Isolation and Reactivity of a BN-Embedded Heterocumulene

Area of Science:

• Synthetic inorganic chemistry
• Organoboron chemistry
• Materials science

Background:

• Cumulenes are carbon-based compounds with cumulative double bonds.
• Incorporating boron and nitrogen (B═N) into cumulenes can alter their electronic properties.
• Free hybrid heterocumulenes with both C═C and B═N bonds have not been previously synthesized.

Purpose of the Study:

• To synthesize a novel hybrid heterocumulene containing both carbon-carbon (C═C) and boron-nitrogen (B═N) bonds.
• To characterize the structure and electronic properties of the synthesized compound.
• To explore the reactivity of this new class of heterocumulenes.

Main Methods:

• Synthesis using N-heterocyclic-substituted diazoalkene and N-heterocyclic imino-substituted borane precursors.
• Single-crystal X-ray diffraction for structural determination.
• Density Functional Theory (DFT) calculations for electronic structure analysis.

Main Results:

• Successful synthesis of a hybrid [4]heterocumulene with a bent C═C═B═N═C framework.
• Demonstrated exceptional π-delocalization along the cumulenic backbone.
• Exhibited high reactivity towards unsaturated substrates like isocyanides, carbon dioxide, and azides.
• Selective formation of three-, four-, and five-membered boron-containing heterocycles.

Conclusions:

• The synthesized BN-embedded heterocumulene possesses unique electronic properties due to the B═N incorporation.
• This new class of heterocumulenes serves as a versatile synthon in boron chemistry.
• The study opens avenues for developing novel boron-containing materials and compounds.