Synthesis, spectroscopy and crystal structures of chiral organic ammonium tetrathiometalates showing N-H.S and C-H.S interactions

Abstract

The reaction of ammonium tetrathiometalate (NH4)2[MS4] (M = W or Mo) with the R(+) or S(-) forms of the organic amine alpha-methylbenzylamine [PhCH(CH3)NH2] results in the formation of the corresponding non-centrosymmetric bis(alpha- methylbenzylammonium) tetrathiometalate complexes [PhCH(CH3)NH3]2[MS4] (R-ammonium M = W 1; R-ammonium M = Mo 2; S-ammonium M = W 3, S-ammonium M = Mo 4) which were characterized by elemental analysis, IR, Raman, UV-Vis and CD spectra, X-ray powder diffractometry and single crystal X-ray crystallography. Compounds 1-4 crystallize in the chiral space group P21 and constitute the first examples of structurally characterized chiral organic ammonium group VI tetrathiometalates. The structures of 1-4 consist of two crystallographically independent chiral organic ammonium cations and a tetrahedral tetrathiometalate dianion. The N-H...S and C-H...S interactions between the anions and cations organise them such that the organic ammonium ions always point towards the S atoms of [MS4]2-.