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Dalton Transactions

The international journal for inorganic, organometallic and bioinorganic chemistry



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Dalton Trans., 2009, 7891 - 7901, DOI: 10.1039/b901822k

Bimetallic complexes based on carboxylate and xanthate ligands: Synthesis and electrochemical investigations

Yvonne H. Lin, Nina H. Leung, Katherine B. Holt, Amber L. Thompson and James D. E. T. Wilton-Ely

The homobimetallic ruthenium(II) and osmium(II) complexes [{RuR(CO)(PPh3)2}2(S2COCH2C6H4CH2OCS2)] (R = CHCHBut, CHCHC6H4Me-4, C(CCPh)CHPh, CHCHCPh2OH) and [{Os(CHCHC6H4Me-4)(CO)(PPh3)2}2(S2COCH2C6H4CH2OCS2)] form readily from the reactions of [MRCl(CO)(BTD)(PPh3)2] (M = Ru or Os; BTD = 2,1,3-benzothiadiazole) with the dixanthate KS2COCH2C6H4CH2OCS2K. Addition of KS2COCH2C6H4CH2OCS2K to two equivalents of cis-[RuCl2(dppm)2] leads to the formation of [{(dppm)2Ru}2(S2COCH2C6H4CH2OCS2)]2+. The benzoate complexes [RuR{O2CC6H4(CH2OH)-4}(CO)(PPh3)2] (R = CHCHBut, CHCHC6H4Me-4, C(CCPh)CHPh) are obtained by treatment of [RuRCl(CO)(BTD)(PPh3)2] with 4-(hydroxymethyl)benzoic acid in the presence of base. Reaction of [RuHCl(CO)(PPh3)3] or [RuRCl(CO)(BTD)(PPh3)2] with 4-(hydroxymethyl)benzoic acid in the absence of base leads to formation of the chloride analogue [RuCl{O2CC6H4(CH2OH)-4}(CO)(PPh3)2]. The unsymmetrical complex [{Ru(CHCHC6H4Me-4)(CO)(PPh3)2}2(O2CC6H4CH2OCS2)] forms from the sequential treatment of [Ru(CHCHC6H4Me-4){O2CC6H4(CH2OH)-4}(CO)(PPh3)2] with base, CS2 and [Ru(CHCHC6H4Me-4)Cl(CO)(BTD)(PPh3)2]. The new mixed-donor xanthate-carboxylate ligand, KO2CC6H4CH2OCS2K is formed by treatment of 4-(hydroxymethyl)benzoic acid with excess KOH and two equivalents of carbon disulfide. This ligand reacts with two equivalents of [Ru(CHCHC6H4Me-4)Cl(BTD)(CO)(PPh3)2] or cis-[RuCl2(dppm)2] to yield [{(dppm)2Ru}2(O2CC6H4CH2OCS2)]2+ or [{Ru(CHCHC6H4Me-4)(CO)(PPh3)2}2(O2CC6H4CH2OCS2)], respectively. Electrochemical experiments are also reported in which communication between the metal centres is investigated.

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