Chiral spin crossover iron(II) complex, fac-Λ-[FeII(HLR)3](ClO4)2·EtOH (HLR = 2-methylimidazol-4-yl-methylideneamino-R-(+)-1-methylphenyl)

A chiral spin crossover iron(II) complex, fac-Λ-[FeII(HLR)3](ClO4)2·EtOH was synthesized and its crystal structures in both the high-spin (HS) and low-spin (LS) states were determined, where HLR denotes 2-methylimidazol-4-yl-methylideneamino-R-(+)-1-methylphenyl. The complex assumes octahedral coordination geometry of N6 donor atoms by three bidentate ligands HLR. The complex exists as the facial-Λ-isomer of fac-Λ-[FeII(HLR)3]2+ of the possible geometrical fac- and mer-isomers and the Δ- and Λ-enantiomorphs. The X-ray structural analyses revealed that the R-form of the ligand (HLR) induces the fac-Λ-isomer of fac-Λ-[FeII(HLR)3]2+ and the S-form of the ligand (HLS) induces the fac-Δ-isomer of fac-Δ-[Fe(HLS)3]2+. The complex fac-Λ-[FeII(HLR)3](ClO4)2·EtOH shows a complete steep spin crossover between the HS and the LS states at T1/2 = 195 K.