Complexes of copper(I) and silver(I) with bis(methimazolyl)borate and dihydrobis(2-mercaptothiazolyl)borate ligands.

The complexes [Cu(BmMe)]3 x 0.77C4H8O (1), [(BmMe)Ag(PPh3)] (2) and [M[kappa3-H(micro-H)B(tiaz)2](PPh3)] (M= Cu (3), Ag (4); BmMe = bis(2-mercapto-1-methylimidazolyl)borate, H2B(tiaz)2 = dihydrobis(2-mercaptothiazolyl)borate) have been prepared and characterised by X-ray crystallographic and spectroscopic methods. The presence of MH-B interactions in these species has been investigated using infrared spectroscopy and crystallography. In [Cu(BmMe)]3, the triangular array of three trigonal-planar copper atoms is coordinated by three chelating and bridging (BmMe)- ligands, and has an unusual, highly unsymmetrical arrangement with one short Cu-Cu distance; this is the first structurally authenticated Bm(Me) complex with a nuclearity greater than two. In complexes 2-4, the metal atom is found in a distorted trigonal-planar geometry, bound by a terminal phosphine ligand and two sulfur atoms of a chelating ligand, supplemented by an MH-B interaction, which appears to be a common feature in the coordination chemistry of the (BmMe)- and [H2B(tiaz)2]- ligands; compounds 1-4 are the first reported complexes of copper(I) and silver(I) with any bis(2-mercaptoimidazolyl)borate ligand or with H2B(tiaz)2.