Synthesis and Characterization of Two New Organically Templated Open-framework Uranium Phosphites

Two organically templated uranium phosphites, (C4H12N)(UO2)(HPO3)(NO3) (Mr = 486.16) 1 and (C16H36N)2(UO2)2(H2PO3)2(HPO3)(NO3)2 (Mr = 1390.95) 2, were prepared by evaporation from aqueous solution of uranyl nitrate, phosphite acid and their respective organic ammonium hydroxids. Their structures were determined by single-crystal X-ray diffraction and further characterized by infrared and fluorescence spectroscopy. In 1, pentagonal [UO7] bipyramids share corners with three [HPO3]2- tetrahedra and one edge with a [NO3]- anion to form [(UO2)- (HPO3)(NO3)]- ladder-like chains parallel to the b axis. The structure of 2 is also based upon one-dimensional anionic [(UO2)2(H2PO3)2(HPO3)(NO3)2]2-chains of corner-sharing penta- gonal [UO7] bipyramids with [H2PO3]- and [HPO3] tetrahedra, which is still unknown in structural chemistry of uranium so far. Crystal data for 1: monoclinic, space group C2/m, a = 21.808(7), b = 6.9605(15), c = 8.357(2) ’, β = 98.327(15)°, V = 1255.2(6) ’3, Z = 4, Dc = 2.573 g/cm3, F(000) = 888, μ = 13.086 mm-1, the final R = 0.0418 and wR = 0.0906 (I > 2σ(I)); and those for 2: monoclinic, space group C2/c, a = 36.4549(8), b = 14.5296(11), c = 20.8253(11) ’, β = 101.7440(8)°, V = 10799.7(10) ’3, Z = 8, Dc = 1.711 g/cm3, F(000) = 5424, μ = 6.144 mm-1, the final R = 0.0368 and wR = 0.0865 (I > 2σ(I)).