A computational thermochemical value for Cr-Cu bond dissociation energy: using crystal field theory to understand the chemical bond in metal clusters

Semi-empirical (PM6) approach was employed to modelling Cr-Cu dimmer. The obtained bond dissociation energy for such specie agrees very well with experimental/reference values. It was verified that in the Cr-Cu dimmer, chromium has only one unpaired electron, meaning that copper behaves, in such dimmer, as a strong field ligand. Such results strongly suggest that 1:1 Cr-Cu bronzes must behave as a one unpaired electron compound and not a five unpaired electrons one, with, of course, remarkable influences on their magnetic properties.