Syntheses, Structures and Luminescent Properties of Cd(II)/Zn(II) Coordination Polymers Based on the Flexible 4-Substituted Bis(1,2,4-triazole) Ligand

Two new cadmium(II) and zinc(II) coordination polymers, {[Cd(btre)(0.5)-(mip)(H2O)(2)]center dot H2O}(n) (1) and [Zn(btre)(mip)](n) (2), were synthesized at room temperature condition and characterized by IR spectra, elemental analyses, single-crystal and powder X-ray diffractions (btre = 1,2-bis(1,2,4-triazol-4-yl) ethane, H(2)mip = 5-methyl-1,3-benzenedicarboxylic acid). Complex 1 belongs to the triclinic system, P (1) over bar space group, with a = 8.9830(6), b = 10.0579(6), c = 10.2479(9) angstrom, alpha = 98.837(6), beta = 115.975(8), gamma = 106.370(6)degrees, V = 756.30(11) angstrom(3) and Z = 2; complex 2 crystallizes in monoclinic, space group P2(1)/c, with a = 7.0332(3), b = 14.9947(7), c = 15.9689(7) angstrom, beta = 97.1170(10)degrees, V = 1671.12(13) angstrom(3) and Z = 4. Compounds 1 and 2 based on the same N/O-donor ligands show different structures. The one-dimensional chains of 1 are further linked by hydrogen bonding and pi-pi interactions to yield a three-dimensional supramolecular structure. The two-dimensional (6,3) networks of 2 are further extended into a 3D framework via pi-pi interactions. Thermal stabilities and luminescence of 1 and 2 were investigated.