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The development of molecular wires where photoactive and electroactive terminals are linked by a large size molecular spacer may open new path in the field of storage and utilization of light energy. An important issue concerns how best to design the spacer that permit controlled transfer of electron along the molecular axis. Our design principle for a molecular wire has to fulfill following criteria : (i) an organometallic redox-active spacer to enhance the capability of transfer information along the molecular axis and (ii) modular synthetic approach to control length. The preparations of multinuclear supramolecular assembled from redox-active biferrocencyl spacer and ruthenium(II) terpyridine chromophore are described. Interestingly, substitution of a methoxy group on terminal terpyridine 4'-position of complex 13 will enhance the electronic coupling between the spacer and Ru2+ metal centers. The detailed properties about complex 13 are described in electrochemical results, UV-visible spectral data, and photo luminescent investigation.

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Very recently, Rotello¡¦s research group synthesized nanoparticles bearing terpyridine (terpy) ligands and studied their self-assembly using a variety of transition metals. This paper describes a synthetic pathway to ferrocene- and biferrocene-functionalized terpyridine octanethiols, and the studies of self-organization of ferrocene- and biferrocene-functionalized terpyridine octanethiols chemisorbed on Au nanoparticles.

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We examine the electrochemical properties of SAM of alkanethiols terminated with biferrocenyl group (complex 7) to understand the interactions between metal surface and molecules. The cyclic voltammogram of complex 8 shows two successive reversible one-electron redox waves corresponding to the oxidation of the biferrocenyl moiety and all peak-to-peak separations are smaller than 59 mV (ideal value of one electron transfer with diffusing controlling). In addition, the peak currents are linear to scan rate, i.e., i£\V. This observation is corresponding to the electrochemical property of SAM, and we would like to suggest that the electron transfer process in the electrochemical measurements is direct controlling. Furthermore, we synthesized a nano-material by using of redox stable biferrocenylalkanethiol attached to gold cluster (complex 10). The clusters are stable in air, soluble in nonpolar organic solvents and the characters could be examining by traditional chemical instruments such as NMR, IR, UV/Vis, TEM. The cyclic voltammogram shows that the electron transfer process in the electrochemical measurements is also direct controlling. Finally, the well-known mechanism of intramolecular electron transfer in mixed-valence biferroceniums and the stable biferrocene on Au (111) surface and on gold clusters let to the more advanced concept. We believe that the microstructure of biferrocene assembled on an electrode surface or on gold clusters might enable to carry out a particular function extraordinarily well, for example, optical switch.

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Ch1 The X-ray structural determinations of the neutral 1',2',1'",2'"-tetranaphthylmethyl- and the 1', 3', 1', 3'-tetranaphthylmethyl- biferrocenium triiodide have been determined. Our Mossbauer measurement for 1.34 and 1.35 indicate that the intramolecular electron transfer rates are quite sensitive to the environmental perturbations caused by the grinding of the sample. An interesting finding is that the Mossbauer results indicate that the unground diffusing sample of 1.34 is valence delocalized on the Mossbauer time scale above 180K. However, the ground diffusing sample of 1.34 exhibits a Mossbauer spectrum characteristic of a valence-trapped cation which remains valence-trapped electronic state at 300K. The effects of grinding of samples are also observed in the EPR and XRD measurements. Ch2 A great deal of research has concentrated on long range electron and energy transport in transition metal- based system and conducting polymer. We have synthesis a new bis-terpyridine bridging ligand (2.40) which the spacer is biferrocene moiety. Incorporating of the Ruthenium (II) subunits via redox-active spacer group promote to construction polynuclear transition metal complexes (i.e. multicomponent system). Cyclic voltammetric analysis indicated that there are Fe-Fe electronic coupling in the bridging ligand, and the degree of Fe-Ru electronic coupling is weak. In addition to dominant UV absorption near 240 and 280 nm from terpyridinyl and MLCT absorption from Ru to terpyridine around 480 nm, the complexes containing ferrocene or biferrocene as endgroup exhibit an unusual absorption band around 560 nm which is due to a feccocene moiety to terpyridine MLCT transition.

