Organosulfur compounds are not only easy to obtain and prepare, but also have very unique properties that allow multiple oxidation states. Among the wide variety of organosulfur compounds, we have focused on sulfone compounds and have been developing molecular transformations. The sulfonyl group is an interesting functional group that has both strong electron-withdrawing and desorbing properties, but methods to convert the carbonsulfonyl bond, which has poor reactivity, are still limited. Therefore, we are developing metal catalysts, organometallic reagents, and unique molecular designs of sulfonyl groups to establish sequential functionalization methods on sp3 carbons by α-functionalization and carbonsulfonyl bond activation. In fact, we have succeeded in developing a rapid and flexible method for the synthesis of various arylmethane derivatives (Angew. Chem. Int. Ed. 2014; J. Am. Chem. Soc. 2018; Nature Commun. 2019; Chem. Sci.. 2021). In the future, we would like to propose new strategies for the synthesis of molecules utilizing the characteristics of sulfones.

Metal nanoparticles and nanoclusters are known to exhibit unique physical properties and reactivity that are very different from those of bulk metals and metal complexes, and they are one of the nanomaterials that have attracted attention in recent years. Many metal nanomaterials with thiol or phosphine ligands have been reported so far. Our group has been working on the synthesis of stable gold nanomaterials by using N-heterocyclic carbenes (NHCs) as ligands, which can strongly bind to metals. For example, we have found that gold nanoparticles can be synthesized by reduction or ligand exchange of NHC-gold complexes (Angew. Chem. Int. Ed. 2017; J. Am. Chem. Soc. 2018). Recently, we have also succeeded in synthesizing various gold nanoclusters by molecular design of NHC ligands (Nature Chem. 2019; J. Am. Chem. Soc. 2019; Chem Sci. 2021). In parallel, we are investigating the functions of the synthesized metal nanomaterials as catalysts and luminescent materials.

In recent years, science based on "light," as represented by photocatalysts and light-emitting materials, has made remarkable progress. Light enables chemical reactions to proceed that are impossible with heating, and it also enables spatiotemporal activation of molecules by controlling the position and time of irradiation. We are challenging to develop new molecular transformation reactions by utilizing light. In addition, we are collaborating with biologists to apply the developed technology as a molecular tool for elucidating biological phenomena.