SYNTHESIS, STRUCTURE AND SUBSTITUTION-REACTIONS OF THE BINUCLEAR PHOSPHIDO-BRIDGED COMPLEX CP(CO)(2)W(MU-PPH(2))W(CO)(5)

Bimetallic phosphido-bridged complexes CpW(CO)(3)(mu-PPh(2))W(CO)(5) (1) and CpW(CO)(2)(mu-PPh(2))W(CO)(5) (2) were prepared by the reaction of CpW(CO)(3)PPh(2) with W(CO)(5)THF. The structures of 1 and 2 were determined by single X-ray diffraction. Crystal data for 1:C25H15O8PW2, space group, P2(1)/n with a = 9.6234 (18) Angstrom, b = 12.4514 (20) Angstrom, c = 20.750 (4) Angstrom, beta = 98.445 (14)degrees, V = 2459.4 (7) Angstrom(3), Z = 4. The structure was refined to R = 0.031 and R(w) = 0.035. Crystal data for 2: C24H15O7PW2, space group, P2(1)/n with a = 14.4801 (11) Angstrom, b = 11.6628 (12) Angstrom, c = 14.732 (3) Angstrom, beta = 97.893 (11)degrees, V= 2464.3 (6) Angstrom(3), Z = 4. The structure was refined to R = 0.054 and R(w) = 0.050. The long distance between W and W (4.5096 (11) Angstrom) in 1 indicates that no metal-metal bond exists in the complex. The W-W distance was 3.1942 (12) Angstrom in 2, indicative of a W-W bond. Substitution reactions between 2 and Lewis bases L (L = PPh(3), PEt(3), P(OMe)(3)) produced CpW(CO)(2)(mu-PPh(2))W(CO)(4)(L) (3) with L regiospecifically and stereospecifically coordinating to the W(CO)(4) moiety trans to the phosphido bridge. The structure of CpW(CO)(2)(mu-PPh(2))W(CO)(4){P(OMe)(3)} (3a) was determined by single-crystal X-ray diffraction. Crystal data for 3a: C26H24O9P2W(2), space group, P2(1) with a = 9.2231 (16) Angstrom, b = 15.868 (3) Angstrom, c = 10.745 (3) Angstrom, beta = 110.282 (18)degrees, V= 1475.1 (5) Angstrom(3), Z = 2. The structure was refined to R = 0.037 and R(w) = 0.039. Under similar reaction conditions, complex 1 did not react with L.