title: Substituent and solvent effects on the electrochemical properties and intervalence transfer in asymmetric mixed-valent complexes consisting of cyclometalated ruthenium and ferrocene.
abstract: Four heterodimetallic complexes [Ru(Fcdpb)(L)](PF6) (Fcdpb=2-deprotonated form of 1,3-di(2-pyridyl)-5-ferrocenylbenzene; L=2,6-bis-(N-methylbenzimidazolyl)-pyridine (Mebip), 2,2':6',2''-terpyridine (tpy), 4-nitro-2,2':6',2''-terpyridine (NO2tpy), and trimethyl-4,4',4''-tricarboxylate-2,2':6',2''-terpyridine (Me3tctpy)) have been prepared. The electrochemical and spectroelectrochemical properties of these complexes have been examined in CH2Cl2, CH3NO2, CH3CN, and acetone. These complexes display two consecutive redox couples owing to the stepwise oxidation of the ferrocene (Fc) and ruthenium units, respectively. The potential difference, ΔE(1/2)(E(1/2)(Ru(II/III))-E(1/2)(Fc(0/+))), decreased slightly with increasing solvent donocity. The mixed-valent states of these complexes have been generated by electrolysis and the resulting intervalence charge-transfer (IVCT) bands have been analyzed by Hush theory. Good linear relationships exist between the energy of the IVCT band, E(op), and ΔE(1/2) of four mixed-valent complexes in a given solvent.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (P.R. China) http://zhongyuwu.iccas.ac.cn/; University of Chinese Academy of Sciences, Beijing 100049 (P.R. China).
authors.forename: Si-Hai
authors.initials: SH
authors.lastname: Wu
authors.forename: Jiang-Yang
authors.initials: JY
authors.lastname: Shao
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Kang
authors.forename: Jiannian
authors.initials: J
authors.lastname: Yao
authors.forename: Yu-Wu
authors.initials: YW
authors.lastname: Zhong
keywords: ferrocene; metalation; mixed-valent compounds; redox chemistry; ruthenium