# [Fe(µ2-OH)6]3− Linked Fe3O Triads: Mössbauer Evidence for Trigonal µ3-O2− or µ3-OH− Groups in Bridged versus Unbridged Complexes

## TL;DR

This paper describes the synthesis and analysis of iron complexes with different bridging oxygen groups, using Mössbauer spectroscopy to confirm their structures.

## Contribution

The study provides Mössbauer evidence distinguishing between µ3-OH and µ3-O bridged iron triads in complex structures.

## Key findings

- Complex C1 contains µ3-OH bridged iron triads.
- Complexes C2 and C3 contain µ3-O bridged iron triads.
- Mössbauer spectroscopy confirms the bridging differences in the iron triads.

## Abstract

The syntheses, coordination chemistry, and Mössbauer spectroscopy of hepta-iron(III) complexes using derivatised salicylaldoxime ligands from two categories; namely, ‘single-headed’ (H2L) and ‘double-headed’ (H4L) salicylaldoximes are described. All compounds presented here share a [Fe3-µ3-O] core in which the iron(III) ions are µ3-hydroxo-bridged in the complex C1 and µ3-oxo-bridged in C2 and C3. Each compound consists of 2 × [Fe3-µ3-O] triads that are linked via a central [Fe(µ2-OH)6]3− ion. In addition to the charge balance and microanalytical evidence, Mössbauer measurements support the fact that the triads in C1 are µ3-OH bridged and are µ3-O bridged in C2 and C3.