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Abstract Manganese catalysts that activate hydrogen peroxide have seen increased use in organic transformations, such as olefin epoxidation and alkane C−H bond oxidation. Proposed mechanisms for these catalysts involve the formation and activation of MnIII‐hydroperoxo intermediates. Examples of well‐defined MnIII‐hydroperoxo complexes are rare, and the properties of these species are often inferred from MnIII‐alkylperoxo analogues. In this study, we show that the reaction of the MnIII‐hydroxo complex [MnIII(OH)(6Medpaq)]+(1) with hydrogen peroxide and acid results in the formation of a dark‐green MnIII‐hydroperoxo species [MnIII(OOH)(6Medpaq)]+(2). The formulation of2is based on electronic absorption,1H NMR, IR, and ESI‐MS data. The thermal decay of2follows a first order process, and variable‐temperature kinetic studies of the decay of2yielded activation parameters that could be compared with those of a MnIII‐alkylperoxo analogue. Complex2reacts with the hydrogen‐atom donor TEMPOH two‐fold faster than the MnIII‐hydroxo complex1. Complex2also oxidizes PPh3, and this MnIII‐hydroperoxo species is 600‐fold more reactive with this substrate than its MnIII‐alkylperoxo analogue [MnIII(OOtBu)(6Medpaq)]+. DFT and time‐dependent (TD) DFT computations are used to compare the electronic structure of2with similar MnIII‐hydroperoxo and MnIII‐alkylperoxo complexes.
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This content will become publicly available on September 23, 2026
Formation of a Mn III –O–Ce IV species from a Mn III -hydroxo complex and ceric ammonium nitrate
The reaction of a MnIII-hydroxo complex with ceric ammonium nitrate generates a product with a MnIII–O–CeIVcore that has enhanced reactivity in one-electron oxidation reactions and new reactivity in two-electron oxidation reactions.
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- Award ID(s):
- 2154955
- PAR ID:
- 10651152
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Dalton Transactions
- Volume:
- 54
- Issue:
- 37
- ISSN:
- 1477-9226
- Page Range / eLocation ID:
- 14001 to 14012
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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