Red-emitting boron difluoride complexes with a mega-large Stokes shift and unexpectedly high fluorescence quantum...

Area of Science:

• Organic Chemistry
• Materials Science
• Biomedical Imaging

Background:

• Boron difluoride complexes are known for their photophysical properties.
• Tetrahydroquinoxaline derivatives can influence electronic and optical characteristics.
• Developing novel fluorescent materials with enhanced properties is crucial for advanced applications.

Purpose of the Study:

• To synthesize novel boron difluoride complexes incorporating a tetrahydroquinoxaline donor.
• To investigate the photophysical properties, including emission spectra, quantum yields, and Stokes shifts.
• To evaluate the potential of these compounds as responsive fluorescent dyes and biological imaging agents.

Main Methods:

• Synthesis of tetrahydroquinoxaline-containing boron difluoride complexes.
• Spectroscopic characterization (UV-Vis absorption, fluorescence emission).
• Measurement of fluorescence quantum yields and Stokes shifts.
• Assessment of solid-state fluorescence response to acid/base fumigation.
• In vitro and in vivo imaging studies in cells and zebrafish.

Main Results:

• The synthesized boron difluoride complexes exhibited extended emission wavelengths (617-684 nm).
• High fluorescence quantum yields (up to 0.68) and large Stokes shifts (up to 209 nm) were achieved.
• Reversible, ratiometric changes in solid-state fluorescence were observed upon acid/base exposure.
• Successful application as fluorescent imaging agents in living cells and zebrafish was demonstrated.

Conclusions:

• The incorporation of tetrahydroquinoxaline donors significantly enhances the photophysical properties of boron difluoride complexes.
• These novel dyes possess tunable and responsive fluorescence, suitable for sensing applications.
• The demonstrated utility in live biological imaging highlights their potential for advanced diagnostics and research.