Radiation-induced macrocycle cleavage in crown ether complexes with Sr(II) and Y(III) chlorides: A comparative study

Abstract Macrocyclic 18-crown-6⋅SrCl2 and 18-crown-6⋅YCl3⋅4.25H2O complexes were synthesized, characterized by FTIR and DSC/TGA analysis and exposed to X-rays irradiation to study their resistance to polyether ring cleavage at early radiolysis stages by using EPR spectroscopy. Yttrium complex was found to be less stable in comparison with that of strontium as evidenced by a higher fraction of acyclic radicals resulted from the macrocycle destruction. An analysis of conformationally sensitive regions of FTIR spectra of 18-crown-6⋅YCl3⋅4.25H2O points to the strong distortion of the macrocycle symmetry that is one of the probable factors affecting the radiolytic cleavage of the polyether ring. The results obtained in the present study contribute to theoretical framework required to develop a radiation stable macrocyclic extractant for separation of the Sr/Y radionuclides.