Synthesis, Structural Characterization, and Magnetic Properties of Two Iron(II) Complexes With Triazole- and Imidazole-Related Ligands

Abstract

Two new mononuclear iron (II) coordination complexes: Fe(L₁)₂(SCN)₂ (1, L₁:5-dimethylether-4-(4-methylphenyl)-3-(2-pyridinyl)-1,2,4-triazole) and Fe(L₂)₃(ClO₄)₂ (2, L₂ :1-ethyl acetate-2-(2-pyridinyl)-imidazole), for the exploration of spin-crossover compounds have been synthesized and characterized. Structural analysis revealed that the framework of complex 1 is featured with 1-D chain structure connected by weak π···π interactions between the adjacent L₁ ligands, while complex 2 featured with various kinds of weak intermolecular hydrogen bonding interactions between Fe(L₂)₃²⁺ cation and ClO₄⁻ anion, which lead to a close crystal packing. The intermolecular interactions have shown a significant influence on the physical properties, and magnetic measurements of complexes 1 and 2 in the solid state at the room temperature revealed that the weak intermolecular interactions in 1 resulted in HS (high-spin) state, while the strong interactions in 2 lead to LS (low-spin) state over the whole temperature range.

Keywords:

• iron (II) complex
• crystal structure
• Hirshfeld surface
• magnetic properties

Supplementary Material

CCDC reference numbers 1036971 and 1051705 contain the supplementary crystallographic data in CIF format for complexes 1 and 2 reported in this paper. This data can be obtained free of charge from the Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/datarequest/cif.

Funding

This work has been supported by the Natural Science Foundation of China (21371031 and 21241009), and Prospective Joint Research Project of Jiangsu province (BY2012193).