Structure and electronics in dimeric boron π expanded azine and salphen complexes.

Area of Science:

• Materials Chemistry
• Supramolecular Chemistry
• Photophysics

Background:

• Boron-based fluorophores with nitrogenous chelating ligands are of significant interest.
• Limited research exists on boron-salphen and azine derivatives as fluorophores.

Purpose of the Study:

• To synthesize and characterize novel π-expanded boron salphen type complexes.
• To investigate the coordination behavior of boron difluoride (BF₂) with azine and salphen ligands.
• To explore the electronic structures and photophysical properties of these new boron complexes.

Main Methods:

• Synthesis of boron complexes incorporating bis(2-hydroxynaphthaldehyde)azine and ortho, meta, para variants of 2-hydroxynaphthaldehyde salphen.
• Full characterization using X-ray diffraction analysis.
• Computational studies employing Density Functional Theory (DFT) and Time-Dependent DFT (TDDFT).

Main Results:

• Formation of a single BF₂ adduct with the azine derivative.
• Observation of dimeric BF₂ binding with the naphth-phen (salphen) compounds.
• Detailed structural and electronic insights obtained from X-ray diffraction and DFT/TDDFT calculations.

Conclusions:

• Successful synthesis of novel π-expanded boron salphen and azine complexes.
• Demonstration of differential BF₂ binding modes based on ligand structure.
• Elucidation of electronic structures providing a foundation for designing new boron-based fluorophores.