Diphenylantimony(V) oxide halides and thiocyanate; the crystal structures of dimeric diphenylantimony(V) bromide oxide and tetrameric diphenylantimony(V) oxide fluoride and thiocyanate

Abstract

Dimers containing a four-membered Sb₂O₂ ring with antimony atoms in distorted trigonal-bipyramidal co-ordination were obtained when either diphenylantimony(III) chloride or bromide was oxidised with tert-butyl hydroperoxide; the crystal structure of [SbPh₂O(Br)]₂ has been determined. Related reactions with the corresponding fluoride and thiocyanate gave products with the same stoichiometry but X-ray crystallography showed these are centrosymmetric tetramers, X₂Ph₂SbO(Ph₂SbO₂SbPh₂)OSbPh₂X₂, which also contain a central four-membered ring. A possible mechanism for formation of these tetramers is presented. Oxidation of phenylantimony dichloride and dibromide on the other hand gave only rearrangement and decomposition products.