Inorganic Chemistry, Vol.51, No.13, 7185-7191, 2012
(UO2)(2)[UO4(trz)(2)](OH)(2): A U(VI) Coordination Intermediate between a Tetraoxido Core and a Uranyl Ion with Cation-Cation Interactions
A uranyl triazole (UO2)(2)[UO4(trz)(2)](OH)(2) (1) (trz = 1,2,4-triazole) was prepared using a mild solvothermal reaction of uranyl acetate with 1,2,4-triazole. Single-crystal X-ray diffraction analysis of 1 revealed it contains sheets of uranium-oxygen polyhedra and that one of the U(VI) cations is in an unusual coordination polyhedron that is intermediate between a tetraoxido core and a uranyl ion. This U(VI) cation also forms cation-cation interactions (CCIs). Infrared, Raman, and XPS spectra are provided, together with a thermogravimetric analysis that demonstrates breakdown of the compound above 300 degrees C. The UV-vis-NIR spectrum of 1 is compared to those of another compound that has a range of U(VI) coordination enviromments.