Two complexes based on 1H-1,2,3-triazole-4,5-dicarboxylic acid: hydrothermal synthesis,crystal structures and spectral properties

Zn₃(tda)₂(bipy)₂(H₂O)_2?·?4H₂O] _n (1) and Co₂(Htda)₂(H₂O)₆·5H₂O] (2) have been synthesized and characterized structurally by X-ray diffraction, where H₃tda?=?1H-1,2,3-triazole-4, 5-dicarboxylic acid and 2,2′-bipy?=?2,2′-bipyridine. Their solid-state structures have been characterized by elemental analysis and IR spectroscopy. The molecular unit of 1 consists of two crystallographically unique Zn(II) ions assuming different coordination geometries, the tda^3? exhibits a hexadentate binding mode chelating three Zn(II) ions; neighboring Zn–Zn distances through tda^3? bridges are 5.910(6), 5.888(5), and 6.279(3)?Å, respectively. In 2, two neighboring Co(II) ions are bridged by two Htda^2? ligands, forming a binuclear structure, with Co–Co distance of 4.091?Å and is further linked to generate a 3-D structure via hydrogen bonds. Fluorescent of 1 was investigated.