Através da abordagem bottom-up, foram desenvolvidos novos sistemas supramoleculares baseados em complexos metálicos ligados por meio do ligante conjugado, trans-1,4-bis[2-(4-piridil)etenil]benzeno (BPEB). A combinação adequada de várias espécies selecionadas, conduziu a compostos bastante interessantes que foram caracterizados por meio 1H-RNM, voltametria cíclica e de espectrometria de massa, espectroscopia eletrônica, espectroeletroquímica. Seus correspondentes filmes moleculares também foram investigados por meio de microscopia de força atômica. Um desses sistemas foi constituído por clusters triangulares de acetato de rutênio com pontes µ-oxo e BPEB. Nesses casos, a espectrometria de massa acoplada à técnica de dissociação induzida por colisão, foi uma ferramenta poderosa para a investigação do processo de fragmentação em fase gasosa, permitindo a caracterização de novos intermediários, bem como a avaliação das energias de ligação envolvidas nos sistemas. Uma correlação linear das energias de ligação e parâmetros eletroquímicos foi demonstrada neste trabalho. Além disso, o comportamento eletrocrômico dos clusters de BPEB suportados sobre dióxido de titânio nanocristalino, também foi explorado na elaboração de dispositivos eletrocrômicos, com ótimo desempenho em termos de mudanças ópticas, reversibilidade e reprodutibilidade. Outro tipo de sistema foi baseado em complexos de rutênio-bipiridina e BPEB. Esses complexos foram empregados com bons resultados como sensibilizadores em células fotoeletroquímicas baseadas em dióxido de titânio nanocristalino, bem como em dispositivos eletrocrômicos de mesma natureza. Finalmente, as características estruturais do BPEB mostraram ser adequadas para exploração do reconhecimento molecular dos complexos na presença de β-ciclodextrina (β-CD). Neste estudo, foram gerados rotaxanos por meio da automontagem coordenativa do complexo binuclear µ-BPEB- bis[pentacianoferrato(II)] na presença de β-CD. Também foi demonstrado por meio de 1H-NMR, que a agregação do complexo de BPEB é bastante pronunciada em espectros de solução aquosa, sendo porém inibida na presença de β-CD. / The bottom up approach has been applied for the development of new supramolecular systems based on metal complexes connected by the linear, conjugated bridging ligand trans-1,4-bis[2-(4-pyridyl)ethenyl]benzene (BPEB). The combination of the many selected species led to very interesting compounds, which have been extensively characterized by means of ESI-MS, electronic spectroscopy, 1H-NMR, cyclic voltammetry and spectroelectrochemistry. Their molecular films have also been investigated by means of atomic force microscopy. One of such systems was constituted by triangular µ-oxo bridged ruthenium acetate clusters containing BPEB. In particular, mass spectrometry coupled with a collision induced dissociation technique provided a versatile tool for the investigation of their fragmentation process, allowing the characterization of novel intermediates, as well as, the evaluation of the binding energies involved in the systems. A linear correlation of the binding energies and electrochemical parameters has also been demonstrated in this work. In addition, the electrochromic behavior of the cluster-BPEB complexes supported on nanocrystalline titanium dioxide has also been exploited for the design of novel electrochromic devices, exhibiting sharp optical changes, high reversibility and great reproducibility. Another interesting type of system was based on polypyridine ruthenium(II) complexes and BPEB. Such species have been successfully employed as sensitizers in nanocrystalline titanium dioxide photoelectrochemical cells, and in photoelectrochromic devices. Finally, the suitable structural characteristics of BPEB have been explored in molecular recognition processes involving the corresponding complexes in the presence of ß-cyclodextrin (ß-CD). In this study, rotaxanes have been generated by coordination self-assembly of the binuclear µ-BPEB- bis[pentacyanoferrate(II)] complex and ß-CD. It has also been shown that the aggregation of the BPEB complexes, which proceeds to a high extent in aqueous solution, can be inhibited by adding ß-CD, as deduced by means of 1H-NMR spectroscopy

