Proton magnetic resonance study of molecular motion in triphenyltin fluoride, chloride, bromide and hydroxide

Abstract

Proton magnetic resonance second moments of triphenyltin fluoride, chloride, and hydroxide have been measured between 77 K and 530 K for the fluoride or the melting point for the chloride and hydroxide. Spin-lattice relaxation times have been obtained by pulse spectrometry over the same temperature ranges for these compounds as well as for triphenyltin bromide. The results are discussed in terms of three possible molecular motions: 180° jump reorientation of the phenyl groups about their Sn—C axes, other (probably fourfold) reorientation of the phenyl groups about the Sn—C bonds, and C₃ reorientation of the triphenyltin group. The experimental results appear to agree best with a probably fourfold reorientatio of phenyl groups about the Sn—C bond in the case of the heat treated fluoride, and with a C₃ reorientation of the whole molecule in the case of the chloride. The second moments of the hydroxide suggest a significantly different packing of molecules in the unit cell to that existing in the chloride. In other respects the behaviour of the hydroxide seems to resemble that of the fluoride. T₁ values for chloride and bromide are similar.