The low-lying empty orbitals of bis(acetylacetonato)copper have been probed by near-edge X-ray absorption fine structure (NEXAFS) spectroscopy at the Cu L<inf>2,3</inf> edges and time-dependent density functional theory (TDDFT) calculations within the Tamm-Dancoff approximation (TDA) coupled to the relativistic zeroth-order regular approximation including spin-orbit effects (SO-ZORA TDDFT-TDA). Both the relative positions of NEXAFS features and their linear dichroism are satisfactorily reproduced. Moreover, a comparison with literature data pertaining to two other square-planar Cu<sup>II</sup> complexes ([CuCl<inf>4</inf>]<sup>2-</sup> and copper phthalocyanine) provided information about how metal-to-ligand charge-transfer transitions associated with excitations from Cu<sup>II</sup> 2p orbitals to low-lying, ligand-based ?* molecular orbitals in a simplified one-electron picture may contribute to the Cu<sup>II</sup> L<inf>2,3</inf> edge intensity and, thus, weaken its believed relationship with the Cu<sup>II</sup>-ligand symmetry-restricted covalency.
Ligand-field strength and symmetry-restricted covalency in CuII complexes - A near-edge X-ray absorption fine structure spectroscopy and time-dependent DFT study
Nardi MV;Cossaro A;Floreano L;Casarin M
2015
Abstract
The low-lying empty orbitals of bis(acetylacetonato)copper have been probed by near-edge X-ray absorption fine structure (NEXAFS) spectroscopy at the Cu LI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.