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Extended X-ray absorption fine structure and multiple-scattering simulation of nickel dithiolene complexes Ni[S2C2(CF3)2]2 n ( n = −2, −1, 0) and an olefin adduct Ni[S2C2(CF3)2]2(1-hexene)
- Source :
-
Journal of Synchrotron Radiation . Jan2015, Vol. 22 Issue 1, p124-129. 6p. - Publication Year :
- 2015
-
Abstract
- A series of Ni dithiolene complexes Ni[S2C2(CF3)]2 n ( n = −2, −1, 0) ( 1, 2, 3) and a 1-hexene adduct Ni[S2C2(CF3)2]2(C6H12) ( 4) have been examined by Ni K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopies. Ni XANES for 1- 3 reveals clear pre-edge features and approximately +0.7 eV shift in the Ni K-edge position for `one-electron' oxidation. EXAFS simulation shows that the Ni-S bond distances for 1, 2 and 3 (2.11-2.16 Å) are within the typical values for square planar complexes and decrease by ∼0.022 Å for each `one-electron' oxidation. The changes in Ni K-edge energy positions and Ni-S distances are consistent with the `non-innocent' character of the dithiolene ligand. The Ni-C interactions at ∼3.0 Å are analyzed and the multiple-scattering parameters are also determined, leading to a better simulation for the overall EXAFS spectra. The 1-hexene adduct 4 presents no pre-edge feature, and its Ni K-edge position shifts by −0.8 eV in comparison with its starting dithiolene complex 3. Consistently, EXAFS also showed that the Ni-S distances in 4 elongate by ∼0.046 Å in comparison with 3. The evidence confirms that the neutral complex is `reduced' upon addition of olefin, presumably by olefin donating the π-electron density to the LUMO of 3 as suggested by UV/visible spectroscopy in the literature. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09090495
- Volume :
- 22
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Journal of Synchrotron Radiation
- Publication Type :
- Academic Journal
- Accession number :
- 100144540
- Full Text :
- https://doi.org/10.1107/S1600577514025041