In situ hydrothermal syntheses of five new cadmium(ii) coordination polymers based on 3-(1H-tetrazol-5-yl)benzoate ligand

Abstract

Five new cadmium(II) tetrazole-based compounds, {[Cd₄(3-tzba)₄(H₂O)₂]·2H₂O (1), [Cd(3-tzba)(2,2′-bipy)₂] (2), [Cd(3-tzba)(1,10-phen)] (3), [Cd₃(3-tzba)₂(NA)₂(H₂O)] (4) and [Cd(3-tzba)(BIO)] (5), where 3-tzba = 3-(1H-tetrazol-5-yl)benzoate, 2,2′-bipy = 2,2′-bipyridine, 1,10-phen = 1,10-phenanthroline, NA = nicotinic acid, BIO = benzo-biimidazolediones}, were successfully synthesized involving the in situ generation of ligand under hydrothermal conditions. The compounds were thoroughly characterized by elemental analyses, Fourier transform infrared spectroscopy, thermal studies, and single crystal and powder X-ray diffraction. Compound 1 represents a three-dimensional (3D) coordination framework built up by the assembly of two-dimensional (2D) Cd-3-tzba wheel layers and 3-tzba linkers, exhibiting a pcu (4¹²·6³) topological net. Compound 2 displays a one-dimensional (1D) zigzag chain formed by the linkage of Cd(II) centers and 3-tzba ligands. Compound 3 shows a 1D pearl-necklace-like chain built by the interconnection of Cd(II) centers and 3-tzba ligands. Compound 4 is a 3D coordination framework which is constructed by 1D [Cd₃] chains with 3-tzba and NA ligands linkers displaying a hxl (3⁶) type net. Compound 5 exhibits a 3D sql (4⁴) topological network, with 1D Cd chains linking the adjacent 3-tzba and BIO ligands. It is noted that the 3-tzba and BIO ligands are generated in situ from the precursor 3-cyanobenzoic acid and 1,2,4,5-benzenetetracarboxylic acid (H₄bta), respectively. In addition, the luminescent properties of these compounds were investigated.