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

摘要

Here, we report two three-dimensional metal−organic framewno r k s o f f ormu l a [Co2 ( 4 -pt z ) 2 ( b p p ) (N3 ) 2 ] n ( 1) andn[Co3(OH)2(bdt)2(bpp)2(H2O)2]n (2), which were synthesized by hydrothermalnreaction from the respective tetrazole ligand (5-(4-pyridyl)tetrazolen(4-H-ptz) for 1 and 5,5′-(1,4-phenylene)bis(1-H-tetrazole) (H2bdt) for 2),nlong and flexible pyridyl-containing ligand 1,3-bi(4-pyridyl)propane (bpp),nNaN3, and CoCl2. Both 1 and 2 consist of well-isolated one-dimensionalncobalt(II) alternating chains further linked by the bpp and/or the tetrazolenligand, while their chain structures are totally different. The chains of 1 arenformed by Co2+ ions bridged by single μ-EE-N3 and triple (μ-EO-N3)(μ-ntetrazole)2 alternately, whereas the Co2+ ions are bridged by μ3−OH to formnCo3(OH)2 chains in compound 2. Magnetic measurements demonstrate thatncompound 1 contains an alternating antiferromagnetic (AF)/ferromagneticn(FM) ferrimagnetic chain, while compound 2 exhibits the coexistence of spin canting, slow magnetic dynamics, and finite-sizeneffect, with alternating AF/AF/FM ferrimagnetic chains.