Tetranuclear [Rh4(mu-PyS2)2(diolefin)4] complexes as building blocks for new inorganic architectures: synthesis of coordination polymers and heteropolynuclear complexes with electrophilic d8 and d10 metal fragments

The reaction of Rh4(mu-PyS2)2(cod)4] (PyS2 = 2,6-pyridinedithiolate, cod = 1,5-cyclooctadiene) with CF3SO3Me gave the cationic complex Rh(4)(mu-PyS(2)Me)(2)(cod)4]CF3SO3]2 (1) with two 6-(thiomethyl)pyridine-2-thiolate bridging ligands from the attack of Me+ at the terminal sulfur atoms of the starting material. Under identical conditions Rh4(mu-PyS2)2(tfbb)4] (tfbb = tetrafluorobenzobarrelene) reacted with CF3SO3Me to give the mixed-ligand complex Rh(4)(mu-PyS2)(mu-PyS2Me)(tfbb)4]CF3SO3] 2. The nucleophilicity of the bridging ligands in the complexes Rh4(mu-PyS2)2(diolefin)4] was exploited to prepare heteropolynuclear species. Reactions with Au(PPh3)(Me2CO)]ClO4] gave the hexanuclear complexes (PPh3)2Au2Rh4(mu-PyS2)2(diolefin)4]ClO4]2 (diolefin = cod (3), tfbb (4)). The structure of 4, solved by X-ray diffraction methods, showed the coordination of the Au(PPh3)]+ fragments to the peripheral sulfur atoms in Rh4(mu-PyS2)2(diolefin)4] along with their interaction with the neighbor rhodium atoms. Neutral coordination polymers of formula ClMRh4(mu-PyS2)2(diolefin)4]n (M = Cu (5, 6), Au (7)) result from the self-assembly of alternating Rh4(mu-PyS2)2(diolefin)4] (Rh4]) blocks and MCl linkers. The formation of the infinite polymetallic chains was found to be chiroselective for M = Cu; one particular chain contains exclusively homochiral Rh4] complexes. Cationic heterometallic coordination polymers of formula MRh4(mu-PyS2)2(diolefin)4]nBF4]n (M = Ag (8, 9), Cu (10, 11)) and Rh5(mu-PyS2)2(diolefin)5]nBF4]n (12, 13) result from the reactions of Rh4] with Cu(CH2CN)4]BF4, AgBF4, and Rh(diolefin)(Me2CO)2]BF4, respectively. The heterometallic coordination polymers exhibit a weak electric conductivity in the solid state in the range (1.2-2.8) x 10(-7) S cm(-1).