Two-Dimensional Van Der Waals Supramolecular Frameworks From Co-Hosted Molecular Assembly And C-60 Dimerization

A two-dimensional van der Waals supramolecular frame-work 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 = CH3 (CH2)(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.