Synthesis and molecular structures of a novel tetranuclear silver(I) cluster [Ag2(Himdc)(PPh3)2]2 (H3imdc = imidazole-4,5-dicarboxylic acid) and a mononuclear silver(I) complex [Ag(H2imdc)(PPh3)2]

A novel tetranuclear silver(I) cluster, [Ag2(Himdc)(PPh3)2]2 1 (H3imdc = imidazole-4,5-dicarboxylic acid; O∧N) was obtained by a reaction of the Ag–O bonding precursor [Ag(R-Hpyrrld)]2 (H2pyrrld = 2-pyrrolidone-5-carboxylic acid), PPh3 and H3imdc. The mononuclear complex, [Ag(H2imdc)(PPh3)2] 2, was also formed by the reactions using increased amounts of PPh3. In the solid state, complex 1 was a “bivalve”-like Ag4 cluster, while complex 2 showed a supramolecular arrangement of the 4-coordinate AgP2(N∧O) unit via the intermolecular hydrogen bonding interaction.