Synthesis and electrochemical, linear and third-order nonlinear optical properties of ferrocene-based D-π-A dyes as novel photoredox catalysts in photopolymerization under visible LED irradiations

Abstract

Four ferrocene-based D-π-A dyes with effective intramolecular charge transfer (ICT) properties are designed and synthesized. These dyes can be used as new photoredox catalysts in free radical photopolymerization under soft blue and green LED irradiations. Different π-conjugation bridge molecules contained in the molecular structures have been shown to affect the photoreactivities of the synthesized dyes in the photoinitiating systems. The UV–Vis absorption, electrochemical, and third-order nonlinear optical properties are investigated. Experimental results are completed with theoretical calculations to gain further insight into the ICT of the dyes with different π-conjugation bridge molecules. A good correlation of the π-conjugation bridge molecule changes of the dyes with the experimental results is established.