ELECTRONIC AND SPATIAL STRUCTURE OF SPIN TRANSITION IRON(II) TRIS(4-AMINO-1,2,4-TRIAZOLE) NITRATE AND PERCHLORATE COMPLEXES

Electronic and spatial structure of polynuclear iron(II) complexes Fe( ATr)(3)(ClO4)(2), Fe(ATr)(3)(NO3)(2), and Fe0.34Zn0.66(ATr)(3)(NO3)(2) (where ATr is 4-amino-1,2,4-triazole) is investigated using EXAFS and XANES spectroscopy and X-ray fluorescent spectroscopy. Changes in the distances to the first four coordination spheres of Fe and Zn atoms u pon spin transitions induced by variations of the anion or temperature are analyzed. It is shown that in polynuclear complexes the spin tran sition (from S = 2 to S = 0) is accompanied by pronounced variations i n the electronic and spatial structure. A mutual effect of Fe and Zn a toms was found which alters the local environment of the low-spin Fe a toms in a magnetically diluted complex as compared to the initial one.