Synthesis, Structure, and Properties of Two Planar BN-Benzofluorenes

Area of Science:

• Organic Chemistry
• Materials Science
• Photophysics

Background:

• Benzofluorenes are important organic molecules with applications in optoelectronics.
• Tuning electronic and photophysical properties of organic molecules is crucial for developing new materials.

Purpose of the Study:

• To synthesize and characterize novel planar boron nitride (BN) doped benzofluorenes.
• To investigate the impact of BN doping on the electronic and photophysical properties.
• To explore the utility of these compounds as intermediates for further functionalization.

Main Methods:

• Palladium-catalyzed intramolecular C-C and C-N coupling reactions for synthesis.
• X-ray crystallographic analysis for structural confirmation.
• UV-vis absorption and fluorescence emission spectroscopy for photophysical studies.

Main Results:

• Successful synthesis of two planar BN-benzofluorenes (BN-BkF and BN-BjF).
• BN doping lowered HOMO and raised LUMO levels compared to carbon analogues.
• Blue shifts observed in UV-vis absorption and fluorescence spectra.
• Efficient synthesis of monohalogenated BN-benzofluorenes as versatile intermediates.

Conclusions:

• BN doping is an effective strategy to tune the electronic and optical properties of benzofluorenes.
• BN-benzofluorenes serve as valuable building blocks for creating functionalized derivatives.
• The photophysical properties are highly dependent on the substituents, offering tunable optoelectronic characteristics.