Over the years, we have paid attention to designing a series of organic molecules acting chromo and fluorogenic behaviors for specific target ions. A novel coumarin-based fluorogenic probe bearing the 2-picolyl unit was developed as a fluorescent chemosensor with high selectivity and suitable affinity in biological system toward Cu2+ over other cations tested. The fluorescence on-off mechanism was studied by femtosecond time-resolved fluorescence (TRF) upconversion technique and ab initio calculations. The receptor can be applied to the monitoring of Cu2+ ion in aqueous solution with a pH span 4-10. To confirm the suitability of the ligand for biological applications, we also employed it for the fluorescence detection of the changes of intracellular Cu2+ in cultured cells. The results indicate that the ligand should be useful for the fluorescence microscopic imaging and the study on the biological functions of Cu2+.
The electrochemiluminescence (ECL) efficiency and radical stability of pyrene, a poor ECL luminophore, are markedly improved as the number of peripheral multidonor units increased in a series of compounds. Photophysical and electrochemical studies and theoretical calculations have contributed to the understanding of the ECL enhancement, which is a step forward in the development of new light-emitting materials.