Luminescence-Decay as an Easy-to-Use Tool for the Study of Lanthanide-Containing Catalysts in Aqueous Solutions

Luminescence-decay measurements were studied as a simple and fast technique to determine inner-sphere water coordination numbers of Ln(III)-based complexes in binary solvent systems that are useful for catalysis. The luminescence-decay rates of Eu(III)-containing complexes were used to elucidate the coordination environment of Eu(III) in these solvent systems. Our findings were used to empirically derive easy-to-use equations to determine the average number of inner-sphere water and solvent molecules in binary aqueous solvent systems. The increased knowledge of the inner-sphere coordination environment of catalysts that our equations enable can be used to study lanthanide-catalyzed reactions and new precatalysts.