One-dimensional Co(II)/Ni(II) complexes of 2-hydroxyisophthalate: Structures and magnetic properties

• Two one-dimensional Co(II)/Ni(II) complexes were solvothermally synthesized.
• The Co-complex exhibits canted antiferromagnetism.
• The Ni-complex exhibits ferromagnetism.
• Both of the complexes display magnetocaloric effect.

The solvothermal reactions of 2-hydroxyisophthalic acid (H3ipO) with M(NO3)2∙6H2O (M=Co, Ni) afforded two complexes [Co2(HipO)2(Py)2(H2O)2] (1) and [Ni(HipO)(Py)H2O] (2) (Py=pyridine). They exhibit similar zig-zag chain structures with the adjacent two metal centers connected by a anti-syn bridging carboxylate group from the HipO2− ligand. The magnetic measurements reveal the dominant antiferromagnetic interactions and spin-canting in 1 while ferromagnetic interactions in 2. Both of them exhibit magnetocaloric effect (MCE) with the resulting entropy changes (−ΔSm) of 12.51 J kg−1 K−1 when ΔH=50 kOe at 3 K for 1 and 11.01 J kg−1 K−1 when ΔH=50 kOe at 3 K for 2, representing the rare examples of one-dimensional complexes with MCE.

Synopsis: Two Co(II)/Ni(II) complexes with zig-zag chain structures have been reported. 1-Co shows cant-antiferromagnetism while 2-Ni shows ferromagnetism. Magnetocaloric effect is also found in both of them.Figure optionsDownload as PowerPoint slide