A Diphenylamine-Functionalized [5]Helicene as a Solvatochromic Fluorescent Sensor for Methanol: Synthesis,
Phiphob Naweephattana1, Punrada Thadatontichok2, Nirawit Kaewnok2
1Center of Excellence in Biocatalyst and Sustainable Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
The Journal of Physical Chemistry. B
|December 27, 2025
Summary
A new [5]helicene derivative (M111) acts as a sensitive fluorescence sensor for methanol detection. Its unique structure allows for real-time monitoring with high accuracy, showing promise for polar solvent analysis.
Area of Science:
- Organic Chemistry
- Materials Science
- Analytical Chemistry
Background:
- Helicene derivatives offer unique photophysical properties due to their rigid helical structures.
- Donor-acceptor architectures are crucial for designing molecules with efficient intramolecular charge transfer (ICT).
- Fluorescence-based sensing provides a sensitive and selective method for detecting specific analytes.
Purpose of the Study:
- To design, synthesize, and characterize a novel [5]helicene derivative (M111) for methanol detection.
- To investigate the photophysical properties and sensing mechanism of M111 in various polar solvents.
- To evaluate the potential of M111 as a real-time fluorescence sensor for methanol.
Main Methods:
- Rational design and synthesis of a diphenylamine- and cyano-substituted [5]helicene derivative (M111).
- Photophysical characterization including solvatochromic studies in solvents of varying polarities.
- Computational investigations using DFT and TD-DFT calculations to elucidate electronic properties and sensing mechanisms.
Main Results:
- M111 exhibited pronounced solvatochromic behavior, with fluorescence quenching in polar media, especially methanol.
- A highly linear fluorescence response was observed in dichloromethane-methanol mixtures, with a low detection limit of 4.5% (v/v).
- Computational studies indicated that dielectric stabilization and hydrogen bonding contribute to the red-shifted emission, confirming the sensing mechanism.
Conclusions:
- M111 is a promising helicene-based platform for selective and real-time fluorescence sensing of methanol.
- The study establishes a strong correlation between molecular design, photophysical properties, and sensing performance.
- This work paves the way for developing advanced helicene-based sensors for polar solvents.
