Electronic Structure of Alkoxychromium(0) Carbene Complexes: A Joint TD-DFT/Experimental Study

The joint computational (TD-DFT) experimental study of the UV−vis spectroscopy of alkoxychromium(0) carbene complexes accurately assigns the vertical transitions responsible for the observed spectra of these compounds. Both the LF and the MLCT band have a remarkably π−π* character, which has been demonstrated by the strong dependence of the absorptions with the donor/acceptor nature of the substituent in p-substituted styrylchromium(0) carbene complexes. The effect of the substituent is also related with the equilibrium geometry of the complexes and the occupations of the p atomic orbital of the carbene carbon atom. Additionally, the ferrocenyl moiety behaves in chromium(0) (Fischer) carbene complexes as a π-donor group.