobility in Solution-Processed 2,7-Dialkyl[1] benzothieno[ 3,2-b][1] benzothiophene- Based Field- Effect Transistors Prepared with a Simplified Deposition Method Journal Article In: CHEMPLUSCHEM, 79 (3), pp. 371–374, 2014, ISSN: 2192-6506. @article{colella_high_2014, title = {High Mobility in Solution-Processed 2,7-Dialkyl[1] benzothieno[ 3,2-b][1] benzothiophene- Based Field- Effect Transistors Prepared with a Simplified Deposition Method}, author = {Colella, Silvia and Ruzie, Christian and Schweicher, Guillaume and Arlin, Jean-Baptiste and Karpinska, Jolanta and Geerts, Yves and Samori, Paolo}, doi = {10.1002/cplu.201300414}, issn = {2192-6506}, year = {2014}, date = {2014-03-01}, journal = {CHEMPLUSCHEM}, volume = {79}, number = {3}, pages = {371--374}, abstract = {A high performing solution-processed field-effect transistors based on 2,7-didodecyl[1]benzothieno[3,2-b][1]benzothiophene (C12-BTBT) has been fabricated by using a simple and straightforward two-step process. We have demonstrated that UV/ozone treatment of the Si/SiO2 substrates makes it possible to notably enhance the field-effect mobility in spin-coated C12-BTBT based OFETs reaching values as high as 2.7cm(2)V(-1)s(-1). The influence of this treatment relies essentially on the coverage of the dielectric surface, while the crystalline order remains unaffected. Importantly, the employed method is simple, cheap and easily up-scalable and provides outstanding OFET performances that are comparable to those obtained using expensive and complicated treatments.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A high performing solution-processed field-effect transistors based on 2,7-didodecyl[1]benzothieno[3,2-b][1]benzothiophene (C12-BTBT) has been fabricated by using a simple and straightforward two-step process. We have demonstrated that UV/ozone treatment of the Si/SiO2 substrates makes it possible to notably enhance the field-effect mobility in spin-coated C12-BTBT based OFETs reaching values as high as 2.7cm(2)V(-1)s(-1). The influence of this treatment relies essentially on the coverage of the dielectric surface, while the crystalline order remains unaffected. Importantly, the employed method is simple, cheap and easily up-scalable and provides outstanding OFET performances that are comparable to those obtained using expensive and complicated treatments. |
Cinti, F; Macri, T; Lechner, W; Pupillo, G; Pohl, T Defect-induced supersolidity with soft-core bosons Journal Article In: NATURE COMMUNICATIONS, 5 , 2014, ISSN: 2041-1723. @article{cinti_defect-induced_2014, title = {Defect-induced supersolidity with soft-core bosons}, author = {Cinti, F. and Macri, T. and Lechner, W. and Pupillo, G. and Pohl, T.}, doi = {10.1038/ncomms4235}, issn = {2041-1723}, year = {2014}, date = {2014-02-01}, journal = {NATURE COMMUNICATIONS}, volume = {5}, abstract = {More than 40 years ago, Andreev, Lifshitz and Chester suggested the possible existence of a peculiar solid phase of matter, the microscopic constituents of which can flow superfluidly without resistance due to the formation of zero-point defects in the ground state of self-assembled crystals. Yet, a physical system where this mechanism is unambiguously established remains to be found, both experimentally and theoretically. Here we investigate the zero-temperature phase diagram of two-dimensional bosons with finite-range soft-core interactions. For low particle densities, the system is shown to feature a solid phase in which zero-point vacancies emerge spontaneously and give rise to superfluid flow of particles through the crystal. This provides the first example of defect-induced, continuous-space supersolidity consistent with the Andreev-Lifshitz-Chester scenario.}, keywords = {}, pubstate = {published}, tppubtype = {article} } More than 40 years ago, Andreev, Lifshitz and Chester suggested the possible existence of a peculiar solid phase of matter, the microscopic constituents of which can flow superfluidly without resistance due to the formation of zero-point defects in the ground state of self-assembled crystals. Yet, a physical system where this mechanism is unambiguously established remains to be found, both experimentally and theoretically. Here we investigate the zero-temperature phase diagram of two-dimensional bosons with finite-range soft-core interactions. For low particle densities, the system is shown to feature a solid phase in which zero-point vacancies emerge spontaneously and give rise to superfluid flow of particles through the crystal. This provides the first example of defect-induced, continuous-space supersolidity consistent with the Andreev-Lifshitz-Chester scenario. |
Durola, Fabien ; Heitz, Valerie ; Reviriego, Felipe ; Roche, Cecile ; Sauvage, Jean-Pierre ; Sour, Angelique ; Trolez, Yann Cyclic [4]Rotaxanes Containing Two Parallel Porphyrinic Plates: Toward Switchable Molecular Receptors and Compressors Journal Article In: ACCOUNTS OF CHEMICAL RESEARCH, 47 (2), pp. 633–645, 2014, ISSN: 0001-4842. @article{durola_cyclic_2014, title = {Cyclic [4]Rotaxanes Containing Two Parallel Porphyrinic Plates: Toward Switchable Molecular Receptors and Compressors}, author = {Durola, Fabien and Heitz, Valerie and Reviriego, Felipe and Roche, Cecile and Sauvage, Jean-Pierre and Sour, Angelique and Trolez, Yann}, doi = {10.1021/ar4002153}, issn = {0001-4842}, year = {2014}, date = {2014-02-01}, journal = {ACCOUNTS OF CHEMICAL RESEARCH}, volume = {47}, number = {2}, pages = {633--645}, abstract = {Twenty years ago, researchers considered the synthesis of simple rotaxanes a challenging task, but with the rapid development of this field, chemists now view these interlocking molecules as accessible synthetic targets. In a major advance for the field, researchers have developed transition metals or organic molecules as templating structures, making it easier to construct these molecular systems. In addition, chemists have found ways to introduce new functional groups, which have given these compounds new properties. Today researchers can also construct multirotaxanes consisting of several individual components, but the synthesis of the most complex structures remains challenging. This Account primarily discusses the cyclic [4]rotaxanes