Stabilizing Borinium Cations [X-B-X]⁺ through Conjugation and Hyperconjugation Effects

Area of Science:

• Inorganic Chemistry
• Computational Chemistry
• Organic Synthesis

Background:

• Borinium cations are two-coordinated boron cations, known as strong Lewis acids.
• Their preparation is challenging due to limited ligands and nucleophilic attack susceptibility.
• Recent synthesis of dimesityl borinium cation shows potential for stabilization via substituents.

Purpose of the Study:

• Investigate stabilization mechanisms for substituted borinium cations [X-B-X]+.
• Explore the role of substituents in enhancing borinium cation stability.
• Identify promising synthetic targets for novel borinium cations.

Main Methods:

• Utilized Natural Bond Orbital (NBO) analysis.
• Employed Bond Lengths and Valencies (BLW) methods for computational analysis.
• Studied a series of borinium cations with varying substituents [X-B-X]+.

Main Results:

• Both π-conjugation and hyperconjugation significantly stabilize substituted borinium cations.
• Substituents like X = C═CH2 provide stabilization through delocalized π-bonding.
• The empty boron p orbitals participate in stabilizing interactions.

Conclusions:

• Substituted borinium cations can be effectively stabilized by electronic effects.
• Borinium cations with X = C═CH2 and X = cyc-N(CH)2 are proposed as viable synthetic targets.
• This research opens avenues for designing novel boron-containing compounds.