Chemisorption of gold(III) from solutions using thallium(I) diisobutyldithiocarbamate: Supramolecular structure and thermal behavior of the polymeric gold(III)-thallium(III) complex ([Au{S2CN(iso-C4H9)2}2][TlCl4]) n

Abstract

Chemisorption of gold(III) from 2 M HCl using thallium(I) diisobutyldithiocarbamate via an ion exchange/redox process gives a polymeric gold(III)-thallium(III) complex of the formula ([Au{S2CN(iso-C4H9)2}2][TlCl4])n (I). Its supramolecular structure determined by X-ray diffraction (CIF file CCDC no. 1009388) comprises three structurally nonequivalent complex cations [Au{S2CN(iso-C4H9)2{2]+ (A, B, and C) and two nonequivalent [TlCl4]−-anions, both the cations and the anions being conformers. The isomeric cations are united through pairs of relatively weak secondary nonvalent Au⋯S contacts into zigzag polymer chains (⋯A⋯B⋯C⋯B⋯)n, with alternating nonequivalent [TlCl4]− anions on both sides. The thermal behavior of complex I was studied by simultaneous thermal analysis. The TG curve shows two steps of its weight loss. The first step involves thermal decomposition of the dithiocarbamate portion of the complex and [TlCl4]− with reduction of gold(III) to metallic gold and release of TlCl. The second step is due to evaporation of TlCl. The final thermolysis product of complex I is reduced metallic gold.