Synthesis and molecular structures of a novel tetranuclear silver(I) cluster [Ag-2(Himdc)(PPh3)(2)](2)(H(3)imdc=imidazole-4,5-dicarboxylic acid) and a mononuclear silver(I) complex [Ag(H(2)imdc)(PPh3)(2)]

A novel tetranuclear silver(I) cluster, [Ag-2(Himdc)(PPh3)(2)](2) 1 (H(3)imdc = imidazole-4,5-dicarboxylic acid; O<^>N) was obtained by a reaction of the Ag-O bonding precursor [Ag(R-Hpyrrld)](2) (H(2)pyrrld = 2-pyrrolidone-5-carboxylic acid), PPh3 and H(3)mide. The mononuclear complex, [Ag(H(2)imdc)(PPh3)(2)](2), was also formed by the reactions using increased amounts of PPh3.In the solid state, complex I was a bivalve-like Ag-4 cluster, while complex 2 showed a supramolecular arrangement of the 4-coordinate AgP2(N<^>O) unit via the intermolecular hydrogen bonding interaction. (c) 2005 Elsevier B.V. All rights reserved.