New family of Hofmann-like coordination polymers constructed with imidazole ligands and associated with spin crossover and anisotropic thermal expansions

• Published in: New journal of chemistry Vol. 46; no. 22; pp. 154 - 1544
• Main Authors: Kosone, Takashi, Kosuge, Ryota, Tanaka, Morie, Kawasaki, Takeshi, Adachi, Naoya
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 06.06.2022
• Subjects: Coordination polymers; Crossovers; Crystal lattices; Crystal structure; Hysteresis loops; Imidazole; Lattice parameters; Ligands; Magnetic properties; Thermal expansion
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d2nj00766e

Instead of the conventionally utilized pyridine derivatives ligands for the Hofmann-like spin crossover (SCO) structure, here we used five-membered-aromatic-ring ligands to afford a new series of Hofmann-like compounds Fe(L) 2 [Ni(CN) 4 ] (L = imidazole (1), 1-methylimidazole (2)). The synthesis, crystal structures, magnetic properties and thermal variation of the lattice constants for 1 and 2 were studied. The structures of the currently synthesized compounds were, as expected, found to be similar to that of traditional Hofmann-like 2D layer structure. Compound 1 showed a high spin state at all temperatures, while compound 2 displayed strong cooperative SCO centered at 144 K accompanied by a 35.2 K-wide hysteresis loop. Interestingly, compound 2 clearly showed anisotropic thermal expansion behaviour. A new series of Hofmann-like compounds made with imidazole ligands display interesting properties.