title: Complex reduction chemistry of (abpy)PtCl2, abpy = 2,2'-azobispyridine: formation of cyclic [(micro,eta2:eta1-abpy)PtCl]2(2+) with a new coordination mode for abpy and a near-infrared ligand-to-ligand intervalence charge transfer absorption of the one-electron reduced state.
abstract: The structurally characterized (abpy)PtCl2, abpy = 2,2'-azobispyridine, reveals a strong metal/ligand pi interaction as supported by DFT calculations. Unexpectedly, its chemical or electrochemical reduction occurs irreversibly to yield EPR-detectable [(micro,eta2:eta2-abpy)[PtCl2]2]*- and, as the main product of chloride dissociation, the structurally identified and DFT-calculated dinuclear [(micro,eta2:eta1-abpy)PtCl]2(2+) with a novel coordination mode for abpy and isolated as tetrachlorozincate. Stepwise reversible one-electron reduction of that dimer, separated by 0.24 V, exhibits an intense near-infrared band for the monocationic intermediate [(abpy(-I))(abpy)Pt2Cl2]*+ at 1220 nm (epsilon = 3370 M(-1) cm(-1)) which is attributed to a ligand-to-ligand intervalence charge-transfer transition.
authors.affiliation: Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
authors.forename: Akbey
authors.initials: A
authors.lastname: Dogan
authors.forename: Biprajit
authors.initials: B
authors.lastname: Sarkar
authors.forename: Axel
authors.initials: A
authors.lastname: Klein
authors.forename: Falk
authors.initials: F
authors.lastname: Lissner
authors.forename: Thomas
authors.initials: T
authors.lastname: Schleid
authors.forename: Jan
authors.initials: J
authors.lastname: Fiedler
authors.forename: Stanislav
authors.initials: S
authors.lastname: Zális
authors.forename: Vimal K
authors.initials: VK
authors.lastname: Jain
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kaim