3‐Hydroxypyridinyl‐Substituted‐1,2,4‐Triazoles as New ESIPT Based Fluorescent Dyes: Synthesis and Structure–Fluorescence Properties Correlations

This report presents the design, synthesis, and photophysical study of two new series promising fluorescent trisubstituted triazoles, 3-hydroxypyridinyl substituted-1,2,4-triazoles (PyOHTr) 2-pyridonyl (PyCOTr). An excited state intramolecular proton transfer (ESIPT) fluorescence mechanism is evidenced for PyOHTr molecules by ab initio theoretical calculations. These dyes possess unique optical properties such as large Stokes shifts, dual emission, solvatochromism, solid-state emission and, one them, a white light rendering them particularly attractive future applications in both medicinal chemistry materials science.