A Modular Approach to Tuning Emissive N-Quinolyl Through-Space Charge Transfer States Using sp³-Scaffolds

Area of Science:

• Organic Chemistry
• Photochemistry
• Materials Science

Background:

• Palladium-catalyzed cascade reactions offer efficient synthetic routes.
• Tuning photophysical properties of organic molecules is key for advanced applications.
• Through-space charge transfer (TSCT) influences luminescence in molecular systems.

Purpose of the Study:

• To develop a modular approach for synthesizing rigid quinoline-containing tetracyclic amines.
• To investigate the structure-activity relationship governing TSCT formation.
• To control and optimize photoluminescence properties for potential biosensor applications.

Main Methods:

• Utilized palladium-catalyzed cascade processes for amine synthesis.
• Systematically varied intramolecular N-aryl distance and quinoline substitution.
• Analyzed the impact of structural modifications on TSCT formation and photoluminescence.

Main Results:

• Achieved modular access to diverse quinoline-containing tetracyclic amines.
• Demonstrated fine-tuning of TSCT state formation by adjusting N-aryl distance.
• Showed that decreasing N-aryl distance enhances TSCT, controlling emission color and quantum yield.
• Methoxylation of quinoline reduced TSCT propensity.

Conclusions:

• Established a structure-activity relationship for TSCT formation in these systems.
• Provided insights into controlling photoluminescence through molecular design.
• Highlighted the relevance of TSCT understanding for biosensors and photoluminescence research.