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A fluorescent probe based on scopoletin-3-carboxylic acid: pH and micellization evaluation
Larissa Sousa Campos1, Luis Garcia-Rio2, Ricardo Ferreira Affeldt1
1Laboratório de Catálise e Fenômenos Interfaciais, Chemistry Department, Federal University of Santa Catarina, 88040-900 Florianópolis, SC, Brazil.
Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
|December 13, 2024
Summary
This study reports the synthesis of 7-hydroxy-6-methoxy-2-oxo-2H-chromene-3-carboxylic acid (3-SCA), a novel coumarin derivative. 3-SCA exhibits excellent photophysical properties, making it a sensitive probe for pH and micelle formation.
Area of Science:
- Organic Chemistry
- Photochemistry
- Analytical Chemistry
Background:
- Coumarins are versatile compounds with significant biological and photophysical properties.
- Their application in analyzing molecular microenvironments and pH is of great interest.
- Understanding coumarin photophysics is crucial for developing new probes.
Purpose of the Study:
- To synthesize and characterize 7-hydroxy-6-methoxy-2-oxo-2H-chromene-3-carboxylic acid (3-SCA).
- To evaluate the photophysical properties of 3-SCA in various solvents and pH conditions.
- To assess the potential of 3-SCA as a probe for pH sensing and micelle formation.
Main Methods:
- Synthesis of 3-SCA.
- Spectroscopic analysis (absorption, emission, excitation) in different solvents and pH.
- Photophysical property evaluation (molar absorption coefficient, lifetime, Stokes Shift).
- Determination of acid equilibrium constants (pKa values).
- Application in critical micellar concentration determination of surfactants.
Main Results:
- 3-SCA was successfully synthesized.
- High fluorescence quantum yield and a lifetime of ~5 ns were observed for 3-SCA.
- High Stokes shift values were obtained, particularly in aqueous media.
- Two pKa values (3.7 and 6.6) were determined for 3-SCA.
- 3-SCA effectively determined the critical micellar concentration of various surfactants.
Conclusions:
- 3-SCA is a promising fluorescent probe with notable photophysical characteristics.
- Its spectral properties are highly sensitive to pH changes.
- 3-SCA demonstrates utility in assessing local pH and detecting micelle formation.
- The compound's high Stokes shift and sensitivity make it valuable for analytical applications.