Através da abordagem bottom-up, foram desenvolvidos novos sistemas supramoleculares baseados em complexos metálicos ligados por meio do ligante conjugado, trans-1,4-bis[2-(4-piridil)etenil]benzeno (BPEB). A combinação adequada de várias espécies selecionadas, conduziu a compostos bastante interessantes que foram caracterizados por meio 1H-RNM, voltametria cíclica e de espectrometria de massa, espectroscopia eletrônica, espectroeletroquímica. Seus correspondentes filmes moleculares também foram investigados por meio de microscopia de força atômica. Um desses sistemas foi constituído por clusters triangulares de acetato de rutênio com pontes µ-oxo e BPEB. Nesses casos, a espectrometria de massa acoplada à técnica de dissociação induzida por colisão, foi uma ferramenta poderosa para a investigação do processo de fragmentação em fase gasosa, permitindo a caracterização de novos intermediários, bem como a avaliação das energias de ligação envolvidas nos sistemas. Uma correlação linear das energias de ligação e parâmetros eletroquímicos foi demonstrada neste trabalho. Além disso, o comportamento eletrocrômico dos clusters de BPEB suportados sobre dióxido de titânio nanocristalino, também foi explorado na elaboração de dispositivos eletrocrômicos, com ótimo desempenho em termos de mudanças ópticas, reversibilidade e reprodutibilidade. Outro tipo de sistema foi baseado em complexos de rutênio-bipiridina e BPEB. Esses complexos foram empregados com bons resultados como sensibilizadores em células fotoeletroquímicas baseadas em dióxido de titânio nanocristalino, bem como em dispositivos eletrocrômicos de mesma natureza. Finalmente, as características estruturais do BPEB mostraram ser adequadas para exploração do reconhecimento molecular dos complexos na presença de β-ciclodextrina (β-CD). Neste estudo, foram gerados rotaxanos por meio da automontagem coordenativa do complexo binuclear µ-BPEB- bis[pentacianoferrato(II)] na presença de β-CD. Também foi demonstrado por meio de 1H-NMR, que a agregação do complexo de BPEB é bastante pronunciada em espectros de solução aquosa, sendo porém inibida na presença de β-CD. / The bottom up approach has been applied for the development of new supramolecular systems based on metal complexes connected by the linear, conjugated bridging ligand trans-1,4-bis[2-(4-pyridyl)ethenyl]benzene (BPEB). The combination of the many selected species led to very interesting compounds, which have been extensively characterized by means of ESI-MS, electronic spectroscopy, 1H-NMR, cyclic voltammetry and spectroelectrochemistry. Their molecular films have also been investigated by means of atomic force microscopy. One of such systems was constituted by triangular µ-oxo bridged ruthenium acetate clusters containing BPEB. In particular, mass spectrometry coupled with a collision induced dissociation technique provided a versatile tool for the investigation of their fragmentation process, allowing the characterization of novel intermediates, as well as, the evaluation of the binding energies involved in the systems. A linear correlation of the binding energies and electrochemical parameters has also been demonstrated in this work. In addition, the electrochromic behavior of the cluster-BPEB complexes supported on nanocrystalline titanium dioxide has also been exploited for the design of novel electrochromic devices, exhibiting sharp optical changes, high reversibility and great reproducibility. Another interesting type of system was based on polypyridine ruthenium(II) complexes and BPEB. Such species have been successfully employed as sensitizers in nanocrystalline titanium dioxide photoelectrochemical cells, and in photoelectrochromic devices. Finally, the suitable structural characteristics of BPEB have been explored in molecular recognition processes involving the corresponding complexes in the presence of ß-cyclodextrin (ß-CD). In this study, rotaxanes have been generated by coordination self-assembly of the binuclear µ-BPEB- bis[pentacyanoferrate(II)] complex and ß-CD. It has also been shown that the aggregation of the BPEB complexes, which proceeds to a high extent in aqueous solution, can be inhibited by adding ß-CD, as deduced by means of 1H-NMR spectroscopy

