NDI-BODIPY-graphene oxide nanosized photocatalysts for LED irradiated organic synthesis

Abstract

Rational design and synthesis of visible-light-absorbing triplet photosensitizers are of great importance for efficient and sustainable photocatalytic utilizations. Herein, we explored two distyryl-NDI-BODIPY systems (9 and 10) with strong visible-light-absorbing antennas and a bridging aromatic core to enable π–π interactions with graphene oxide (GO), resulting in NDI-BODIPY-GO nanocomposites (GO-9 and GO-10). The presence of iodine moieties on 10 empowered the formation of a long-lived triplet state for efficient singlet oxygen generation. The relaxation pathway of the heavy-atom-free system (9 and GO-9) did not permit efficient population of the triplet manifold, whereas the iodine-bearing compounds 10 and GO-10 nanocomposite exhibited good performance to generate singlet oxygen and could be applied effectively in the photocatalysis of 1,5-dihydroxynaphthalene (DHN) to juglone under mild conditions. The singlet oxygen quantum yield of 10 (Φ_Δ = 0.7) reached the value of 0.81 for GO-10, and the photooxidation of DHN to juglone with 10 was enhanced with the use of the GO-based nanocomposite.