Synthesis and Crystal Structure of a New Zn(Ⅱ) Coordination Polymer Constructed by 1,2,4,5-Benzenetetracarboxylate

A new Zn(Ⅱ) coordination polymer [Zn3(btec)(OH)2(H2O)2]n (1, btec = 1,2,4,5- benzenetetracarboxylate) has been synthesized by hydrothermal reaction and its structure was determined by single-crystal X-ray diffraction analysis. The title compound crystallizes in mono- clinic, space group C2/c, with a = 19.580(3), b = 5.0137(8), c = 15.975(3), β = 121.629(2)°, V = 1335.3(4)3, C10H8O12Zn3, Mr = 516.27, Z = 4, Dc = 2.568g/cm3, μ = 5.419 mm-1, F(000) = 1016, R = 0.0590 and Rw = 0.1279 for 1110 observed reflections (I > 2σ(I)). X-ray analysis shows that the asymmetric unit of the title compound contains two crystallographically unique Zn(Ⅱ) atoms which are connected through the bridging carboxylate oxygen atoms of the btec ligands and μ2-bridging oxygen atoms of water molecules to generate an infinite one-dimensional chain. The adjacent chains are linked together through the benzene rings of the btec ligands to form a two-dimensional polymeric network. The adjacent two-dimensional layers are further connected together by the benzene rings of btec ligands to give the final three-dimensional structure. The benzene rings act as pillars between two layers.