FACE-selective fluorogenic cycloaddition reaction between coumarin azides and sugar terminal alkynes: an experimental...

Area of Science:

• Organic Chemistry
• Materials Science
• Photophysics

Background:

• Coumarin derivatives are known for their fluorescence properties.
• Azide-alkyne cycloaddition reactions are versatile tools in organic synthesis.
• Developing novel fluorescent probes with tunable properties is of significant interest.

Purpose of the Study:

• To synthesize novel fluorescent coumarin-sugar triazoles via copper-catalyzed azide-alkyne cycloaddition (CuAAC).
• To investigate the influence of substituents on the photophysical properties of the synthesized triazoles.
• To computationally support experimental findings using TD-DFT studies.

Main Methods:

• Copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction between coumarin azides and sugar terminal alkynes.
• Characterization of synthesized coumarin-sugar triazoles.
• Photophysical property measurements (e.g., fluorescence intensity, emission spectra).
• Time-dependent Density Functional Theory (TD-DFT) calculations.

Main Results:

• Synthesis of intense fluorescent 1,2,3-triazoles from non-fluorescent coumarin azides and sugar alkynes with 75-85% yield.
• Demonstrated significant influence of substituents at the 6th and 7th positions on coumarin-sugar triazole photophysical properties.
• Experimental observations were corroborated by TD-DFT computational studies.

Conclusions:

• The CuAAC reaction is an effective method for synthesizing fluorescent coumarin-sugar triazoles.
• Tunable photophysical properties can be achieved by strategic substituent modification.
• TD-DFT calculations provide valuable insights into the electronic and optical properties of these novel fluorescent molecules.