Fig. 2: Self-assembled BCPM network on Au(111).
From: Extending on-surface synthesis from 2D to 3D by cycloaddition with C60
a Scanning tunneling microscopy (STM) image of an extended network of BCPM on Au(111), where the unit mesh is marked by a white rhombus (Vs = –1250 mV, It = –0.27 nA). b Close-view STM image (left) of BCPM on Au(111) presenting the sub-molecular resolution, in good accordance with the density functional theory (DFT)-calculated image (right); the inset shows the morphology of a single BCPM superimposed by the BCPM structural model (Vs = + 1250 mV, It = +0.66 nA). c Top and side views of DFT-optimized structural model of a single BCPM on Au(111), presenting the flatly-adsorbed bis(carboxylic acid)-phenyl group and the tilted maleimide group. d DFT-optimized structure and (e) electron density difference map of BCPM network on Au(111) (the isosurface value is 0.01 e/Å3), revealing that each BCPM molecule is anchored on the substrate with ligand bonding between the lower oxygen atom of its maleimide group and the substrate Au atom.
