Design of hybrid nanomaterials made of organophosphorus transition metal complexes covalently bonded to metal naoparticles / Martin Morales, Elena  

Public ISBD Titre : Design of hybrid nanomaterials made of organophosphorus transition metal complexes covalently bonded to metal naoparticles Type de document : texte imprimé Auteurs : Martin Morales, Elena ; Igau, Alain, Directeur de thèse ; Karine Philippot, Directeur de thèse Année de publication : 2020 Langues : Anglais (eng) Tags : COORDINATION CHEMISTRY  NANOCHEMISTRY  METAL NANOPARTICLES  ORGANOPHOSPHOROUS RUTHENIUM COMPLEXES  HYBRID NANOMATERIALS  ELECTROCHEMISTRY Résumé : "The unique properties of metal nanoparticles (MNPs), commonly considered at the borderline between those displayed by molecular compounds and those typical of bulk metals, account for their extended application in diverse fields like electronics, optics, medicine or catalysis. The stabilization of MNPs can be performed in solution by the use of various stabilizers such as polyols, polymers, surfactants, ionic liquids or ligands that are deliberately added in the synthesis medium. The adequate choice of the stabilizer is also a way to functionalize the MNPs and confer them specific properties like solubility in a given media, enantioselective catalytic properties or optical properties, as non-exhaustive examples. Because of their large panel of applications, transition metal complexes (TMCs) have been associated to MNPs to form hybrid nanomaterials mainly through the use of pendant ligands. This fundamental PhD work lies in this domain of research, with the aim to achieve novel hybrid nanomaterials via a direct coordination of TMCs at the surface of MNPs. This type of hybrid nanomaterials may give rise to additional properties, different from their two respective original entities. On the basis of coordination chemistry and nanochemistry tools, unprecedented hybrid nanomaterials made of mononuclear organophosphorus Ru(II)-polypyridyl complexes covalently bonded onto the surface of ruthenium nanoparticles (RuNPs) were successfully synthesized following a one-pot organometallic procedure. A complete characterization of the prepared hybrid nanomaterials, by the combination of physical and chemical analytic techniques, is reported. Besides state-of-the-art techniques for nanoparticle characterization (TEM, WAXS, XPS), liquid and solid-state NMR techniques were applied in order to determine the surface environment of the RuNPs. DFT theoretical calculations, based on a Ru55 cluster model, strongly supported the experimental results and showed that the most stable nanohybrid conformer involves a covalent interaction between the chlorine atom of the organophosphorus Ru(II)-polypyridyl complex and the RuNP surface, thus forming a direct bridge between the complex and the NPs. An additional aromatic pi-type chelating interaction between one of the bipyridine ligands and the RuNP metal surface was also evidenced. NMR spectroscopy data evidenced that in addition to the inner stabilizing layer resulting from the direct coordination of the complex onto the NP surface, other organophosphorus Ru(II)-polypyridyl complexes surround the hybrids, thus forming an outer stabilizing layer. Electrostatic interaction is believed to occur between the complex counterparts from the inner and outer layers. The electronic properties of the nanohybrid were studied by voltammetric techniques and DFT calculations (projected Density of States). The behavior experimentally observed evidenced the unique hybrid character of the nanomaterial, which displays an electrochemical gap (Eox-Ered) typical of a "molecule-like" redox character and very different from that observed for RuNPs stabilized by classical ligands. Preliminary catalytic studies on the photoinduced hydrogen evolution reaction, as a part of the water-splitting process, and the transformation of CO2 into formic acid have also been performed. As perspectives, the synthesis of other Ru-based nanohybrids was evaluated by using Ru(II)-polypyridyl complexes bearing organophosphorus ligands of different nature. Also, first results in the synthesis of nanohybrids made of NPs of other metals (Co, Pt) have been obtained. This work reports an effective way to potentially access a large variety of unprecedented hybrid nanomaterials made of mononuclear transition metal complexes covalently bonded to well-defined metal nanoparticles. Given its versatility, our procedure should allow developing hybrid nanomaterials with tunable properties towards a large domain of applications." Document : Thèse de doctorat Etablissement_delivrance : Université de Toulouse Date_soutenance : 06/07/2020 Ecole_doctorale : Sciences de la Matière (université Toulouse III P. Sabatier) Domaine : Chimie Organométallique et de