Bispidines for dual imaging.

Area of Science:

• Coordination Chemistry
• Bioinorganic Chemistry
• Medical Imaging

Background:

• Bispidine derivatives offer versatile platforms for developing functional molecules.
• BODIPY dyes are widely used as fluorescent probes.
• Targeted imaging requires probes with specific metal-binding capabilities and detectable signals.

Purpose of the Study:

• To synthesize and characterize a novel BODIPY-substituted bispidine ligand.
• To investigate the photophysical properties of the ligand and its metal complexes.
• To evaluate the potential of the ligand for targeted imaging applications, particularly with radioactive copper.

Main Methods:

• Synthesis of hexadentate bispidine carbamate derivatives.
• Characterization using analytical methods, single crystal X-ray diffraction, and radiolabeling.
• Photophysical analysis including luminescence studies with various metal ions.
• Transmetalation experiments to assess complex stability.
• Investigation of lanthanide complexes for dual emission.

Main Results:

• A BODIPY-substituted bispidine ligand (3) was successfully synthesized and characterized.
• Ligand 3 exhibits metal-dependent fluorescence modulation: Cu(II) quenches fluorescence, while Ni(II) and Zn(II) do not.
• The (64)Cu(II)-3 complex demonstrates high stability, confirmed by transmetalation studies.
• The fluorescence of the ligand is restored by decay products (64)Ni(II) and (64)Zn(II), enabling simultaneous monitoring of radiation and fluorescence.
• Lanthanide complexes (Tb(III), Eu(III), Nd(III)) show dual emission from both the BODIPY ligand and the lanthanide ion.

Conclusions:

• The developed BODIPY-bispidine ligand is a promising platform for targeted imaging.
• The metal-dependent fluorescence switching provides a built-in reporter mechanism.
• The ligand's stability and dual-mode detection capabilities are advantageous for advanced imaging applications.