Intramolecular Charge Transfer in Antiaromatic Donor/Acceptor-Fused s-Indacenes

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Donor/acceptor-fused small molecules are crucial for organic electronics.
• Understanding the relationship between molecular structure, antiaromaticity, and charge transfer is key for designing new materials.

Purpose of the Study:

• To synthesize and characterize novel donor/acceptor-fused s-indacenes.
• To investigate the impact of molecular asymmetry on antiaromaticity and intramolecular charge transfer (ICT).
• To establish structure-property relationships for these novel organic materials.

Main Methods:

• Synthesis of unsymmetrical benzofuran/benzothiophene-s-indacene regioisomers.
• Late-stage oxidation to form donor/acceptor-fused s-indacenes.
• Experimental characterization (e.g., spectroscopy, electrochemistry).
• Computational analysis (e.g., DFT calculations).

Main Results:

• Successfully synthesized four novel donor/acceptor-fused s-indacenes.
• Demonstrated that molecular asymmetry influences antiaromaticity and ICT.
• Observed a strong correlation between antiaromaticity and ICT strength.
• The two most antiaromatic isomers showed significant ICT with large solvatochromic shifts (30 and 40 nm).

Conclusions:

• Molecular asymmetry is a critical factor in tuning the electronic properties of fused s-indacenes.
• Antiaromaticity and ICT are strongly linked in these systems, controllable via fusion orientation.
• These findings provide insights for designing advanced organic materials with tailored optoelectronic properties.