Spectroscopic and Computational Studies of a Series of High-Spin Ni(II) Thiolate Complexes
| Autor: | Jaeheung Cho, Timothy Dingee, Thomas C. Brunold, Charles G. Riordan, Katherine M. Van Heuvelen |
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| Rok vydání: | 2010 |
| Předmět: |
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Molecular Magnetic circular dichroism Chemistry Analytical chemistry Spectrum Analysis Raman Resonance (chemistry) Article Spectral line Inorganic Chemistry Crystallography symbols.namesake Coordination Complexes Nickel Excited state symbols Quantum Theory Sulfhydryl Compounds Physical and Theoretical Chemistry Absorption (chemistry) Raman spectroscopy Spin (physics) Excitation |
| Zdroj: | Inorganic Chemistry. 49:6535-6544 |
| ISSN: | 1520-510X 0020-1669 |
| DOI: | 10.1021/ic100362q |
| Popis: | The electronic structures of a series of high-spin Ni(II)-thiolate complexes of the form [PhTt(tBu)]Ni(SR) (R = CPh(3), 2; C(6)F(5), 3; C(6)H(5), 4; PhTt(tBu) = phenyltris((tert-butylthio)methyl)borate) have been characterized using a combined spectroscopic and computational approach. Resonance Raman (rR) spectroscopic data reveal that the nu(Ni-SR) vibrational feature occurs between 404 and 436 cm(-1) in these species. The corresponding rR excitation profiles display a striking de-enhancement behavior because of interference effects involving energetically proximate electronic excited states. These data were analyzed in the framework of time-dependent Heller theory to obtain quantitative insight into excited state nuclear distortions. The electronic absorption and magnetic circular dichroism spectra of 2-4 are characterized by numerous charge transfer (CT) transitions. The dominant absorption feature, which occurs at approximately 18,000 cm(-1) in all three complexes, is assigned as a thiolate-to-Ni CT transition involving molecular orbitals that are of pi-symmetry with respect to the Ni-S bond, reminiscent of the characteristic absorption feature of blue copper proteins. Density functional theory computational data provide molecular orbital descriptions for 2-4 and allow for detailed assignments of the key spectral features. A comparison of the results obtained in this study to those reported for similar Ni-thiolate species reveals that the supporting ligand plays a secondary role in determining the spectroscopic properties, as the electronic structure is primarily determined by the metal-thiolate bonding interaction. |
| Databáze: | OpenAIRE |
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