Solvation and complexation of europium(III) ions in triflate and chloride aqueous-organic solutions by TRLF spectroscopy

Solvation of europium ions in mixed aqueous-organic solvents was studied in the solutions of europium(III) triflate and chloride. Europium ions are preferentially solvated by organic solvent only in water-dimethylsulfoxide systems. In aqueous dimethylformamide and dimethylacetamide preferential hydration in water-deficient region was observed. The total solvation number was proved to decrease from 9 in neat water to 8 in neat dimethylsulfoxide and dimethylformamide and to 7 in neat dimethylacetamide. The formation of chlorocomplexes in neat water and aqueous dimethylacetamide was observed.