A Structural study on uranyl (VI) nitrate complexes with cyclic amides; -butyl-2-pyrrolidone, -cyclohexylmethyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidone

Koshino, Nobuyoshi*; Harada, Masayuki*; Nogami, Masanobu*; Morita, Yasuji  ; Kikuchi, Toshiaki*; Ikeda, Yasuhisa*

Structural analyses of UO(NO)L [L=-butyl-2-pyrrolidone, N-cyclohexylmethyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidone] have been carried out using X-ray diffraction method. These uranyl complexes were found to have a hexagonal bipyramidal structure. The bond distances of U=O and U-O (ligand), and bond angles of U-O-C(carbonyl) are determined. In uranyl nitrate complexes with cyclic amides such as 2-pyrrolidone, urea, and caprolactam derivatives, a linear correlation was found to hold between U-O (ligand) bond distances and U-O-C(carbonyl) bond angles. Vibrational frequencies of UO(NO)L have also been measured by IR and Raman spectrophotometers. Using relationships between vibrational frequencies of O=U=O bonds and donor numbers (DNs) of ligands, donicities of N-substituted-2-pyrrolidones were determined.