Five metal-organic frameworks based on 5-(pyridine-3-yl)pyrazole-3-carboxylic acid ligand: Syntheses, structures and properties

Five new polymers based on 5-(pyridine-3-yl)pyrazole-3-carboxylic acid (H(2)ppca), namely, [Cd-2(ppca) (bix)(SO4)](n) (1), {[Cd(HPPca)(2)]center dot H2O}(n) (2), {[Mn(Hppca)(2)]center dot H2O}(n) (3), [Zn(2()ppca)(2)](n) (4) and [Cu(ppca)](n) (5) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analyses and IR spectroscopy. Structural analyses reveal that polymer 1 possesses a 2-fold interpenetrating three-dimensional (3D) framework. Polymers 2 and 3 display 4-connected 2D frameworks, while polymer 4 features a (3,3)-connected topology with the Schlafli symbol (4.8.10). 5 exhibits a 2D structure with the Schlafli symbol (4.8(2)). Furthermore, the fluorescence properties of the five polymers are also investigated in the solid state, showing the fluorescence signal changes in comparing with that of free ligand mbbz. Polymer 5 with square pyramid geometry (tau(cu1), 0.069) implies that there is strong antiferromagnetic interactions between two adjacent Cu1C and Cul, and the magnetic interactions are mainly transferred by the bridging N,N-triazole ligands. (C) 2016 Elsevier B.V. All rights reserved.