Site-selective chemical reactions by on-water surface sequential assembly

Area of Science:

• Organic Chemistry
• Surface Chemistry
• Supramolecular Chemistry

Background:

• Controlling site-selectivity and reactivity is a major challenge in synthetic chemistry.
• Developing new methods for chemical reactions on surfaces is crucial for advanced materials and synthesis.

Purpose of the Study:

• To discover and demonstrate site-selective chemical reactions on a water surface.
• To establish a sequential assembly approach for controlled synthesis on interfaces.

Main Methods:

• Utilizing a negatively charged surfactant monolayer to guide reagent assembly on the water surface.
• Employing surface-specific in-situ spectroscopies to analyze reaction mechanisms.
• Demonstrating site-selective bond formation (imide, imine, imidazole) through sequential assembly.

Main Results:

• Achieved electrostatically driven, epitaxial, and aligned assembly of amino-substituted porphyrin molecules into J-aggregated structures.
• Directed the alignment of perylenetetracarboxylic dianhydride, enabling selective one-sided imide bond formation.
• Confirmed multilayer growth of the site-selective imide product via dynamic interfacial mechanisms.

Conclusions:

• The sequential assembly approach enables precise control over site-selective reactions on water surfaces.
• This method facilitates the development of on-water surface synthesis as a key area in modern organic chemistry.
• Demonstrated versatility through multiple reversible and irreversible bond formations involving porphyrin molecules.