Ag₂CO₃-Mediated Oxidative Access to Calix[4]Diphenoquinones: Synthesis, Conformational Features, and Cavity...

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Calix[4]diphenoquinones are redox-active macrocycles with potential in functional materials.
• Systematic synthesis and structural characterization of these compounds are limited.

Purpose of the Study:

• To develop a mild and efficient synthesis for calix[4]diphenoquinones.
• To characterize the redox behavior, electronic properties, and conformations of these macrocycles.

Main Methods:

• Ag2CO3-mediated oxidation for synthesis.
• Electrochemical measurements (cyclic voltammetry) to determine redox behavior and LUMO levels.
• NMR spectroscopy and single-crystal X-ray diffraction for structural and conformational analysis.

Main Results:

• Near-quantitative synthesis of DPQ1-4 achieved using a novel Ag2CO3-mediated oxidation.
• Electrochemical data indicate well-defined redox behavior and LUMO levels around -4.0 eV, suggesting air-stable electron-transporting characteristics.
• NMR and crystallographic studies revealed tunable conformations (cone, 1,3-alternate) influenced by intramolecular interactions and steric effects, with DPQ2 forming a chair-like 1,3-alternate structure encapsulating ethanol.

Conclusions:

• A mild and efficient Ag2CO3-mediated oxidation strategy enables the synthesis of calix[4]diphenoquinones.
• These macrocycles exhibit promising air-stable electron-transporting properties and tunable conformations.
• The structural diversity and encapsulation capabilities highlight their potential in supramolecular chemistry and functional organic materials.