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Rebound or cage escape?: the role of the rebound barrier for the reactivity of non-heme high-valent FeIV=O species

Owing to their high reactivity and selectivity, variations in the spin ground state and a range of possible pathways, high-valent FeIV=O species are popular models with potential bioinspired applications. An interesting example of a structure-reactivity pattern is the detailed study with five nonhem...

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Hauptverfasser: Kumar, Ravi (VerfasserIn) , Ansari, Azaj (VerfasserIn) , Comba, Peter (VerfasserIn) , Rajaraman, Gopalan (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: 06 November 2023
In: Chemistry - a European journal
Year: 2023, Pages: 1-11
ISSN:1521-3765
DOI:10.1002/chem.202303300
Online-Zugang:Verlag, kostenfrei, Volltext: https://doi.org/10.1002/chem.202303300
Verlag, kostenfrei, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.202303300
Volltext
Verfasserangaben:Ravi Kumar, Azaj Ansari, Peter Comba, Gopalan Rajaraman
Beschreibung
Zusammenfassung:Owing to their high reactivity and selectivity, variations in the spin ground state and a range of possible pathways, high-valent FeIV=O species are popular models with potential bioinspired applications. An interesting example of a structure-reactivity pattern is the detailed study with five nonheme amine-pyridine pentadentate ligand FeIV=O species, including N4py: [(L1)FeIV=O]2+ (1), bntpen: [(L2)FeIV=O]2+ (2), py2tacn: [(L3)FeIV=O]2+ (3), and two isomeric bispidine derivatives: [(L4)FeIV=O]2+ (4) and [(L5)FeIV=O]2+ (5). In this set, the order of increasing reactivity in the hydroxylation of cyclohexane differs from that with cyclohexadiene as substrate. A comprehensive DFT, ab initio CASSCF/NEVPT2 and DLPNO-CCSD(T) study is presented to untangle the observed patterns. These are well reproduced when both activation barriers for the C−H abstraction and the OH rebound are taken into account. An MO, NBO and deformation energy analysis reveals the importance of π(pyr) → π*xz(FeIII-OH) electron donation for weakening the FeIII-OH bond and thus reducing the rebound barrier. This requires that pyridine rings are oriented perpendicularly to the FeIII-OH bond and this is a subtle but crucial point in ligand design for non-heme iron alkane hydroxylation.
Beschreibung:Im Zusatz zum Titel ist "VI" hochgestellt
Gesehen am 25.01.2024
Beschreibung:Online Resource
ISSN:1521-3765
DOI:10.1002/chem.202303300

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