Single-molecule chemistry [1] has progressed together with the development of scanning probe microscopy and its related methods. Scanning tunneling microscopy (STM) has been widely used for the observation and control of configurational changes and reactions for individual molecules on surfaces. As a complemental method, noncontact atomic force microscopy (ncAFM) also provides superior insights into chemistry at the single-atom/molecule level; ncAFM with a molecule/atom-functionalized tips visualizes atomic structures of organic molecules [2], and interatomic force measurements clarify the mechanisms of tip-induced configurational changes [3].
With ncAFM, we demonstrated ultrahigh spatial resolution imaging of on-surface-synthesized organic molecules [4] and hydrogen-bonding networks of water monolayers [5]. Furthermore, we established an “ON-OFF-ON” toggle switch of a single nitric oxide molecule, which can be controlled by functionalized tips [6]. In this talk, I report on these ncAFM studies and a recent study of chemical reaction of a single molecule induced by a metal tip.

[1]     W. Ho, J. Chem. Phys. 117, 11033 (2002)
[2]     L. Gross et al., Science 325, 1110 (2009).
[3]     J. N. Ladenthin et al., Nat. Chem. 8, 935 (2016).
[4]     A. Shiotari and Y. Sugimoto, Nat. Commun. 8, 16089 (2017).
[5]     A. Shiotari et al., Nat. Commun. 8, 14313 (2017).
[6]     A. Shiotari, T. Odani, and Y. Sugimto, Phys. Rev. Lett. 121, 116101 (2018).