Spin crossover in iron(II) tris(2-(2-pyridyl)benzimidazole) complex monitored by the variable temperature EXAFS

Standard EXAFS equipment has been utilized in conducting the variable tempe rature experiments using the [Fe(pybzim)(3)](ClO4)(2). H2O sample, pybzim b eing a bidentate 2-(2-pyridyl)benzimidazole ligand. There is a jump in the metal-ligand (Fe-N) distance comparable with the step in the effective magn etic moment. The distance increases from 1.95 to 2.11 Angstrom. In the tran sition region, the error bars are much broader than before and after this r egion. The transition temperature taken from the fittings is 132 K, which i s about 9 K lower than that from magnetic susceptibility measurements. (C) 2000 Published by Elsevier Science B.V.