A Direct S<sub>0</sub>→T<sub><i>n</i></sub> Transition in the Photoreaction of Heavy‐Atom‐Containing Molecules
Masaya Nakajima, Sho Nagasawa, Koki Matsumoto, Takahito Kuribara, Atsuya Muranaka, Masanobu Uchiyama, Tetsuhiro Nemoto
Abstract
Abstract According to the Grotthuss–Draper law, light must be absorbed by a substrate to initiate a photoreaction. There have been several reports, however, on the promotion of photoreactions using hypervalent iodine during irradiation with light from a non‐absorbing region. This contradiction gave rise to a mystery regarding photoreactions involving hypervalent iodine. We demonstrated that the photoactivation of hypervalent iodine with light from the apparently non‐absorbing region proceeds via a direct S 0 →T n transition, which has been considered a forbidden process. Spectroscopic, computational, and synthetic experimental results support this conclusion. Moreover, the photoactivation mode could be extended to monovalent iodine and bromine, as well as bismuth(III)‐containing molecules, providing new possibilities for studying photoreactions that involve heavy‐atom‐containing molecules.