Precipitation of a dioxouranium(VI) species from a room temperature ionic liquid medium

The novel complex 1-butyl-3-methylimidazolium mu4-(O,O,O',O'-ethane- 1,2-dioato)-bis[bis(nitrato-O,O)dioxouranate(VI)] (1) has been precipitated from a room-temperature ionic liquid medium containing 1-butyl-3-methylimidazolium nitrate, nitric acid, and acetone. X-ray analysis of complex 1 shows the unit cell contains four [C(4)mim](+) cations and two independent [{(UO2)(NO2)(2)}(2)-(mu(4)-C2O4)](2-) moieties, both of which are located about inversion centers. The [C(4)mim](+) cations are arranged such that they produce large channels in which the anions are located. This arrangement of [{ (UO2)(NO3)(2)}(2*)(mu-C2O4)](2-) groups is unique to this compound, Crystal data for compound 1: M = 1154,56, monoclinic, space group P2(1)/c, a = 15.452(2) Angstrom, b = 20.354(3) Angstrom, c = 10.822(4) Angstrom,beta = 106.84(2)degrees, U = 3258(1) Angstrom(-3), Z = 4, mu = 10.023 mm(-1), R-int = 0.0788.