Rigid π-Extended Boron Difluoride Complex with Mega-Stokes Shift for Bioimaging

Area of Science:

• Organic Chemistry
• Materials Science
• Biomedical Imaging

Background:

• Development of novel fluorophores is crucial for advanced imaging techniques.
• π-extended ligands are key components in designing functional organic materials.
• Boron complexes offer unique photophysical properties for various applications.

Purpose of the Study:

• To rationally design and synthesize a rigid π-extended ligand for four-coordinate boron complexes.
• To characterize the photophysical properties of the resulting novel fluorophore.
• To evaluate the potential of the boron complex as a fluorescent probe for cancer cell imaging.

Main Methods:

• Synthesis of a fused hexacyclic structure (carbazolo[2,1-c]phenanthridine).
• Photophysical characterization including determination of Stokes shift.
• Computational calculations to elucidate the origin of intramolecular charge transfer.
• Demonstration of cancer cell imaging using the N,N-difluoroboryl complex.

Main Results:

• Successful synthesis of a novel fused hexacyclic carbazolo[2,1-c]phenanthridine structure.
• The novel fluorophore exhibits a significant Stokes shift.
• Computational studies confirmed intramolecular charge transfer as the origin of the large Stokes shift.
• The N,N-difluoroboryl complex demonstrated effective fluorescence imaging of cancer cells.

Conclusions:

• A novel rigid π-extended ligand and its corresponding boron complex were successfully synthesized.
• The developed fluorophore possesses a large Stokes shift attributed to intramolecular charge transfer.
• The N,N-difluoroboryl complex is a promising fluorescent probe for cancer cell imaging applications.