Mössbauer spectroscopic study on valence-detrapping and trapping of mixed-valence trinuclear iron(III, III, II) fluorine-substituted benzoate complexes

Abstract

Four mixed-valence trinuclear iron(III, III, II) fluorine-substituted benzoate complexes were synthesized; Fe3O(C6F5COO)6(C5H5N)3·CH2Cl2 (1), Fe3O(C6F5COO)6(C5H5N)3 (2), Fe3O(2H-C6F4COO)6(C5H5N)3 (3), and Fe3O(4H-C6F4COO)6(C5H5N)3 (4), in which valence-detrapping and trapping phenomena have been investigated by 57Fe- Mossbauer spectroscopy. The valence state of the three iron ions is trapped at lower temperatures while it is fully detrapped at higher temperatures for 1. Valence detrapping is not observed for 2, 3, and 4 even at room temperature, although Mossbauer spectra for 3 and 4 show complicated temperature dependence.