STABILIZATION AND REACTION BEHAVIOR OF A TERMINAL PHOSPHIDO UNIT ON AMONONUCLEAR PT(II) CENTER - SYNTHESIS AND X-RAY STRUCTURE OF A CATIONIC DIPHENYLPHOSPHINE COMPLEX [PT(C6H3(CH(2)NME(2))(2)-2,6)(PHPH(2))][OSO2CF3] AND A DIPHENYLPHOSPHIDO-BRIDGED PT(II) PD(II) COMPLEX 6)H(4)CH(2)NME(2)-2)-(H2O)][BF4]CENTER-DOT-CH2CL2/

Reaction of diphenylphosphine with the complexes [Pt(NCN)(H2O)]X (NCN = C6H3(CH(2)NMe(2))(2)-2,6; X = BF4 (1a), OSO2CF3 (1b)) leads to subst itution of the H2O ligand to afford the ionic Pt(II) complexes [Pt(NCN )(PHPh(2))]X (X = BF4 (2a), OSO2CF3 (2b)). The X-ray structure of the square-planar diphenylphosphine complex 2b is described; triclinic, sp ace group P $($) over bar$$ 1, a = 12.168(1), b = 12.407(1), c = 18.67 6 (1) Angstrom, alpha = 90.78(1), beta = 104.55(1), gamma = 94.18(1)de grees, Z = 4, R = 0.038. Deprotonation of the PHPh(2) ligand of 2 with n-BuLi affords the unprecedented, neutral, mononuclear, Pt(II) termin al phosphido complex [Pt(NCN)(PPh(2))] (3), the characterization of wh ich in solution by P-31{H-1} and H-1 NMR is described. Complex 3 react s with the complex cations of [Pt(NCN)(H2O)][BF4] and [Pd{C(6)H(4)CH(2 )NMe(2)-2-C,N}(N = CMe)(2)][BF4] to afford the new, ionic, dinuclear p hosphido-bridged complexes [{Pt(NCN)}(2)(mu-PPh(2))][BF4] (4) and CN)( mu-PPh(2))Pd(C(6)H(4)CH(2)NMe(2)-2)(H2O)][BF4] (5), respectively. The X-ray crystal structure of the heterobimetallic complex 5 . CH2Cl2 is reported: monoclinic, space group P2(1)/n, a = 14.476(1), b = 14.452(1 ), c = 18.209(2) Angstrom, beta = 94.12(1)degrees, Z = 4, R = 0.049. T he reaction of Mel with 3 gives, rather than Pt(IV) oxidative addition products, the new Pt(II) trans-bis(methyldiphenylphosphine) complex [ Pt(C6H3(CH(2)NMe(2))(2)-2,6-C)(I)(PMePh(2))(2)] (6) and known [Pt{C6H3 (CH(2)NMe(2))(2)-2,6-N,C,N'}(I)]. The chemical behaviour and NMR data of the phosphido complex 3 are consistent with this complex being form ulated as a kind of tertiary phosphine, PPh(2)R, in which R is an orga nometallic moiety {Pt(NCN)} bonded through platinum to phosphorus.