incorporating porphyrins that the Strasbourg group has synthesized and studied during the past few years. These cyclic [4]rotaxanes consist of two rigid rods threaded through the four rings of two molecules of a bis-macrocycle, and the synthetic strategy used for making them relies on the copper(I)-driven “gathering-and-threading' reaction. The formation of the threaded precursors was mostly quantitative, and the quadruple stoppering reaction leading to the target compound produces high yields because of the efficient copper-catalyzed azide-alkyne cycloaddition (CuAAC) or click chemistry reaction. These rotaxanes behave as receptors for various ditopic guests. We prepared and studied two types of molecules: (i) a rigid compound whose copper(I) complex has a well-defined shape, with high selectivity for the guest geometry and (ii) a much more flexible [4]rotaxane host that could act as a distensible receptor. The rigid [4]rotaxane was crystallized, affording a spectacular X-ray structure that matched the expected chemical structure. In addition, metalation or demetalation of the rigid [4]rotaxane induces a drastic geometric rearrangement. The metal-free compound is flat without a binding pocket, while the copper-complexed species forms a rectangle-like structure. The removal of copper(I) also expels any complexed guest molecule, and this process is reversible, making the rigid porphyrinic [4]rotaxane a switchable receptor. The rigid [4]rotaxane was highly selective for short, ditopic guests In its copper(I)-complexed form, but the flexible copper(I)-complexed [4]rotaxane proved to be a versatile receptor. Its conformation can adjust to the size of the guest molecule similar to the induced fit mechanism that some enzymes employ with substrates.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Twenty years ago, researchers considered the synthesis of simple rotaxanes a challenging task, but with the rapid development of this field, chemists now view these interlocking molecules as accessible synthetic targets. In a major advance for the field, researchers have developed transition metals or organic molecules as templating structures, making it easier to construct these molecular systems. In addition, chemists have found ways to introduce new functional groups, which have given these compounds new properties. Today researchers can also construct multirotaxanes consisting of several individual components, but the synthesis of the most complex structures remains challenging. This Account primarily discusses the cyclic [4]rotaxanes incorporating porphyrins that the Strasbourg group has synthesized and studied during the past few years. These cyclic [4]rotaxanes consist of two rigid rods threaded through the four rings of two molecules of a bis-macrocycle, and the synthetic strategy used for making them relies on the copper(I)-driven “gathering-and-threading' reaction. The formation of the threaded precursors was mostly quantitative, and the quadruple stoppering reaction leading to the target compound produces high yields because of the efficient copper-catalyzed azide-alkyne cycloaddition (CuAAC) or click chemistry reaction. These rotaxanes behave as receptors for various ditopic guests. We prepared and studied two types of molecules: (i) a rigid compound whose copper(I) complex has a well-defined shape, with high selectivity for the guest geometry and (ii) a much more flexible [4]rotaxane host that could act as a distensible receptor. The rigid [4]rotaxane was crystallized, affording a spectacular X-ray structure that matched the expected chemical structure. In addition, metalation or demetalation of the rigid [4]rotaxane induces a drastic geometric rearrangement. The metal-free compound is flat without a binding pocket, while the copper-complexed species forms a rectangle-like structure. The removal of copper(I) also expels any complexed guest molecule, and this process is reversible, making the rigid porphyrinic [4]rotaxane a switchable receptor. The rigid [4]rotaxane was highly selective for short, ditopic guests In its copper(I)-complexed form, but the flexible copper(I)-complexed [4]rotaxane proved to be a versatile receptor. Its conformation can adjust to the size of the guest molecule similar to the induced fit mechanism that some enzymes employ with substrates. |
Prasetyanto, Eko Adi ; Manini, Paola ; Napolitano, Alessandra ; Crescenzi, Orlando ; d'Ischia , Marco ; De Cola, Luisa Towards Eumelanin@Zeolite Hybrids: Pore-Size-Controlled 5,6-Dihydroxyindole Polymerization Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (6), pp. 1597–1601, 2014, ISSN: 0947-6539. @article{prasetyanto_towards_2014, title = {Towards Eumelanin@Zeolite Hybrids: Pore-Size-Controlled 5,6-Dihydroxyindole Polymerization}, author = {Prasetyanto, Eko Adi and Manini, Paola and Napolitano, Alessandra and Crescenzi, Orlando and d'Ischia, Marco and De Cola, Luisa}, doi = {10.1002/chem.201303682}, issn = {0947-6539}, year = {2014}, date = {2014-02-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {20}, number = {6}, pages = {1597--1601}, abstract = {5,6-Dihydroxyindole (1) and its N-methyl derivative (2), key eumelanin building blocks, were inserted into zeolite L by sublimation at 175 degrees C for 5 days. At a 10 mg/300 mg indole/zeolite ratio, the resulting hybrids displayed a stable deep red coloration. CP/MAS C-13 NMR and UV/Vis spectroscopy of the red species suggested the generation and accommodation of quinonoid biindole derivative(s) within the void space of the acidic zeolite channels. Removal of the zeolite matrix by treatment with HF gave a stable species that could be separated by HPLC and characterized by mass spectrometry as an oxygenated biindole derivative (or a mixture of isomers), suggesting addition of water to the original dimer and subsequent re-oxidation. The characterization was corroborated by optimized molecular geometries and simulated UV spectra with density functional calculations. Loading 1 or 2 into the larger pores of SBA-15 type mesoporous silica resulted in black eumelanin-type polymers, confirming channel size dependence over the polymerization process.