Investigations on the trigonal twist process in the pseudooctahedral complexes [MX(CO)(2)(P-P)(eta(3)-R)] (M = Mo or W; X = halide or pseudohalide; P-P = bidentate P-donor ligand; R = cycloheptatrienyl, cyclohexenyl or cyclooctenyl)

摘要

A series of complexes [MX(CO)(2)(P-P)(eta(3)-R)] [M = Mo or W; X = halide, NCO or NCS; P-P = Ph2P(CH2)(n)PPh2 (n = 1-3)] have been prepared. Variable temperature P-31{H-1}-NMR investigations reveal the operation of a trigonal twist fluxional process in complexes where R = cycloheptatrienyl (C7H7), cyclohexenyl (C6H9) or cyclooctenyl (C8H13) with DeltaG(C)(double dagger) (the free energy of activation at the temperature of coalescence) strongly R-dependent. Using the cycloheptatrienyl complexes [MX(CO)(2){PhP(CH2)(n)PPh2}(eta(3)-C7H7)] detailed investigations have been made to establish the effect on DeltaG(C)(double dagger) of variation of X, n and M. (C) 2002 Published by Elsevier Science B.V. [References: 17]