ChemInform Abstract: The CO-CO Interactions in Transition-Metal Hexacarbonyls Studied by Penning Ionization Electron Spectroscopy: Cr(CO)6, Mo(CO)6 and W(CO)6.

Abstract

Penning ionization electron spectra resulting from thermal collisions of He*(2 3S) metastable atoms with gaseous Cr(CO)6, Mo(CO)6, and W(CO)6 were measured to probe the CO–CO interactions. The energy splitting of the CO 5σ‐derived levels [I.P.(8a1g)−I.P.(8t1u)] was determined for the first time. Further, the spectra show that the through‐space interaction among the CO 5σ orbitals not only stabilizes the orbital energy of the CO 5σ‐derived 8a1g molecular orbital, but also gives rise to a diffuse electron distribution. The CO–CO interactions in the transition‐metal (TM) carbonyls were compared to those in the CO overlayer formed on TM surfaces.