"Turn-On" Fluorescent and Colorimetric Detection of Zn 2+ Ions by Rhodamine-Cinnamaldehyde Derivative

• Published in: Journal of nanoscience and nanotechnology Vol. 18; no. 8; p. 5333
• Main Authors: Lee, Sang-Oh, An, Kyoung-Lyong, Shin, Seung-Rim, Jun, Kun, Naveen, Mergu, Son, Young-A
• Format: Journal Article
• Language: English
• Published: United States 01.08.2018
• ISSN: 1533-4880
• DOI: 10.1166/jnn.2018.15380

We report the design and synthesis of a novel chemosensor (Rh6G-Cin) rhodamine-based indicator for selective detection of Zn2+ ion. Rh6G-Cin displayed high selectivity towards Zn2+ from various metal ions, including Ca2+, Ag+, Cd2+, Co2+, Cu2+, Al3+, Zn2+, Cr3+, Ba2+, Fe2+, Fe3+, Gd3+, Hg2+, Mg2+, Mn2+, Nd3+, Pb2+, Sr2+ and Ni2+, and the resultant complex is [Rh6G-Cin-Zn2+]. The obvious change from colorless to pink upon the addition of Zn2+ could make it a suitable "naked eye" indicator for Zn2+. More significantly, the sensor displayed a remarkable colorless to yellowish green fluorescence switch in the presence of Zn2+ ions. The ring-opening mechanism of the rhodamine spirolactam was induced by Zn2+ binding, and the 3:1 stoichiometric structure between Rh6G-Cin and Zn2+ was adequately supported by the Job's plot evaluation, optical titration and 1H NMR results.