# Investigating Ligand Sphere Perturbations on MnIII–Alkylperoxo Complexes

## TL;DR

This paper studies how changes in ligand structures affect the reactivity and stability of manganese complexes involved in oxidation reactions.

## Contribution

The study introduces two room-temperature-stable MnIII–alkylperoxo complexes and explores their reactivity and stability using new ligand designs.

## Key findings

- A ligand perturbation increased reactivity toward an organic substrate.
- The O–O cleavage product distribution shifted slightly between homolytic and heterolytic pathways.
- Thermal stability remained largely unaffected by the ligand modifications.

## Abstract

Manganese catalysts that activate hydrogen peroxide carry out several different hydrocarbon oxidation reactions with high stereoselectivity. The commonly proposed mechanism for these reactions involves a key manganese(III)-hydroperoxo intermediate, which decays via O–O bond heterolysis to generate a Mn(V)–oxo species that institutes substrate oxidation. Due to the scarcity of characterized MnIII–hydroperoxo complexes, MnIII–alkylperoxo complexes are employed to understand factors that affect the mechanism of the O–O cleavage. Herein, we report a series of novel complexes, including two room-temperature-stable MnIII–alkylperoxo species, supported by a new amide-containing pentadentate ligand (6Medpaq5NO2). We use a combination of spectroscopic methods and density functional theory computations to probe the effects of the electronic changes in the ligand sphere trans to the hydroxo and alkylperoxo units to thermal stability and reactivity. The structural characterizations for both MnII(OTf)(6Medpaq5NO2) and [MnIII(OH)(6Medpaq5NO2)](OTf) were obtained via single-crystal X-ray crystallography. A perturbation to the ligand sphere allowed for a marked increase in reactivity towards an organic substrate, a modest change in the distribution of the O–O cleavage products from homolytic and heterolytic pathways, and little change in thermal stability.