作者:Leijun Hao、Ian R. Jobe、Jagadese J. Vittal、Richard J. Puddephatt
DOI:10.1021/om00006a026
日期:1995.6
A study of steric effects of the ligands R(2)PCH(2)PR(2), R = aryl, on the formation and chemistry of the clusters [Pt-3(mu(3)-CO)(mu-R(2)PCH(2)PR(2))(3)(O2CCF3)](+), 4, and [Pt-3(mu(3)-CO)(mu-R(2)PCH(2)PR(2))(3)](2+), 8, is reported. When R = 2-MeC(6)H(4), reduction of [Pt(O2CCF3)(2)(R(2)PCH(2)PR(2))] by CO/H2O gave only the binuclear complex [Pt2H(CO)(mu-R(2)PCH(2)PR(2))(2)](+), but with smaller groups R, further reduction to 4 (R = 4-MeC(6)H(4), 3-MeC(6)H(4), 3,5-Me(2)C(6)H(3), 3,5-F2C6H3, 3,5-Cl2C6H3) or to [Pt-4(mu-CO)(2)(mu-H)(mu-R(2)PCH(2)PR(2))(3)(R(2)PCH(2)PR(2))](+) (R = 4-MeC(6)H(4), 3,5-F2C6H3) occurred. The complexes were characterized spectroscopically and for 4(CF3CO2), R;= 3,5-Cl2C6H3, crystallographically [C80H42Cl24F6O5P6Pt3 . 0.5CH(2)Cl(2) . 1.5H(2)O, monoclinic, P2(1)/n, a = 23.365(4) Angstrom, b = 24.599(4) Angstrom, c = 19.141(7) Angstrom, beta = 102.44(2)degrees, Z = 4, R = 0.0727]. The complexes 8 can all form adducts with I-, SCN-, and CF3CO2- though evidence is presented that coordination of CF3CO2- is reversible in solution when R = 3,5-Cl2C6H3. Reactions of 8 with the ligands L = PPh(3), PMePh(2), P(OPh)(3), and P(OMe)(3) to form the adducts [Pt-3(mu(3)-CO)(mu-R(2)PCH(2)PR(2))(3)L](2+) are reversible, and the position of equilibrium depends on the steric effects of R, indicating the steric sequence R = 4-MeC(6)H(4), 3-MeC(6)H(4) < 3,5-Me(2)C(6)H(3) < 3,5-F2C6H3 < 3,5-Cl2C6H3.