Hydrothermal syntheses, crystal structures, and characteristics of a series of Cd-btx coordination polymers (btx=1,4-bis(triazol-1-ylmethyl)benzene)

Four novel cadmium-btx (btx = 1,4-bis(triazol-1-ylmethyl)benzene) coordination polymers [Cd(btx)(2)(NO3)(2)](n) (1), [Cd(btx)(2)Cl-2](n) (2), [Cd(btx)(SO4)(H2O)(2)](n) (3), and [Cd(btx)(S2O7)(H2O)](n) (4) have been prepared by hydrothermal reaction (140 or 180 degreesC) and characterized. Both 1 and 2 have two-dimensional rhombohedral grid structures, 3 possesses a two-dimensional rectangular grid structure, and 4 displays a three-dimensional framework, which is formed by btx bridging parallel layers. To the author's best knowledge, polymer 4 is the first Cd(II) polymer in which the Cd(II) ion is eight-coordinated in a hexagonal bipyrimidal geometry. In addition, we studied the effects of temperature on the hydrothermal reaction system of btx and CdSO4 and found that different products can be obtained at different temperatures. Furthermore, polymer 3 possesses a very strong third-order NLO absorptive effect with an alpha(2) value of 1.15 x 10(-9) m W-1. Polymers 2-4 display strong fluorescent emissions in the solid state at room temperature. The DTA and TGA results of the four polymers are in agreement with the crystal structures.