Premium
Closed Shell Iron(IV) Oxo Complex with an Fe–O Triple Bond: Computational Design, Synthesis, and Reactivity
Author(s) -
Andris Erik,
Segers Koen,
Mehara Jaya,
Rulíšek Lubomír,
Roithová Jana
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202009347
Subject(s) - reactivity (psychology) , chemistry , antibonding molecular orbital , ligand (biochemistry) , photochemistry , photodissociation , triple bond , singlet state , atomic orbital , unpaired electron , computational chemistry , crystallography , electron , radical , double bond , atomic physics , medicine , physics , organic chemistry , polymer chemistry , biochemistry , alternative medicine , receptor , pathology , quantum mechanics , excited state
Abstract 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.