Does Charge Influence the Response in Oxyanion Binding Europium(III) Complexes?

Through the synthesis of a positively charged europium complex, with a structure derived from the DO2A (1, 4, 7, 10-tetraazacyclododecane-1, 7-diacetic acid), we were able to explore the influence of charge on the interaction between coordinatively unsaturated lanthanide complexes and charged oxyanions. The data suggest that the positive charge of the lanthanide host does not allow better selectivity between the differently and negatively charged oxyanion guests. Although, binding constants seem greatly improved with charge for the alpha-hydroxycarboxylates investigated here.