Steep Spin-crossover and LIESST Effect of a New Fe(II) Complex with a Tridentate Ligand Derived from 2-Phenyl-4-formylimidazole and N-Methylethylenediamine

Abstract

Abstract A novel FeII spin-crossover (SC) complex, [FeII(HL)2](ClO4)2, has been synthesized, where HL denotes tridentate N3 ligand N-methyl[2-[[(2-phenylimidazol-4-yl)methylidene]amino]ethyl]amine). The FeII complex showed a steep SC at T1/2 = 175 K without frozen-in effect and hysteresis. The crystal structures at the high-spin (HS) and low-spin (LS) states were determined. Though there is no intermolecular interaction and no frozen-in effect, LIESST (light-induced excited spin state trapping) and reverse-LIESST effects were observed.