Theoretical studies of inorganic and organometallic reaction mechanisms. 1. Cis labilization in carbonyl substitution reactions of hexacoordinate chromium(0) and manganese(I) pentacarbonyl complexes Academic Article uri icon


  • Hartree-Fock-Roothaan calculations are reported for the pentacarbonyls M(CO)5L (M = Cr, L = PH3, NH3; M = Mn, L = Cl, H) and for the fragments formed by carbonyl loss. Analytical gradient techniques were used to completely optimize the geometries. The loss of a carbonyl cis to the heteroligand is favored over trans loss by 3–9 kcal/mol. For most complexes this difference is split between ground-state effects and relaxation effects in the intermediate. The importance of relaxation effects increases as the π-donor ability of L increases. Direct conversion of the trans-loss to cis-loss intermediate is calculated to require approximately 10 kcal/mol in the gas phase. However, an indirect mode of trans-carbonyl incorporation has a calculated activation energy of only 1 kcal/mol. © 1989, American Chemical Society. All rights reserved.

author list (cited authors)

  • Davy, R. D., & Hall, M. B.

citation count

  • 23

publication date

  • September 1989