Spectroscopic Properties and Reactivity of a MnIII-hydroperoxo Complex that is Stable at Room Temperature.
Chemistry
; : e202403051, 2024 Sep 11.
Article
en En
| MEDLINE
| ID: mdl-39259036
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 MnIIIalkylperoxo 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 of 2 is based on electronic absorption, 1H NMR, IR, and ESI-MS data. The thermal decay of 2 follows a first order process, and variable-temperature kinetic studies of the decay of 2 yielded activation parameters that could be compared with those of a MnIII-alkylperoxo analogue. Complex 2 reacts with the hydrogen-atom donor TEMPOH two-fold faster than the MnIII-hydroxo complex 1. Complex 2 also 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 of 2 with similar MnIII-hydroperoxo and MnIII-alkylperoxo complexes.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Chemistry
Asunto de la revista:
QUIMICA
Año:
2024
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Alemania