Complexation of uranium(VI) with glycerol 1-phosphate

The complex formation of uranium(VI) with glycerol 1-phosphate was determined by potentiometric titration, UV-vis and TRLFS spectroscopy. Three complexes were found by potentiometry in the pH range 3 - 8, and the stability constants were calculated for I = 0.1 M: 1 : 1 complex UO₂(C₃H₇O₃PO₃) (log beta₁₁ = 6.23 ± 0.09); 1 : 2 complex UO₂(C₃H₇O₃PO₃)₂ ^2- (log beta₁₂ = 10.22 ± 0.13); 2 : 3 complex (UO₂)₂(C₃H₇O₃PO₃)₃ ^2- (log beta₂₃ = 20.28 ± 0.03). The UV-vis spectra at pH 2 to 4 show an increase of the absorption intensity with increasing ligand concentration, connected with a red shift of the main absorption bands. The three complexes could be isolated by deconvolution of the measured spectra and the stability constants were determined (at I = 0.5 M) to be: log beta₁₁ = 6.15 ± 0.20, log beta₁₂ = 10.38 ± 0.39, and log beta₂₃ = 19.34 ± 0.65. The TRLFS spectra at pH = 4 show also an increase of the fluorescence intensity connected with a red shift of the emission spectra. But contrary to the both above mentioned methods only the 1 : 1 complex UO₂(C₃H₇O₃PO₃) could be detected under the specific experimental conditions. The main fluorescence emission bands and the lifetime of this complex were determined. The complex stability constant at I = 0.1 M was calculated to be log beta₁₁ = 6.15 ± 0.05.