Two-Dimensional van der Waals Supramolecular Frameworks from Co-Hosted Molecular Assembly and C₆₀ Dimerization

Abstract

A two-dimensional van der Waals supramolecular framework is created by self-assembled cocrystallization of C 60 and octanethiol molecules on the Au(111) surfaces. The framework is characterized by the two-dimensional C 60 network, in which the pores are filled by RS-Au-SR (R = CH 3 (CH 2 ) 7 S) staples. The framework is stabilized by cooperative interactions involving collective self-assembly instead of the commonly observed pairwise interactions between the nearest neighbors. The pairing of two adjacent C 60 molecules and the formation of C 60 dimer are visualized by low temperature scanning tunneling microscopic imaging, in conjunction with first-principles calculations, suggesting a charge transfer in each C 60 dimer. Such van der Waals C 60 supramolecular framework with intermolecular charge transfer, serving a rare example in artificial 2D molecular crystal for inert C 60 molecules, is very promising in applications of optics and devices.

Complex supramolecular tessellations with on-surface self-synthesized C60 tiles through van der Waals interaction

“…In a previous study, we observed the formation of porous C60 frameworks with OT filling the pores. 17 The C60/OT ratio can be changed by heating the sample up. The desorption temperature of OT is more than 200 K lower than that for C60, hence the coverage of OT can be reduced by gentle heating the sample with little effect on the coverage of C60.…”

“…In this image, one can see three distinct structures. i) Porous C60/OT framework 17 which occupies about 80% of the surface. ii) Pure striped phase of OT exhibiting parallel rows.…”

“…The OT rows in the stripped phase are known to align in the [112 ̅ ] direction. 17 Using the OT row as a reference, the azimuthal orientation of the (C60)7 clusters can be determined. As shown in Fig.…”

“…By comparison, multicomponent systems are more versatile for creating more complex supramolecular tessellations. 1,[13][14][15][16] Effects of spatial confinement and molecular crowding between different kinds of components can prevent molecules, especially for the molecules without specific functional groups, from forming close-packed arrangement 17,18 and hence facilitate the formation of various supramolecular structures. Meanwhile, the aggregation of various numbers of molecules into clusters can be exploited as means of on-surface synthesis of new tiles.…”

Zero-to-Two Nanoarchitectonics: Fabrication of Two-Dimensional Materials from Zero-Dimensional Fullerene

“…The shapes of grown frameworks should be mainly influenced by the van der Waals interactions between the alkane chain and the C60 molecules. Gao, Pan, Guo, and coworkers investigated a two-dimensional van der Waals supramolecular framework consisting of C 60 molecules and octane thiol molecules on the Au(111) substrate by self-assembled co-crystallization method [119]. The porous framework was a result of cooperative self-organization with the C 60 molecule and octane thiol as cohosts of the framework, in which the pores were filled by RS-Au-SR (R = CH 3 (CH 2 ) 7 S) staples.…”