Chemistry on Boranils: an entry to functionalized fluorescent dyes

Area of Science:

• Organic Chemistry
• Bioconjugation Chemistry
• Fluorescent Materials Science

Background:

• Boranil fluorophores are valuable scaffolds for developing novel functional materials.
• Nitro-aromatic compounds can be chemically modified to yield diverse derivatives.

Purpose of the Study:

• To synthesize novel fluorescent dyes from a Boranil fluorophore.
• To investigate the utility of these dyes in bioconjugation applications.
• To characterize the photophysical properties of the labeled biomolecule.

Main Methods:

• Selective reduction of a nitro-phenyl Boranil fluorophore to its anilino form.
• Conversion of the anilino derivative to amide, imine, urea, and thiourea compounds.
• Isolation of an isothiocyanate intermediate.
• Labeling of Bovine Serum Albumin (BSA) with the isothiocyanate derivative.
• Characterization of the luminescent properties of the labeled BSA.

Main Results:

• Successful synthesis of fluorescent amide, imine, urea, and thiourea derivatives.
• Development of an isothiocyanate intermediate for bioconjugation.
• Preparation of purified, labeled BSA with strong luminescence.
• Quantification of a high fluorescence quantum yield (Φ(f) = 47%) in BSA.

Conclusions:

• The synthesized Boranil derivatives are effective fluorescent dyes.
• The isothiocyanate intermediate enables efficient labeling of proteins like BSA.
• The resulting labeled BSA exhibits excellent luminescent properties, suitable for bioimaging and sensing applications.