Structure and stereodynamics of [M(CO)5{P(C6H4Me-o)3}](M = Cr, Mo or W) and [Cr(CO)3{P(C6H4Me-o)3}]
作者:James A. S. Howell、Paul C. Yates、Michael G. Palin、Patrick McArdle、Desmond Cunningham、Zeev Goldschmidt、Hugo E. Gottlieb、Daphna Hezroni-Langerman
DOI:10.1039/dt9930002775
日期:——
The crystal structure of [Cr(CO)5P(C6H4Me-o)3}] has been determined. It reveals an exo2 conformation for the phosphine ligand, in agreement with molecular mechanics calculations. Barriers to P-C rotation in the series [M(CO)5P(C6H4Me-o)3}] (M = Cr, Mo or W) are in the range 36-42 kJ mol-1; restricted M-P rotation is also evident in the low-temperature (CO)-C-13 NMR spectrum of [Cr(CO)5P(CH4Me-o)3}]. The crystal structure of the pi complex [Cr(CO)3P(C6H4Me-o)}3] is most consistent with an electron-acceptor character for the P(C6H4Me-o)2 substituent. Crystal data: [Cr(CO)5P(CH4Me-o)3}], monoclinic, space group P2(1)/n, a = 10.774(2), b = 14.951 (5), c = 14.687(7) angstrom, beta = 91.45(2)-degrees, Z = 4, R' = 0.0980 for 209 variable parameters and 2326 observed reflections; [Cr(CO)3P(C6H4Me-o)3}], monoclinic, space group P2(1)/a, a = 16.725(2), b = 7.340(1), c = 17.675(4), beta = 92.66(2)-degrees, Z = 4, R' = 0.1187 for 263 variable parameters and 1848 observed reflections.