A p-quinodimethane-bridged porphyrin dimer

Area of Science:

• Organic Chemistry
• Materials Science
• Photophysics

Background:

• Porphyrin dimers are crucial in developing advanced materials.
• Tuning electronic and optical properties of porphyrins is key for new applications.

Purpose of the Study:

• To synthesize a novel p-quinodimethane (p-QDM)-bridged porphyrin dimer.
• To investigate its optical and electronic properties, including near-infrared (NIR) absorption.
• To explore its potential as a chromophore.

Main Methods:

• Synthesis of the p-QDM-bridged porphyrin dimer via intramolecular Friedel-Crafts alkylation.
• Characterization using one-photon absorption (OPA) and two-photon absorption (TPA) spectroscopy.
• Electrochemical analysis using cyclic voltammetry.
• Computational studies using density functional theory (DFT).

Main Results:

• Successful synthesis of the p-QDM-bridged porphyrin dimer (1).
• Compound 1 exhibits intense NIR OPA (λmax=955 nm) and a large TPA cross-section (σ(2)max=2080 GM at 1800 nm).
• The dimer shows a short singlet excited-state lifetime (25 ps) and a small electrochemical energy gap (0.86 eV).

Conclusions:

• The p-QDM unit significantly impacts the porphyrin framework's optical and electronic properties.
• The synthesized dimer is a novel NIR chromophore with potential applications in optics and electronics.
• The study provides insights into structure-property relationships in bridged porphyrin systems.