Designing Pancake-Bonded Heterodimers for Scanning Probe Microscopy

Area of Science:

• Surface Science
• Computational Chemistry
• Scanning Probe Microscopy

Background:

• Multicenter covalent-like interactions, termed pancake bonds, are crucial in molecular assembly.
• Characterizing these interactions, especially with radical molecules, presents significant challenges.
• Fullerenes (C60) are versatile building blocks with unique electronic properties.

Purpose of the Study:

• To investigate the feasibility of using scanning probe microscopy (SPM) to characterize pancake bonds.
• To explore the formation and properties of heterodimers between radical molecules and monoanionic C60 (C60-).
• To computationally design and analyze novel radical-molecule/C60- heterodimers.

Main Methods:

• Employed computational modeling to simulate heterodimer formation and interactions.
• Proposed a method involving functionalizing the SPM tip with C60 and inducing its monoanionic state.
• Analyzed structural and energetic properties to distinguish pancake bonds from van der Waals interactions.

Main Results:

• Computational models confirm SPM's potential to characterize pancake bonds on surfaces.
• All three designed radical/diradical molecules readily form pancake-bonded dimers with C60-.
• Two novel heterodimers exhibit intermolecular C-C distances shorter than previously reported pancake bonds.

Conclusions:

• SPM, particularly with a C60- functionalized tip, is a viable technique for studying pancake bonding.
• The designed heterodimers offer new possibilities for intermolecular interactions with record short bond distances.
• This work encourages further research into radical molecule interactions using SPM.