}, keywords = {}, pubstate = {published}, tppubtype = {article} } 5,6-Dihydroxyindole (1) and its N-methyl derivative (2), key eumelanin building blocks, were inserted into zeolite L by sublimation at 175 degrees C for 5 days. At a 10 mg/300 mg indole/zeolite ratio, the resulting hybrids displayed a stable deep red coloration. CP/MAS C-13 NMR and UV/Vis spectroscopy of the red species suggested the generation and accommodation of quinonoid biindole derivative(s) within the void space of the acidic zeolite channels. Removal of the zeolite matrix by treatment with HF gave a stable species that could be separated by HPLC and characterized by mass spectrometry as an oxygenated biindole derivative (or a mixture of isomers), suggesting addition of water to the original dimer and subsequent re-oxidation. The characterization was corroborated by optimized molecular geometries and simulated UV spectra with density functional calculations. Loading 1 or 2 into the larger pores of SBA-15 type mesoporous silica resulted in black eumelanin-type polymers, confirming channel size dependence over the polymerization process. |
Ramachandra, Srinidhi ; Strassert, Cristian Alejandro ; Reinhoudt, David N; Vanmaekelbergh, Daniel ; De Cola, Luisa Bidirectional Photoinduced Energy Transfer in Nanoassemblies of Quantum Dots and Luminescent Metal Complexes Journal Article In: ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES, 69 (2), pp. 263–274, 2014, ISSN: 0932-0776. @article{ramachandra_bidirectional_2014, title = {Bidirectional Photoinduced Energy Transfer in Nanoassemblies of Quantum Dots and Luminescent Metal Complexes}, author = {Ramachandra, Srinidhi and Strassert, Cristian Alejandro and Reinhoudt, David N. and Vanmaekelbergh, Daniel and De Cola, Luisa}, doi = {10.5560/ZNB.2014-3323}, issn = {0932-0776}, year = {2014}, date = {2014-02-01}, journal = {ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES}, volume = {69}, number = {2}, pages = {263--274}, abstract = {This work describes the synthesis and photophysical characterization of Ir(III) and R(II)) complexes bearing terminal amino groups, which act as anchoring units for the attachment to quantum dots, QDs. The photophysical properties of the metal complexes in combination with different types of QDs, allows directional photoinduced processes in the assemblies. In particular, we show photoinduced energy transfer from the luminescent excited Ir(III) unit to the CdTe nanocrystals, with an efficiency of 40%. The directionality was then inverted by employing an emitting Ru(II) complex as energy acceptor, in combination with photoluminescent CdSe/ZnS quantum dots. The efficiency of the photoinduced energy transfer from the nanocrystals to the Ru(II) center was estimated to be as high as 75%. This work provides model systems for nanoassemblies based on quantum dots and metal complexes for optoelectronic applications, and as active light-harvesting systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This work describes the synthesis and photophysical characterization of Ir(III) and R(II)) complexes bearing terminal amino groups, which act as anchoring units for the attachment to quantum dots, QDs. The photophysical properties of the metal complexes in combination with different types of QDs, allows directional photoinduced processes in the assemblies. In particular, we show photoinduced energy transfer from the luminescent excited Ir(III) unit to the CdTe nanocrystals, with an efficiency of 40%. The directionality was then inverted by employing an emitting Ru(II) complex as energy acceptor, in combination with photoluminescent CdSe/ZnS quantum dots. The efficiency of the photoinduced energy transfer from the nanocrystals to the Ru(II) center was estimated to be as high as 75%. This work provides model systems for nanoassemblies based on quantum dots and metal complexes for optoelectronic applications, and as active light-harvesting systems. |
Mosciatti, Thomas ; Orgiu, Emanuele ; Raimondo, Corinna ; Samori, Paolo The role of size and coating in Au nanoparticles incorporated into bi-component polymeric thin-film transistors Journal Article In: NANOSCALE, 6 (10), pp. 5075–5080, 2014, ISSN: 2040-3364. @article{mosciatti_role_2014, title = {The role of size and coating in Au nanoparticles incorporated into bi-component polymeric thin-film transistors}, author = {Mosciatti, Thomas and Orgiu, Emanuele and Raimondo, Corinna and Samori, Paolo}, doi = {10.1039/c4nr00076e}, issn = {2040-3364}, year = {2014}, date = {2014-01-01}, journal = {NANOSCALE}, volume = {6}, number = {10}, pages = {5075--5080}, abstract = {We describe the effect of blending poly(3-hexylthiophene) (P3HT) with Au nanoparticles (AuNPs) on the performance of organic thin-film transistors. To this end we have used AuNPs of two different sizes coated with chemisorbed SAMs of oligophenyl-thiols possessing increasing lengths. The electrical characteristics of the hybrid materials revealed changes in the field-effect mobility depending primarily on the AuNP size, as a result of the variable energy level of the coated metallic nanocluster and by the degree of modification of the P3HT crystalline structure.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We describe the effect of blending poly(3-hexylthiophene) (P3HT) with Au nanoparticles (AuNPs) on the performance of organic thin-film transistors. To this end we have used AuNPs of two different sizes coated with chemisorbed SAMs of oligophenyl-thiols possessing increasing lengths. The electrical characteristics of the hybrid materials revealed changes in the field-effect mobility depending primarily on the AuNP size, as a result of the variable energy level of the coated metallic nanocluster and by the degree of modification of the P3HT crystalline structure. |
