Closed Shell Iron(IV) Oxo Complex with an Fe–O Triple Bond: Computational Design, Synthesis, and Reactivity

0534141 - ÚOCHB 2021 RIV DE eng J - Journal Article
Andris, Erik - Segers, K. - Mehara, J. - Rulíšek, Lubomír - Roithová, J.
Closed Shell Iron(IV) Oxo Complex with an Fe–O Triple Bond: Computational Design, Synthesis, and Reactivity.
Angewandte Chemie - International Edition. Roč. 59, č. 51 (2020), s. 23137-23144. ISSN 1433-7851. E-ISSN 1521-3773
R&D Projects: GA MŠMT(CZ) LTAUSA19148
Institutional support: RVO:61388963
Keywords : ion spectroscop * iron oxo complexes * ligand design * spin state
OECD category: Physical chemistry
Impact factor: 15.336, year: 2020
Method of publishing: Open access
https://doi.org/10.1002/anie.202009347

Iron(IV)‐oxo intermediates in nature contain two unpaired electrons in the Fe–O antibonding orbitals, which are thought to contribute to their high reactivity. To challenge this hypothesis, we designed and synthesized closed‐shell singlet iron(IV) oxo complex [(quinisox)Fe(O)]+ (1+, quinisox‐H=(N‐(2‐(2‐isoxazoline‐3‐yl)phenyl)quinoline‐8‐carboxamide). We identified the quinisox ligand by DFT computational screening out of over 450 candidates. After the ligand synthesis, we detected 1+ in the gas phase and confirmed its spin state by visible and infrared photodissociation spectroscopy (IRPD). The Fe–O stretching frequency in 1+ is 960.5 cm−1, consistent with an Fe–O triple bond, which was also confirmed by multireference calculations. The unprecedented bond strength is accompanied by high gas‐phase reactivity of 1+ in oxygen atom transfer (OAT) and in proton‐coupled electron transfer reactions. This challenges the current view of the spin‐state driven reactivity of the Fe–O complexes.
Permanent Link: http://hdl.handle.net/11104/0312440