Anion-Induced Coordination Versatility of 1H-1,2,4-Triazole-3-thiol (HtrzSH) Affording a New Hybrid System of Cadmium(II) Polymers: Synthesis, Structure, and Luminescent Properties

A new hybrid system of cadmium(II) polymers has been synthesized by using 1H-1,2,4-triazole-3-thiol (HtrzSH) and cadmium salts, affording six novel luminescent complexes, that is, [Cd(H2trzS)2Cl2] (1), [Cd(HtrzS)Br] (2), [Cd(HtrzS)I] (3), [Cd2(HtrzS)2(SO4)] (4), [Cd(H2trzS)(H2Edta)]·(H2O) (5), and [Cd(trzS)2] (6). In these materials, owing to the effective inducement of inorganic or organic anions, coordination versatility of the HtrzSH ligand manifests as many as six bridging modes (type A−F), and five of them (type B−F) are first reported. The structure of complex 1 is a one-dimensional chain constructed from the neutral monodentate and bidentate H2trzS ligand (type A−B), whereas two-dimensional complexes 2−3 and the three-dimensional complex 4 possess the deprotonated tridentate to quadridentate HtrzS ligands (type C−E). Zero-dimensional complex 5 and peristyle-like three-dimensional complex 6 are synthesized by means of organic anions, and in the latter complex a bideprotonated quadridentate trzS ligand is presented (type F). All complexes exhibit strong photoluminescence with fluorescent emissions varying from blue to orange in the solid state. Some structure related red or blue emission shifts compared to the free ligand are studied, as well as several advantageous structural factors to obtain longer fluorescence lifetime. X-ray powder diffraction and thermal studies are used to investigate the bulk properties of these compounds.