Visualizing Chiral Interactions in Carbohydrates Adsorbed on Au(111) by High-Resolution STM Imaging

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Carbohydrate Chemistry

Background:

• Carbohydrates are Earth's most abundant organic molecules, crucial in biological systems.
• Synthetic carbohydrate material engineering lags behind proteins and nucleic acids.
• Bottom-up engineering requires atomic-level understanding of molecular structure and interactions.

Purpose of the Study:

• To visualize the 3D structure and interactions of cellulose oligomers at submolecular resolution.
• To understand the driving forces behind carbohydrate assembly.
• To explore enantioselective self-assembly for material design.

Main Methods:

• High-resolution scanning tunneling microscopy (STM) on Au(111).
• Ab initio calculations for theoretical support.
• Comparison of D- and L-cellulose oligomer assembly.

Main Results:

• STM revealed the precise orientation of glycosidic bonds and pyranose rings.
• Detailed intermolecular interactions governing oligomer assembly were identified.
• Enantioselective interactions driving spontaneous separation of D- and L-cellulose chains were observed.

Conclusions:

• Atomic-level visualization enables understanding of carbohydrate assembly.
• Enantioselective interactions are key for controlling carbohydrate self-assembly.
• This work paves the way for engineered carbohydrate materials with designed properties.