Synthesis, characterization, and structure of a uranyl complex with a disulfide ligand, bis(di-n-propylammonium) disulfidobis(di-n-propylthiocarbamato)dioxouranate(VI)

Olive green crystals of the title compound, ((n-C/sub 3/H/sub 7/)/sub 2/NH/sub 2//sup +/)/sub 2/(UO/sub 2/((n-C/sub 3/H/sub 7/)/sub 2/NCOS)/sub 2/(S/sub 2/))/sup 2 -/, are orthorhombic, space group Pcan, with a = 15.326 (6) A, b = 17.474 (6) A, c = 14.728 (6) A, and Z = 4 (d/sub x/ = 1.45 g/cm/sup 3/). For 1833 data, I > sigma/sub I/, R = 0.052, and R/sub w/ = 0.069. The structure was revealed by single-crystal x-ray diffraction studies to consist of ((n-C/sub 3/H/sub 7/)/sub 2/NH/sub 2/)/sup +/ cations and (UO/sub 2/((n-C/sub 3/H/sub 7/)/sub 2/NCOS)/sub 2/(S/sub 2/))/sup 2 -/ anions with the uranium atom at the center of an irregular hexagonal bipyramid. The uranyl oxygen atoms occupy the axial positions. The equatorial coordiantion plane contains the disulfide (S/sub 2//sup 2 -/) group bonded in a side-on fashion and two oxygen and two sulfur donor atoms from the monothiocarbamate ligands. Interatomic distances are S-S = 2.05 (1) A and U-S = 2.711 (3) A (disulfide), U-S = 2.873 (3) A and U-O = 2.48 (1) A (thiocarbamate), and U-0 = 1.82 (1) A (uranyl). The nitrogen atom in the dipropylammonium cation is hydrogen bonded to the uranyl oxygen atoms.