Synthesis and structural studies on polymeric assemblies derived from antimony(III) halide complexes with bi- and tri-dentate and macrocyclic thio- and seleno-etherligands

Abstract

SbX₃ (X = Cl, Br or in some cases I) reacts with one molar equivalent of L [L = MeS(CH₂)₂SMe, MeS(CH₂)₃SMe, MeSe(CH₂)₂SeMe, MeC(CH₂SMe)₃, MeC(CH₂SeMe)₃, [12]aneS₄ (1,4,7,10-tetrathiacyclododecane), [14]aneS₄ (1,4,8,11-tetrathiacyclotetradecane), [16]aneS₄ (1,5,9,13-tetrathiacyclohexadecane), [8]aneSe₂ (1,5-diselenacyclooctane) or [16]aneSe₄ (1,5,9,13-tetraselenacyclohexadecane)] in anhydrous CH₂Cl₂, MeCN or thf solution to afford colourless to red-orange powdered solids involving a 1 ∶ 1 Sb ∶ L ratio in most cases, and occasionally a 2 ∶ 1 Sb ∶ L ratio. The crystal structures of [SbCl₃{MeS(CH₂)₂SMe}], [(SbBr₃)₂([14]aneS₄)], [SbCl₃{MeC(CH₂SMe)₃}], [SbI₃{MeC(CH₂SMe)₃}] and [SbBr₃{MeC(CH₂SeMe)₃}] all exhibit infinite one- or three-dimensional networks which are assembled from distorted five or six coordinate Sb(III) with primary Sb–X bonding, secondary Sb–S or Sb–Se interactions and retention of the pyramidal SbX₃ unit found in the parent halides. The structures of these compounds are discussed in terms of the bonding model used by others for antimony phosphine complexes. They are also compared with the structures of other reported thioether complexes of Sb(III), and with their Bi(III) analogues.