Diarylethene Self-Assembled Monolayers: Cocrystallization and Mixing-Induced Cooperativity Highlighted by Scanning Tunneling Microscopy at the Liquid/Solid Interface

International audienceThe control over 2-D multi-component molecular orderings on surfaces is a key technology to realize advanced materials with stimuli-responsive properties. The fractional coverage (θ) at a given concentration can be determined from two parameters: the equilibrium constant (Ke) and the degree of cooperativity (σ). The parameters for the formation of self-assembled monolayer of pure diarylethene isomers were obtained by STM measurements on HOPG. These mono-component parameters were used as references to highlight a cocrystallization process between the open-and closed-ring isomers. Moreover it was observed that the presence of the closed-ring isomer induces cooperativity in the formation of the molecular ordering of the open-ring isomer. The quantitative analysis of the ordering formation process by using a model simulation presented in this work provides a better understanding of mixing of components in a molecular ordering and photoinduced interchanges at the liquid/solid interface. (1) Sakano, T.; Imaizumi, Y.; Hirose, T.; Matsuda, K. Chem. Lett. 2013, 42, 1537. (2) Yokoyama, S.; Hirose, T.; Matsuda, K. Chem. Commun. 2014, 50, 5964. (3) Frath, D.; Sakano, T.; Imaizumi, Y.; Yokoyama, S.; Hirose, T.; Matsuda, K. Chem. Eur. J. 2015, 21, 11350

Diarylethene Self-Assembled Monolayers: Cocrystallization and Mixing-Induced Cooperativity Highlighted by Scanning Tunneling Microscopy at the Liquid/Solid Interface

International audienceThe control over 2-D multi-component molecular orderings on surfaces is a key technology to realize advanced materials with stimuli-responsive properties. The fractional coverage (θ) at a given concentration can be determined from two parameters: the equilibrium constant (Ke) and the degree of cooperativity (σ). The parameters for the formation of self-assembled monolayer of pure diarylethene isomers were obtained by STM measurements on HOPG. These mono-component parameters were used as references to highlight a cocrystallization process between the open-and closed-ring isomers. Moreover it was observed that the presence of the closed-ring isomer induces cooperativity in the formation of the molecular ordering of the open-ring isomer. The quantitative analysis of the ordering formation process by using a model simulation presented in this work provides a better understanding of mixing of components in a molecular ordering and photoinduced interchanges at the liquid/solid interface

Cooperativity Analysis of the Open-, Closed-and Annulated-Isomers of Diarylethene that form 2-D Ordering at the Liquid/Solid Interface and their Photochemical Interchanges

International audienc

Unprecedented light induced aggregation of cationic 1,4,5,8-naphthalenediimide amphiphiles

Bola amphiphiles from naphthalenediimide (NDI-bas) with quaternary ammonium groups (DC4, DaP, and DaO) display association in solution, as well as, surprisingly, visible light promoted photochromism in concentrated solutions of water, acetonitrile and THF. The photochromism is correlated with an aggregation process that leads to a significant modification of the electronic transitions, resulting in an unusual absorption band distribution that points out to a type of H-aggregation in transverse. This assembly can be reversibly broken up by heating at 70 °C and adding bulk salt (NaBF4). By 1H-NMR spectroscopic analysis of the irradiation/heating cycle the assembly/disassembly process can be followed by the changes in peak width and intensity. These photoinduced aggregates can sensitize dissolved O2 to give singlet oxygen, a surprising observation when it comes to sensitization efficiency for dyes where aggregation usually decreases the sensitization yield. Laser-induced luminescence measurements corroborate the existence of triplet states as phosphorescence was detected, being particularly intense in concentrated THF solutions

