A unified treatment of the relationship between ligand substituents and spin state in a family of iron(II) complexes
| Autor: | Laurence J. Kershaw Cook, Robert J. Deeth, Stephen Dudley, Rafal Kulmaczewski, Marc A. Little, Malcolm A. Halcrow, Simon A. Barrett, Rufeida Mohammed |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Spin states
Stereochemistry Substituent 010402 general chemistry 01 natural sciences Catalysis Ion Electronegativity chemistry.chemical_compound iron N ligands Pyridine QD Spin State substituent effects Ligand 010405 organic chemistry Communication Bioinorganic chemistry General Chemistry General Medicine Communications 3. Good health 0104 chemical sciences Crystallography chemistry density functional calculations |
| Zdroj: | Angewandte Chemie (International Ed. in English) |
| ISSN: | 1433-7851 |
| Popis: | The influence of ligands on the spin state of a metal ion is of central importance for bioinorganic chemistry, and the production of base-metal catalysts for synthesis applications. Complexes derived from [Fe(bpp)2]2+ (bpp=2,6-di{pyrazol-1-yl}pyridine) can be high-spin, low-spin, or spin-crossover (SCO) active depending on the ligand substituents. Plots of the SCO midpoint temperature (Tinline image ) in solution vs. the relevant Hammett parameter show that the low-spin state of the complex is stabilized by electron-withdrawing pyridyl (“X”) substituents, but also by electron-donating pyrazolyl (“Y”) substituents. Moreover, when a subset of complexes with halogeno X or Y substituents is considered, the two sets of compounds instead show identical trends of a small reduction in Tinline image for increasing substituent electronegativity. DFT calculations reproduce these disparate trends, which arise from competing influences of pyridyl and pyrazolyl ligand substituents on Fe-L σ and π bonding. |
| Databáze: | OpenAIRE |
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