Phenylantimony(V) fluoride halides: isolation and crystal structures of SbPh2Br2F·SbPh2Br3, (SbPh2BrF)2O and SbPh3Cl1.8F0.2

Abstract

Oxidation of diphenylantimony fluoride with chlorine leads to diphenylantimony trichloride as the only isolable product, while the corresponding reaction with bromine gives, in addition to SbPh₂Br₃, the bromide fluorides, Sb₂Ph₄Br₅F, SbPh₂Br₂F, Sb₂Ph₄Br₃F₃ and SbPh₂BrF₂. The structure of the first compound has been confirmed by X-ray diffraction as a fluorine-bridged diantimony compound, SbPh₂Br₂F·SbPh₂Br₃, where the antimony atoms are, respectively, in trigonal-bipyramidal and distorted-octahedral co-ordination. Hydrolysis during attempts to obtain crystals of the second compound produced the oxygen-bridged (SbPh₂BrF)₂O, which contains a strong intramolecular fluorine bridge, again giving antimony atoms in both trigonal-bipyramidal and octahedral co-ordination. As an alternative approach to the preparation of mixed chloride fluorides, reactions between diphenylantimony trichloride and KF, AgF and arsenic trifluoride were investigated. There was no reaction with the first two reagents but the product with arsenic trifluoride was a disordered mixed halide, shown by X-ray crystallography to be SbPh₃Cl_1.8F_0.2.