Naphthalimide-based conjugated macrocycles possessing tunable self-assembly and supramolecular binding behaviours

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Organic Electronics

Background:

• Pi-conjugated macrocycles are crucial for materials science due to unique geometric and optoelectronic properties.
• Modifying macrocycles with different building units can tune their configuration and intramolecular charge transfer for advanced applications.

Purpose of the Study:

• To synthesize and characterize novel pi-conjugated macrocycles incorporating naphthalimide (NMI) electron acceptor units.
• To investigate the impact of aryl versus alkyl substitutions on NMI on macrocycle self-assembly and C70 encapsulation.

Main Methods:

• Synthesis of four new pi-conjugated macrocycles with varying NMI substitutions (aryl/alkyl).
• Analysis of self-assembly behaviors in solution.
• Investigation of supramolecular encapsulation of C70 fullerene.

Main Results:

• Alkyl-substituted macrocycles (NP2b, NP3b) exhibited significant self-aggregation, unlike aryl-substituted ones (NP2a, NP3a) due to steric hindrance.
• All macrocycles demonstrated supramolecular encapsulation of C70.
• Larger, twisted macrocycles (NP3a, NP3b) showed enhanced binding affinity for C70 compared to smaller, planar analogues (NP2a, NP2b).

Conclusions:

• NMI-based macrocycle family is expanded, offering new possibilities for supramolecular chemistry.
• Substituent-directed self-assembly and C70 binding highlight potential for optoelectronic device applications.
• Macrocycle geometry and size are key factors in tuning supramolecular interactions and performance.