Dioxygen activation and pyrrole α-cleavage with calix(4)pyrrolato aluminates: enzyme model by structural constraint

The present work describes the reaction of triplet dioxygen with the porphyrinogenic calix[4]pyrrolato aluminates to alkylperoxido aluminates in high selectivity. Multiconfigurational quantum chemical computations disclose the mechanism for this spin-forbidden process. Despite a negligible spin-orbi...

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Main Authors: Sigmund, Lukas M. (Author) , Ehlert, Christopher (Author) , Enders, Markus (Author) , Graf, Jürgen (Author) , Gryn’ova, Ganna (Author) , Greb, Lutz (Author)
Format: Article (Journal)
Language:English
Published: 2021
In: Angewandte Chemie. International edition
Year: 2021, Volume: 60, Issue: 28, Pages: 15632-15640
ISSN:1521-3773
DOI:10.1002/anie.202104916
Online Access:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1002/anie.202104916
Verlag, lizenzpflichtig, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202104916
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Author Notes:Lukas Maximilian Sigmund, Christopher Ehlert, Markus Enders, Jürgen Graf, Ganna Gryn'ova, and Lutz Greb
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Summary:The present work describes the reaction of triplet dioxygen with the porphyrinogenic calix[4]pyrrolato aluminates to alkylperoxido aluminates in high selectivity. Multiconfigurational quantum chemical computations disclose the mechanism for this spin-forbidden process. Despite a negligible spin-orbit coupling constant, the intersystem crossing (ISC) is facilitated by singlet and triplet state degeneracy and spin-vibronic coupling. The formed peroxides are stable toward external substrates but undergo an unprecedented oxidative pyrrole α-cleavage by ligand aromatization/dearomatization-initiated O−O σ-bond scission. A detailed comparison of the calix[4]pyrrolato aluminates with dioxygen-related enzymology provides insights into the ISC of metal- or cofactor-free enzymes. It substantiates the importance of structural constraint and element-ligand cooperativity for the functions of aerobic life.
Item Description:First published: 06 May 2021
Gesehen am 29.11.2022
Physical Description:Online Resource
ISSN:1521-3773
DOI:10.1002/anie.202104916