A Fluorescent 18-Crown-6 Based Luminescence Sensor for Lanthanide Ions

The synthesis and photophysical behavior of a luminescent chemosensor for the early lanthanide elements is described. The sensor is a 1,4-diphenylethynyl-benzene chromophore having 18-crown-6 moieties bound to the outer phenyl rings. The chromophore is luminescent and the emission is quenched by lanthanide (Ln3+) ions with larger ionic radii and existing f–f transitions (Ce3+, Pr3+ and Nd3+). Alkali, alkaline earth ions and lanthanides with smaller radii (Ge3+, Tb3+, Dy3+, and Yb3+) do not affect the emission.