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 L2,3 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 CuII complexes ([CuCl4]2– and copper phthalocyanine) provided information about how metal-to-ligand charge-transfer transitions associated with excitations from CuII 2p orbitals to low-lying, ligand-based π* molecular orbitals in a simplified one-electron picture may contribute to the CuII L2,3 edge intensity and, thus, weaken its believed relationship with the CuII–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

MANGIONE, GIULIA;PANDOLFO, LUCIANO;SAMBI, MAURO;CASARIN, MAURIZIO
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 L2,3 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 CuII complexes ([CuCl4]2– and copper phthalocyanine) provided information about how metal-to-ligand charge-transfer transitions associated with excitations from CuII 2p orbitals to low-lying, ligand-based π* molecular orbitals in a simplified one-electron picture may contribute to the CuII L2,3 edge intensity and, thus, weaken its believed relationship with the CuII–ligand symmetry-restricted covalency.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3186872
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