Efficient synthesis and photophysical properties of some salophens to produce optical chemosensors for the analysis of transition metal ions

Abstract

Salen-type Schiff base ligands with big π-conjugated systems usually exhibit strong UV-Vis absorption and fluorescence with or without metal ions, and there are many reports on the salen-type optical chemosensors for the analysis of metal ions, such as Zn²⁺, Cu²⁺, Hg²⁺. In this study, salophen-type ligands derived from 1,2-phenylenediamine and 5-substituted salicylaldehydes were prepared efficiently using ultrasounds. These ligands were characterised by specific spectroscopies including NMR, IR and ESI-MS, and their photophysical properties of UV-Vis absorption and fluorescence were determined as well. The salophen ligands can be used as highly selective and sensitive chemosensors for the detection of some transition metal ions such as Hg²⁺, Cu²⁺, Zn²⁺ hopefully