148571-92-0Relevant articles and documents
Restricted metal-arene and phosphorus-carbon bond rotation in (arene)Cr(CO)2L complexes (L = PPh3, P(o-tolyl)3)
Howell, James A. S.,Palin, Michael G.,McArdle, Patrick,Cunningham, Desmond,Goldschmidt, Zeev,Gottlieb, Hugo E.,Hezroni-Langerman, Daphna
, p. 1694 - 1701 (1993)
(1,4-Di-tert-butylbenzene)Cr(CO)2PPh3 exhibits restricted arene-Cr bond rotation in solution (ΔG?203 = 31.6 kJ mol-1). A series of (arene)Cr(CO)2P(o-tolyl)3 complexes have been prepared which exhibit restricted P-C rotation in solution; in cases where planar chirality is present, diastereoisomers may be observed which differ in the helicity of the exo2 phosphine conformation. Diastereoisomer interconversion and o-tolyl ring exchange occur with very similar activation energies. Crystal structure data: (1,4-di-tert-butylbenzene)Cr(CO)2PPh3, monoclinic, space group P21/n, a = 10.137(1) A?, b = 13.992(2) A?, c = 20.882(3) A?, β = 96.16(2)°, Z = 4, Rw = 9.18% for 345 refined parameters and 3643 observed reflections; (p-xylene)Cr(CO)2P(o-tolyl)3, monoclinic, space group P21/n, a = 8.552(1) A?, b = 17.410(2) A?, c = 17.558(2) A?, β = 91.95(2)°, Z = 4, Rw = 9.96% for 317 defined parameters and 3392 observed reflections; (benzene)Cr-(CO)2P(m-tolyl)3, monoclinic, space group P21/n, a = 11.120(3) A?, b = 11.227(1) A?, c = 20.289(4) A?, β = 100.63(2)°, Z = 4, Rw = 6.49% for 299 defined parameters and 3127 observed reflections.
