Syntheses, Crystal Structures, Characterization, Optical Band Gaps and Photoluminescence of Two Zn(II) Coordination Polymers

Two novel coordination polymers based on Zn(II) ions, 1-((1 H -1,2,4-triazol-1-yl)methyl)-3-(4-pyridyl)-5-(3-pyridyl)-1,2,4-triazole (3,4′-tmbpt), and two aromatic polycarboxylate anions, namely [Zn(3,4′-tmbpt)( m -bdc)(H 2 O)]·H 2 O ( 1 ) and [Zn 2 (3,4′-tmbpt)(btc)(OH)] ( 2 ) ( m -H 2 bdc = 1,3-benzenedicarboxylic acid and H 3 btc = 1,3,5-benzenetricarboxylic acid), have been synthesized. The structures of 1 and 2 have been characterized by single-crystal X-ray diffraction analyses, elemental analyses, infrared spectra, powder X-ray diffraction analyses and thermogravimetric analyses. Compound 1 shows a 2D layered structure, which is extended by the hydrogen bonding interactions to form a 3D supramolecular architecture. Compound 2 exhibits a 3D twofold interpenetrating framework with a Schläfli symbol of (6 3 )(6 9 ·8). Diffuse reflection spectra of 1 and 2 indicate that the band gaps of 1 and 2 are 3.42 and 3.63 eV, respectively. The results indicate that compounds 1 and 2 may be potential semiconductive materials with wide band gaps. Moreover, 1 and 2 display intense blue-green emission and appear to be potential photoactive materials. Graphic Abstract Two new coordination polymers based on a multidentate N-donor ligand, Zn(II) ions, and two aromatic polycarboxylate anions have been synthesized and characterized. The optical band gaps and photoluminescent spectra of the compounds have been investigated.