Synthesis of novel 1,10-phenanthroline derivatives and it used as probes for sensitive detection of Zn2+ and Cd2+ metal ions - Spectroscopic and theoretical approach.

A novel class of unexpected 1,10-phenanthrolinederivatives were synthesized from 2,3-dihydroacridin-4(1H)-ones with 3-aminonaphthalen-2-carboxylic acid in presence of phosphorus oxychloride at 130°C and simple perceptive emission intensity increasing assay was developed effectively to detect the very low concentrations of Zn2+ and Cd2+ ions. Emission intensity of compounds 3(a-c) directly related to the concentrations of Zn2+ and Cd2+ ions was due to metal chelating enhanced fluorescence (CHEF) effect and also its further validated by fluorescence lifetime measurement. Furthermore, the sensing mechanism for compounds 3(a-c) of Zn2+ and Cd2+ were sustained by theoretical calculations. Computational analysis results reveals that compounds 3(a-c) are more interested in Zn2+ ions than that of Cd2+ ions, while, compound 3c is more interested with Zn2+ and Cd2+ ions than those of the rest of the compounds. In addition, this proposed detection analysis has the direct application for monitoring Zn2+ and Cd2+ concentrations in tap and drinking water samples.