Individual forms of gold(III) binding from solutions with zinc N,N-cyclo-hexamethylenedithiocarbamate: Structural self-organization and thermal behavior of gold complexes of composition [Au{S2CN(CH2)(6)}(2)][AuCl4] and ([Au{S2CN(CH2)(6)}(2)](3)[AuCl4][AuCl2](2)) (n)

摘要

A reaction of binuclear zinc N,N-cyclo-hexamethylenedithiocarbamate with [AuCl4](-) anions in 2 M HCl solution was studied. Two types of crystals, plates and needles, were obtained from acetone solution of products of the heterogeneous reaction; the crystals are complexes of composition [Au{S2CN(CH2)(6)}(2)][AuCl4] (I) and ([Au{S2CN(CH2)(6)}(2)](3)[AuCl4][AuCl2](2)) (n) (II). Crystal and supramolecular structures of the prepared compounds were established by X-ray diffraction analysis. The structure of ionic complex I is built of alternating discrete [Au{S2CN(CH2)(6)}(2)](+) cations and [AuCl4](-) anions. A complex supramolecular structure II, which includes isomeric [Au{S2CN(CH2)(6)}(2)](+) cations (A and B) with different structur functions, is formed due to secondary Aua <-S and Aua <-Cl bonds. Non-centrosymmetric cations B unite via pairs of secondary Aua <-S bond to form binuclear species [Au-2{S2CN(CH2)(6)}(4)](2+) which together with centrosymmetric cations A participate in formation of polymeric chains (a <-[Ba <-B]a <-Aa <-) (n) . Moreover, each cation A binds a pair of [AuCl2](-) anions due to secondary Aua <-S bonds. In its turn, [AuCl4](-) anions unite the chains into 2D polymeric network to produce pairs of secondary Cla <-Au bonds with gold atoms of binuclear cations [Au-2{S2CN(CH2)(6)}(4)](2+) of neighboring chains. Thermal behavior of the complexes was studied by simultaneous thermal analysis and conditions of recovery of bound gold were revealed. The thermal destruction of I and II proceeds via intermediate stages of formation of Au2S and AuCl. Reduced elemental gold is the final product of thermal transformations of the complexes.