Large polycyclic aromatic hydrocarbons (PAHs), the so-called nanographenes, are attractive materials for the creation of two-and/or three-dimensional (2D and/or 3D) thin films. However, they exhibit no solubilities in organic solvents and water. To overcome this issue, in the present study, we employed water-soluble micellar capsules consisting of V-shaped amphiphilic molecules. Characteristic dicoronylene and C96H30 adlayers were successfully prepared on Au(111) using the water-soluble micellar capsules. The details on the adlayer structures were clearly revealed by scanning tunneling microscopy imaging with molecular resolutions. The result indicates that our molecular containers method based on the water-soluble micellar capsules can apply to form larger PAH adlayers.

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Carbon materials such as graphene have been extensively studied for their application in electronic devices,electrocatalysis, and sensors. In contrast, polycyclic aromatic hydrocarbons (PAHs), the so-called nanographenes, are excellent materials for the creation of two-dimensional (2D) nanosheets.[1] The formation of adlayers on electrode surfaces is challenging because PAHs without peripheral substituents are used as 2D molecular templates and applications in conductance enhancement and organic field-effect transistors.[2] However, large PAHs tend to exhibit poor or no solubilities in organic solvents and water. To overcome this issue, in this study, we employed water-soluble micellar capsules consisting of V-shaped amphiphilic molecules. Characteristic electrochemical behaviors were observed in 0.1 M H2SO4 in the presence of the water-soluble capsules containing PAHs such as dicoronylene. Furthermore, under these conditions, PAHs were released from the capsules, resulting in the formation of a 2D adlayer of PAHs at the electrochemical interface. Finally, using electrochemical scanning tunneling microscopy (EC-STM), we demonstrate that our molecular containers based on the water-soluble molecular capsules allow the facile preparation of 2D PAH adlayers in addition to structurally controlling nanostructure formation on Au surfaces.In particular, dicoronylene molecules formed a highly ordered adlayer with c(4 x 8√3)rect adlattice.[3] References: [1] J. Wu, W. Pisula, K. Müllen, Chem. Rev. 2007, 107, 718. [2] L. Zhang, Y. Cao, N. S. Colella, Y. Liang, J.-L. Brédas, K. N. Houk, A. L. Briseno, Acc. Chem. Res. 2015, 48, 500. [3] S. Origuchi, M. Kishimoto, M. Yoshizawa, S. Yoshimoto, Angew. Chem., Int. Ed. 2018, 57, 15481.