Mativetsky, Jeffrey M; Loo, Yueh-Lin ; Samori, Paolo Elucidating the nanoscale origins of organic electronic function by conductive atomic force microscopy Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 2 (17), pp. 3118–3128, 2014, ISSN: 2050-7526. @article{mativetsky_elucidating_2014, title = {Elucidating the nanoscale origins of organic electronic function by conductive atomic force microscopy}, author = {Mativetsky, Jeffrey M. and Loo, Yueh-Lin and Samori, Paolo}, doi = {10.1039/c3tc32050b}, issn = {2050-7526}, year = {2014}, date = {2014-01-01}, journal = {JOURNAL OF MATERIALS CHEMISTRY C}, volume = {2}, number = {17}, pages = {3118--3128}, abstract = {Electronic and optoelectronic devices comprising organic materials are highly promising for mechanically flexible and low-cost applications. In recent years, conductive atomic force microscopy (C-AFM) has played a significant part in deciphering the nanoscopic and mesoscopic origins of organic electronic function. C-AFM is uniquely capable of measuring local electrical properties with nanoscale resolution; moreover, in conjunction with complementary atomic force microscope modes, C-AFM enables simultaneous mapping of nanoscale structure and electrical function. This feature article highlights recent progress in applying C-AFM to characterize organic electronic systems including self-assembled monolayers, graphene and related materials, organic semiconductors, and organic photovoltaic heterojunctions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Electronic and optoelectronic devices comprising organic materials are highly promising for mechanically flexible and low-cost applications. In recent years, conductive atomic force microscopy (C-AFM) has played a significant part in deciphering the nanoscopic and mesoscopic origins of organic electronic function. C-AFM is uniquely capable of measuring local electrical properties with nanoscale resolution; moreover, in conjunction with complementary atomic force microscope modes, C-AFM enables simultaneous mapping of nanoscale structure and electrical function. This feature article highlights recent progress in applying C-AFM to characterize organic electronic systems including self-assembled monolayers, graphene and related materials, organic semiconductors, and organic photovoltaic heterojunctions. |
Schlierf, A; Samori, P; Palermo, V Graphene-organic composites for electronics: optical and electronic interactions in vacuum, liquids and thin solid films Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 2 (17), pp. 3129–3143, 2014, ISSN: 2050-7526. @article{schlierf_graphene-organic_2014, title = {Graphene-organic composites for electronics: optical and electronic interactions in vacuum, liquids and thin solid films}, author = {Schlierf, A. and Samori, P. and Palermo, V.}, doi = {10.1039/c3tc32153c}, issn = {2050-7526}, year = {2014}, date = {2014-01-01}, journal = {JOURNAL OF MATERIALS CHEMISTRY C}, volume = {2}, number = {17}, pages = {3129--3143}, abstract = {Graphene exhibits exceptional mechanical, optical and electrical properties that are unfortunately accompanied by poor processability and tunability of its properties. The controlled interaction of graphene with tailor-made organic semiconductors (OSs) can offer a solution to solve these two problems simultaneously. The use of well-chosen organic semiconducting molecules interacting with graphene enables optimal control over the molecular self-assembly process forming low-dimensional graphene-organic architectures. Moreover, OSs allow modulation of numerous physical and chemical properties of graphene, including controlled electrical doping, ultimately making it possible to boost the performance of conventional organic electronic devices. Significantly, the interaction of organic molecules with graphene is strong not only at short distances but it is relevant also at longer distances, up to 30 nm. This feature article reviews some of the most enlightening results in the field, giving an overview of the interaction between graphene and organic molecules, starting from the simplest systems at the molecular scale, single molecules on single layer graphene in UHV, up to mesoscopic, more complex systems i.e., thick interpenetrated layers of graphene-organic composites embedded in working electronic or photovoltaic devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Graphene exhibits exceptional mechanical, optical and electrical properties that are unfortunately accompanied by poor processability and tunability of its properties. The controlled interaction of graphene with tailor-made organic semiconductors (OSs) can offer a solution to solve these two problems simultaneously. The use of well-chosen organic semiconducting molecules interacting with graphene enables optimal control over the molecular self-assembly process forming low-dimensional graphene-organic architectures. Moreover, OSs allow modulation of numerous physical and chemical properties of graphene, including controlled electrical doping, ultimately making it possible to boost the performance of conventional organic electronic devices. Significantly, the interaction of organic molecules with graphene is strong not only at short distances but it is relevant also at longer distances, up to 30 nm. This feature article reviews some of the most enlightening results in the field, giving an overview of the interaction between graphene and organic molecules, starting from the simplest systems at the molecular scale, single molecules on single layer graphene in UHV, up to mesoscopic, more complex systems i.e., thick interpenetrated layers of graphene-organic composites embedded in working electronic or photovoltaic devices. |
Ciesielski, Artur ; Samori, Paolo Graphene via sonication assisted liquid-phase exfoliation Journal Article In: CHEMICAL SOCIETY REVIEWS, 43 (1), pp. 381–398, 2014, ISSN: 0306-0012. @article{ciesielski_graphene_2014, title = {Graphene via sonication assisted liquid-phase exfoliation}, author = {Ciesielski, Artur and Samori, Paolo}, doi = {10.1039/c3cs60217f}, issn = {0306-0012}, year = {2014}, date = {2014-01-01}, journal = {CHEMICAL SOCIETY REVIEWS}, volume = {43}, number = {1}, pages = {381--398}, abstract = {Graphene, the 2D form of carbon based material existing as a single layer of atoms arranged in a honeycomb lattice, has set the science and technology sectors alight with interest in the last decade in view of its astounding electrical and thermal properties, combined with its mechanical stiffness, strength and elasticity. Two distinct strategies have been undertaken for graphene production, i.e. the bottom-up and the top-down. The former relies on the generation of graphene from suitably designed molecular building blocks