Synthesis and crystal structures of two new uranyl coordination compounds obtained in aqueous solutions of 1-butyl-2,3-dimethylimidazolium chloride

Two new uranyl coordination compounds, [C9H17N2](3)[(UO2)(2)(CrO4)(2)Cl-2(H2O)(2)]Cl5H(2)O (1) and (C9H17N2)[(UO2)(C2O4)Cl] (2), have been synthesized by adding potassium dichromate (K2Cr2O7) or oxalic acid dihydrate (H(2)C(2)O(4)2H(2)O) solution into an aqueous solution of uranyl nitrate and 1-butyl-2,3-dimethylimidazolium chloride [Bmmim]Cl. [Bmmim]Cl provides the charge balance and Cl ions that coordinate with uranyl ions. The fundamental building units of 1 and 2 are UO6Cl pentagonal bipyramidal structures. Compound 1 exhibits a graphene-like structure with a system molar ratio of 1:1 for U:Cr and crystallizes in the orthorhombic space group Pbca, with a=25.644(3) angstrom, b=12.996(14) angstrom and c=29.198(4) angstrom. 16-Membered rings are formed by CrO42- and UO22+ in the crystal structure of 1. Compound 2 crystallizes in monoclinic space group P2(1)/n, with a=10.759(3) angstrom, b=11.395(3) angstrom, c=14.149(4) angstrom, =102.962(9)degrees and shows one-dimensional (1D) serrated chains. Within the crystal structures of 1 and 2, C-H[Bmmim]ClO hydrogen bonds are identified. O-HwaterCl hydrogen bonds are also detected in the crystal structure for 1.