Activation parameters for rotation about an M–Ccarb bond from temperature dependent 1H n.m.r. spectra of RhI carbene complexes
Abstract
Restricted rotation on the n.m.r. time scale about the Rh–Ccarb bond in complexes [RhLEt(Y)Y′(Z)][LEt= [graphic omitted](Et)] is demonstrated; for trans-[Rh(LEt)2(CO)Cl], variable temperature observations provid rotational activation parameters including a relatively low activation energy (⩽ 10 kcal mol–1) and a negative activation entropy.