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

•Five polymers have been synthesized and characterized.•Polymer 1 possesses a 2-fold interpenetrating three-dimensional framework.•The fluorescence properties of 1–5 are studied.•Magnetic properties of 5 are also investigated.

Five new polymers based on 5-(pyridine-3-yl)pyrazole-3-carboxylic acid (H2ppca), namely, [Cd2(ppca)(bix)(SO4)]n (1), {[Cd(Hppca)2]·H2O}n (2), {[Mn(Hppca)2]·H2O}n (3), [Zn2(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 Schläfli symbol (4·8·10). 5 exhibits a 2D structure with the Schläfli symbol (4·82). 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 (τCu1, 0.069) implies that there is strong antiferromagnetic interactions between two adjacent Cu1C and Cu1, and the magnetic interactions are mainly transferred by the bridging N,N-triazole ligands.

Graphical abstractFive polymers have been synthesized and characterized. Polymer 1 possesses a 2-fold interpenetrating three-dimensional framework. Polymers 2–5 exhibit the 2D structures. The fluorescence properties of 1–5 are studied. Magnetic properties of 5 are also investigated.Figure optionsDownload full-size imageDownload as PowerPoint slide