A highly selective Cd2+ sensor of naphthyridine: fluorescent enhancement and red-shift by the synergistic action of forming binuclear complex

A series of new fluorophore derivatives from 1,8-naphthyridine have been developed. Compound D1 is the first naphthyridine PET sensor that can signal Cd2+ selectively with fluorescent enhancement and red-shift. A binuclear metal complex structure has been demonstrated in the D1-Cd2+ complex.