A phosphorus-31 magnetic resonance study of ligand exchange on tetrakis(hexamethylphosphoramide)zinc(II) ion

Abstract

The rate of the associative ligand exchange process on tetrakis (hexamethylphosphoramide)zinc(II) ion in CD2Cl2 solution, determined by 31P n.m.r. spectroscopy, is given by: ������������������� rate = 4k2[O=P(Nme2)3][Zn(O=P(NMe2)3)42+] The characteristic kinetic parameters are: k2(240 K) 304�17 dm3 mol-1 s-1, ΔH2‡ 22.7�0.9 kJ mol-1, and ΔS2‡ -101�4 J K-1 mol-1. ��� The preparations of [Zn(O=P(NMe2)3)4](ClO4)2, [Zn(O=P(OMe)3)5] (ClO4)2 and [Zn {O=P(Me)-(OMe)2}5](ClO4)2 are reported. The rate of ligand exchange upon the last two species was found to be in the fast-exchange limit of the n.m.r. time scale.