R. Wiley, R. Dreele, T. M. Brown
Nov 1, 1980
Citations
0
Influential Citations
16
Citations
Journal
Inorganic Chemistry
Abstract
The synthesis of tetraethylammonium pentakis(isothiocyanato)bis(2,2'-bipyridine)uranate(IV) has been accomplished, and it was characterized by classical physical methods. The crystal and molecular structure was determined from single-crystal x-ray data collected by the theta-2theta technique on an automated diffractometer. The compound consists of pentakis(isothiocyanato)bis (2,2'-bipyridine)uranate(IV) anions and disordered tetraethylammonium cations. Uranium is bound to nine nitrogen atoms in a highly distorted monocapped square antiprism in which one bipyridine occupies a position bridging the cap and the near square while the other bipyridine spans the opposite edge of the far square. Distortion from the ideal geometry is caused by the small ligand bite of the bipyridine ligand. An alternative description of the coordination geometry is derived from the seven-coordinate pentagonal bipyramid in which each bipyridine ligand is assumed to occupy an axial position with the five thiocyanato ligands forming the pentagonal girdle. The U-N bond distances vary from 2.35 to 2.47 A for the thiocyanato ligands and from 2.61 to 2.65 A for the bipyridine ligands. The structure was solved by standard heavy-atom techniques and refined by large-block matrix least squares to a final R value of 0.083 for 3878 independent observed reflections. The compound crystallized in the monoclinic space group P2/sub 1//c, Zmore » = 4, with lattice parameters a = 14.427 (10) A, b = 18.612 (17) A, c = 15.710 (10) A, and ..beta.. = 105.17 (7)/sup 0/, rho/sub obsd/ = 1.57 g cm/sup -3/ (rho/sub calcd/ = 1.58 g cm/sup -3/).« less