PNNL

Abstract

The complex [UO2(NO3)2(TMMA)] (TMMA = N,N,N',N'-tetramethymalonamide) was structurally characterized by single-crystal X-ray diffraction. The complex consists of two bindentate nitrate ions and one bidentate TMMA ligand coordinated to the UO22+ ion. The complex [UO2(THMA)2]2+ (THMA = N,N,N',N'-tetrahexylmalonamide) was prepared as the BF4- salt; this material tended to form an oil. However, [UO2(TMMA)2]( OTf)2 (OTf = triflate) was isolated as a crystalline solid. Comparison of the Fourier transform infrared spectra of these complexes to the spectra of complexes formed in liquid-liquid extraction systems supports the hypothesis that complexes of the type [UO2(NO3)2L] and [UO2L2](NO3)2 (L = diamide extractant) form in the extraction systems.