Mononuclear and mixed-metal copper(I)-silver(I) complexes containing 2,2′-bibenzimidazole and triphenylphosphane as ligands:: crystal structures of [Cu(tmbbimH2)(PPh3)2](MeCOO) • 0.2C7H8 and [Ag0.55Cu1.45(μ-bbim)(PPh3)4] • 4CH2Cl2

Novel mononuclear [Cu(bbimH(2))(PPh3)(2)](MeCOO) (1), [Cu(tmbbimH(2))(PPh3)(2)](MeCOO).0.2C(7)H(8) (2) .0.2C(7)H(8), and mixed-metal [Ag0.55Cu1.45(mu-bbim)(PPh3)(4)].4CH(2)Cl(2) (3) .4CH(2)Cl(2) complexes (bbimH(2) = 2,2'-bi-(1H)-benzimidazole, tmbbimH(2) = 5,5',6,6'-tetramethyl-2,2'-bi-(1H)-benzimidazole) have been prepared. Compounds (2) .0.2C(7)H(8) and (3) .4CH(2)Cl(2) have been characterized by single-crystal X-ray structure analyses. In the solvate of (2), the Cu-I ion sits on a distorted tetrahedral site, being coordinated to two nitrogen atoms and two phosphorus atoms. The coordination sphere of (1) is proposed to be analogous to that of (2). In the solvate of (3), there are two equivalent distorted tetrahedral sites, each one consists of 27.5% of Ag-I and 72.5% of Cu-I ions, bridged by the planar tetradentate ligand bbim(2-). The H-1- and P-31{H-1}-n.m.r. data are discussed and related to the structures.