Construction of cadmium(II) and zinc(II) coordination frameworks based on 3,5-bis(benzoimidazo-1-ly)pyridine and carboxylate acids: Synthesis, crystal structures and photoluminescent properties

Two new metal coordination polymers [Cd2(ba)4(L)2]n (1) and [Zn(tda)(L)]n (2) [Hba = benzoic acid, H2tda = 2,5-thiophenedicarboxylic acid and L = 3,5-bis(benzoimidazo-1-ly)pyridine] have been successfully synthesized and structurally characterized by IR, elemental analysis, X-ray powder diffraction and X-ray single-crystal diffraction. For complex 1, two Cd(II) ions and four ba ligands form the dimetal clusters, which are further connected through the L ligands to give rise to a uninodal 3-connected hcb Shubnikov hexagonal plane net with the 63 topology. Complex 2 features the 3-connected topological net with 82 ∙ 10 topology (so-called “tongue-and groove” structure). The Zn(II) node together with the four surrounding coordinated ligands form a typical T-shaped molecular bilayer motif, which is rarely reported previously. Their X-ray powder diffraction patterns were then carried out to confirm the validity of the crystal structures. In addition, the luminescent properties of 1 and 2 are investigated in the solid state at room temperature, and the thermogravimetric analyses were carried out to study the thermal stability of the two complexes.