Flavonol dyes with different substituents in photopolymerization

Abstract

To further expand the applications of flavonol dyes (3HFs) in photopolymerization, six flavonol dyes with different substituents were prepared by using the Algar–Flynn–Oyamada method. The steady-state photolysis and fluorescence quenching of 3HFs under the 385 nm LED light source showed that the proton transfer reaction preceded the charge transfer reaction between 3HFs and triethanolamine (TEOA) or iodonium salts (ONI), and groups with different electron properties could affect the photochemistry of 3HFs. The influence of substituents on the free radical polymerization efficiencies of 3HFs/TEOA and 3HFs/ONI was evaluated. Results showed that charge transfer occurred in the oxidation or reduction processes between 3HFs and TEOA or ONI. The possible mechanism was speculated, and the thermal feasibility of charge transfer between 3HFs and TEOA or ONI was calculated on the basis of the free energy changes of photoinduced electron transfer.