# Carboxylate and coordination influence on the formation of an active RuV Oxo species

## TL;DR

This study identifies a stable Ru(V)-oxo species and its formation mechanism, which could help in developing catalysts for green hydrogen production.

## Contribution

The study reports the EPR detection of a Ru(V)-oxo intermediate stabilized by specific ligands and explains its formation mechanism.

## Key findings

- A Ru(V)-oxo intermediate was detected using EPR and stabilized by terpyridine and phenanthroline carboxylate ligands.
- The carboxylate group and PCET-dependent hemilability are critical for achieving the high-valent state.
- Coordination environment changes significantly influence the formation of the active species.

## Abstract

Understanding the structure of Ru(V)-oxo species is crucial for designing novel catalysts for sustainable energy applications, such as water splitting for green hydrogen production. This study reports the EPR detection of a Ru(V)-oxo intermediate stabilized by terpyridine and phenanthroline carboxylate ligands. The interaction between the carboxylate group and the ruthenium center, along with PCET-dependent hemilability under oxidative conditions, plays a critical role in achieving the high-valent state. Subtle changes in the coordination environment around the central metal also proved to be essential. Low-temperature NMR, high-resolution mass spectrometry, UV–Vis spectroscopy, and density functional theory calculations support these findings.