Synthesis of a Phenazine-Based 1,2,3-Triazole from Naturally Occurring Naphthoquinone Designed as a Probe for Cd2+ Ions

The synthesis of a phenazine‐based 1,2,3‐triazole luminescent probe was successfully accomplished from the available natural product lapachol, which was easily extracted from the heartwood of Tabebuia sp. (Tecoma). Photophysics and fluorescence studies were conducted by using the probe in the presence of metal ions (Cd2+, Ca2+, Co2+, Cu2+, Fe3+, Hg2+, Mg2+, Na+, Ni2+, Ag+, Pb2+, Zr2+, and Zn2+ as their chloride salts with the exceptions of silver and lead that were used as acetates). The probe was able to detect Cd2+ ions in H2O/CH3CN (8.5:1.5 v/v) medium. Studies performed with the sensor in a solution of cadmium chloride resulted in a green color after ultraviolet excitation, but for most metals blue color was observed, which could be detected by the naked eye. This is the first report of a lapachol, an accessible naphthoquinoidal compound, having been used to prepare a probe to detect the heavy metal cadmium. In this study, the synthesis of a phenazine luminescent probe obtained from the natural product lapachol is described. The compound is modified through click chemistry to generate a binding site for Cd2+ ions. Photophysics and fluorescence studies are conducted to prove the efficiency of this sensor.