A Novel Homoconjugated Propellane Triimide: Synthesis, Structural Analyses, and Gas Separation

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Rigid three-dimensional (3D) polycyclic propellanes offer unique conformational spaces for applications in selectivity and electronic studies.
• Through-space electronic interactions in rigid frameworks are of significant interest for developing novel functional materials.

Purpose of the Study:

• To synthesize and characterize a novel rigid propellane, trinaphtho[3.3.3]propellane triimide.
• To investigate the electronic and supramolecular properties of the synthesized propellane triimide.
• To explore its potential applications in gas separation, specifically for ethane/ethylene purification.

Main Methods:

• Synthesis of trinaphtho[3.3.3]propellane triimide.
• Spectroscopic analysis (UV-Vis, fluorescence) to determine electronic properties.
• Electrochemical measurements to assess reduction potential.
• Computational studies (DFT) to understand through-space orbital interactions.
• Single-crystal X-ray diffraction (XRD) for structural analysis.
• Gas adsorption studies to evaluate separation capabilities.

Main Results:

• A novel rigid propellane triimide was successfully synthesized.
• The propellane triimide exhibited a large bathochromic shift, amplified molar absorptivity, enhanced fluorescence, and a lower reduction potential compared to its subunits.
• Computational and experimental data confirmed through-space π-orbital interactions (homoconjugation).
• Single-crystal XRD revealed a quasi-D3h symmetric structure that forms superstructures based on alkyl chain modifications.
• A porous 3D superstructure demonstrated high selectivity for ethane over ethylene adsorption, enabling efficient C2H4 purification.

Conclusions:

• Trinaphtho[3.3.3]propellane triimide represents a new class of 3D polycyclic propellanes with significant electronic and supramolecular properties.
• The material's ability to form porous superstructures with selective gas adsorption capabilities highlights its potential for practical applications in gas purification.
• This study opens avenues for designing advanced materials based on rigid propellane frameworks for targeted separation and electronic applications.