Synthesis and ion detection studies of Schiff base derivatives

This study combines the structural advantages of Schiff base compounds with the excited-state intramolecular proton transfer (ESIPT) mechanism to develop photoactive molecular fluorescence probes. Three derivatives, 2-benzylaminophenol, 2-hydroxybenzylphenol, and 2-((2-hydroxybenzyl)amino)phenol, were synthesized and structurally confirmed by nuclear magnetic resonance (NMR) spectroscopy and X-ray crystal analysis. Their metal ion coordination behaviors and photophysical properties were systematically investigated using UV-Vis absorption and fluorescence spectroscopy. The results reveal that 2-benzylaminophenol functions as a dual-responsive fluorescent probe for Al3+/Fe3+, while 2-hydroxybenzylphenol demonstrates selective recognition of Al3+. Remarkably, 2-((2-hydroxybenzyl)amino)phenol exhibits an enhanced fluorescence response specifically toward Al3+. All probes display superior sensitivity and ion selectivity, underscoring their dual utility in trace-level metal ion detection and biomedical sensing applications. This work advances rational design principles of Schiff base-based fluorescent platforms, expanding their potential in environmental monitoring and precision biomedicine through tailored molecular recognition capabilities. KEY WORDS: Schiff base, ESIPT, Fluorescent probe, Metal ion Bull. Chem. Soc. Ethiop. 2026, 40(2), 283-295 DOI: https://dx.doi.org/10.4314/bcse.v40i2.2