Magnetic and thermal properties of three ionothermally synthesized metal–carboxylate frameworks of [M3(ip)4][EMIm]2 (M = Co, Ni, Mn, H2ip = isophthalic acid, EMIm = 1-ethyl-3-methyl imidazolium)

Abstract

Three metal–organic frameworks, [M₃(ip)₄][EMIm]₂ (M = Co 1, Ni 2, Mn 3, H₂ip = isophthalic acid, EMIm = 1-ethyl-3-methyl imidazolium) were prepared from an ionic liquid medium. All the compounds feature the same (4²⁴)(6⁴) topology based on linear trinuclear clusters as eight-connected nodes. Compounds 1 and 2 are isostructural, while compound 3 exhibits a different structure due to the slight difference in the arrangement of M₃(OOCR)₈ SBUs. Magnetic property measurements reveal that all the compounds display anti-ferromagnetic coupling, where compounds 2 and 3 show isotropic exchange interactions of −0.10 cm⁻¹ for 2 and −1.6 cm⁻¹ for 3. Investigation of the thermal diffusivity shows that the thermal diffusivity of 1 is higher than that of 3, while that of 3 is higher than that of 2.