undergoing chemical reaction to form covalently linked 2D networks. The latter occurs via exfoliation of graphite into graphene. Bottom-up techniques, based on the organic syntheses starting from small molecular modules, when performed in liquid media, are both size limited, because macromolecules become more and more insoluble with increasing size, and suffer from the occurrence of side reactions with increasing molecular weight. Because of these reasons such a synthesis has been performed more and more on a solid (ideally catalytically active) surface. Substrate-based growth of single layers can be done also by chemical vapor deposition (CVD) or via reduction of silicon carbide, which unfortunately relies on the ability to follow a narrow thermodynamic path. Top-down approaches can be accomplished under different environmental conditions. Alongside the mechanical cleavage based on the scotch tape approach, liquid-phase exfoliation (LPE) methods are becoming more and more interesting because they are extremely versatile, potentially up-scalable, and can be used to deposit graphene in a variety of environments and on different substrates not available using mechanical cleavage or growth methods. Interestingly, LPE can be applied to produce different layered systems exhibiting different compositions such as BN, MoS2, WS2, NbSe2, and TaS2, thereby enabling the tuning of numerous physico-chemical properties of the material. Furthermore, LPE can be employed to produce graphene-based composites or films, which are key components for many applications, such as thin-film transistors, conductive transparent electrodes for indium tin oxide replacement, e. g. in light-emitting diodes, or photovoltaics. In this review, we highlight the recent progress that has led to successful production of high quality graphene by means of LPE of graphite. In particular, we discuss the mechanisms of exfoliation and methods that are employed for graphene characterization. We then describe a variety of successful liquid-phase exfoliation methods by categorizing them into two major classes, i.e. surfactant-free and surfactant-assisted LPE. Furthermore, exfoliation in aqueous and organic solutions is presented and discussed separately.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Graphene, the 2D form of carbon based material existing as a single layer of atoms arranged in a honeycomb lattice, has set the science and technology sectors alight with interest in the last decade in view of its astounding electrical and thermal properties, combined with its mechanical stiffness, strength and elasticity. Two distinct strategies have been undertaken for graphene production, i.e. the bottom-up and the top-down. The former relies on the generation of graphene from suitably designed molecular building blocks undergoing chemical reaction to form covalently linked 2D networks. The latter occurs via exfoliation of graphite into graphene. Bottom-up techniques, based on the organic syntheses starting from small molecular modules, when performed in liquid media, are both size limited, because macromolecules become more and more insoluble with increasing size, and suffer from the occurrence of side reactions with increasing molecular weight. Because of these reasons such a synthesis has been performed more and more on a solid (ideally catalytically active) surface. Substrate-based growth of single layers can be done also by chemical vapor deposition (CVD) or via reduction of silicon carbide, which unfortunately relies on the ability to follow a narrow thermodynamic path. Top-down approaches can be accomplished under different environmental conditions. Alongside the mechanical cleavage based on the scotch tape approach, liquid-phase exfoliation (LPE) methods are becoming more and more interesting because they are extremely versatile, potentially up-scalable, and can be used to deposit graphene in a variety of environments and on different substrates not available using mechanical cleavage or growth methods. Interestingly, LPE can be applied to produce different layered systems exhibiting different compositions such as BN, MoS2, WS2, NbSe2, and TaS2, thereby enabling the tuning of numerous physico-chemical properties of the material. Furthermore, LPE can be employed to produce graphene-based composites or films, which are key components for many applications, such as thin-film transistors, conductive transparent electrodes for indium tin oxide replacement, e. g. in light-emitting diodes, or photovoltaics. In this review, we highlight the recent progress that has led to successful production of high quality graphene by means of LPE of graphite. In particular, we discuss the mechanisms of exfoliation and methods that are employed for graphene characterization. We then describe a variety of successful liquid-phase exfoliation methods by categorizing them into two major classes, i.e. surfactant-free and surfactant-assisted LPE. Furthermore, exfoliation in aqueous and organic solutions is presented and discussed separately. |
Hirsch, Anna K H; Reutenauer, Philippe ; Le Moignan, Marc ; Ulrich, Sebastien ; Boul, Peter J; Harrowfield, Jack M; Jarowski, Peter D; Lehn, Jean-Marie Theoretical and Structural Analysis of Long C-C Bonds in the Adducts of Polycyanoethylene and Anthracene Derivatives and Their Connection to the Reversibility of Diels-Alder Reactions Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (4), pp. 1073–1080, 2014, ISSN: 0947-6539. @article{hirsch_theoretical_2014, title = {Theoretical and Structural Analysis of Long C-C Bonds in the Adducts of Polycyanoethylene and Anthracene Derivatives and Their Connection to the Reversibility of Diels-Alder Reactions}, author = {Hirsch, Anna K. H. and Reutenauer, Philippe and Le Moignan, Marc and Ulrich, Sebastien and Boul, Peter J. and Harrowfield, Jack M. and Jarowski, Peter D. and Lehn, Jean-Marie}, doi = {10.1002/chem.201303276}, issn = {0947-6539}, year = {2014}, date = {2014-01-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {20}, number = {4}, pages = {1073--1080}, abstract = {X-ray structure determinations on four Diels-Alder adducts derived from the reactions of cyano- and ester-substituted alkenes with anthracene and 