SUBSTITUTED METAL-CARBONYLS .20. UNEXPECTED FORMATION OF 2 DIPHENYLPHOSPHINE COMPLEXES FROM THE OXIDATION OF PENTACARBONYLRHENATE BY CHLORODIPHENYLPHOSPHINE - CRYSTAL AND MOLECULAR-STRUCTURES OF EQ-RE2(CO)9(PPH2H) AND CIS-RECL(CO)4(PPH2H)

Oxidation of [Re(CO)5]- by a molar equivalent of PPh2Cl at ca. -70-deg rees-C yielded three dinuclear complexes, Re2(mu-Cl)(mu-PPh2)(CO)8 (1) , Re2(CO)9(PPh2H) (2) and Re2(mu-H)(mu-PPh2)(CO)8 (3), as major produc ts. When PPh2Cl was present in two-fold excess, only 2 and ReCl(CO),(P Ph2H) (4) were isolated. All the complexes were characterized by IR an d NMR (H-1 and P-31) spectroscopy. The crystal structures of 2 and 4 w ere determined by single-crystal X-ray diffraction analyses. Crystal d ata: ReCl(CO)4(PPh2H), space group P2(1)/c, a = 11.358(1), b = 10.365( 1), c = 14.765(3) angstrom, beta = 96.07(1)-degrees, final R = 0.022 f or 1891 observations; Re 2(CO)9(PPh2H), space group P 2, la, a = 12.70 9(1), b = 12.072(2), c = 15.462(2) angstrom, beta = 92.14(1)-degrees, final R = 0.029 for 2093 observations. Complex 2 is the first structur ally characterized Re2(CO)9(PR3) complex with the phosphine substituen t at the equatorial site. The complex Re2(mu-PPh2)2(CO), was not detec ted and there is no evidence of direct nucleophilic attack of the rhen ate on chlorodiphenylphosphine.