Asymmetric Mixed-Valence Complexes that Consist of Cyclometalated Ruthenium and Ferrocene: Synthesis, Characterization, and Electronic-Coupling Studies

Graphical Penny mix : Three bis-tridentate ferrocene-containing cyclometalated ruthenium complexes have been prepared and characterized, in which the ferrocene units are either substituted on the NNN ligand, on the NCN ligand, or on both sides. A combined experimental and computational study has shown that the electronic coupling between the iron and ruthenium sites is strongly dependent on the connection mode between the two redox-active centers. en This link goes to a English section zh This link goes to a English section Three bis-tridentate ferrocene-containing cyclometalated ruthenium complexes, [(Fcdpb)Ru(tpy)] + ( 1 + ), [(Fctpy)Ru(dpb)] + ( 2 + ), and [(Fcdpb)Ru(Fctpy)] + ( 3 + ), have been prepared and characterized, where Fcdpb is the 2-deprotonated form of 1,3-di(2-pyridyl)-5-ferrocenylbenzene, tpy is 2,2′:6′,2“-terpyridine, dpb is the 2-deprotonated form of 1,3-di(2-pyridyl)benzene, and Fctpy is 4′-ferrocenyl-2,2′:6′,2”-terpyridine. Single crystals of compounds 2 + and 3 + have been studied by X-ray analysis. Complexes 1 + and 2 + displayed two anodic redox waves, whilst three well-separated redox couples were observed for compound 3 + . A combined experimental and computational study suggested that the ferrocene unit on the Fcdpb moiety in compounds 1 + and 3 + was oxidized first. In contrast, the order of the oxidation of ruthenium and ferrocene in complex 2 + was reversed. Metal-to-metal-charge-transfer transitions (MM′CT) have been observed for the singly oxidized states 1 2+ , 2 2+ , and 3 2+ in the near-infrared region. Hush analysis showed that the metal–metal electronic couplings in compounds 1 2+ and 3 2+ were much stronger than those in compound 2 2+ . en This link goes to a English section zh This link goes to a English section 1