PLATINUM METAL-COMPLEXES OF SECONDARY PHOSPHINES - SYNTHESIS AND NMR SPECTROSCOPIC STUDIES OF [M(PCY2H)OCL]+, M=PT, PD

Reaction of MCl2 (M = Pd, Pt) with PCy2H in EtOH under dinitrogen yiel ded the unusual tris-secondary phosphine complexes [MCl(PCy2H)3]X(X=Cl -, BF4, PF6) in high yield as stable products. Retention of the second ary phosphine protons in these complexes has been confirmed by H-1, P- 31 and Pt-195 NMR spectroscopic studies. These results confirm that th e P-H bond in coordinated PCy2H is stronger than in coordinated PPh2 H . Similar reaction of NiCl2.6H2O with PCy2H yields the bis-secondary p hosphine complex [NiCl2(PCY2H)2] as reported previously (R. A. Palmer, H. F. Giles and D. R. Whitcomb, J. Chem. Soc., Dalton Trans. 1978, 16 71 ; R. A. Palmer and D. R. Whitcombe, J. Mag. Res. 1980, 39,371). Var iable temperature P-31 NMR spectroscopy confirms that the cis isomer e xists exclusively in CH2Cl2 solution. while the trans isomer is the do minant form in benzene solution. Addition of excess PCy2H leads to spe cies with higher phosphine: metal ratios at low temperature as seen by P-31 NMR spectroscopy and FAB mass spectrometry.