Abstract Dr. Kawai, a leader of Nanoprobe group, Center for Basic Research on Materials, NIMS is working in the field of scanning probe microscopy, specially focusing on on-surface chemistry with high-resolution imaging. He received a PhD degree from the University of Tokyo in 2005, and worked in EMPA and University of Basel, Switzerland for almost 10 years. He came back to Japan as a NIMS principal researcher in 2016 and was then promoted to be a group leader and also an associate professor in Tsukuba University in 2020. From 2013 to 2017, he conducted JST-PRESTO in a session of Molecular Technology (Chair. Prof. Kato). So far, he has published more than 110 articles, including Science, Science Advances, Nature Chemistry, Nature Synthesis, and Nature Communications. His achievement led to the Awards of the MEXT Young Scientist’s Prize, the Kazato Prize, the FY2019 JSPS Prize, and Kao Prize.27Fig. 2. Bond-resolved image of silabenzene incorporated covalent organic frameworks[4].On-surface Synthesis Studied with High-resolution Scanning Probe Microscopy Shigeki Kawai Since the invention of scanning tunnelling microscopy and atomic force microscopy, it has been explored single atoms and molecules in detail. Particularly, combining with bond-resolved scanning probe microscopy,[1] the field of on-surface synthesis has been rapidly developed.Here, we present our recent activities about syntheses of nanocarbon structures and tip-induced manipulations of single molecules with low-temperature scanning probe microscopy. We synthesized three-dimensional organometallic compound and graphene nanoribbon by homo-coupling hexabromo substituted-propellane molecules on Au(111) and Ag(111).[2] In the structure, the C-Br bonds distant from the substrate remained intact even after the reaction. The radical species were formed by tip-induced debromination and were subsequently stabilized by either tip-manipulated Br atom or fullerene molecule. Systematic tip-induced isomerization among two chiral dehydroazulene and diradical units was demonstrated as embedding ascii texts of “NIMS” (Figure1).[3] We found that the diradical unit has the spin coupling of 90 meV. For heteroatom substitution, we presented on-surface syntheses of graphene nanoribbon and covalent organic frameworks with silabenzene units (Figure2).[4] The heavier congeners of cyclic aromatic compounds have been studied as an elusive target product for organic synthesis due to their high reactivity at ambient temperature and difficult isolation, but now became achievable.Group Leader / Nanoprobe Group / CBRM NIMS Talk: S1-4Fig. 1 Systematic local probe isomerization of azulene unit on 3D-OMC. “Nanoprobe GRP. NIMS©” in 8-bit binary ascii code is embedded via sequential 71 isomerization[3].[1] Gross, F. Mohn, N. Moll, P. Lilkeroth, G. Meyer, Science 325, 1110 (2009)[2] S. Kawai, et al Sci. Adv. 6, eaay8913 (2020).[3] S. Kawai, et al Nat. Commun. 14, 7741 (2023).[4] K. Sun et al, Nat. Chem. 15, 136 (2023).
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