Benzene Ring Knitting Achieved by Ambient-Temperature Dehalogenation via Mechanochemical Ullmann-Type Reductive...

Area of Science:

• Materials Science
• Organic Chemistry
• Nanotechnology

Background:

• Current methods for synthesizing conjugated porous networks (CPNs) are limited by harsh conditions, expensive catalysts, or substrate restrictions.
• Existing techniques include solution-based coupling, ultrahigh-vacuum polymerization, and mechanochemical Scholl reactions.

Purpose of the Study:

• To develop a simple, scalable, and ambient condition method for CPN synthesis.
• To introduce a novel mechanochemical Ullmann-type reaction for direct aromatic ring knitting.

Main Methods:

• Mechanochemical Ullmann-type coupling utilizing Grignard reagent intermediates formed from dehalogenation of aromatic halides in the presence of magnesium.
• Synthesis of phenyl-based CPNs (Ph-CPN-1) from 1,2,4,5-tetrabromobenzene (TBB).
• Demonstration of versatility by synthesizing CPNs from pyrene and triphenylene monomers, and crystalline graphite.

Main Results:

• Successful synthesis of CPNs with high surface areas and mesoporous architectures via direct C-C bond formation.
• Demonstrated versatility across various aromatic monomers.
• Obtained highly crystalline graphite product.
• CPNs showed promising electrochemical performance as anode materials for lithium-ion batteries (LIBs).

Conclusions:

• The developed mechanochemical Ullmann-type reaction provides a novel and complementary approach to existing CPN synthesis methods.
• This strategy enables the scalable production of CPNs under neat and ambient conditions.
• The synthesized CPNs hold potential for advanced applications, particularly in energy storage devices like LIBs.