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Different ways of anions introduction were applied to construct cluster-based frameworks, owning to the versatile coordination ability of the formate anion and its sensitivity to the pH value of the reaction system. Three tetra-, penta-, and hexanuclear cluster-based cobalt-organic frameworks, [Co2(L)3(HCO2)·MeOH]n (1), [Co5(L)6(OH)2(NO3)2·2H2O]n (2), and [CoL(HCO2)]n (3) [L = (E)-3-(pyridin-3-yl)acrylate], have been successfully synthesized. In these complexes, each CoII cluster is linked by twelve L ligands with different connectivities to generate unique topological nets. In 1, two formate anions link four CoII ions forming a tetranuclear cluster, and each of the tetranuclear clusters is connected to eight neighbors by L ligands, giving an 8-connected 36418536 net. In 2, the pentanuclear cluster is formed by five CoII ions linked through two OH– and six carboxylate groups, which are further connected by L ligands to afford a pcu (primitive cubic lattice) net. Different from 1 and 2, complex 3 is a 2-fo...

Three new CoII–azido complexes, [Co3(L)2(o-BDC)2(N3)2]n (1), [Co3(L)2(m-BDC)2(N3)2]n·nH2O (2), and [Co2(L)2(p-BDC)(N3)2]n·2nMeOH (3) [o-BDC = 1,2-benzenedicarboxylate, m-BDC = 1,3-benzenedicarboxylate, p-BDC = 1,4-benzenedicarboxylate, and L = di(1H-imidazol-1-yl)methane], have been constructed from di(1H-imidazol-1-yl)methane, azido, and different aromatic dicarboxylates under hydrothermal conditions. Complex 1 takes a dia topology with the Co3 units as connecting nodes, and complex 2 is a two-dimensional sql layer that further extends to a three-dimensional (3D) supramolecular network via π···π interaction between m-BDC ligands, while complex 3 forms a 3D pcu network based on Co2 units as nodes. The investigaton of magnetic properties of complexes 1–3 demonstrates that they all display ferromagnetic coupling between CoII ions but antiferromagnetic interaction between Co3 or Co2 units.

The reactions of Mn(II) ions with azido ligands in the presence of nicotinic/isonicotinic acids gave two manganese(II) azido coordination polymers, [Mn(3)(L(1))(2)(N(3))(4)](n).nH(2)O (1) and [Mn(2)(L(2))(N(3))(3)](n) (2), where L(1) = nicotinate and L(2) = isonicotinate, with different topological structures. Complex 1 consists of 2D azido-Mn(II) planes, which is further linked by L(1) to form a 3D framework with unprecedented 3,6-connected 4-nodal net topology, and complex 2 presents an unprecedented 3,4,6-connected 6-nodal 3D azido-Mn(II) structure with L(2) as the coligand. Magnetic susceptibility measurements reveal dominant antiferromagnetic coupling existing in 1 and 2. Complex 1 is a spin-competitive system and enters into a weak ferromagnetic-to-magnetic phase transition at the critical temperature of 6 K due to spin canting. Complex 2 is an antiferromagnet and exhibits field-induced spin-flop behavior.

A new azido-NiII complex constructed from nicotinate has been obtained by cation−anion pairs as templates under hydrothermal conditions, which exhibits three-dimensional Kagome topology and ferromagnetic coupling.

Two new 3D copper(II) azido isomers, [Cu(N3)(nic)]infinity (1 and 2) (nic = nicotinate), have been synthesized and characterized. To the best of our knowledge, 1 is the first metal azido complex showing rutile-type topology, while 2 is a chiral compound obtained by spontaneous resolution upon crystallization.