Abstract: Two novel Cd(Ⅱ) coordination polymers, [Cd₂(C₁₀H₂O₈)\5(H₂O)₆]_n (1) and [Cd₄(C₆H₄O₂N)₈(H₂O)₄]_n (2) (C₁₀H₂O₈=1,2,4,5-benzenetetracarboxyl and C₆H₄O₂N=nicotinato), were hydrothermally synthesized and characterized by X-ray diffraction of the single-crystal and fluorescence spectra. Complex 1 crystallizes in triclinic system, space group P1 with a=0.559 62(7) nm, b=0.777 58(6) nm, c=0.969 75(10) nm, α=111.981(5)°, β=101.649(6)°, γ=98.240(5)°, and Z=1. Final R=0.024 8(wR=0.078 5). Complex 2 belongs to orthorhombic system, space group Pbca with unit cell dimensions a=1.144 94(19) nm, b=1.209 69(6) nm, c=1.740 73(8) nm and Z=8. Final R=0.018 5(wR=0.034 8). Both the two complexes are coordination polymers with a two-dimensional infinite structure, the repeat unit is [Cd₂(C₁₀H₂O₈)(H₂O)₆] (1) and [Cd₄(C₆H₄O₂N)₈(H₂O)₄] (2) which are bridged by the ligands of 1,2,4,5-benzenetetracarboxyl(C₁₀H₂O₈) and nicotinato(NA), respectively. The two polymers show strong fluorescence with λ_em=433 nm(λ_ex=333 nm, 1) and λ_em=423 nm(λ_ex=330 nm, 2) in the solid state at room temperature. The emissions observed in the polymers are tentatively assigned to the ligands fluorescence(LLCT).

Key words: Cd(Ⅱ) coordination polymer, Synthesis, Crystal structure, Fluorescence property