Modular Two-Step Access to π-Extended Naphthyridine Systems-Potent Building Blocks for Organic Electronics

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Incorporating nitrogen into polyaromatic compounds (PACs) for π-extended systems and optoelectronic property modification is challenging.
• Existing methods for synthesizing nitrogen-containing PACs often lack versatility and control over regiochemistry.

Purpose of the Study:

• To develop a novel and versatile synthetic pathway for constructing naphthyridine-based PACs.
• To explore the influence of substituents on the electronic and structural properties of these novel PACs.
• To investigate the potential application of these compounds as proton sensors.

Main Methods:

• Utilized a gold-catalyzed synthesis of 2-aminoquinolines.
• Developed an in situ desulfonation and condensation strategy for precursor elaboration.
• Employed late-stage functionalization by varying anthranile and ynamide components.
• Characterized compounds using single-crystal X-ray diffraction and electronic property measurements.

Main Results:

• Successfully synthesized a new class of non-symmetric and regioisomeric naphthyridine-based PACs.
• Demonstrated that the shape and type of functional groups can be tuned in late synthetic stages.
• Observed halochromic behavior in all synthesized naphthyridine-based PACs.
• Confirmed the influence of substituents on the electronic properties and molecular structure.

Conclusions:

• The developed synthetic protocol offers a versatile approach to naphthyridine-based PACs.
• The halochromic properties suggest these compounds are highly sensitive proton sensors in non-protic solvents.
• This work expands the toolkit for designing functional π-extended systems with tunable optoelectronic properties.