Red light initiated azo bond reduction with perylene-3,4,9,10-tetracarboxylic dianhydride radical anions

Due to the high bond energy and stability of N = N double bond, their reduction using low-energy visible light remains a great challenge. We herein present the development and application of a novel perylene-3,4,9,10-tetracarboxylic dianhydride-based photocatalyst, which generates anionic radicals in situ upon reduction by vitamin C and demonstrates significant red light catalytic capabilities. The catalyst effectively reduced azo bonds under red light, yielding various substituted azobenzenes with moderate to good efficiency. Additionally, it facilitated the dehalogenation of bromoacetophenone, highlighting its potential in small-molecule pharmaceutical synthesis and pre-drug design. The findings indicate that red light-activated photocatalysis can offer a versatile and efficient approach for complex organic transformations, addressing challenges in bio-optical window applications and expanding the toolkit for synthetic chemistry and biomedicine.