New fluorescent borate complexes : syntheses, properties, applications

Les travaux réalisés aux cours de cette thèse ont portés sur la création de nouveaux complexes borates fluorescents. Des voies de synthèse relativement simples et efficaces ont permis d’accéder à deux nouvelles familles de fluorophores : les Boranils et les Boricos. Les Boranils présentent des coefficients d’absorption molaire élevés, des rendements quantiques pouvant atteindre 90% et la capacité à agir comme antenne efficace pour du transfert d’énergie photoinduit. De nombreuses modifications post-synthétiques ont été mises au point permettant l’accès à des fonctions de greffage utile pour des applications dans le domaine des cristaux liquides ou l’imagerie biomédicale. Enfin, l’extension de la conjugaison des Boranils a permis de déplacer les émissions vers le proche infrarouge. Les Boricos présentent des coefficients d’absorption élevés, des rendements quantiques allant jusqu'à 81% et la capacité à agir comme antenne ou accepteur dans des systèmes de transfert d’énergie photoinduit.This work is dealing with new fluorescent boron complexes. Simple and efficient synthetic pathways have been described to access to two new families of fluorophores: Boranils and Boricos. Boranils present good molar absorption coefficients, high quantum yields up to 90% and the ability to act as efficient antennae for photoinduced energy transfer. Several post-synthetic modifications have been carried out leading to linking functions useful in the liquid crystal and biomedical imaging fields. Then the electronic delocalization has been extended on Boranils resulting in near-infrared emitting dyes. Boricos present good molar absorption coefficients, high quantum yield up to 81%, and the ability to act as an antenna or acceptor in photoinduced energy transfer systems

New fluorescent borate complexes : syntheses, properties, applications

Les travaux réalisés aux cours de cette thèse ont portés sur la création de nouveaux complexes borates fluorescents. Des voies de synthèse relativement simples et efficaces ont permis d’accéder à deux nouvelles familles de fluorophores : les Boranils et les Boricos. Les Boranils présentent des coefficients d’absorption molaire élevés, des rendements quantiques pouvant atteindre 90% et la capacité à agir comme antenne efficace pour du transfert d’énergie photoinduit. De nombreuses modifications post-synthétiques ont été mises au point permettant l’accès à des fonctions de greffage utile pour des applications dans le domaine des cristaux liquides ou l’imagerie biomédicale. Enfin, l’extension de la conjugaison des Boranils a permis de déplacer les émissions vers le proche infrarouge. Les Boricos présentent des coefficients d’absorption élevés, des rendements quantiques allant jusqu'à 81% et la capacité à agir comme antenne ou accepteur dans des systèmes de transfert d’énergie photoinduit.This work is dealing with new fluorescent boron complexes. Simple and efficient synthetic pathways have been described to access to two new families of fluorophores: Boranils and Boricos. Boranils present good molar absorption coefficients, high quantum yields up to 90% and the ability to act as efficient antennae for photoinduced energy transfer. Several post-synthetic modifications have been carried out leading to linking functions useful in the liquid crystal and biomedical imaging fields. Then the electronic delocalization has been extended on Boranils resulting in near-infrared emitting dyes. Boricos present good molar absorption coefficients, high quantum yield up to 81%, and the ability to act as an antenna or acceptor in photoinduced energy transfer systems

Nouveaux complexes borates fluorescents : synthèses, propriétés et applications

This work is dealing with new fluorescent boron complexes. Simple and efficient synthetic pathways have been described to access to two new families of fluorophores: Boranils and Boricos. Boranils present good molar absorption coefficients, high quantum yields up to 90% and the ability to act as efficient antennae for photoinduced energy transfer. Several post-synthetic modifications have been carried out leading to linking functions useful in the liquid crystal and biomedical imaging fields. Then the electronic delocalization has been extended on Boranils resulting in near-infrared emitting dyes. Boricos present good molar absorption coefficients, high quantum yield up to 81%, and the ability to act as an antenna or acceptor in photoinduced energy transfer systems.Les travaux réalisés aux cours de cette thèse ont portés sur la création de nouveaux complexes borates fluorescents. Des voies de synthèse relativement simples et efficaces ont permis d’accéder à deux nouvelles familles de fluorophores : les Boranils et les Boricos. Les Boranils présentent des coefficients d’absorption molaire élevés, des rendements quantiques pouvant atteindre 90% et la capacité à agir comme antenne efficace pour du transfert d’énergie photoinduit. De nombreuses modifications post-synthétiques ont été mises au point permettant l’accès à des fonctions de greffage utile pour des applications dans le domaine des cristaux liquides ou l’imagerie biomédicale. Enfin, l’extension de la conjugaison des Boranils a permis de déplacer les émissions vers le proche infrarouge. Les Boricos présentent des coefficients d’absorption élevés, des rendements quantiques allant jusqu'à 81% et la capacité à agir comme antenne ou accepteur dans des systèmes de transfert d’énergie photoinduit

