Syntheses, Crystal Structures and Characterization of Layered and Layer-pillared Zinc Arsonates

Two zinc arsonate coordination polymers, Zn(4-apa)·H2O (1, 4-apaH2 = 4-amino- phenylarsonatic acid) and Zn(4-apa) (2), have been hydrothermally synthesized and characterized by elemental analysis, IR and single-crystal and powder X-ray diffraction. Crystal data for 1: monoclinic, space group C2/c with a = 23.056(5), b = 5.4224(11), c = 15.027(3) , β = 121.22(3)°, V = 1606.6(6) ?3, Dc = 2.468 g·cm-3, F(000) = 1168, μ = 7.122 mm-1, Z = 8, the final R = 0.0309 and wR = 0.0752 for 1763 observed reflections with I > 2σ(I). For 2: monoclinic, space group P21/c with a = 8.7852(18), b = 9.2744(19), c = 9.752(2) , β = 103.45(3)°, V = 772.7(3)3, Dc = 2.410 g·cm-3, F(000) = 544, μ = 7.387 mm-1, Z = 4, the final R = 0.0321 and wR = 0.0741 for 1696 observed reflections with I > 2σ(I). The structure of 1 shows a two-dimensional (4,4)-network composed of an inorganic ladder chain bridged by the phenyl-linkers of 4-apa ligands. Compound 2 exhibits a 3D layer-pillared framework with crb net, in which inorganic (4-82)-networks are joined by the phenyl-linkers.