Preparation, spectroscopy and oxidation of [Re(C3S5)3]– and [ReO(C3S5)2]– complexes and crystal structure of [PPh4][ReO(C3S5)2]

Abstract

Reaction of ReCl₅ with Na₂[C₃S₅][C₃S₅^2–= 4,5-dimercapto-1,3-dithiole-2-thionate(2–)] in ethanol in the presence of [PPh₄]Br gave [PPh₄][ReO(C₃S₅)₂]1. The salt [NBuⁿ₄][Re(C₃S₅)₃]2 was obtained by reaction of ReCl₅ with [NBuⁿ₄]₂[Zn(C₃S₅)₂] in acetonitrile. Oxidation reactions of 2 with iodine or [Fe(C₅H₅)₂][PF₆] in dichloromethane afforded [Re(C₃S₅)₃](contaminated with 5 or 10% of 2). These oxidized complexes have electrical conductivities of 2.2 × 10^–2 and 4.6 × 10^–3 S cm^–1 at room temperature for compacted pellets. Cyclic voltammetry and electronic absorption spectra of 1 and 2, together with IR, ESR and X-ray photoelectron spectra of the oxidized species of 2 are discussed. X-Ray structure analysis of 1 reveals that the anions having a square-pyramidal geometry around the Re^V are separately arranged in the crystal: monoclinic, space group P2₁/n, a= 12.437(8), b= 25.56(4), c= 11.137(8)Å, β= 105.58(6)° and Z= 4. Block-diagonal least-squares refinement based on 4591 reflections with |F_o| > 3σ(F) converged at R= 0.052.