Synthesis and characterization of the bimetallic polymers [MS 4Ag 2(Hmimt) 2] n (where M = Mo or W, Hmimt = 1-methylimidazoline-2(3H)-thione): crystal structures of [WS 4Ag 2(Hmimt) 2] n and [Ag 2I 2(Hmimt)] n

Abstract

The title compounds were synthesized by the reactions of [NH 4] 2[MS 4] (M = Mo, W), AgI and Hmimt in acetone and characterized by IR, 1H NMR and UV–Vis spectroscopy. The polymeric structure of [WS 4Ag 2(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 μ 2-S bridging Hmimt and one S atom of a monodentate WS 4 unit. The other is surrounded by four sulfur atoms belonging in pairs to two WS 4 fragments; the coordination geometry is distorted tetrahedral. The [WS 4Ag 2(Hmimt) 2] n polymer represents the first example of tetrathiometalate anions [MS 4] 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.