9,10-dimethylanthracene have shown the bonds formed in the adduction to be particularly long. Their lengths range from 1.58 to 1.62 angstrom, some of the longest known for Diels-Alder adducts. Formation of the four adducts is detectably reversible at ambient temperature and is associated with free energies of reaction ranging from -2.5 to -40.6kJmol(-1). The solution equilibria have been experimentally characterised by NMR spectroscopy. Density-functional-theory calculations at the MPW1K/6-31+G(d,p) level with PCM solvation agree with experiment with average errors of 6kJmol(-1) in free energies of reaction and structural agreement in adduct bond lengths of 0.013 angstrom. To understand more fully the cause of the reversibility and its relationship to the long adduct bond lengths, natural-bond-orbital (NBO) analysis was applied to quantify donor-acceptor interactions within the molecules. Both electron donation into the sigma*-anti-bonding orbital of the adduct bond and electron withdrawal from the sigma-bonding orbital are found to be responsible for this bond elongation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } X-ray structure determinations on four Diels-Alder adducts derived from the reactions of cyano- and ester-substituted alkenes with anthracene and 9,10-dimethylanthracene have shown the bonds formed in the adduction to be particularly long. Their lengths range from 1.58 to 1.62 angstrom, some of the longest known for Diels-Alder adducts. Formation of the four adducts is detectably reversible at ambient temperature and is associated with free energies of reaction ranging from -2.5 to -40.6kJmol(-1). The solution equilibria have been experimentally characterised by NMR spectroscopy. Density-functional-theory calculations at the MPW1K/6-31+G(d,p) level with PCM solvation agree with experiment with average errors of 6kJmol(-1) in free energies of reaction and structural agreement in adduct bond lengths of 0.013 angstrom. To understand more fully the cause of the reversibility and its relationship to the long adduct bond lengths, natural-bond-orbital (NBO) analysis was applied to quantify donor-acceptor interactions within the molecules. Both electron donation into the sigma*-anti-bonding orbital of the adduct bond and electron withdrawal from the sigma-bonding orbital are found to be responsible for this bond elongation. |
Schaeffer, Gael ; Fuhr, Olaf ; Fenske, Dieter ; Lehn, Jean-Marie Self-Assembly of a Highly Organized, Hexameric Supramolecular Architecture: Formation, Structure and Properties Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (1), pp. 179–186, 2014, ISSN: 0947-6539. @article{schaeffer_self-assembly_2014, title = {Self-Assembly of a Highly Organized, Hexameric Supramolecular Architecture: Formation, Structure and Properties}, author = {Schaeffer, Gael and Fuhr, Olaf and Fenske, Dieter and Lehn, Jean-Marie}, doi = {10.1002/chem.201303186}, issn = {0947-6539}, year = {2014}, date = {2014-01-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {20}, number = {1}, pages = {179--186}, abstract = {Two derivatives, L-3 and L-9, of a ditopic, multiply hydrogen-bonding molecule, known for more than a decade, have been found, in the solid state as well as in solvents of low polarity at room temperature, to exist not as monomers, but to undergo a remarkable self-assembly into a complex supramolecular species. The solid-state molecular structure of L-3, determined by single-crystal X-ray crystallography, revealed that it forms a highly organized hexameric entity L-3(6) with a capsular shape, resulting from the interlocking of two sets of three monomolecular components, linked through hydrogen-bonding interactions. The complicated (HNMR)-H-1 spectra observed in o-dichlorobenzene (o-DCB) for L-3 and L-9 are consistent with the presence of a hexamer of D-3 symmetry in both cases. DOSY measurements confirm the hexameric constitution in solution. In contrast, in a hydrogen-bond-disrupting solvent, such as DMSO, the (HNMR)-H-1 spectra are very simple and consistent with the presence of isolated monomers only. Extensive temperature-dependent (HNMR)-H-1 studies in o-DCB showed that the L-6 species dissociated progressively into the monomeric unit on increasing th temperature, up to complete dissociation at about 90 degrees C. The coexistence of the hexamer and the monomer indicated that exchange was slow on the NMR timescale. Remarkably, no species other than hexamer and monomer were detected in the equilibrating mixtures. The relative amounts of each entity showed a reversible sigmoidal variation with temperature, indicating that the assembly proceeded with positive cooperativity. A full thermodynamic analysis has been applied to the data.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two derivatives, L-3 and L-9, of a ditopic, multiply hydrogen-bonding molecule, known for more than a decade, have been found, in the solid state as well as in solvents of low polarity at room temperature, to exist not as monomers, but to undergo a remarkable self-assembly into a complex supramolecular species. The solid-state molecular structure of L-3, determined by single-crystal X-ray crystallography, revealed that it forms a highly organized hexameric entity L-3(6) with a capsular shape, resulting from the interlocking of two sets of three monomolecular components, linked through hydrogen-bonding interactions. The complicated (HNMR)-H-1 spectra observed in o-dichlorobenzene (o-DCB) for L-3 and L-9 are consistent with the presence of a hexamer of D-3 symmetry in both cases. DOSY measurements confirm the hexameric constitution in solution. In contrast, in a hydrogen-bond-disrupting solvent, such as DMSO, the (HNMR)-H-1 spectra are very simple and consistent with the presence of isolated monomers only. Extensive temperature-dependent (HNMR)-H-1 studies in o-DCB showed that the L-6 species dissociated progressively into the monomeric unit on increasing th temperature, up to complete dissociation at about 90 degrees C. The coexistence of the hexamer and the monomer indicated that exchange was slow on the NMR timescale. Remarkably, no species other than hexamer and monomer were detected in the equilibrating mixtures. The relative amounts of each entity showed a reversible sigmoidal variation with temperature, indicating that the assembly proceeded with positive cooperativity. A full thermodynamic analysis has been applied to the data. |
