Spectroscopic Study of a Photoactive Antibacterial Agent: 2,3-Distyrylindole.

Area of Science:

• Photochemistry
• Molecular Spectroscopy
• Computational Chemistry

Background:

• Indole derivatives are explored for their photophysical properties.
• Antibacterial chromophores are crucial for developing new therapeutic agents.

Purpose of the Study:

• To investigate the optical properties and fluorescence decay dynamics of the 2,3-distyrylindole (23DSI) system.
• To evaluate the potential of 23DSI for biological imaging and photodynamic inactivation.

Main Methods:

• Steady-state UV-vis and fluorescence spectroscopy.
• Time-resolved fluorescence upconversion and single-photon counting spectroscopy.
• Density Functional Theory (DFT) calculations.

Main Results:

• 23DSI exhibits two- and three-photon absorption in solution and solid phases.
• The molecule shows ultrafast fluorescence decay with a lifetime of 1 ns and a fast decay constant of 34 ps.
• DFT calculations confirm electron delocalization responsible for multiphoton absorption, matching experimental data.

Conclusions:

• 23DSI possesses excellent multiphoton absorption capabilities due to optimal electron delocalization.
• The molecule does not produce singlet oxygen, indicating a specific mechanism for photodynamic inactivation.
• 23DSI shows promise for applications in biological imaging and photodynamic inactivation.