Chiral Helices in a 3D Network of Zn_2(en)V_2O_7 (en = Ethylenediamine)

摘要

An inorganic-organic hybrid vanadate complex, Zn_2(en)V_2O_7 (en = ethylenediamine) has been hydrothermally synthesized and characterized by single-crystal X-ray crystallography, TG analysis, IR spectroscopy, and elemental analysis. The title compound crystallizes in the monoclinic space group P2_1 with a = 7.0885(7), b = 8.6040(9), c = 8.1869(8) A, β = 112.224(2)° and V = 462.22(8) A~3, T = 298±2 K and R_1[I>2σ(I)] = 0.0291 for 2170 observed reflections. The structure consists of undulating sheets constructed from helical chains that share Zn coordination centers with repeating units propagated into a helix by the two-fold screw axes at 0, y, 1/2 and pillared with alternating VO_4 tetrahedra to generate a 3D chiral network. Neighboring helices are interconnected by μ2-O bridges to form the three-dimensional network. The strength of the network is reinforced by hydrogen bonding. TG analysis shows thermal stability of the network up to 283°C.