Luminescence and Stability of 1,4,5‐Triaryl‐1,2,3‐Triazoles

Abstract

AbstractThe fluorescence, phosphorescence, and photochemical properties of di‐ and triaryl‐substituted‐1,2,3‐triazoles are reported in this work. The ease of synthesis of regioisomers of substituted triazoles enables a systematic study on the correlation between regiochemistry and excited state properties, which include the solvent dependence of fluorescence, energy gap between singlet and triplet emitters, and propensity to photon‐triggered transformations. The triazoles that carry electron (e)‐donor and e‐acceptor aryl substituents show high fluorescence quantum yields in weakly polar solvents and exhibit solvent‐dependent fluorescence. The luminescence properties of these compounds in glass matrices at 77 K are characterized. The thermal and photo‐stability, two parameters that are crucial to their potential utilities in optical devices, of these compounds are determined. The position of the e‐donor substituent has a significant impact on the fluorescence emission energy and solvent sensitivity, singlet‐triplet energy gap, and photochemical reactivity and stability. The experimental observations on the structural correlation with the photophysical and photochemical properties are explained by quantum chemical calculations. This study provides a rationale on the placement of substituent on a donor‐acceptor type fluorophore to maneuver a range of photo‐related properties.