title: Dinuclear complexes with bis(benzenedithiolate) ligands.
abstract: As a part of a broader study directed towards helical coordination compounds with benzenedithiolate donors, we have synthesized the bis(benzenedithiol) ligands 1,2-bis(2,3-dimercaptobenzamido)ethane (H(4)-1) and 1,2-bis(2,3-dimercaptophenyl)ethane (H(4)-2). Both ligands form dinuclear complexes with Ni(II), Ni(III) and, after air-oxidation, Co(III) ions under equilibrium conditions. Complexes (NEt(4))(4)[Ni(II)(2)(1)(2)] (11 b), (NEt(4))(2)[Ni(III)(2)(1)(2)] (13), and Na(4)[Ni(II)(2)(2)(2)] (14) were characterized by X-ray diffraction. In all complexes, two square-planar [Ni(S(2)C(6)H(3)R)(2)] units are linked in a double-stranded fashion by the carbon backbone and they assume a coplanar arrangement in a stair-like manner. Cyclic voltammetric investigations show a strong dependence of the redox potential on the type of the ligand. The substitution of 1(4-) for 2(4-) on nickel (-785 mV for 11 b versus -1130 mV for 14, relative to ferrocene) affects the redox potential to a similar degree as the substitution of nickel for cobalt (-1160 mV for [Co(2)(1)(2)](2-)/[Co(2)(1)(2)](4-), relative to ferrocene). The redox waves display a markedly less reversible behavior for complexes with the shorter bridged ligand 2(4-) compared to those of 1(4-).
authors.affiliation: Anorganisch-chemisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 8, 48149 Münster, Germany.
authors.forename: Han Vinh
authors.initials: HV
authors.lastname: Huynh
authors.forename: Christian
authors.initials: C
authors.lastname: Schulze-Isfort
authors.forename: Wolfram W
authors.initials: WW
authors.lastname: Seidel
authors.forename: Thomas
authors.initials: T
authors.lastname: Lügger
authors.forename: Roland
authors.initials: R
authors.lastname: Fröhlich
authors.forename: Olga
authors.initials: O
authors.lastname: Kataeva
authors.forename: F Ekkehardt
authors.initials: FE
authors.lastname: Hahn