Syntheses, structures, characterizations and charge-density matching of novel amino-templated uranyl selenates

Five hybrid organic–inorganic uranyl selenates have been synthesized, characterized and their structures have been determined. The structure of (C2H8N)2[(UO2)2(SeO4)3(H2O)] (EthylAUSe) is monoclinic, P21, a=8.290(1), b=12.349(2), c=11.038(2) Å, β=104.439(4)°, V=1094.3(3) Å3, Z=2, R1=0.0425. The structure of (C7H10N)2[(UO2)(SeO4)2(H2O)]H2O (BenzylAUSe) is orthorhombic, Pna21, a=24.221(2), b=11.917(1), c=7.4528(7) Å, V=2151.1(3) Å3, Z=4, R1=0.0307. The structure of (C2H10N2)[(UO2)(SeO4)2(H2O)](H2O)2 (EDAUSe) is monoclinic, P21/c, a=11.677(2), b=7.908(1), c=15.698(2) Å, β=98.813(3)°, V=1432.4(3) Å3, Z=4, R1=0.0371. The structure of (C6H22N4)[(UO2)(SeO4)2(H2O)](H2O) (TETAUSe) is monoclinic, P21/n, a=13.002(2), b=7.962(1), c=14.754(2) Å, β=114.077(2)°, V=1394.5(3) Å3, Z=4, R1=0.0323. The structure of (C6H21N4)[(UO2)(SeO4)2(HSeO4)] (TAEAUSe) is monoclinic, P21/m, a=9.2218(6), b=12.2768(9), c=9.4464(7) Å, β=116.1650(10)°, V=959.88(12) Å3, Z=2, R1=0.0322. The inorganic structural units in these compounds are composed of uranyl pentagonal bipyramids and selenate tetrahedra. In each case, tetrahedra link bipyramids through vertex-sharing, resulting in chain or sheet topologies. The charge-density matching principle is discussed relative to the orientations of the organic molecules between the inorganic structural units.