Synthesis, Crystal Structures and Luminescence Properties of Three New Cadmium 3D Coordination Polymers

The new rigid planar ligand 2,5-bis(3-(pyridine-4-yl)phenyl)thiazolo[5,4-d]thiazole (BPPT) has been synthesized, which is an excellent building block for assembling coordination polymer. Under solvothermal reaction conditions, cadmium ion with BPPT in the presence of various carboxylic acids including (1,1′-biphenyl)-4,4′-dicarboxylic acid (BPDC), isophthalic acid (IP), and benzene-1,3,5-tricarboxylic acid (BTC) gave rise to three coordination complexes, viz, [Cd(BPPT)(BPDA)](BPPT)n (1), [Cd(BPPT) (IP)] (CH(3)OH) (2), and [Cd(3)(BPPT)(3)(BTC)(2)(H(2)O)(2)] (3). The structures of 1, 2, and 3 were characterized by single crystal X-ray diffraction. The IR spectra as well as thermogravimetric and luminescence properties were also investigated. Complex 1 is a two-dimensional (2D) network and further stretched to a 3D supramolecular structure through π–π stacking interaction. The complexes 2 and 3 show 3D framework. The complexes 1, 2, and 3 exhibited luminescence property at room temperature.