Spectrofluorometric study of thallium (I) complexes with several macrocyclic ligands in methanol solution

The fluorescent signal of T1(+) was employed as a sensitive probe to study the complexation reactions between this cation and several macrocyclic ligands in methanol solution at 20 degrees C. The stability constants of the resulting 1:1 complexes were determined and found to vary in the order C222 > C221 > 18C6 > DC18C6 > DB30C10 > DB18C6 > 15C5 > DA18C6 > B15C5 > DA15C5. The influence of a number of members in the macrocycle the nature of substituents on the polyether ring and of the dimensionality of the ligands on the stability and selectivity of the complexes is discussed.