Crystal structures of [NBun4]2[M(C3S5)(C3Se5)](M = Ni or Pd) and properties of the nickel(II) complex

Abstract

The complexes [NBuⁿ₄]₂[M(C₃S₅)(C₃Se₅)](M = Ni 1 or Pd 2) were isolated. Oxidation reactions of 1 with [Fe(C₅H₅)₂][PF₆], [Fe(C₅Me₅)₂][BF₄] and [ttf]₃[BF₄]₂(ttf˙⁺= the radical cation of tetrathiafulvalene) and the current-controlled electrolysis of 1 afforded partially oxidized complexes [NBuⁿ₄]_0.7[Ni(C₃S₅)(C₃Se₅)], [Fe(C₅Me₅)₂]_0.7[Ni(C₃S₅)(C₃Se₅)], [ttf]_0.7[Ni(C₃S₅)(C₃Se₅)] and [NBuⁿ₄]_0.3[Ni(C₃S₅)(C₃Se₅)], respectively. These partially oxidized complexes have electrical conductivities of 4.2 × 10^–1–5.5 × 10^–5 S cm^–1 at 25 °C for compacted pellets. Cyclic voltammetry and electronic absorption spectra of 1, together with IR, ESR and powder reflectance spectra of the partially oxidized species, are discussed. Single-crystal X-ray structure analysis of 1 and 2 reveal that the anions are separately arranged in the crystal phase and that the metal atoms are located at centres of symmetry, the positions of the S and Se atoms being disordered. The monoclinic crystals, space group P2₁/c, have cell dimensions a= 8.498(5), b= 14.981(6), c= 19.620(7)Å, β= 96.13(4)° and Z= 2 for 1 and a= 8.5837(5), b= 15.012(1), c= 19.717(3)Å, β= 96.31(1)° and Z= 2 for 2. Block-diagonal least-squares refinements, based on 1825 and 2723 reflections [|F_o| > 3σ(F)], converged at R= 0.076 and 0.062 for 1 and 2, respectively.