Sb. Erenburg et al., Optically induced spin transition effect on structure of Fe(II) polymeric complexes by XAFS spectroscopy, J MAGN MAGN, 226, 2001, pp. 1967-1969
Changes in the electronic and spatial structure of polymeric Fe(II) complex
es with 1,2,4-triazoles and various anions upon spin transition was studied
using XAFS spectroscopy. The compounds exhibit an abrupt thermally driven
spin transition (S = 0-2) at temperatures varying from 175 to 400 K dependi
ng on the composition. Spin transition and structural changes were induced
by variations of the anion, dilution with Zn, under the heating or the acti
on of light. XAFS measurements were performed at the Budker Institute of Nu
clear Physics in Novosibirsk. In all complexes, the spin transition is acco
mpanied by drastic changes in the local environment of Fe atoms. High spin
metastable long life states was detected and studied in the polymeric compl
ex Fe(atrz)(3)(ClO4)(2). It was established that the changes in structure o
f polymeric complexes upon the transition to a metastable high spin state u
nder the action of light differ from those in the thermally induced spin tr
ansition. Such difference is determined by mutual influence of Fe atoms in
high spin and low spin states in polymeric chains. (C) 2001 Elsevier Scienc
e B.V. All rights reserved.