Chalcogenolato complexes of bismuth and antimony. Syntheses, thermolysis reactions, and crystal structure of Sb(SC6H2Pri3-2,4,6)3

Abstract

Antimony(III) and bismuth(III) complexes of sterically demanding arenechalcogenolato ligands, M(EC₆H₂R′₃-2,4,6)₃(E = S or Se; M = Sb or Bi; R′= Me, Prⁱ or Bu^t) have been prepared by either protolysis of the amides M[N(SiMe₃)₂]₃ with arenechalcogenols, or from MCl₃ by halide exchange (M = Bi or Sb). The complexes are monomeric in the solid state and sublime readily. The crystal structure of Sb(SC₆H₂Prⁱ₃-2,4,6)₃ has been determined by X-ray diffraction. The compound possesses a trigonal-pyramidal geometry, with Sb–S distances of 2.418(2)–2.438(2)Å and S–Sb–S angles of 94.69(7)–98.29(8)°. Preliminary X-ray results on Bi(SeC₆H₂Prⁱ₃-2,4,6)₃ showed that the compounds of Sb and Bi are isostructural. Thermolytic decomposition of some of the compounds has been carried out in the solid state. Compounds with R′= Me or Prⁱ undergo reductive elimination to give elemental bismuth or antimony, whereas the bulky selenolates M(SeC₆H₂Bu^t₃-2,4,6)₃ afford M₂Se₃.