Synthesis, structure and electrochemistry of mononuclear and dinuclear ruthenium-thiophenecarboxylate complexes

Three 3-thiophenecarboxylate-containing and one 2,2'-bithiophene-5-carboxylate-containing diruthenium complexes, [Ru-2(mu-O2CR)(4)(MeOH)(2)]PF6 (R = -C4H3S 1, -CH2C4H3S 2, -CH=CHC4H3S 3 and -C8H5S2 4), were prepared using a facile carboxylate exchange reaction and characterized using elemental analysis, IR and UV-Vis spectroscopy. Disassembly of complexes 1-4 using 1,2-bis(diphenylphosphino)-ethane (dppe) yielded the mononuclear ruthenium(II) complexes, [Ru(eta(2)-O2CR)(dppe)2]PF6 (R = -C4H3S 5, -CH2C4H3S 6, -CH=CHC4H3S 7 and -C8H5S2 8), which were characterized as above as well as by H-1 and P-31 NMR and single crystal X-ray analysis. All of the complexes were studied using cyclic voltammetry to assess the ability of the thiophene moieties to undergo oxidative polymerization with complex 4 showing the greatest promise. (c) 2007 Elsevier Ltd. All rights reserved.