New Principle for Simple Water Detection using Fluorescence Lifetime Triangulenium Probes

The fluorescence of phenol-substituted ADOTA triangulenium fluorophores is quenched as function of the water content in acetonitrile. We investigate three phenol-ADOTA derivatives in various solvent mixtures and conclude that water acts as a dynamic quencher by serving as a proton acceptor in a proton coupled electron transfer reaction with the excited ADOTA. Beyond the mechanistic insights into this quenching mechanism we demonstrate how these ADOTA dyes can probe the water content from a simple calibration free single-point measurement of the fluorescence lifetime. Three phenol-ADOTA derivatives were investigated regarding their sensing of water in acetonitrile using their fluorescence lifetime as a calibration free readout. Water promotes dynamic quenching by acting as proton acceptor in a proton coupled electron transfer (PCET) reaction with the excited phenol-ADOTA fluorophore.image

Automated summary

The fluorescence of phenol-substituted ADOTA triangulenium fluorophores is quenched as the water content in acetonitrile increases. The study reveals that water acts as a dynamic quencher by serving as a proton acceptor in a proton coupled electron transfer reaction with the excited ADOTA. Additionally, the ADOTA dyes can be used to probe water content by measuring the fluorescence lifetime.