A multi-stimuli-responsive fluorescence material based on 1,8-naphthalimide

Area of Science:

• Organic Chemistry
• Materials Science
• Photophysics

Background:

• 1,8-naphthalimides (NPIs) are a class of organic compounds with notable photophysical properties.
• Functionalization of NPIs can tune their optical and responsive characteristics.

Purpose of the Study:

• To design and synthesize novel amino-containing 1,8-naphthalimide derivatives.
• To investigate the photophysical properties and stimuli-responsive behavior of the synthesized NPIs.

Main Methods:

• Chemical synthesis of two 1,8-naphthalimide derivatives.
• Structural confirmation using NMR, HR-MS, and FT-IR spectroscopy.
• Systematic investigation of photophysical properties in various solvents and conditions.

Main Results:

• Successful synthesis and structural elucidation of two NPIs functionalized with 4-diethylaminosalicylaldehyde and 4-diethylaminobenzaldehyde.
• Distinct emission differences observed between the two NPIs during self-assembly, attributed to excited-state intramolecular proton transfer in the hydroxyl-containing NPI.
• The 4-diethylaminosalicylaldehyde-functionalized NPI exhibited multi-stimuli-responsive fluorescence (mechanofluorochromism, vapor sensing), while the other showed no significant response.

Conclusions:

• The hydroxyl group in the functionalized NPI plays a crucial role in its unique photophysical behavior and stimuli-responsive properties.
• The synthesized NPIs demonstrate potential applications in sensing and responsive materials.
• Differences in functionalization lead to significantly varied photoluminescence responses under external stimuli.