PHOSPHINE DERIVATIVES OF MERCURY AND CADMIUM DITHIOLATES - AN ELECTROSPRAY MASS-SPECTROMETRIC STUDY

Electrospray mass spectrometry (ESMS) has been used to investigate the ionic species present in solutions of mercury and cadmium diethyldith iocarbamates (dtc) and diethyldithiophosphates (dtp) after reaction wi th phosphine ligands. After reaction between the dithiolates (S-S) and monodentate ligands, ESMS shows the presence of both [Hg(S-S)(PR(3))] (+) and [Hg(S-S)(PR(3))(2)](+), but only [Cd(S-S)(PR(3))(2)](+). The 1 :1 Cd(S-S)(2) phosphine complex observed by NMR methods is thought to be the neutral Cd(S-S)(2)(PR(3)). Reaction of all the metal dithiolate s with polydentate ligands in solution gives systems which are labile on the NMR timescale, but ESMS shows the presence of [M(S-S)(phos)](+) in each case. This work emphasises the complementary nature of NMR an d ESMS techniques.