Three-Dimensional Polymeric Thallium(I) Morpholinedithiocarbamate [Tl₂{S₂CN(CH₂)₄O}₂]_n and Its Capability of Binding Gold(III) from Solutions: Chemisorption Synthesis of a Heteronuclear Gold(III)–Thallium(III) Complex of the Ionic Type, ([Au{S₂CN(CH₂)₄O}₂][TlCl₄])_n, the Role of Secondary Interactions Tl…O, Tl…S, and Au…S in the Supramolecular Self-Organization, ¹³C MAS NMR, and Thermal Behavior

Crystalline polymeric thallium(I) morpholinedithiocarbamate [Tl₂{S₂CN(CH₂)₄O}₂]_n (I) and the heteronuclear ion–polymeric gold(III)–thalium(III) complex ([Au{S₂CN(CH₂)₄O}₂][TlCl₄])_n (II) are preparatively isolated and characterized by X-ray diffraction analysis and ¹³C MAS NMR spectroscopy. According to the X-ray diffraction data, the main structural units of compounds I and II (CIF files CCDC 1548079 and 1548080) are presented by the binuclear centrosymmetric molecule [Tl₂{S₂CN(CH₂)₄O}₂], noncentrosymmetric complex cation [Au{S₂CN(CH₂)₄O{₂]⁺, and isomeric complex anions [TlCl₄]^–. The formation of the three-dimensional polymeric structure (coordination number of Tl is 7), which is not characteristic of thallium(I) dithiocarbamates, is a consequence of the participation of the secondary Tl…O and Tl…S bonds of two types in the supramolecular self-organization of compound I. Nonequivalent secondary interactions of the first type join the binuclear molecules [Tl₂{S₂CN(CH₂)₄O}₂] into polymer layers, which, in turn, form the three-dimensional polymeric framework due to the secondary bonds Tl…S. The revealed ability of freshly precipitated compound I to the chemisorption of gold(III) from solutions (2 M HCl) makes it possible to obtain heteronuclear supramolecular complex II as an individual form of binding. In the structure of the latter, the pairs of stronger secondary Au…S bonds join the gold(III) cations into dimers [Au₂{S₂CN(CH₂)₄O}₄]²⁺ of the angular structure, the structural ordering of which is achieved in the cationcationic polymeric chain ([Au₂{S₂CN(CH₂)₄O}₄]²⁺)_n of the helical type involving the pairs of less strong Au…S bonds between the adjacent binuclear units. The distorted tetrahedral anions [TlCl₄]^– are localized between the polymeric chains. The study of the thermal behavior of compounds I and II by simultaneous thermal analysis makes it possible to establish the character of thermal transformations of the substances and to identify Tl₂S (I), TlCl, and elemental gold (II) as thermolysis products.