Bimetallic Ruthenium Vinyl Complexes Bridged by Electronic Substituent Phenylenes: Spectroelectrochemical and Computational Studies

摘要

A combination of in-situ IR and UV/vis/NIR spectroelectrochemistry and DFT/TDDFT calculationshave been employed to explore the spectroscopic and electronic properties of a series of dinuclearruthenium vinyl complexes 1a-1d [RuCl(CO)(PMe3)3]2(-CH=CH-Ar-CH=CH) (Ar = C6H2(CH3)2-2,5(1a), C6H2(OCH3)2-2,5 (1b), C6H2F2-2,5 (1c) and C6H2(CF3)2-2,5 (1d)). The spectroelectrochemicalresults combined with theoretical calculations reveal that there are no real electronic couplingsbetween two ruthenium centers for 1a-1d despite high half-wave potential splittings observed. Thecomplexes 1a-1d are characterized by localized oxidations of the bridging ligands and electron- releasing substituents render these localized oxidation processes more facile. In addition, the observed+ + strong near-IR absorptions of [1a] and [1b] are mainly attributed to the metal-to-ligand charge- transfer (MLCT) transitions.