Individual Gold(III)-Binding Species Sorbed from Solutions by Zinc Dimethyldithiocarbamate: Structural Organization and Thermal Behavior of the Heteropolynuclear Complex [Au2{S2CN(GH3)2}4][ZnCl4] and Heterovalent Complex ([Au{S2CN(CH3)2}2][AuCl2])_n

摘要

Recent studies showed that dithiocarbamate complexes may be of interest as promising sorbents for concentrating and extraction of noble metals from solutions. Previously [1—7], we studied the chemi-sorption properties of cadmium dialkyldithiocarbam-ate complexes toward gold(III) in 2 M HC1 solutions in a wide concentration range. Both heteropolynuclear gold(III)—cadmium complexes and polynuclear gold(III) complexes were preparatively isolated from chemisorption systems at different saturation stages. The structure and properties of these complexes were established by X-ray diffraction analysis, ~(13)C, ~(15)N, and ~(113)Cd CP/MAS NMR, and simultaneous thermal analysis (STA). However, gold binding in most cases is accompanied by the release of toxic cadmium into solution, which is a considerable drawback of these sorbents. In this context, it was of interest to study the chemisorption interaction of zinc dithiocarbamate complexes with gold(III) and to reveal polynuclear complexes as individual gold-binding species.