URANIUM(IV) COMPLEXES WITH THE OXYGEN TRIPOD LIGAND L- = CPCO[P(O)(OET)2]3- - X-RAY CRYSTAL-STRUCTURE OF L2UCL2

Reaction of UX4 with NaL (L = (C5H5)Co[P(O)(OEt)2]3) gave the complexes LUX3 (X = BH4 (1), Cl (2)). The trichloride 2 reacted with NaL or TiCp (Cp = C5H5) to afford respectively the compounds L2UCl2 (3) and LCpUCl2 (4). Crystals of 3 belong to space group P21/c. The unit cell has a = 13.229 (4) angstrom, b = 20.011 (2) angstrom, c = 21.080 (1) angstrom, beta = 103.97 (3)-degrees, V = 5415 (3) angstrom 3 and contains four molecules. For the 2321 independent reflections with I > 3-sigma(I), the final conventional and weighted discrepency factors are 0.052 and 0.054, respectively. The geometry of the UO6Cl2 core is intermediate between a bicapped trigonal prism and a square antiprism. The average U-Cl distance is 2.728 (8) angstrom, and the average U-O distance is 2.36 (5) angstrom.