Abstract
Two Cd(II) coordination polymers have been synthesized with derivatives of pyrazine-1,4-dioxide and thiocyanate anion as bridging ligands and structurally determined by X-ray crystallography. Complex 1, [Cd(μ1,3-SCN−)2(μ1,6-L1)] n (L1 = 2,5-dimethylpyrazine-1,4-dioxide), belongs to the triclinic, space group P 1 with a = 5.7627(18) Å, b = 7.182(2) Å, c = 7.509(2) Å, α = 74.042(3)°, β = 84.766(4)°, γ = 88.162(4)°; complex 2, [Cd2(μ1,3-SCN−)4(μ4-L2)] n (L2 = 2,3,5,6-tetramethylpyrazine-1,4-dioxide), crystallizes in a monoclinic system with space group C2/m with a = 10.194(4) Å, b = 13.491(6) Å, c = 8.140(3) Å, β = 120.372(4)°. Complex 1 shows a two-dimensional sheet structure, and in a direction the Cd(II) ions were coordinated by μ1,3-SCN− forming the one-dimensional chain and the L1 bridging ligand made the chains connect in the c direction leading to formation of a two-dimensional sheet on the ac plane. For 2 the one-dimensional chains in the a axis were constructed by coordination of μ1,3-SCN− bridging ligands with the Cd(II) ions, and in b and c directions the chains were joined by L2 bridging ligands leading to a three-dimensional structure. In 2 L2 displays a μ4-bridging coordination mode. Both complexes exhibit strong fluorescence emission.
Acknowledgement
This work was supported by the National Natural Science Foundation of China (No. 20271043) and the Natural Science Foundation of Shandong Province (Y2005B25).