Lewis Acidity and Basicity: Another Measure of Carbene Reactivity.

Area of Science:

• Computational chemistry
• Quantum chemistry
• Organic chemistry

Background:

• Carbenes are reactive intermediates with diverse chemical behaviors.
• Understanding carbene reactivity is crucial for predicting reaction outcomes.
• Existing classifications may not fully capture the spectrum of carbene behavior.

Purpose of the Study:

• To evaluate the structural and energetic reactivities of various carbenes.
• To understand carbene reactivity modes and mechanisms through affinities.
• To facilitate the classification of carbenes as nucleophilic or electrophilic.

Main Methods:

• Utilizing electronic structure calculations.
• Employing the composite correlated molecular orbital theory G3MP2 level.
• Assessing reactivities against standard electrophile (proton) and nucleophile (fluoride).

Main Results:

• Proton and fluoride affinities were calculated for various carbenes.
• Reactivity patterns were elucidated based on calculated affinities.
• A basis for classifying carbenes as singlet nucleophilic or electrophilic was established.

Conclusions:

• The study provides a framework for understanding carbene reactivity.
• Calculated affinities offer insights into carbene reaction mechanisms.
• The need for refined classification of borderline electrophilic/nucleophilic carbenes is highlighted.