Synthesis and Crystal Structure of a New Double 2D Layer Complex Assembled by H4btec

Assembly of H4btec with cobalt(Ⅱ) acetate afforded a new double 2D layer coor- dination polymer, Co(btec)1/2(H2O)4·2H2O]n (H4btec = benzene-1,2,4,5-tetracarboxylic acid) 1. The polymeric structure has been characterized by single-crystal X-ray diffraction, FT-IR and thermal analysis. The crystal is of triclinic, space group P with a = 10.8762(2), b = 11.1411(1), c = 11.5084(3)(A), α = 82.8950(10), β = 63.0050(10), γ = 62.1500(10)°, V = 1091.72(4)(A)3, C5H13CoO10, Mr = 292.08, Z = 4, Dc = 1.777 g/cm3, μ = 1.612 mm-1, F(000) = 600, R = 0.0578, and wR = 0.2162 for 3576 observed reflections (I > 2σ(I)). Complex 1 consists of a new double 2D layer structure Co(btec)1/2(H2O)4]n, both consisting of 4 + 4 grids with the sizes of 11.3667(2)(A) × 11.5084(3)(A)(Co(1)-Co(1A) × Co(2A)-Co(2B)) and 11.5084(3)(A)× 11.3667(2)(A) (Co(3)-Co(3C) × Co(4)- Co(4A)), respectively. The phenyl rings are at the corners while the Co(Ⅱ) atoms are in the sides of the grids, and lattice water molecules decorate between the layers. Hydrogen bonds between the layers and lattice water molecules result in the final 3D framework.