Spin canting and long-range magnetic ordering in a 2-D cobalt–organic framework incorporated with a new bent connector: 1,4-bis(5-(4-pyridyl)-1H-1,2,4-triazol-3-yl)benzene

Structural diversity and magnetic properties of six cobalt coordination polymers based on 2,2'-phosphinico-dibenzoate ligand

Six novel Co(ii) coordination polymers, namely, [Co₁₀L₆(OH)₂(H₂O)₉]·10.5H₂O (1), [Co₃L₂(3-abpt)₂]·4H₂O (2), [Co₃L₂(4-azpy)₂(H₂O)₂(EtOH)] (3), [Co₃L₂(4,4'-bipy)₂(H₂O)₂(MeCN)] (4), [Co₃L₂(4,4'-bipy)₂] (5), and [Co₅L₂(OH)₂(ina)₂(H₂O)₂] (6) (H₃L = 2,2'-phosphinico-dibenzoic acid, 3-abpt = 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole, 4-azpy = 4,4'-azobispyridine, 4,4'-bipy = 4,4'-bipyridine, Hina = isonicotinic acid), have been hydrothermally synthesized and their magnetic properties have been characterized. The L^3- anion displays six types of coordination modes in the compounds. Compound 1 exhibits a novel 1D ladder-like structure, which consists of non-centrosymmetric Co₁₀ units. Compounds 2-4 comprise 2D networks assembled from Co₃L₂ chains and N-heterocyclic linkers. Compound 5 comprises a 3D framework built from six neighboring parallel Co₃L₂ ladders bridged by 4,4'-bipy linkers. Compound 6 features a 3D framework that exhibits pcu topology with the Schläfli symbol of (4¹²·6³) using a pentanuclear [Co₅(OH)₂]⁸⁺ cluster as the node. Variable-temperature magnetic susceptibility studies indicate that the six coordination polymers exhibit remarkable magnetic behavior such as spin-canted antiferromagnetism and spin glass, which were found to coexist in compound 6.

A series of multidimensional MOFs incorporating a new N-heterocyclic building block: 5,5′-di(pyridin-4-yl)-3,3′-bi(1,2,4-triazole)

By using a new N-heterocyclic building block: 4,4′-H₂dbpt, six novel coordination polymers with diversiform connectivity from one to three dimensional were constructed and characterized by X-ray crystallography successfully.