Synthesis and crystal structure of potassium and manganese complexes of 1,2,3-triazole-4,5-dicarboxylic acid

Three coordination compounds [K(H2TDA)H2O] n (1), [K(H2TDA)(H3TDA)2H2O] n (2), and Mn2(phen)2(HTDA)2(H2O)4 (3) have been synthesized and characterized structurally by X-ray diffraction, where H3TDA = 1,2,3-triazole-4,5-dicarboxylic acid and phen = 1,10-phenanthroline. Their solid-state structures have been characterized by elemental analysis and IR spectroscopy. In 1, a 3-D (4, 8)-connected metal-organic framework has been constructed using dinuclear potassium clusters as eight-connected nodes and the ligands as four-connected nodes; it represents the fluorite topology network. Compound 2 exhibits 1-D chains along c-axis, which are connected by strong hydrogen-bond interactions in 2-D layers; the layers are further stacked via hydrogen bonds in the b-direction. In 3, two neighboring Mn(II) ions are bridged by two 1,2,3-triazole-4,5-dicarboxylic groups, forming a binuclear structure, with Mn(II) ··· Mn(II) distance of 4.356 Å, which is further linked to generate a 2-D layer structure via interdimer hydrogen bonds. The fluorescence for these compounds was investigated.