A structural and spectrophotometric study on the complexation of Am(III) with TMOGA in comparison with the extracted complex of DMDOOGA

作者：Tian Guoxin^*; Shuh David K; Beavers Christine M; Teat Simon J

来源：Dalton Transactions, 2015, 44(42): 18469-18474.

DOI：10.1039/c4dt02882a

Complexation of Am(III) with tetramethyl-3-oxa-glutaramide (TMOGA, L-I) is studied by spectrophotometric titrations and single crystal X-ray diffraction. Three successive complex species, [AmLI](3+), [AmL2I](3+), and [AmL3I](3+), have been identified and their stability constants are calculated to be 3.71 +/- 0.012, 5.95 +/- 0.021, and 6.93 +/- 0.034 respectively, from the absorption spectra collected from the titrations of Am(III) with LI at 25 degrees C in 1 M NaNO3. Single crystals of AmL3I(ClO4)(3) have been grown from a HClO4 solution containing Am3+ and L-I. The crystal structure of AmL3I(ClO4)(3) shows that Am(III) is coordinated by nine oxygen atoms from three L-I ligands. The deconvoluted UV-Vis absorption spectrum of [AmL3I](3+) in aqueous solution is nearly identical to the diffusion reflectance spectrum of AmL3I(ClO4)(3) in the solid state, indicating that the coordination geometry of the complexes is nearly the same. In addition, to provide parallels to solvent exaction, the extracted Am(III) complex with N,N'-dimethyl-N,N'-dioctyl-3-oxa-glutaramide (DMDOOGA, L-II) is also prepared and studied using spectrophotometry. The similarity in UV-Vis absorption of the extracted complex of Am(III) with L-II and [AmL3I](3+) suggests that the Am(III) ion is also coordinated by three tridentate L-II ligands existing as [AmL3II](3+) in the organic phase of solvent extraction.

• 出版日期2015
• 单位中国原子能科学研究院