X-ray structural studies of cis-Mo(CO)4(PR3)2 (R = Me, Et, n-Bu) derivatives and their relationship to solution isomerization processes in these octahedral species Academic Article uri icon

abstract

  • The crystal and molecular structures of cis-Mo(CO)4(PMe3)2 (1), cis-Mo(CO)4(PEt3)2 (2), and cis-Mo(CO)4[P(n-Bu)3]2 (3) have been determined for the purpose of seeking correlations between structural features—especially evidence of intramolecular strain—and reactivity. The main results are as follows. 1: space group P21/n, with unit cell dimensions of a = 9.770 (1) Å, b = 12.109 (1) Å, c = 14.183 (1) Å, β = 95.435 (7)°, V = 1670.5 (5) Å3, and Z = 4. The Mo-P distances average 2.522 (1) Å, and ∠P-Mo-P = 97.54 (4)°. 2: space group P21/c, with unit cell dimensions of a = 9.740 (3) Å, b = 16.399 (1) Å, c = 14.601 (2) Å, β = 109.49 (2)°, V = 2199 (1) Å3, and Z = 4. The Mo-P distances average 2.544 (4) Å, and ∠P-Mo-P = 100.27 (3)°. 3: space group P21/c, with unit cell dimensions of a = 20.27 (1) Å, b = 9.442 (3) Å, c = 19.011 (6) Å, β = 107.59 (3)°, V = 3468 (4) Å3, and Z = 4. The Mo-P distances average 2.552 (8) Å, and ZP-Mo-P = 99.29 (4)°. Within this set of three compounds, there is a fairly good correlation of both steric strain, as evidenced by the P-Mo-P angles, and tendency to isomerize to the trans structure with the steric bulk of the PR3 ligands as indicated by cone angles. However, comparison of structural variations in a total of seven cis-Mo(CO)4(PR3)2 compounds shows that more subtle factors are also at work. © 1982, American Chemical Society. All rights reserved.

author list (cited authors)

  • Cotton, F. A., Darensbourg, D. J., Klein, S., & Kolthammer, B.

citation count

  • 32

publication date

  • July 1982