L-edge X-ray absorption spectroscopy of non-heme iron sites: Experimental determination of differential orbital covalency
| Autor: | Wasinger, EC, de Groot, FMF, Hedman, B, Hodgson, KO, Solomon, EI, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis |
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| Přispěvatelé: | Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis |
| Jazyk: | angličtina |
| Rok vydání: | 2003 |
| Předmět: |
Ligand field theory
Models Molecular Absorption spectroscopy Heme PHENYLALANINE-HYDROXYLASE Biochemistry Ferric Compounds Catalysis Spectral line INHOMOGENEOUS ELECTRON-GAS Colloid and Surface Chemistry Absorptiometry Photon Atomic orbital COPPER MODEL COMPLEXES Taverne Molecular orbital CRYSTAL-STRUCTURE Ferrous Compounds Multiplet Chemistry K-EDGE BRANCHING RATIO General Chemistry CORRELATION-ENERGY Models Chemical GROUND-STATE PRE-EDGE ACTIVE-SITES Density functional theory Atomic physics Ground state |
| Zdroj: | Journal of the American Chemical Society, 125(42), 12894. American Chemical Society |
| ISSN: | 0002-7863 |
| Popis: | X-ray absorption spectroscopy has been utilized to obtain the L-edge multiplet spectra for a series of non-heme ferric and ferrous complexes. Using these data, a methodology for determining the total covalency and the differential orbital covalency (DOC), that is, differences in covalency in the different symmetry sets of the d orbitals, has been developed. The integrated L-edge intensity is proportional to the number of one-electron transition pathways to the unoccupied molecular orbitals as well as to the covalency of the iron site, which reduces the total L-edge intensity and redistributes intensity, producing shake-up satellites. Furthermore, differential orbital covalency leads to differences in intensity for the different symmetry sets of orbitals and, thus, further modifies the experimental spectra. The ligand field multiplet model commonly used to simulate L-edge spectra does not adequately reproduce the spectral features, especially the charge transfer satellites. The inclusion of charge transfer states with differences in covalency gives excellent fits to the data and experimental estimates of the different contributions of charge transfer shake-up pathways to the t(2g) and e(g) symmetry orbitals. The resulting experimentally determined DOC is compared to values calculated from density functional theory and used to understand chemical trends in high- and low-spin ferrous and ferric complexes with different covalent environments. The utility of this method toward problems in bioinorganic chemistry is discussed. |
| Databáze: | OpenAIRE |
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