May 26, 2014
Journal Article

Kinetics and Mechanism of the Hydrogenation of CpCr(CO)3•/[CpCr(CO)3]2 Equilibrium to CpCr(CO)3H

Abstract

The kinetics of the hydrogenation of 2 CpCr(CO)3•/[CpCr(CO)3]2 to CpCr(CO)3H has been investigated. The reaction is second-order in Cr and first-order in H2, with a rate constant of 45 M 2s 1 at 25 °C in benzene. DFT calculations rule out an H2 complex as an intermediate, and suggest (a) end-on approach of H2 to one Cr of [CpCr(CO)3]2 as the Cr-Cr bond undergoes heterolytic cleavage, (b) heterolytic cleavage of the coordinated H2 between O and Cr, and (c) isomerization of the resulting O-protonated CpCr(CO)2(COH) to CpCr(CO)3H. The work at Pacific Northwest National Laboratory (PNNL) was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences; Battelle operates PNNL for DOE.

Revised: January 12, 2015 | Published: May 26, 2014

Citation

Norton J.R., T. Spataru, D.M. Camaioni, S. Lee, G. Li, J. Choi, and J.A. Franz. 2014. Kinetics and Mechanism of the Hydrogenation of CpCr(CO)3•/[CpCr(CO)3]2 Equilibrium to CpCr(CO)3H. Organometallics 33, no. 10:2496-2502. PNNL-SA-90665. doi:10.1021/om4012399