MULTINUCLEAR (P-31, SE-77, CD-113, HG-199) MAGNETIC-RESONANCE, ELECTROSPRAY MASS-SPECTROMETRIC AND ELECTROCHEMICAL STUDIES ON THE REACTIONSOF M(S2P(OET)2)2 (M=CD, HG) WITH POTENTIALLY BIDENTATE MIXED GROUP-15GROUP-16 AND GROUP-16 DONOR LIGANDS

Extensive studies of the labile Hg(dtp)2/dpmSe (dtp = (S2P{OEt}2); dpm Se = Ph2P(Se)CH2PPh2) system by multinuclear magnetic resonance (NMR), electrospray mass spectrometry (ESMS) and electrochemical-techniques show that in solution both Hg(dtp)2 itself and the mixed Hg(dtp)2/dpmS e system consist of many competign equilibria with the species being i dentified as dtp-, Hg(dtp)2, [Hg(dtp)3]-, [Hg2(dtp)3]+, dpmSe, Hg(dtp) 2(dpmSe), [Hg(dtp)(dpmSe)]+ and [Hg(dtp)(dpmSe)2]+. NMR studies show t hat Hg(dtp)2 reacts with dpmSe in 1:1 molar proportions to give produc ts which, at room temperature in dichloromethane solution, are labile with exchange of both types of ligand occurring. Upon cooling to -30-d egrees-C the dpmSe ligand becomes chelated and static on the NMR times cale, but the dithiophosphate ligands still undergo rapid exchange. Fu rther cooling causes the exchange of the dithiophosphate ligands to be come slow and two species are observed at -100-degrees-C which are ide ntified as [(eta2-dpmSe)Hg(eta2-dtp)][S2P(OEt)2] and (eta2-dpmSe)Hg(et a1-dtp)2. ESMS studies on solutions of Hg(dtp2 show the presence of dt p-, [Hg(dtp)3]- and [Hg2(dtp)3]+ and, after addition of dpmSe to the s olution, ESMS confirmed the presence of [Hg(dtp)(dpmSe)]+. Differentia l pulse and direct current sampled polarograms re-emphasise the labile nature of this system and provide further evidence of mixed ligand co mpound formation as well as thermodynamic data. NMR studies on the Cd( dtp)2/dpmSe system show it to be more labile than its mercury analogue and the interpretation of the NMR data is ambiguous. NMR studies on t he M(dtp)2/dpmS (or dpmSe2 or dpmS2) systems (M = Hg, Cd; dpmSe2 or dp mS2 = Ph2P(E)CH2P(E)Ph2; E = Se, S) are even less definitive. ESMS con firms the presence in solution of the cations [(ligand)M(dtp)]+ for al l the systems studied.