Fused Hexabenzocoronene-Porphyrin Conjugates with Tailorable Excited-State Lifetimes

Area of Science:

• Organic Chemistry
• Materials Science
• Photophysics

Background:

• Tetrapyrrolic chromophores are essential in various optoelectronic applications.
• Developing novel π-extended systems with tailored properties remains a key challenge.
• Fusion of distinct aromatic systems offers a route to advanced functional materials.

Purpose of the Study:

• To introduce a novel strategy for fusing N-heterocyclic and carbon-pure systems.
• To synthesize and characterize new C-C bond-fused porphyrin-hexabenzocoronene (HBC) conjugates.
• To investigate the impact of fused ring systems on photophysical properties for applications in organic photovoltaics and NIR dyes.

Main Methods:

• Oxidative cyclodehydrogenation of tailor-made nickel porphyrin precursors.
• Synthesis of three novel C-C bond-fused porphyrin-HBC conjugates.
• Quantum chemical calculations for electronic structure analysis.
• Comprehensive optoelectronic and time-resolved characterization.

Main Results:

• Highly soluble π-extended porphyrins were synthesized in excellent yields.
• Porphyrin-HBC conjugates exhibited significantly broadened absorption cross-sections.
• Quantum chemical calculations revealed induced biradicaloid character in the porphyrin core.
• Characterization confirmed short-lived excited states with significantly faster decay rates.

Conclusions:

• A versatile platform for multi-purpose tetrapyrrolic chromophores was established.
• The novel fused systems demonstrate potential for advanced organic photovoltaics and NIR dye applications.
• The induced biradicaloid character significantly influences excited state dynamics, offering new avenues for material design.