Correlation between structures and physical properties for pi-conjugated multinuclear complexes

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In the research of 7t-conjugated multinuclear transition metal complexes, it is important to investigate the correlation between structures and strength of intermuclear electronic interactions with physical properties. In this study, we have synthesized new oligomeric and polymeric compounds involving ferrocene, cobaltadithiolene and terpyridine complexes, and investigated the correlation between their structures and redox, optical and magnetic properties.New azo-bridged ferrocene trimers, Fc-Fc'-N=N-Fc and Fc-N=N-Fc'-N=N-Fc, where Fc and Fc' refer to (eta^5-C_5H_5)Fe(eta^5-C_5H_4-) and Fe(eta^5-C_5H_4-)_2, respectively, were synthesized. Their electrochemical and optical properties indicate that the electronic structures of their mixed-valence states can be expressed as Fc^+-N_2-Fc'-N_2-Fc, Fc^+-N_2-Fc'-N_2-Fc^+, and Fc^+-Fc'-N_2-Fc, Fc^+-Fc' -N_2-Fc^+, respectively. The solvent effect of the IT band in their mixed-valence states on nu_<max> cannot be interpreted only by the parameter … More s in the Marcus-Hush theory, indicating that the nature of the solvent as donor or acceptor should be taken into account in the electron-exchange process in the mixed-valence states.Redox properties and optical properties of o, m, and p-bis (ferrocenylethynyl) benzene indicate that the electronic interaction between ferrocene units is most significant when they locate at para position. Physical properties of hexaxis (ferrocenylethynyl) benzene can be semi-quantitatively interpreted by considering the contribution of all electronic interaction between ferrocene units at o, m and p-positions.New Co-M-Co (M=Mo, W) cluster complexes were synthesized by the reaction of cobaltadithiolene complex with M(CO)_3py_3 and their X-ray crystallographic structures determined. Physical properties of them and their reduced forms indicate the existence of strong electronic interaction between two Co sites via the central metal.A new bis (terpyridine) ligand with azobenzene as the linker, tpy-AB-tpy and their Rh, Ru and Co dinuclear complexes were synthesized. Their photoisomerization reactions and redox properties were revealed. Less