On-Surface Synthesis of Isotactic Double-Stranded Corannulene Polymers Steered by Hierarchical Supramolecular...

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Science

Background:

• On-surface synthesis enables functional nanostructure construction.
• Polymer tacticity significantly influences material properties and applications.
• Controlling tacticity typically requires chiral catalysts, limiting synthetic approaches.

Purpose of the Study:

• To explore polymer tacticity in on-surface polymerization.
• To develop a method for synthesizing isotactic polymers without chiral auxiliaries.
• To investigate the role of surface confinement and monomer preorganization.

Main Methods:

• Synthesized a corannulene-substituted terphenylene monomer.
• Utilized two-dimensional surface confinement on Ag(111) for monomer preorganization.
• Performed Ullmann polymerization of self-assembled monomers.
• Employed scanning tunneling microscopy for characterization and manipulation.

Main Results:

• Achieved monomer self-assembly into double strands via C-H···π bonding and aromatic stacking.
• Synthesized double-stranded isotactic polyphenylenes through on-surface Ullmann polymerization.
• Observed formation of higher-order crystalline domains due to stereoregularity.
• Demonstrated mechanical unzipping of polymer duplexes into individual chains.

Conclusions:

• Surface confinement and monomer preorganization enable on-surface synthesis of isotactic polymers without chiral control.
• The synthesized polymers exhibit high stereoregularity and form ordered crystalline structures.
• This method offers a new pathway for creating precisely controlled polymer architectures on surfaces.