Preparation, supramolecular self-organization and thermal behavior of polymeric complex of composition ([Au{S2CN(C3H7)(2)}(2)](3)[Bi3Cl12]) (n) with unusual geometry of bismuth(III) complex anion

摘要

A reaction of freshly precipitated bismuth(III) N,N-dipropyldithiocarbamate (PDtc) with AuCl3 solution in 2 M HCl was studied. A heteropolynuclear gold(III)-bismuth complex of ionic type [Au{S2CN(C3H7)(2)}(2)](3)[Bi3Cl12] (I) was isolated by crystallization of products of the heterogeneous reaction from acetone-chloroform (1: 1) solution. Crystal and supramolecular structure of compound I established by X-ray diffraction study includes structurally nonequivalent complex cations [Au{S2CN(C3H7)(2)}(2)](+) related to each other as conformers (hereinafter cations A, B, C, and D) in 1: 1: 2: 2 ratio. Due to secondary Aua <-S bonds (3.386-3.617 ), the isomeric cations form trinuclear species of two types: [Ca <-Aa <-C] and [Da <-Ba <-D] that differ in the character of intercationic binding and Au-Au distances. Relatively weak aurophilic Aua <-Au bonds (3.4704(3) ) unite the neighboring cationic triads into zigzag polymeric chains of type (a <-[Ca <-Aa <-C]a <-[Da <-Ba <-D]a <-) (n) oriented along the crystallographic axis b. The spatial isolation of neighboring chains is provided by discrete trinuclear anions [Bi3Cl12](3-) where metal atoms bind four bridging (mu(2) and mu(3)) chlorine atoms, while each bismuth atom forms distorted octahedral chromophore [BiCl6]. The complex tribismuth anion in the structure I is the first example of [Bi3Cl12](3-) anion of angle rather than linear structure: Bi(1)Bi(2)Bi(3) angle is 72.358A degrees. The thermal behavior of compound I was studied by simultaneous thermal analysis. The multistage process of thermal destruction includes the thermolysis of dithiocarbamate portion of the complex and [Bi3Cl12](3-) accompanied by reduction of gold(III) to metal and release of BiCl3 (followed by its evaporation) and partial formation of Bi2S3. In the temperature range 680-760A degrees C, bismuth sulfide undergoes oxidation to (BiO)(2)SO4, which decomposes above 760A degrees C to give Bi2O3. Residue after thermolysis of compound I is gold metal and bismuth(III) oxide.