Synthesis and characterization of the bimetallic polymers [MS4Ag2(Hmimt)2]n (where M = Mo or W, Hmimt=1-methylimidazoline-2(3H)-thione):: crystal structures of [WS4Ag2(Hmimt)2]n and [Ag2I2(Hmimt)]n

The title compounds were synthesized by the reactions of [NH4](2)[MS4] (M = Mo, W), AgI and Hmimt in acetone and characterized by IR, H-1 NMR and UV-Vis spectroscopy. The polymeric structure of [WS(4)Ag2(HmiMt)(2)](n) was determined by X-ray crystallography. In this compound, there are two distinctly different coordination modes for the silver atoms. One Ag atom has a pseudo-tetrahedral geometry with one terminal monodentate-S Hmimt, two mu(2)-S bridging Hmimt and one S atom of a monodentate WS4 unit. The other is surrounded by four sulfur atoms belonging in pairs to two WS4 fragments; the coordination geometry is distorted tetrahedral. The [WS4Ag2(HMiMt)(2)](n) polymer represents the first example of tetrathiometalate anions [MS4](2-) (M = Mo, W, or V) coordinated to another metal atom in a monodentate fashion. In both crystal structures determined the Hmimt ligands are present in the thione form, with coordination taking place via the sulfur atom only. (C) 2004 Elsevier Ltd. All rights reserved.