[Fe(µ 2 -OH) 6 ] 3- Linked Fe 3 O Triads: Mössbauer Evidence for Trigonal µ 3 -O 2- or µ 3 -OH - Groups in Bridged versus Unbridged Complexes

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