2-Fold interpenetrating zinc(II) coordination polymer with multi-heterocyclic ligand: Synthesis, structure and properties

A novel 2-fold interpenetrating layered complex [Zn(4-PTA)2·2H2O]n (1) has been synthesized by hydrothermal reactions of ZnBr2 and 4-PTN (or 4-PTA and 4-CCP), and characterized by single crystal X-ray diffraction, elemental analysis, IR, XRD and TGA (where 4-PTA = 2-(5-(pyridin-2-yl)-2H-tetrazol-2-yl)acetic acid, 4-PTN = 2-(5-(pyridin-2-yl)-2H-tetrazol-2-yl)acetonitrile and 4-CCP = 4-cyano-1-(cyanomethyl)pyridinium bromide). The tetrahedral Zn(II) centers are bridged by 4-PTA ligands into a 2D (4, 4)-connected topology net. Then the adjacent nets were intertwined to result in a 2D–2D parallel interpenetrating layer. The H-bonding weak interactions further stabilized the complex. Furthermore, solid-state fluorescence spectrum of complex 1 exhibits intense broad emissions at 413 nm at room temperature, which is red-shifted by 32 nm relative to that of free 4-PTA ligand. This synthesis provides a new impetus about applying in situ hydrothermal reaction chemistry to a new system.