Title:Cholesterol Decorated Pyridinium Urea and Carbamate as π-Gelators for
Selective Recognition of F- Ions
Volume: 5
Issue: 2
Author(s): Santanu Panja*Kumaresh Ghosh*
Affiliation:
- Department of Chemistry, University of Kalyani, Kalyani-741235, India
- Faculty of Science, Department of Chemistry, University of Kalyani, Kalyani-
741235, India
Keywords:
Functional materials, cholesterol, pyridinium salts, supramolecular gel, F- sensing, fluorescence.
Abstract: Aim: The design and synthesis of new molecules capable of forming self-assembled gels
are indispensable to harvest new functional materials. Supramolecular gels have potential in many areas,
particularly in biology and materials chemistry. Of the different types of applications, visual sensing
of biologically relevant ionic analytes is a fairly recent trend. Here we describe naked-eye detection
of fluoride ions involving sol-gel methodology.
Methods: To execute this, cholesterol substituted pyridinium salts 1-4 have been designed and synthesized,
of which compounds 3 and 4 served as potential gelators for the naked-eye detection of F- ions
in DMSO and DMSO-H2O (1:1, v/v), respectively.
Results: Addition of F- ions to the solutions of 3 and 4 in DMSO and DMSO: H2O (1:1, v/v) respectively,
resulted in the formation of yellow and brown colored gels instantly at room temperature.
Conclusion: Gelation study reveals that not only the aromatic surface is crucial for the selfaggregation
of molecules via π-π stacking interactions, but also polarity, rigidity, and conformational
flexibility of the molecules that govern the intermolecular association of gelators are important. Moreover,
the incorporation of fluorophore (naphthalene) as an aromatic surface in the molecular designs
enables the gelator molecules to execute the sensing of F- with a high degree of sensitivity in the solution
phase.
