Affiliation:
1. Department of Applied Chemistry, School of Engineering Tokyo University of Technology Hachioji Tokyo Japan
2. Research Center for Advanced Lignin‐based Materials Tokyo University of Technology Hachioji Japan
3. San Apro Ltd. Kyoto Japan
Abstract
AbstractDiaryliodonium salts (Ar2I+X−) are used as a photosensitive initiator that generates acid or radical species by ultraviolet light irradiation. Recently, sensitization of Ar2I+X− has gained importance owing to the escalating demand for high‐sensitive initiators with longer wavelength absorption such as 365 and 436 nm. However, the mechanism of photolysis of Ar2I+X− has not been strictly elucidated. This paper shows discussions of the details of its mechanism. Herein, we analyzed the photosensitization of Ar2I+X− with 2–isopropylthioxanthone (ITX) based on transient absorption techniques. As a result, it was revealed that electron transfer occurred from a triplet excited state of ITX to Ar2I+X− with an electron transfer rate constant of 4.2 × 109 s−1. Furthermore, high performance liquid chromatography measurements found the quantum yield of the photolysis was determined to be 0.48.