Magnetic and thermal properties of three ionothermally synthesized metal-carboxylate frameworks of [M_3(ip)_4][EMIm] _2 (M = Co, Ni, Mn, H_2ip = isophthalic acid, EMIm = 1-ethyl-3-methyl imidazolium)

摘要

Three metal-organic frameworks, [M_3(ip)_4][EMIm] _2 (M = Co 1, Ni 2, Mn 3, H_2ip = isophthalic acid, EMIm = 1-ethyl-3-methyl imidazolium) were prepared from an ionic liquid medium. All the compounds feature the same (4~(24))(6~4) 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 M_3(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.