Paramagnetic Resonance of Cobalt(II) Trispyrazolylmethanes and Counterion Association
| Autor: | Vivien L. Clayton, Robert M. McCarrick, Abed Hasheminasab, Amy R. Marts, David L. Tierney, Joshua C. Kaine, Laura J. Cordonnier, Christopher J. Ziegler, Robert R. Baum, Laura A. Crandall, Jami R. Bennett |
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| Rok vydání: | 2016 |
| Předmět: |
chemistry.chemical_classification
010405 organic chemistry Ligand Resonance chemistry.chemical_element 010402 general chemistry 01 natural sciences 0104 chemical sciences law.invention Inorganic Chemistry Paramagnetism Crystallography chemistry.chemical_compound chemistry law Physical and Theoretical Chemistry Counterion Electron paramagnetic resonance Hyperfine structure Cobalt Methyl group |
| Zdroj: | Inorganic Chemistry. 56:618-626 |
| ISSN: | 1520-510X 0020-1669 |
| DOI: | 10.1021/acs.inorgchem.6b02520 |
| Popis: | Paramagnetic resonance studies (EPR, ESEEM, ENDOR, and NMR) of a series of cobalt(II) bis-trispyrazolylmethane tetrafluoroborates are presented. The complexes studied include the parent, unsubstituted ligand (Tpm), two pyrazole-substituted derivatives (4Me and 3,5-diMe), and tris(1-pyrazolyl)ethane (Tpe), which includes a methyl group on the apical carbon atom. NMR and ENDOR establish the magnitude of 1H hyperfine couplings, while ESEEM provides information on the coordinated 14N. The data show that the pyrazole 3-position is more electron rich in the Tpm analogues, that the geometry about the apical atom influences the magnetic resonance, and that apical atom geometry appears more fixed in Tpm than in Tp. NMR and ENDOR establish that the BF4– counterion remains associated in fluid solution. In the case of the Tpm3,5Me complex, it appears to associate in solution, in the same position it occupies in the X-ray structure. |
| Databáze: | OpenAIRE |
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