SYNTHESIS AND CHARACTERIZATION OF CHIRAL (HYDRIDOTRIS(3,5-DIMETHYLPYRAZOLYL)BORATO)TUNGSTEN(II) ALKYNE COMPLEXES

A series of neutral (hydridotris(3,5-dimethylpyrazolyl)borato)tungsten(II) alkyne complexes of the type Tp'W(CO)(I)(RC = CR') (R = R' = Me; R = Ph, R' = H, Me) has been synthesized. Cationic complexes of the form [Tp'(L)(CO)W(RC = CR')][BF4] (L = CO, CH3CN; R = R' = Me; R = Ph, R' = Ph, Me, H; R = H, R' = CMe = CH2) and [Tp'W(CO)(L)(PhC = CMe)][BF4] (L = P(OMe)3, NCEt) have also been synthesized. These new complexes have been characterized by NMR, IR, and elemental analyses. In addition, single-crystal X-ray diffraction was used to structurally characterize two complexes, [Tp'W(CO)-(MeCN)(PhC = CPh)][BF4] and Tp'W(CO)(I)(PhC = CMe). Crystals of the former are of the orthorhombic space group P2(1)2(1)2(1), Z = 4, with unit cell dimensions of a = 15.671 (4)' angstrom, b = 14.709 (3) angstrom, and c = 15.053 (6) angstrom. Refinement of 214 variables led to an R value of 6.0% and R(w) = 4.4% over 2141 reflections. The latter crystallized in the monoclinic space group P2(1)/n with unit cell dimensions of a = 11.368 (7) angstrom, b = 15.241 (6) angstrom, c = 17.300 (3) angstrom, and beta = 94.24 (4)-degrees, with Z = 4. In this case refinement of 336 variables led to R = 7.3% and R(w) = 9.5% over 3377 reflections.