Cette thèse fait partie d’un projet franco-keyan dénommé ELEPHOX (ELEctrochemical and PHOto Properties of Some Remarkable Ruthenium and Iron CompleXes). En particulier, notre focus est la continuation du travail de C. Muhavini Wawire, Damien Jouvenot, Fréd erique Loiseau, Pablo Baudin, Sébastien Liatard, Lydia Njenga, Geoffrey Kamau, et Mark E. Casida, “Density-Functional Study of Lumininescence in Polypyridine Ruthenium Complexes,” J. Photochem. and Photobiol. A 276, 8 (2014). Cet article a proposé une indice orbitalaire de temps de luminescence pour les complexesde ruthénium. Cependant cet article n’était limité qu’à quelques mnolecules. Afin d’avoir une théorie plus fiable et donc potentiellement plus utile, il faudra tester l’indice de luminescence sur beaucoup plus de molécules. Ayant établi le protocol, il était “évident” mais toujours un défi de le tester sur encore une centaine de molécules pour démonter ou infirmer l’indice proposée. Pour ce faire, j’ai examainé les 98 pages de la Table I de A. Juris, V. Balzani, F. Bargelleti, S. Campagna, P. Belser, et A.V. Zelewsky, “Ru(II) polypyridine complexes: Photophysics, photochemistry, electrochemistry, and chemiluminescence,” Chem. Rev. 84, 85 (1988) et j’ai extrait un nombre important de données susceptibles à comparaison avec les résultats des calculs de la théorie de la fonctionelle de la densité (DFT) et la DFT dépendante du temps (TD-DFT). Comme les résultats étaient suffisament encourageant, le modèle DFT était examiné de plus près avec la méthode d’une théorie de champs de ligands (LFT) à la base de la densité des états partielle (PDOS). Ainsi j’ai pu tester l’indice de luminescence proposée précédement par laméthode PDOS-LFT et j’ai trouvé des difficultés avec l’indice initialement proposée. Par contre, nous avons pu proposer une nouvelle indice de luminescence qui, à quelques exceptions près, a une corrélation linéaire avec une barrière énergétique moyenne pour l’état triplet excité dérivée à partir des données experimentales. À l’avenir nous pouvons proposer une investigation plus directe de la barrière sur la surface triplet excité pour remplacer la valeur approximative déduite de l’expérience. Puis nous voulons voir sinotre indice de luminescence s’appliquent aux cas des complexes d’iridium. / This thesis is part of the Franco-Kenyan project ELEPHOX (ELEctrochemicaland PHOto Properties of Some Remarkable Ruthenium and Iron CompleXes)project. In particular, it focused on the continuation of the work ofC. Muhavini Wawire, Damien Jouvenot, Fréd erique Loiseau, Pablo Baudin,Sébastien Liatard, Lydia Njenga, Geoffrey Kamau, and Mark E. Casida,“Density-Functional Study of Lumininescence in Polypyridine RutheniumComplexes,” J. Photochem. and Photobiol. A 276, 8 (2014). That paperproposed a luminescence index for estimating whether a ruthenium complexwill luminesce or not. However that paper only tested the theory ona few molecules. In order for the theory to have a significant impact, itmust be tested on many more molecules. Now that the protocol has beenworked out, it was a straightforward but still quite challenging matter todo another 100 or so molecules to prove or disprove the theory. In order todo so, I went through the 98 pages of Table I of A. Juris, V. Balzani, F.Bargelleti, S. Campagna, P. Belser, and A.V. Zelewsky, “Ru(II) polypyridinecomplexes: Photophysics, photochemistry, electrochemistry, and chemiluminescence,”Chem. Rev. 84, 85 (1988) and extracted data suitable for comparingagainst density-functional theory (DFT) and time-dependent (TD-)DFT.Since the results were sufficiently encouraging, the DFT model was examinedin the light of partial density of states ligand field theory (PDOS-LFT) andthe previously proposed luminescence indices were tested. In fact, the originallyproposed indices were not found to be very reliable but we were able topropose a new luminescence index based upon much more data and in analogywith frontier-molecular orbital ideas. Except for a few compounds, this index provides a luminescence index with a good linear correlation with anexperimentally-derived average excited-state activation energy barrier. Futurework should be aimed at both explicit theoretical calculations of thisbarrier for ruthenium complexes and extension of the luminescence indexidea to iridium complexes.