THEORETICAL-STUDIES OF INORGANIC AND ORGANOMETALLIC REACTION-MECHANISMS .1. CIS LABILIZATION IN CARBONYL SUBSTITUTION-REACTIONS OF HEXACOORDINATE CHROMIUM(0) AND MANGANESE(I) PENTACARBONYL COMPLEXES

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 39 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 -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.

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