⁵⁷Fe Mössbauer, UV-visible, and FT-IR Study on Photoinduced Spin Transition of Fe^II -Triazole Complex

Abstract

We have synthesized a novel spin crossover Fe^II -triazole complex Fe (AZ-trz), where AZ-trz denotes 4-phenylazo-N-[1, 2, 4]triazole-4-yl-benzamide. ⁵⁷Fe Mössbauer spectra and magnetic susceptibility measurements of this compound exhibited a gradual spin crossover behavior by thermal change and also a light-induced excited spin state trapping (LIESST) effect. Both UV-visible absorption spectra and IR spectra confirmed the phenomena. The Fe^II high-spin, HS, state was induced by exciting a d-d electronic transition band of the Fe^II low-spin state species. Furthermore, the measurements revealed the lifetime of excited Fe^II HS state to be 1 min.