Electron-responsive Molecular and Supramolecular Materials Based on Porphyrins and Boranils

National audienceThe key elements in the development of nanoscience are to observe, modify and control mater at the nanoscale. One strategy proposed to meet these immense challenges is to develop responsive molecular or supramolecular systems for which a structural reorganization is obtained when exposed to an external stimulus. Systems that endure structural changes leading to major modification of macroscopic properties are of great interest for the controlled capture and release of guest molecules, the development of molecular machines and molecular electronics. The strategy developed at the Chemistry Laboratory of ENS Lyon is to exploit the switching and assembly properties of π-conjugated organic radicals that can be generated in-situ by electrical or light excitation.[ -3] This concept is based on molecular or supramolecular engineering strategies aiming at promoting the formation of -dimers in solution under usual conditions of temperature and concentration. A first approach consists in favoring the formation of π-dimers inside cavitands molecules such as cucurbituril in order to control the reversible association/dissociation of molecular building blocks into 1D or 2D-supramolecular assembly.[1,2] Another approach consists in connecting viologen subunits with mobile covalent linker in order to guide and facilitate an electron-transfer triggered switching.[3] These strategies are very promising for the development of molecular and supramolecular materials based on Porphyrins and Boranils with switchable magnetic/optical properties.[3,4][1]S. Chowdhury, Y. Nassar, L. Guy, D. Frath, F. Chevallier, E. Dumont, A. P. Ramos, G. J.-F. Demets, C. Bucher, Electrochim. Acta 2019, 316, 79–92.[2]S. Chowdhury, P. Hennequin, O. Calabi, S. Denis-Quanquin, E. Saint-Aman, D. Frath, F. Chevallier, C. Bucher, J. Porphyrins Phthalocyanines 2023, under review.[3]S. Al Shehimy, O. Baydoun, S. Denis-Quanquin, J.-C. Mulatier, L. Khrouz, D. Frath, E. Dumont, M. Murugesu, F. Chevallier, C. Bucher, J. Am. Chem. Soc. 2022, 144, 17955–17965.[4]D. Frath, S. Azizi, G. Ulrich, P. Retailleau, R. Ziessel, Org. Lett. 2011, 13, 3414–3417

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Nouveaux complexes borates fluorescents (synthèses, propriétés et applications)

Les travaux réalisés aux cours de cette thèse ont portés sur la création de nouveaux complexes borates fluorescents. Des voies de synthèse relativement simples et efficaces ont permis d accéder à deux nouvelles familles de fluorophores : les Boranils et les Boricos. Les Boranils présentent des coefficients d absorption molaire élevés, des rendements quantiques pouvant atteindre 90% et la capacité à agir comme antenne efficace pour du transfert d énergie photoinduit. De nombreuses modifications post-synthétiques ont été mises au point permettant l accès à des fonctions de greffage utile pour des applications dans le domaine des cristaux liquides ou l imagerie biomédicale. Enfin, l extension de la conjugaison des Boranils a permis de déplacer les émissions vers le proche infrarouge. Les Boricos présentent des coefficients d absorption élevés, des rendements quantiques allant jusqu'à 81% et la capacité à agir comme antenne ou accepteur dans des systèmes de transfert d énergie photoinduit.This work is dealing with new fluorescent boron complexes. Simple and efficient synthetic pathways have been described to access to two new families of fluorophores: Boranils and Boricos. Boranils present good molar absorption coefficients, high quantum yields up to 90% and the ability to act as efficient antennae for photoinduced energy transfer. Several post-synthetic modifications have been carried out leading to linking functions useful in the liquid crystal and biomedical imaging fields. Then the electronic delocalization has been extended on Boranils resulting in near-infrared emitting dyes. Boricos present good molar absorption coefficients, high quantum yield up to 81%, and the ability to act as an antenna or acceptor in photoinduced energy transfer systems.STRASBOURG-Bib.electronique 063 (674829902) / SudocSudocFranceF