A highly selective turn-on fluorescent chemosensor for copper(II) ion

A new pyrene derivative (1) containing a diaminomaleonitrile moiety exhibits high selectivity for Cu2+ detection. Significant fluorescence enhancement was observed with chemosensor 1 in the presence of Cu2+. However, the metal ions Ag+, Ca2+, Cd2+, Co2+, Fe2+, Fe3+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+, and Zn2+ produced only minor changes in fluorescence values for the system. The apparent association constant (Ka) of Cu2+ binding in chemosensor 1 was found to be 5.55×103 M−1. The maximum fluorescence enhancement caused by Cu2+ binding in chemosensor 1 was observed over the pH range 5–7.5.