SOME BRIDGE-CLEAVAGE CHEMISTRY OF CYCLOMETALATED (PD, PT) DIMERIC COMPLEXES OF TRIMESITYLPHOSPHINE

The cyclometallated dimers, [M(Pmes2C6H2(CH3)2CH2)Cl]2 (M=Pd, Pt), rea ct with PPh3, AsPh3, P(OPh)3 and 5-phenyldibenzophosphole (DBP) via br idge-cleavage of the MCl2M bridge unit to give the corresponding monom ers, trans-[M(Pmes2C6H2(CH3)2CH2)Cl(L). A cis complex is observed only for the case of M = Pt, L = SbPh3. Ligand comparisons are made qualit atively in terms of reactivity and trans-influence exerted. Chemistry for the species [M(Pmes2C6H2(CH3)2CH2) X (PPh3)] (X = Cl, Br, I, Pz), is pursued in some detail to investigate the effects of the nature of X. Phosphorus-31 NMR data for [MCl2(PPh3)2] (M=Pd, Pt) are reported fo r the first time.