Four coordination polymers based on bifunctional ligands: Syntheses, crystal structures and physical properties

Four coordination polymers, namely, Co(HIMB)₂ (1), Cd(HIMB)₂·2.58H₂O (2), Cd₂ (TAB)₂·3H₂O (3) and Zn₂ (TAB)₂·H₂O (4) (H₂IMB = 4,4'-((1H-imidazole-1-yl)methylene)dibenzoic acid and H₂TAB = 4,4'-((4H-1,2,4-triazol-4-yl)azanediyl)dibenzoic acid), have been synthesized under solvothermal conditions and characterized by IR, elemental analysis, thermogravimetric (TG) analysis and single crystal X-ray diffraction. In 1, each Co(II) ion is linked by four partially deprotonation HIMB anions to generate a typical three-dimensional (3D) 2-fold interpenetrating diamondoid network. Complex 2 exhibits a rare 3D (3,6)-connected framework with sit topology. Complex 3 features a predocumented 3D (4,8)-connected net with (4¹⁰.6¹⁵.8³) (4⁵.6)₂ topology, whereas complex 4 displays a scarce 3D framework with (3,3,6,6)-connected (6³)₄ (6⁶.8⁸.10) (6⁶.8⁹) topology. A comparison of all complexes suggested that the structural diversity of the complexes could be tuned by altering the metal ion and organic ligand. The thermal stabilities and photoluminescent properties in the solid state for complexes 1–4 have been discussed. Moreover, the photodegradation properties of four complexes have also investigated.