.pi. Acidity of tris(2-cyanoethyl)phosphine. X-ray structural studies of M(CO)5P(CH2CH2CN)3 (M = chromium, molybdenum) and Mo(CO)5P(C6H5)3 Academic Article uri icon

abstract

  • The X-ray crystal structures and IR spectra of the compounds M(CO)5P(CH2CH2CN)3, M = Cr (1) and Mo (2), and Mo(CO)5P(C6H5)3 (3) are reported. Compounds 1 and 2 are isomorphous and crystallize in the monoclinic space group P2Jn with unit cell parameters a = 16.913 (5) Å, 17.140 (2) Å, b = 6.538 (3) Å, 6.639 (1) Å, c = 17.402 (4) Å, 17.574 (2) Å, β = 117.91 (2)°, 118.09 (1)°, v = 1700 (2) Å3,1764.3 (9) Å3, and Z = 4,4, where the two figures for each parameter refer to the Cr and Mo compounds, respectively. Each molecule occupies a general position within the unit cell. The M-P distances are 2.364 (1) and 2.506 (1) A for the Cr and Mo compounds, and the average M-COax and M-COeq distances are 1.876 (4) and 1.891 (4) Å and 2.008 (4) and 2.044 (5) Å, respectively. Compound 3 crystallizes in the triclinic space group PI with unit cell parameters a = 9.653 (5) Å, b = 12.301 (5) Å, c = 9.503 (8) Å, α = 90.88 (5)°, β = 95.73 (5)°, y = 74.89 (4)°, V = 1084 (2) Å3, and Z =2. Again, each molecule occupies a general position within the cell. The Mo-P distance is 2.560 (1) A and the average Mo-COax and Mo-COeq distances are 1.995 (3) and 2.046 (4) Å, respectively. On the basis of these structural data as well as v(CO) infrared data, tris(2-cyanoethyl)phosphine can be described as a good π-acceptor ligand. © 1981, American Chemical Society. All rights reserved.

author list (cited authors)

  • Cotton, F. A., Darensbourg, D. J., & Ilsley, W. H.

citation count

  • 61

publication date

  • February 1981