Pseudo-cyclic face-to-face rigid structure caused by the intramolecular ion pair effect

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry

Background:

• Zwitterions are versatile molecules with diverse applications.
• Understanding the structural properties of novel zwitterionic compounds is crucial for their further development.

Purpose of the Study:

• To synthesize novel 3-methylpyridine and quinoline zwitterions.
• To elucidate the unique pseudo-cyclic, face-to-face rigid structure of these synthesized zwitterions.
• To investigate the driving forces behind the observed molecular structure.

Main Methods:

• Synthesis of six 3-methylpyridine zwitterions and six quinoline zwitterions.
• Utilizing 4-hydroxycoumarins, p-benzoquinone, and corresponding N-aromatics as reactants.
• Structural elucidation using proton nuclear magnetic resonance ((1)H-NMR) spectroscopy at variable temperatures.

Main Results:

• Successful synthesis of twelve novel zwitterionic compounds.
• Characterization of a novel pseudo-cyclic, face-to-face rigid structure in the synthesized zwitterions.
• Evidence suggesting intramolecular ion pair attraction and steric interactions as key factors in stabilizing the rigid structure.

Conclusions:

• The study presents a new class of rigid zwitterions with potential applications in materials science.
• The findings provide insights into the non-covalent interactions governing the self-assembly and structural rigidity of zwitterionic systems.
• Further research can explore the functional properties and applications of these unique molecular architectures.