Ce manuscrit de thèse décrit la conception, l’élaboration et l’étude de complexes organofers électro-actifs dans lesquels deux unités terminales Cp*(dppe)FeII/III sont reliés par un pont fonctionnel. Dans le premier chapitre, nous avons présenté une réaction à la fois originale et efficace catalysée par le Pd(0) qui permet d’accèder à la [5,5’-{(Cp*(dppe)Fe–C≡C}2-(μ-2,2’-bipy)]. Le deuxième chapitre porte sur la présentation d’une voie de synthèse rapide et efficace du métallo-ligand [6,6’-{Cp*(dppe)Fe–C≡C}2-(μ-2,2’-bipy)]. Le troisième chapitre de ce mémoire est consacré à l’utilisation du ligand 1’,1’’’-bis(éthynyle)biferrocényle comme pont entre deux terminaisons électroactives Cp*(dppe)FeII/III. L’espaceur électro-actif joue le rôle de relais moléculaire favorisant le transfert électronique d’une terminaison à l’autre par sauts successifs. Afin d’ajuster les potentiels redox des terminaisons par rapport à ceux du biferrocényle, les terminaisons Cp(PPh3)2M (M = Ru, Os) ont également été utilisées pour substituer un ou deux sites organofers. Le chapitre quatre est dédié aux travaux réalisés sur le système hybride Cp*(dppe)Fe-C≡C-TTMe3. Dans cette molécule, le site Cp*(dppe)FeII/III interagit à travers le pont acétylure avec le fragment tétrathiafulvalényle. La nouvelle molécule est stable sous trois degrés d’oxydation. L’espèce monocationique se comporte comme un composé à valence mixte de classe II et le couplage électronique entre les deux électrophores a été déterminé (Hab = 320 cm-1). Dans le cinquième et dernier chapitre nous mettrons à profit la découverte d’une réaction d’activation de la liaison C-H du groupement méthyle situé sur le même cycle du TTF et de l’acétylure de fer dans le composé [Cp*(dppe)Fe-C≡C-TTMe3](PF6)3. Cette réaction permet la synthèse du complexe moléculaire multifonctionnel [Cp*(dppe)Fe=C=C=TTFMe2=CH-CH=TTFMe2=C=C=Fe(dppe)Cp*][PF6]2 avec de très bon rendement. Les propriétés physicochimiques de ce nouveau complexe analysées avec le support de la chimie quantique permettent de révéler les caractéristiques originales de ce composé inédit. / This thesis highlights the conception, synthesis and studies of redox-active organoiron complexes in which the two termini Cp*(dppe)FeII/III are linked by a functional bridge. In chapter I, an original and efficient synthetic Pd(0) catalysed homocoupling procedure is reported involving mononuclear organoiron(II) intermediates allowing us to isolate [5,5’-{Cp*(dppe)Fe–C≡C}2-(μ-2,2’-bipy)]. In chapter II, a rapid and efficient synthetic access to the redox-active metallo-ligand [6,6’-{cp*(dppe)Fe–C≡C}2-(μ-2,2’-bipy)] is described. In chapter III, the synthesis and properties of a series of complexes containing bis(ethynyl)biferrocene as a bridge between different redoxactive groups is pointed out. The redox bridge acts as a molecular relay for the electronic exchange between the termini via an electron hopping pathway. In order to tune the redox potential compared with those of biferrocene, one or two organoiron groups have been substituted by the Cp(PPh3)2M (M = Ru, Os) groups. In chapter IV, works are dedicated to the hybrid system Cp*(dppe)Fe-C≡C-TTMe3. In this molecule, electronic interactions take place between the Cp*(dppe)FeII/III center and the tetrathiafulvalene core through the ethynyl bridge. The new molecule is stable under three redox states. The mono-oxidized species behaves as a mixed valence species with an electronic coupling Hab = 320 cm-1 between the two electrophores. In the fifth and final chapter, the discovery of a CH bond activation of a methyl group located on the same cycle of the TTF core and the iron acetylide for the compound [Cp*(dppe)Fe-C≡C-TTMe3](PF6)3 is reported. This new reaction allows the synthesis of the multicomponent molecule [Cp*(dppe)Fe=C=C=TTFMe2=CH-CH=TTFMe2=C=C=Fe(dppe)Cp*][PF6]2 in good yield. The resulting device displays specific properties analysed with the support of the quantum chemistry.