Greb, Daniel ; Lehn, Christian Base Manifolds for Lagrangian Fibrations on Hyperkahler Manifolds Journal Article In: INTERNATIONAL MATHEMATICS RESEARCH NOTICES, (19), pp. 5483–5487, 2014, ISSN: 1073-7928. @article{greb_base_2014, title = {Base Manifolds for Lagrangian Fibrations on Hyperkahler Manifolds}, author = {Greb, Daniel and Lehn, Christian}, doi = {10.1093/imrn/rnt133}, issn = {1073-7928}, year = {2014}, date = {2014-01-01}, journal = {INTERNATIONAL MATHEMATICS RESEARCH NOTICES}, number = {19}, pages = {5483--5487}, abstract = {Let f: X -textbackslashtextbackslashtextgreater B be a fibration from a hyperkahler manifold to a complex space B. Assuming that B is smooth, we show that B congruent to P-n. This generalizes a theorem of Hwang to the Kahler case.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Let f: X -textbackslashtextbackslashtextgreater B be a fibration from a hyperkahler manifold to a complex space B. Assuming that B is smooth, we show that B congruent to P-n. This generalizes a theorem of Hwang to the Kahler case. |
Yang, Qing-Yuan ; Wu, Kai ; Jiang, Ji-Jun ; Hsu, Chien-Wei ; Pan, Mei ; Lehn, Jean-Marie ; Su, Cheng-Yong Pure white-light and yellow-to-blue emission tuning in single crystals of Dy(III) metal-organic frameworks Journal Article In: CHEMICAL COMMUNICATIONS, 50 (57), pp. 7702–7704, 2014, ISSN: 1359-7345. @article{yang_pure_2014, title = {Pure white-light and yellow-to-blue emission tuning in single crystals of Dy(III) metal-organic frameworks}, author = {Yang, Qing-Yuan and Wu, Kai and Jiang, Ji-Jun and Hsu, Chien-Wei and Pan, Mei and Lehn, Jean-Marie and Su, Cheng-Yong}, doi = {10.1039/c4cc01763c}, issn = {1359-7345}, year = {2014}, date = {2014-01-01}, journal = {CHEMICAL COMMUNICATIONS}, volume = {50}, number = {57}, pages = {7702--7704}, abstract = {Direct white-light emission was first achieved in a single phase material of a Dy(III) metal-organic framework, which also shows tunable yellow-to-blue photoluminescence upon variation of excitation wavelengths.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Direct white-light emission was first achieved in a single phase material of a Dy(III) metal-organic framework, which also shows tunable yellow-to-blue photoluminescence upon variation of excitation wavelengths. |
Publications
2014 |
Breaking the dichotomy of reactivity vs. chemoselectivity in catalytic S(N)1 reactions of alcohols Journal Article In: ORGANIC & BIOMOLECULAR CHEMISTRY, 12 (31), pp. 5990–5994, 2014, ISSN: 1477-0520. |
Allosteric regulation of pentameric ligand-gated ion channels An emerging mechanistic perspective Journal Article In: CHANNELS, 8 (4), pp. 350–360, 2014, ISSN: 1933-6950. |
Multifunctional Inorganic Nanocontainers for DNA and Drug Delivery into Living Cells Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (35, SI), pp. 10900–10904, 2014, ISSN: 0947-6539. |
Vectorial Diffusion for Facile Solution-Processed Self-Assembly of Insoluble Semiconductors: A Case Study on Metal Phthalocyanines Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (35, SI), pp. 10990–10995, 2014, ISSN: 0947-6539. |
Assembling metal complexes for tuning their photophysical properties Journal Article In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 248 , 2014, ISSN: 0065-7727. |
Porous (nano)materials: Properties, self-assembly, and applications Journal Article In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 248 , 2014, ISSN: 0065-7727. |
Design, synthesis and characterization luminescent new materials by self-assembly of copper nanoclusters/Cu(I) complexes in nanoporous materials Journal Article In: LUMINESCENCE, 29 (1, SI), pp. 43–44, 2014, ISSN: 1522-7235. |
Photoswitching Azobenzene Derivatives in Single Molecule Junctions: A Theoretical Insight into the I/V Characteristics Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY C, 118 (32), pp. 18721–18729, 2014, ISSN: 1932-7447. |
Light-induced reversible modification of the work function of a new perfluorinated biphenyl azobenzene chemisorbed on Au (111) Journal Article In: NANOSCALE, 6 (15), pp. 8969–8977, 2014, ISSN: 2040-3364. |
Synthetic Polyamine BPA-C8 Inhibits TGF-beta 1-Mediated Conversion of Human Dermal Fibroblast to Myofibroblasts and Establishment of Galectin-1-Rich Extracellular Matrix in Vitro Journal Article In: CHEMBIOCHEM, 15 (10), pp. 1465–1470, 2014, ISSN: 1439-4227. |
Adaptation in Constitutional Dynamic Libraries and Networks, Switching between Orthogonal Metalloselection and Photoselection Processes Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 136 (26), pp. 9509–9518, 2014, ISSN: 0002-7863. |
Molecular Muscles: From Species in Solution to Materials and Devices Journal Article In: CHEMISTRY LETTERS, 43 (7), pp. 964–974, 2014, ISSN: 0366-7022. |
Protrusion Fluctuations Direct Cell Motion Journal Article In: BIOPHYSICAL JOURNAL, 107 (1), pp. 34–42, 2014, ISSN: 0006-3495. |
Leveraging the Ambipolar Transport in Polymeric Field-Effect Transistors via Blending with Liquid-Phase Exfoliated Graphene Journal Article In: ADVANCED MATERIALS, 26 (28), pp. 4814+, 2014, ISSN: 0935-9648. |
Multivalency by Self-Assembly: Binding of ConcanavalinA to Metallosupramolecular Architectures Decorated with Multiple Carbohydrate Groups Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (23), pp. 6960–6977, 2014, ISSN: 0947-6539. |
Myo- inositol trispyrophosphate- mediated hypoxia reversion controls pancreatic cancer in rodents and enhances gemcitabine efficacy Journal Article In: INTERNATIONAL JOURNAL OF CANCER, 134 (11), pp. 2572–2582, 2014, ISSN: 0020-7136. |
Cu(I)/Zn2+ exchange has no geometrical effect in a cyclic [4]rotaxane whereas it induces rearrangement in a simpler [3]rotaxane Journal Article In: INORGANICA CHIMICA ACTA, 417 , pp. 186–191, 2014, ISSN: 0020-1693. |
Plasmonic crystal enhanced refractive index sensing Journal Article In: APPLIED PHYSICS LETTERS, 104 (25), 2014, ISSN: 0003-6951. |
Titanium Dioxide Mesoporous Electrodes for Solid-State Dye-Sensitized Solar Cells: Cross-Analysis of the Critical Parameters Journal Article In: ADVANCED ENERGY MATERIALS, 4 (9), 2014, ISSN: 1614-6832. |
