Physical organic chemistry of transition metal carbene complexes: thermodynamic and kinetic acidities of (CO)5ClCr double bond C(OCH3)CH3 and (CO)5Cr double bond C(OCH3)CH2Ph in aqueous acetonitrile

An analysis of the physical organic chemistry of transition metal carbene complexes involved the measurement of rate constants for proton transfer from (methoxymethylcarbene)pentacarbonylchromium(0) to OH- and amine bases, and from (benzylmethoxycarbene)pentacarbonylchromium(0), to OH- amines, carboxylate ions and H2O. Aqueous acetonitrile ensured 2- and 4.8-fold enhancements in the deprotonation rate of (CO)5Cr double bond C(OCH3)CH3 by OH- and piperidine.