Comment on “Revisiting π backbonding: the influence of d orbitals on metal–CO bonds and ligand red shifts” by D. Koch, Y. Chen, P. Golub and S. Manzhos, Phys. Chem. Chem. Phys., 2019, 21, 20814

Abstract

We challenge the statement of Koch et al. that the M → CO charge transfer and the decrease of the CO stretching frequency in metal carbonyl complexes do not depend on the metal d orbitals. The approach of the authors is severely flawed and leads to misleading conclusions.