THE STRUCTURAL-ANALYSIS OF ACETONITRILE-CIS-DICARBONYL(ETA-5-CYCLOPENTADIENYL)(TRIPHENYLPHOSPHINE)MOLYBDENUM(II) TETRAFLUOROBORATE, CIS-[(ETA-5-C5H5)MO(CO)2(PPH3)(NCCH3)]+[BF4]-

The crystal structure of the title compound has been determined by means of single crystal X-ray diffraction techniques. The subject compound crystallizes in the monoclinic space group P2(1)/c (No. 14, C2h5). The lattice constants are a = 12.997(3), b = 11.729(3), c = 17.681(4) angstrom and beta = 100.73(2)-degrees. Anisotropic refinement based on 3655 unique reflections using a full-matrix least-squares program has yielded R = 0.046 and R(w) = 0.051. There are four molecules per unit cell, D(m) = 1.52(3) and D(x) = 1.52 Mg m-3. The tetrafluoroborate anion displayed a great deal of disorder. Utilizing cone angle calculations, a 'ligand profile' describes the steric bulk of the triphenylphosphine functional group. The resulting maximum cone angle, theta, for the triphenylphosphine group is 120-degrees. Important metrical details are: Mo-P = 2.5356(8); Mo-N = 2.156(3); Mo-C = 1.978(4) and 1.950(4); C = N = 1.120(4); and C = O = 1.156(5) and 1.147(4) angstrom.