Synthesis, structure, and properties of complexes based on 3, 5-di-(Triazole-1-yl)-Benzoic acid ligands

Two kinds of new complexes based on 3, 5-bis (triazol-1-yl) benzoic acid (HL) and 1, 3, 5-benzenetricarboxylic acid (H 3 bta), {[Zn 2 (μ 4 -L)(μ 3 -bta(3H 2 O)]∙H 2 O}n( 1 ) and {[Cd 2 (μ 4 -L)(μ 3 -bta(3H 2 O)]∙4H 2 O}n( 2 ), were prepared by solvothermal reactions and the structures were characterized by single-crystal X-ray diffraction. The experimental results showed that complexes 1 and 2 were isomorphic, in which metal ions were separately chelated with the ligands to form one mononuclear Cd 1 and another binuclear Cd 2 O 4 structure. Each metal center (M) can be considered as a three-connection, each M 2 O 4 as a six-connection, and the ligands of HL and H 3 bta can be used as three-junctions. Finally, complex 1 and 2 showed a (3, 6)-connection of {6 3 } 6 {6 6 ;8 6 ;10 2 ;12} topology. Solid-state fluorescence experiments showed that only complex 1 could selectively identify Fe 3+ (detection limit: 0.11 ​mM) and Cr 6+ (detection limit: 0.1 ​mM) in aqueous solution by a fluorescence quenching mechanism and the fluorescence quenching constant of Fe 3+ reached 10 4 . Dye adsorption experiments showed that the complexes could absorb different organic dyes and the adsorption capacity was 1  ​> ​ 2 . Furthermore, the adsorption efficiency of 1 for methylene blue was as high as 97.64%.