SCHEDULED MAINTENANCE
Spin polarization assisted facile C–H activation by an S = 1 iron(iv)–bisimido complex: a comprehensive spectroscopic and theoretical investigation†
a
Qing
Liu,
b
Barbara
Lavina,
cd
Michael Y.
Hu,
c
Jiyong
Zhao,
c
Liang
Deng,
*b
Shengfa
Ye
*e
and
Yisong
Guo
*a
Abstract
High valent iron terminal imido species (Fe![[double bond, length as m-dash]](https://www.rsc.org/images/entities/char_e001.gif)
NR) have been shown to be key reactive intermediates in C–H functionalization. However, the detailed structure–reactivity relationship in FeNR species derived from studies of structurally well-characterized high-valent FeNR complexes are still scarce, and the impact of imido N-substituents (electron-donating vs. electron-withdrawing) on their electronic structures and reactivities has not been thoroughly explored. In this study, we report spectroscopic and computational studies on a rare S = 1 iron(IV)–bisimido complex featuring trifluoromethyl groups on the imido N-substituents, [(IPr)Fe(NC(CF3)2Ph)2] (2), and two closely related S = 0 congeners bearing alkyl and aryl substituents, [(IPr)Fe(NC(CMe3)2Ph)2] (3) and [(IPr)Fe(NDipp)2] (1), respectively. Compared with 1 and 3, 2 exhibits a decreased FeNR bond covalency due to the electron-withdrawing and the steric effect of the N-substituents, which further leads to a pseudo doubly degenerate ground electronic structure and spin polarization induced β spin density on the imido nitrogens. This unique electronic structure, which differs from those of the well-studied Fe(IV)–oxido complexes and many previously reported Fe(IV)–imido complexes, provides both kinetic and thermodynamic advantages for facile C–H activation, compared to the S = 0 counterparts.
- This article is part of the themed collections: Spotlight Collection: Bioinorganic Chemistry and 2023 Chemical Science Covers
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