Two cobalt metal-organic frameworks constructed from mixed ligands and their magnetic properties

The reaction of the polycarboxylic acid ligand tri(2-carboxyethyl)-isocyanurate (${\text{H}}_3{\text{L}}_1$), polyazo bridged ligand 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (${\text{L}}_2$), ${\text{CoCl}}_2\cdot 6{\text{H}}_2\text{O}$, and different organic solvents lead to the formation of two novel coordination complexes: $\left[{\text{Co}}_3\right({\text{L}}_1{)}_2\left({\text{L}}_2{)}_2\right({\text{H}}_2\text{O}{)}_4{]}_n$ (1), $\left[{\text{Co}}_3\right({\text{L}}_1{)}_2\left({\text{L}}_2{)}_2\right({\text{H}}_2\text{O}{)}_2{]}_n\cdot 2{\text{nH}}_2\text{O}$ (2). Two complexes were prepared under solvothermal conditions and characterized by the single-crystal X-ray diffraction, thermal analysis, element analysis, X-ray powder diffraction, and IR spectra. Single-crystal X-ray analysis reveals that complex 1 features a three-dimensional framework and 2 is a two-dimensional layer structure. Variable-temperature magnetic susceptibility measurements show that both complexes display anti-ferromagnetic interactions between adjacent Co(II) centers.

Graphic abstract

Two cobalt metal-organic frameworks constructed from mixed ligands and exhibited different top networks and magnetic properties. .