Chirality generation on carbon nanosheets by chemical modification.

Chirality is an intriguing property of molecules, and an exciting area of study involves the generation of chirality in nanographenes (NGs), also known as graphene quantum dots. Unlike those synthesized through stepwise carbon-carbon bond formation by organic reactions (bottom-up method), NGs obtained by cutting parent carbons (top-down method) pose challenges in precisely regulating their three-dimensional structures by post-synthesis. This includes the incorporation of non-hexagonal rings and helicene-like structures in carbon frameworks.

Intermediate Color Emission via Nanographenes with Organic Fluorophores.

Photoluminescence (PL) color can be tuned by mixing fluorophores emitting the three primary colors in an appropriate ratio. When color tuning is achieved on a single substrate, we can simplify device structures. We demonstrated that nanographenes (NGs), which are graphene fragments with a size of tens of nanometers, could be utilized as carriers of fluorophores.

Induction of Chirality on Nanographenes.

Chirality induction is an important topic in studies of nanographenes (NGs). We report chirality enhancements of NGs through postsynthetic chemical modifications of NGs with pyrene and m-terphenyl groups. These substituents were installed into N-(p-bromophenylethyl)imides on the edges of the NGs with Pd-catalyzed cross-coupling reactions.