Optically induced spin transition effect on structure of Fe(II) polymeric complexes by XAFS spectroscopy

• Published in: Journal of magnetism and magnetic materials 2001-05, Vol.226, p.1967-1969
• Main Authors: Erenburg, S.B, Bausk, N.V, Lavrenova, L.G, Mazalov, L.N
• Format: Article
• Language: English
• Subjects: EXAFS; Metastable phases; Polymers; Spin crossover
• ISSN: 0304-8853
• DOI: 10.1016/S0304-8853(01)00006-3

Changes in the electronic and spatial structure of polymeric Fe(II) complexes 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 depending on the composition. Spin transition and structural changes were induced by variations of the anion, dilution with Zn, under the heating or the action of light. XAFS measurements were performed at the Budker Institute of Nuclear Physics in Novosibirsk. In all complexes, the spin transition is accompanied by drastic changes in the local environment of Fe atoms. High spin metastable long life states was detected and studied in the polymeric complex Fe(atrz) 3(ClO 4) 2. It was established that the changes in structure of polymeric complexes upon the transition to a metastable high spin state under the action of light differ from those in the thermally induced spin transition. Such difference is determined by mutual influence of Fe atoms in high spin and low spin states in polymeric chains.