NOVEL ROUTE TO THE UNSYMMETRICAL DIALKYL COMPLEX CPW(NO)(CH2SIME3)(CH2CPH3) AND FORMATION OF METALLACYCLES BY THERMOLYSIS OF CPW(NO)(CH2SIME3)(CH2CR2PH) (R=ME, PH)

Treatment of CpW(NO)(CH2SiMe3)2 (CP =eta5-C5H5) with [Ph3C]PF6 results in cleavage of the Si-C bond and formation of the unsymmetrical dialkyl complex CpW(NO) (CH2SiMe3)(CH2CPh3) (1). Crystal data for 1: a = 10.930(2) angstrom, b = 14.048(2) angstrom, c = 9.357(2) angstrom, alpha = 92.781(16)-degrees, beta = 90.186(18)-degrees, gamma = 111.929(13)-degrees, Z = 2, space group P1BAR, R = 0.041, R(W) = 0.040 for 3379 reflections with I greater-than-or-equal-to 3sigma(I). Complex 1 is thermally unstable and converts to the metallacyclic complex CpW(NO)(CH2C(C6H4)Ph2) (NCMe) (2) in acetonitrile. Crystal data for 2: a = 13.632(4) angstrom, b = 10.009(2) angstrom, c = 16.081(2) angstrom, beta = 93.401(12)-degrees, Z = 4, space group P2(1)/c, R = 0.040, R(W) = 0.046 for 3427 reflections with I greater-than-or-equal-to 3sigma(I). The structures of 1 and 2 were solved by conventional heavy-atom methods and were refined by full-matrix least-squares procedures. In the presence of PPh3, complex 1 thermally decomposes in CH2Cl2 to CPW(NO)(CH2C(C6H4)Ph2)(PPhs) (4). The neophyl analogue of 1, CpW(NO)(CH2SiMe3)(CH2CMe2Ph) (5), can be prepared from CpW(NO)(CH2SiMe3)Cl and, like 1, readily undergoes ortho metalation in the presence of PPh3 and converts to CpW(NO)(CH2C(C6H4)Me2)(PPh3) (6).