Isatin-1,8-Naphthalimide Hydrazones: A Study of Their Sensor and ON/OFF Functionality

Area of Science:

• Organic Chemistry
• Analytical Chemistry
• Supramolecular Chemistry

Background:

• Isatin-derived hydrazones are explored for their sensing capabilities.
• Tautomerism and photoisomerization are key properties influencing sensor performance.
• Developing selective and sensitive anion sensors remains a significant challenge in analytical chemistry.

Purpose of the Study:

• To synthesize novel isatin-based hydrazones as potential anion sensors.
• To investigate the tautomeric equilibrium and photoisomerization behavior of these hydrazones.
• To evaluate the anion recognition capabilities and detection limits of the synthesized compounds.

Main Methods:

• Synthesis of five novel hydrazone derivatives from substituted isatins.
• Characterization using UV-VIS, FTIR, and NMR spectroscopy.
• Fluorescence spectroscopy to study anion binding and photoisomerization.

Main Results:

• The synthesized hydrazones exhibited tautomeric equilibrium and Z-E photoisomerization.
• Selective recognition of various anions including PF₆⁻, HSO₄⁻, Br⁻, Cl⁻, NO₃⁻, F⁻, and CH₃COO⁻ was observed.
• The compounds demonstrated light-stimulated ON-OFF sensing functionality.

Conclusions:

• The novel hydrazones are effective anion sensors with tunable properties.
• Photoisomerization and tautomerism play crucial roles in the sensing mechanism.
• These compounds show promise for applications in light-responsive anion detection systems.