Novel An Efficient Fluorescent Probe Based on Calix[4]triazacrown-5 With Naphthalimide Group for Co2+, Cd2+ and Dopamine Detection

A novel naphthalimide-substituted calix[4]triazacrown-5 (Nap-Calix) at cone conformation was designed and synthesized to employ as a fluorescent probe, which enables the simultaneously detection of Co2+ and Cd2+ metal ions as well as dopamine (DA). H-1-NMR, C-13-NMR, ESI-MS and elemental analysis techniques were carried out to characterize its structure. Cation binding property of Nap-Calix against various metal ions such as Ba2+, Co2+, Ni2+, Pb2+, Zn2+, and Cd2+ exhibited that the sensor selectively binds to Co2+ and Cd2+ metal ions with a remarkable affinity. Introduction of Co2+ and Cd2+ metal ions to a solution of Nap-Calix in DMF/water (1:1, v/v) resulted with a new emission band at 370 nm when excited at 283 nm. In addition, the fluorescence sensing affinity of the probe Nap-Calix against a catecholamine neurotransmitter (dopamine) was investigated in a wide range of concentration of DA (0-0.1 mmol L-1) in 50% DMF/PBS (pH = 5.0). The fluorescence intensity of Nap-Calix, with excitation/emission peaks at 283/327 nm, is highly enhanced by DA. It was also observed that Nap-Calix exhibits excellent fluorescence behavior towards DA with a very low detection limit as 0.21 mu mol L-1.

Automated summary

A novel naphthalimide-substituted calix[4]triazacrown-5 (Nap-Calix) was designed and synthesized as a fluorescent probe for the simultaneous detection of Co2+, Cd2+, and dopamine (DA). The structure of Nap-Calix was characterized using various techniques including H-1-NMR, C-13-NMR, ESI-MS, and elemental analysis. The binding property of Nap-Calix towards various metal ions showed a selective affinity towards Co2+ and Cd2+ ions. Furthermore, Nap-Calix exhibited excellent fluorescence behavior towards dopamine with a very low detection limit of 0.21 µmol L-1.