# Synthesis, structure, and magnetic properties of Fe3+ and Ru3+ metal chalcogenide (O,S) complexes with bidentate ligands

## TL;DR

This paper explores how Fe3+ and Ru3+ metals interact with specific ligands to form complexes with distinct magnetic properties.

## Contribution

The study reveals how substituting oxygen with sulfur in ligands affects the structure and magnetic behavior of Fe3+ and Ru3+ complexes.

## Key findings

- Fe3+ complexes with oxygen-donor ligands form isostructural compounds with antiferromagnetic interactions.
- Sulfur-substituted ligands produce a sodium-bridged binuclear Ru3+ complex with low-spin magnetic behavior.
- Spin delocalization onto ligands is observed in sulfur-containing Ru complexes.

## Abstract

Hydroxypyridinones represent a versatile class of bidentate ligands for the construction of coordination compounds with tuneable structural and magnetic properties. In this work, we systematically investigate the coordination chemistry and magnetic behaviour of two group VIII trivalent transition metals (Fe3+ and Ru3+) with 1,2-dimethyl-3-hydroxy-4-pyridinone and its thione analogue, 1,2-dimethyl-3-hydroxy-4-pyridinethione. Tris-chelated octahedral complexes are readily obtained with the oxygen-donor ligand, yielding isostructural compounds stabilized by extended hydrogen-bond networks in the solid state. Substitution of the ketonic oxygen with sulphur markedly alters the reactivity, leading to the formation of a tris-chelated Fe3+ complex and an unprecedented sodium-bridged binuclear Ru3+ species. Magnetic measurements reveal high-spin (S = 5/2) Fe3+ behaviour with significant intermolecular antiferromagnetic interactions, while the Ru3+ derivatives exhibit a low-spin S = 1/2 character. In the sulphur-containing Ru system, the data suggest partial spin delocalization onto the ligand framework. These results elucidate how subtle changes in the donor atom identity and metal electronic structure govern coordination modes, solid-state organization, and magnetic properties, providing valuable insights for the rational design of hydroxypyridinone-based molecular magnetic materials.

In this work, we analyse the reactivity and magnetic properties of Fe3+ and Ru3+ with OPO/OPTO ligands.