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Peripherally ethynylated carbazole-based core-modified porphyrins.

Chihiro Maeda¹, Naoki Yoshioka

¹Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan. cmaeda@applc.keio.ac.jp

Organic & Biomolecular Chemistry

|May 19, 2012

Summary

New carbazole-based porphyrins with ethynyl groups were synthesized. These molecules show excellent π-electron delocalization across the entire structure, confirmed by experiments and calculations.

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Area of Science:

Organic Chemistry
Materials Science
Computational Chemistry

Background:

Porphyrins are vital macrocyclic compounds with diverse applications.
Carbazole derivatives offer unique electronic properties for materials.
Modifying porphyrin cores can tune their photophysical and electronic characteristics.

Purpose of the Study:

To synthesize novel peripherally ethynylated carbazole-based core-modified porphyrins.
To investigate the electronic properties and π-conjugation in these new porphyrin structures.
To understand the impact of ethynyl substituents on the macrocyclic π-system.

Main Methods:

Synthesis via sequential metal-catalyzed coupling reactions.
Annulation reactions for porphyrin core formation.
Experimental characterization (e.g., spectroscopy, electrochemistry).
Density Functional Theory (DFT) calculations for electronic structure analysis.

Main Results:

Successful synthesis of target carbazole-based porphyrins.
Experimental and computational evidence of extensive π-electron delocalization.
Delocalization confirmed to encompass the entire macrocycle, including ethynyl groups.
Demonstration of effective electronic communication through the ethynyl linkers.

Conclusions:

Peripherally ethynylated carbazole-based porphyrins represent a new class of functional macrocycles.
The ethynyl substituents enhance π-conjugation, leading to delocalization over the entire porphyrin system.
These findings open avenues for designing advanced organic electronic materials.