13C and 119Sn NMR Study of some four- and five-coordinate triphenyltin(IV) compounds

Abstract

The 13C and 119Sn NMR spectra of four- and five-coordinate triphenyltin(IV) compounds have been examined. The chemical shifts δ( 119Sn) and the coupling constants 1 J( 119Sn- 13C) depend markedly on the coordination number of the tin atom and on the geometry of the coordination sphere. The chemical shifts and the coupling constants 1 J( 119Sn- 13C) for four-coordinate compounds are in the range −40 to −120 ppm and 550–660 Hz, respectively. The δ( 119Sn) values for five-coordinate compounds (trigonal bipyramid arrangement) are in the range −180 to −260 ppm. The 1 J( 119Sn- 13C) values for the compounds with three phenyl groups in the equatorial plane and the other ligands in axial positions ( trans) are in the range 750–850 Hz. The chelate compound with two phenyl groups in the equatorial plane and the third in the axial position and the two donor atoms of chelating ligand in equatorial and axial positions, respectively, have the coupling constants in the range 600–660 Hz. The NMR spectra are discussed in terms of a three-centre molecular orbital model.