Coordination Localisation : LCC En ligne : https://tel.archives-ouvertes.fr/tel-03549245 Design of hybrid nanomaterials made of organophosphorus transition metal complexes covalently bonded to metal naoparticles [texte imprimé] / Martin Morales, Elena ; Igau, Alain, Directeur de thèse ; Karine Philippot, Directeur de thèse . - 2020. Langues : Anglais (eng) Tags : COORDINATION CHEMISTRY  NANOCHEMISTRY  METAL NANOPARTICLES  ORGANOPHOSPHOROUS RUTHENIUM COMPLEXES  HYBRID NANOMATERIALS  ELECTROCHEMISTRY Résumé : "The unique properties of metal nanoparticles (MNPs), commonly considered at the borderline between those displayed by molecular compounds and those typical of bulk metals, account for their extended application in diverse fields like electronics, optics, medicine or catalysis. The stabilization of MNPs can be performed in solution by the use of various stabilizers such as polyols, polymers, surfactants, ionic liquids or ligands that are deliberately added in the synthesis medium. The adequate choice of the stabilizer is also a way to functionalize the MNPs and confer them specific properties like solubility in a given media, enantioselective catalytic properties or optical properties, as non-exhaustive examples. Because of their large panel of applications, transition metal complexes (TMCs) have been associated to MNPs to form hybrid nanomaterials mainly through the use of pendant ligands. This fundamental PhD work lies in this domain of research, with the aim to achieve novel hybrid nanomaterials via a direct coordination of TMCs at the surface of MNPs. This type of hybrid nanomaterials may give rise to additional properties, different from their two respective original entities. On the basis of coordination chemistry and nanochemistry tools, unprecedented hybrid nanomaterials made of mononuclear organophosphorus Ru(II)-polypyridyl complexes covalently bonded onto the surface of ruthenium nanoparticles (RuNPs) were successfully synthesized following a one-pot organometallic procedure. A complete characterization of the prepared hybrid nanomaterials, by the combination of physical and chemical analytic techniques, is reported. Besides state-of-the-art techniques for nanoparticle characterization (TEM, WAXS, XPS), liquid and solid-state NMR techniques were applied in order to determine the surface environment of the RuNPs. DFT theoretical calculations, based on a Ru55 cluster model, strongly supported the experimental results and showed that the most stable nanohybrid conformer involves a covalent interaction between the chlorine atom of the organophosphorus Ru(II)-polypyridyl complex and the RuNP surface, thus forming a direct bridge between the complex and the NPs. An additional aromatic pi-type chelating interaction between one of the bipyridine ligands and the RuNP metal surface was also evidenced. NMR spectroscopy data evidenced that in addition to the inner stabilizing layer resulting from the direct coordination of the complex onto the NP surface, other organophosphorus Ru(II)-polypyridyl complexes surround the hybrids, thus forming an outer stabilizing layer. Electrostatic interaction is believed to occur between the complex counterparts from the inner and outer layers. The electronic properties of the nanohybrid were studied by voltammetric techniques and DFT calculations (projected Density of States). The behavior experimentally observed evidenced the unique hybrid character of the nanomaterial, which displays an electrochemical gap (Eox-Ered) typical of a "molecule-like" redox character and very different from that observed for RuNPs stabilized by classical ligands. Preliminary catalytic studies on the photoinduced hydrogen evolution reaction, as a part of the water-splitting process, and the transformation of CO2 into formic acid have also been performed. As perspectives, the synthesis of other Ru-based nanohybrids was evaluated by using Ru(II)-polypyridyl complexes bearing organophosphorus ligands of different nature. Also, first results in the synthesis of nanohybrids made of NPs of other metals (Co, Pt) have been obtained. This work reports an effective way to potentially access a large variety of unprecedented hybrid nanomaterials made of mononuclear transition metal complexes covalently bonded to well-defined metal nanoparticles. Given its versatility, our procedure should allow developing hybrid nanomaterials with tunable properties towards a large domain of applications." Document : Thèse de doctorat Etablissement_delivrance : Université de Toulouse Date_soutenance : 06/07/2020 Ecole_doctorale : Sciences de la Matière (université Toulouse III P. Sabatier) Domaine : Chimie Organométallique et de Coordination Localisation : LCC En ligne : https://tel.archives-ouvertes.fr/tel-03549245

---

1 (1 - 1 / 1) Par page : 25 50 100 200