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

摘要

Four mixed-valence trinuclear iron(Ⅲ, Ⅲ, Ⅱ) fluorine-substituted benzoate complexes were synthesized; Fe_3O(C_6F_5COO)_6(C_5H_5N)_3CH_2Cl_2 (1), Fe_13O(C_6F_5COO)_6(C_5H_5N)_3 (2), Fe_3O(2H-C_6F_4COO)_6(C_5H_5N)_3 (3), and Fe_3O(4H-C_6F_4COO)_6(C_5H_5N)_3 (4), in which valence-detrapping and trapping phenomena have been investigated by ~(57)Fe- Moessbauer 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 Moessbauer spectra for 3 and 4 show complicated temperature dependence.