日本語
 
Help Privacy Policy ポリシー/免責事項
  詳細検索ブラウズ

アイテム詳細


公開

学術論文

Electron Paramagnetic Resonance Signature of Tetragonal Low Spin Iron(V)-Nitrido and -Oxo Complexes Derived from the Electronic Structure Analysis of Heme and Non-Heme Archetypes

MPS-Authors
/persons/resource/persons237823

Mondal,  Bhaskar
Research Department Neese, Max Planck Institute for Chemical Energy Conversion, Max Planck Society;

/persons/resource/persons237790

Fang,  Huayi
Research Department Neese, Max Planck Institute for Chemical Energy Conversion, Max Planck Society;

/persons/resource/persons216825

Neese,  Frank
Research Department Neese, Max-Planck-Institut für Kohlenforschung, Max Planck Society;

/persons/resource/persons137604

Bill,  Eckhard
Research Department DeBeer, Max Planck Institute for Chemical Energy Conversion, Max Planck Society;

External Resource
There are no locators available
Fulltext (restricted access)
There are currently no full texts shared for your IP range.
フルテキスト (公開)
公開されているフルテキストはありません
付随資料 (公開)
There is no public supplementary material available
引用

Chang, H.-C., Mondal, B., Fang, H., Neese, F., Bill, E., & Ye, S. (2019). Electron Paramagnetic Resonance Signature of Tetragonal Low Spin Iron(V)-Nitrido and -Oxo Complexes Derived from the Electronic Structure Analysis of Heme and Non-Heme Archetypes. Journal of the American Chemical Society, 141(6), 2421-2434. doi:10.1021/jacs.8b11429.


引用: https://hdl.handle.net/21.11116/0000-0005-A9F2-B
要旨
Iron(V)-nitrido and -oxo complexes have been proposed as key intermediates in a diverse array of chemical transformations. Herein we present a detailed electronic-structure analysis of [Fe-V(N)(TPP)] (1, TPP2- = tetraphenylporphyrinato), and [Fe-V(N)(cyclam-ac)](+) (2, cyclam-ac = 1,4,8,11-tetraazacyclotetradecane-1-acetato) using electron paramagnetic resonance (EPR) and Fe-57 Mossbauer spectroscopy coupled with wave function based complete active-space self-consistent field (CASSCF) calculations. The findings were compared with all other well-characterized genuine iron(V)-nitrido and -oxo complexes, [Fe-V(N)(MePy(2)tacn)](PF6)(2) (3, MePy(2)tacn = methyl-N',N ''-bis(2-picolyl)-1,4,7-triazacyclononane), [Fe-V(N){PhB(t-BuIm)(3)}](+) (4, PhB((t)BuIm)(3)(-) = phenyltris(3-tert-butylimidazol-2-ylidene)borate), and [Fe-V(O)(TAML)](-) (5, TAML(4-) = tetraamido macrocyclic ligand). Our results revealed that complex 1 is an authenticated iron(V)-nitrido species and contrasts with its oxo congener, compound I, which contains a ferry] unit interacting with a porphyrin radical. More importantly, tetragonal iron(V)-nitrido and-oxo complexes 1-3 and 5 all possess an orbitally nearly doubly degenerate S = 1/2 ground state. Consequently, analogous near-axial EPR spectra with g(parallel to) < g(perpendicular to) <= 2 were measured for them, and their g(parallel to) and g(perpendicular to) values were found to obey a simple relation of g(perpendicular to)(2) + (2 - g(parallel to))(2) = 4. However, the bonding situation for trigonal iron(V)-nitrido complex 4 is completely different as evidenced by its distinct EPR spectrum with g(parallel to) < 2 < g(perpendicular to). Further in-depth analyses suggested that tetragonal low spin iron(V)-nitrido and-oxo complexes feature electronic structures akin to those found for complexes 1-3 and 5. Therefore, the characteristic EPR signals determined for 1-3 and 5 can be used as a spectroscopic marker to identify such highly reactive intermediates in catalytic processes.