Ferromagnetic Coupling in Copper(II) [2 x 2] Grid-like Complexes Journal Article In: INORGANIC CHEMISTRY, 53 (9), pp. 4275–4277, 2014, ISSN: 0020-1669. |
Investigations of alpha-helix textbackslashtextbackslashtextless-textbackslashtextbackslashtextgreaterbeta-sheet transition pathways in a miniprotein using the finite-temperature string method Journal Article In: JOURNAL OF CHEMICAL PHYSICS, 140 (17), 2014, ISSN: 0021-9606. |
NIR Dual Luminescence from an Extended Porphyrin. Spectroscopy, Photophysics and Theory Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY A, 118 (20), pp. 3616–3624, 2014, ISSN: 1089-5639. |
A Facile Solution-Doping Method to Improve a LowTemperature Zinc Oxide Precursor: Towards Low-Cost Electronics on Plastic Foil Journal Article In: ADVANCED FUNCTIONAL MATERIALS, 24 (17), pp. 2537–2543, 2014, ISSN: 1616-301X. |
Bright White- Light Emission from a Single Organic Compound in the Solid State Journal Article In: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 53 (18), pp. 4572–4577, 2014, ISSN: 1433-7851. |
First Passage Analysis of the Folding of a beta-Sheet Miniprotein: Is it More Realistic Than the Standard Equilibrium Approach? Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY B, 118 (16), pp. 4287–4299, 2014, ISSN: 1520-6106. |
Reconfigurable Long-Range Phonon Dynamics in Optomechanical Arrays Journal Article In: PHYSICAL REVIEW LETTERS, 112 (13), 2014, ISSN: 0031-9007. |
Interconversion between a Vertically Oriented Transition Metal-Complexed Figure-of-Eight and a Horizontally Disposed One Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 136 (16), pp. 5876–5879, 2014, ISSN: 0002-7863. |
Quantum Yield of Polariton Emission from Hybrid Light-Matter States Journal Article In: JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 5 (8), pp. 1433–1439, 2014, ISSN: 1948-7185. |
Beaming Visible Light with a Plasmonic Aperture Antenna Journal Article In: ACS PHOTONICS, 1 (4), pp. 365–370, 2014, ISSN: 2330-4022. |
Coupled Nanomechanical Motions: Metal-Ion-Effected, pH-Modulated, Simultaneous Extension/Contraction Motions of Double-Domain Helical/Linear Molecular Strands Journal Article In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 136 (9), pp. 3400–3409, 2014, ISSN: 0002-7863. |
Coordination Chemistry-Assembled Multicomponent Systems Built from a Gable-Like Bis-Porphyrin: Synthesis and Photophysical Properties Journal Article In: PHOTOCHEMISTRY AND PHOTOBIOLOGY, 90 (2), pp. 275–286, 2014, ISSN: 0031-8655. |
Tracking Intramolecular Interactions in Flexibly Linked Binuclear Platinum(II) Complexes Journal Article In: ORGANOMETALLICS, 33 (6), pp. 1345–1355, 2014, ISSN: 0276-7333. |
Light and electrical responsive porous materials Journal Article In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 247 , 2014, ISSN: 0065-7727. |
Luminescent metal complexes and their assemblies Journal Article In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 247 , 2014, ISSN: 0065-7727. |
Scanning probe microscopies beyond imaging: Unraveling the dynamic properties of the supramolecular world Journal Article In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 247 , 2014, ISSN: 0065-7727. |
Nanoscale Electrical Investigation of Layer-by-Layer Grown Molecular Wires Journal Article In: ADVANCED MATERIALS, 26 (11), pp. 1688–1693, 2014, ISSN: 0935-9648. |
25th Anniversary Article: Organic Electronics Marries Photochromism: Generation of Multifunctional Interfaces, Materials, and Devices Journal Article In: ADVANCED MATERIALS, 26 (12), pp. 1827–1845, 2014, ISSN: 0935-9648. |
High Mobility in Solution-Processed 2,7-Dialkyl[1] benzothieno[ 3,2-b][1] benzothiophene- Based Field- Effect Transistors Prepared with a Simplified Deposition Method Journal Article In: CHEMPLUSCHEM, 79 (3), pp. 371–374, 2014, ISSN: 2192-6506. |
Defect-induced supersolidity with soft-core bosons Journal Article In: NATURE COMMUNICATIONS, 5 , 2014, ISSN: 2041-1723. |
Cyclic [4]Rotaxanes Containing Two Parallel Porphyrinic Plates: Toward Switchable Molecular Receptors and Compressors Journal Article In: ACCOUNTS OF CHEMICAL RESEARCH, 47 (2), pp. 633–645, 2014, ISSN: 0001-4842. |
Towards Eumelanin@Zeolite Hybrids: Pore-Size-Controlled 5,6-Dihydroxyindole Polymerization Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (6), pp. 1597–1601, 2014, ISSN: 0947-6539. |
Bidirectional Photoinduced Energy Transfer in Nanoassemblies of Quantum Dots and Luminescent Metal Complexes Journal Article In: ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES, 69 (2), pp. 263–274, 2014, ISSN: 0932-0776. |
The role of size and coating in Au nanoparticles incorporated into bi-component polymeric thin-film transistors Journal Article In: NANOSCALE, 6 (10), pp. 5075–5080, 2014, ISSN: 2040-3364. |
Elucidating the nanoscale origins of organic electronic function by conductive atomic force microscopy Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 2 (17), pp. 3118–3128, 2014, ISSN: 2050-7526. |
Graphene-organic composites for electronics: optical and electronic interactions in vacuum, liquids and thin solid films Journal Article In: JOURNAL OF MATERIALS CHEMISTRY C, 2 (17), pp. 3129–3143, 2014, ISSN: 2050-7526. |
Graphene via sonication assisted liquid-phase exfoliation Journal Article In: CHEMICAL SOCIETY REVIEWS, 43 (1), pp. 381–398, 2014, ISSN: 0306-0012. |
Theoretical and Structural Analysis of Long C-C Bonds in the Adducts of Polycyanoethylene and Anthracene Derivatives and Their Connection to the Reversibility of Diels-Alder Reactions Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (4), pp. 1073–1080, 2014, ISSN: 0947-6539. |
Self-Assembly of a Highly Organized, Hexameric Supramolecular Architecture: Formation, Structure and Properties Journal Article In: CHEMISTRY-A EUROPEAN JOURNAL, 20 (1), pp. 179–186, 2014, ISSN: 0947-6539. |
Base Manifolds for Lagrangian Fibrations on Hyperkahler Manifolds Journal Article In: INTERNATIONAL MATHEMATICS RESEARCH NOTICES, (19), pp. 5483–5487, 2014, ISSN: 1073-7928. |
Pure white-light and yellow-to-blue emission tuning in single crystals of Dy(III) metal-organic frameworks Journal Article In: CHEMICAL COMMUNICATIONS, 50 (57), pp. 7702–7704, 2014, ISSN: 1359-7345. |