A fluorescent chemosensor for transition-metal ions based on optically active polybinaphthyl and 2,2′-bipyridine

The linear conjugated polymer based on the 5,5'-positions of chiral 1,1'-binaphthyl shows strong green-blue fluorescence with high fluorescence quantum efficiency due to the extended pi-electronic structure between the chiral repeating unit and the 2,2'-bipyridyl conjugated linker unit. Cu2+ and Ni2+ can form non-radiative metal-to-ligand charge-transfer complexes with the polymer, and Co2+, Mn2+, Cd2+, Zn2+, Fe2+ can cause effective fluorescent quenching, which can be attributed to an energy transfer from the pi-conjugated chiral polymer to the metal complexes. A better understanding of energy-transfer processes in the polymers can provide information for the design of more sensitive materials.