31P, 13C and 17O nuclear magnetic relaxation in triphenylphosphine oxide (TPPO) and its complexes. I. 31P nuclearrelaxation mechanisms and 17O quadrupolar coupling constant in TPPO, free and in the complex Zn (TPPO)4(BF4)2

Abstract

The contributions of the different relaxation mechanisms for the 31P nucleus in Triphenylphosphine oxide (TPPO), free and engaged in the complex Zn(TPPO)4(BF4)2, have been determined and compared from a study of the longitudinal relaxation times at different frequencies. The quadrupolar coupling constants of the 17O nucleus have been deduced usinG the chemical shift anisotropy data obtained by 31P NMR on solid samples and the linewidth OF the 17O NMR signals. The variation of these parameters between the ligand and the complex is discussed.