Département de chimie moléculaire

Mn coordination compds. were studied by x-ray absorption spectroscopy (XAS). The K-pre-edge spectra are interpreted with the aid of time-dependent d. functional theory (TD-DFT). This method was calibrated for the prediction of Mn K-pre-edges with different functionals. The nature of all obsd. features could be identified and classified according to the corresponding set of acceptor orbitals, either 1s to 3d transitions or metal-to-ligand charge transfer (MLCT) bands. The observable MLCT bands are further divided into features that correspond to transitions into empty $π$* orbitals of $π$-donor ligands and those of $π$-acceptor ligands. The ability to computationally reproduce the obsd. features at the correct relative transition energy is strongly dependent on the nature of the transition. A detailed anal. of the electronic structure of Mn coordination compds. reveals that the different classes of observable transitions provide added insight into metal-ligand bonding interactions. [on SciFinder(R)]