MACROCYCLE COMPLEXATION CHEMISTRY .37. THE ISOLATION AND CRYSTALLOGRAPHIC CHARACTERIZATION OF THE U4+ AND UO-2(2+) EXTRACTION COMPLEXES [(H5O2)(DICYCLOHEXANO-24-CROWN-8)]2 [UO2CL4].MEOH AND [(H5O2) (DICYCLOHEXANO-24-CROWN-8)]2 [UCL6].MEOH

The reaction of dicyclohexano-24-crown-8 with UCl4 in 3/1 THF:MeOH under anhydrous conditions and with exposure to air, resulted in the isolation of the hydronium ion complexes, [(H5O2)(dicyclohexano-24-crown-8)]2[UO2Cl4].MeOH and [(H5O2)(dicyclohexano-24-crown-8)]2[UCl6].MeOH. The [UO2Cl4]2- complex crystallizes in the monoclinic space group, P2(1)/n, with a = 15.200(8), b = 26.565(9), c = 16.977(8) angstrom, beta = 95.89(6)-degrees and D(calc) = 1.40 g cm-3 for Z = 4 formula units. A final R value of 0.051 was obtained utilizing 5913 independent observed [F(o) greater-than-or-equal-to 5-sigma(F(o))] reflections. One ether is complexed by an ordered H5O2+ ion, while the second crown ether is hydrogen bonded to a disordered H5O2+ ion. The [UCl6]2- complex is tetragonal, P4/n, with (at -150-degrees-C) a = 16.320(4), c = 12.542(2) angstrom and D(calc) = 1.47 g cm-3 for Z = 2. A final R value of 0.038 was obtained utilizing 2466 observed reflections. The anion resides on a four-fold axis and the crown ether cation around a crystallographic two-fold axis. The H5O2+ ion is disordered into two orientations within the macrocycle cavity. All three crystallographically independent crown ether environments in these two structures have essentially identical conformations.