Two New Coordination Polymers Containing Metal-carboxylate Helix

Two novel compounds, {[Cd(nbdc)(bpp)(H2O)]·H2O}n 1 and {[Cd(nbdc)(dpds)-(H2O)]·H2O}n 2(H2nbdc = 4-nitro-1,2-benzenedicarboxylic acid, bpp = 1,3-bis(4-pyridyl)propane and dpds = 4,4ˊ-dipyridyldisulfide), were solvothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis(TGA), fluorescent analysis and single-crystal X-ray diffraction. Complex 1 is of monoclinic system, space group P21/c with a = 14.4370(17), b = 8.4090(10), c = 19.168(2) , β = 104.5050(10)°, V = 2252.8(5) 3, Dc = 1.639 g/cm3, Mr = 555.81, Z = 4, F(000) = 1120, μ = 1.022 mm-1, the final R = 0.0269 and wR = 0.0599 for 16656 observed reflections with I > 2σ(I). 2 is isostructural to 1 with a = 14.4175(11), b = 8.4737(7), c = 18.0120(14) , β = 106.7220(10)°, V = 2107.5(3)3, Dc = 1.821 g/cm3, Mr = 577.85, Z = 4, F(000) = 1152, μ = 1.287 mm-1, the final R = 0.0280 and wR = 0.0705 for 15136 observed reflections with I> 2σ(I). Both complexes present intimately related structures featuring infinite Cd-carboxylate helix of [CdⅡ(nbdc)(H2O)]n connected by bpp(or dpds) molecule to produce the 2D layer frameworks.