Here, we report two three-dimensional metal–organic frameworks of formula [Co2(4-ptz)2(bpp)(N3)2]n (1) and [Co3(OH)2(bdt)2(bpp)2(H2O)2]n (2), which were synthesized by hydrothermal reaction from the respective tetrazole ligand (5-(4-pyridyl)tetrazole (4-H-ptz) for 1 and 5,5′-(1,4-phenylene)bis(1-H-tetrazole) (H2bdt) for 2), long and flexible pyridyl-containing ligand 1,3-bi(4-pyridyl)propane (bpp), NaN3, and CoCl2. Both 1 and 2 consist of well-isolated one-dimensional cobalt(II) alternating chains further linked by the bpp and/or the tetrazole ligand, while their chain structures are totally different. The chains of 1 are formed by Co2+ ions bridged by single μ-EE-N3 and triple (μ-EO-N3)(μ-tetrazole)2 alternately, whereas the Co2+ ions are bridged by μ3–OH to form Co3(OH)2 chains in compound 2. Magnetic measurements demonstrate that compound 1 contains an alternating antiferromagnetic (AF)/ferromagnetic (FM) ferrimagnetic chain, while compound 2 exhibits the coexistence of spin canting, slow magnetic dynamics, and finite-size effect, with alternating AF/AF/FM ferrimagnetic chains.
Two metal-organic frameworks constructed from one dimensional cobalt(II) ferrimagnetic chains with alternating antiferromagnetic/ferromagnetic and AF/AF/FM interaction: synthesis, structures, and magnetic properties