π-Extended Phosphepines: Redox and Optically Active P-Heterocycles with Nonplanar Framework

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Dithieno[b,f]phosphepines are a class of heterocyclic compounds with potential electronic applications.
• Tuning the optoelectronic properties of organic semiconductors is crucial for advancing organic electronics.

Purpose of the Study:

• To synthesize a new family of π-extended dithieno[b,f]phosphepines.
• To investigate the effect of substituents on their optical and redox properties.
• To evaluate their potential as semiconductors in organic field-effect transistors (OFETs).

Main Methods:

• Synthesis of π-extended dithieno[b,f]phosphepines via palladium-catalyzed direct arylation.
• Spectroscopic characterization (absorption/emission).
• Electrochemical characterization (redox properties).
• Density Functional Theory (DFT) calculations for property rationalization.
• Fabrication and characterization of p-type organic field-effect transistors (OFETs).

Main Results:

• Successful synthesis of a new family of π-extended dithieno[b,f]phosphepines.
• Palladium-catalyzed arylation enabled tuning of absorption/emission wavelengths and redox potentials.
• DFT calculations provided insights into structure-property relationships.
• Ambipolar phosphepine derivatives with diphenylamino substituents exhibited promising semiconductor characteristics for p-type OFETs.

Conclusions:

• The developed synthetic strategy allows for versatile functionalization of dithieno[b,f]phosphepines.
• These π-extended systems possess tunable optoelectronic properties suitable for organic electronics.
• The demonstrated performance in p-type OFETs highlights their potential for future applications in organic semiconductor devices.