Diphenylantimony(III) fluoride: preparation and crystal structure
Abstract
Attempts to prepare SbPh2F by the modification of methods which give the corresponding chloride have not been successful, but this compound can be obtained by treating SbF3 with [NH4]2[SiPhF5]. Comparison of the mass spectra of SbPh2F and SbPh2Cl suggests the formation of strong fluorine bridges in the former, which has been confirmed by an X-ray analysis. Crystals of SbPh2F are orthorhombic with a= 8.18(1), b= 11.04(1), c= 12.02(1)Å, space group P212121, and Z= 4. Atomic positions have been determined by Patterson and Fourier methods from X-ray diffractometer data and refined by least squares to R 0.042 for 1 170 reflections. The structure consists of infinite chains of SbPh2F units, resulting from the formation of strong intermolecular fluorine bridges [Sb ⋯ F 2.221(5)Å]; the corresponding intramolecular Sb–F distance is 2.166(5)Å and the angle at the bridging fluorine is 140.2(3)°. The antimony lone pair of electrons is stereochemically active giving a structure based on a trigonal bipyramid with fluorines in axial positions and the phenyl groups occupying two of the equatorial positions. The mean Sb–C distance is 2.13 Å and angle between the phenyl groups [C(1)–Sb(1)–C(7)] is 99.9(4)°.