Boranes Paving the Way to Anionic Cyclic (Alkyl)(amino)carbenes (Ani-cAACs)

Area of Science:

• Organometallic Chemistry
• Ligand Design
• Boron Chemistry

Background:

• Anionic cyclic (alkyl)(amino)carbenes (Ani-cAACs) are a class of ligands with unique electronic properties.
• Tuning the electronic and steric profiles of Ani-cAACs is crucial for developing new catalytic systems and materials.

Purpose of the Study:

• To synthesize and characterize the first examples of Ani-cAACs featuring borane substituents.
• To investigate how borane substituents modulate the electronic properties (σ-donor and π-acceptor abilities) of Ani-cAACs.
• To explore the reactivity and potential applications of these novel ligands.

Main Methods:

• Synthesis of borane-substituted Ani-cAACs, including a B(CN)3-substituted derivative and a C2F5BF2-substituted Ani-cAAC.
• In situ generation and reaction of Ani-cAAC intermediates.
• Characterization of novel anionic selenium adducts and an Ani-cAAC gold complex.
• Theoretical calculations to understand electronic and steric properties.

Main Results:

• Successful synthesis of anionic cyclic (alkyl)(amino)carbenes with borane substituents.
• Demonstrated modulation of σ-donor and π-acceptor abilities by borane groups.
• Obtained high yields of a C2F5BF2-substituted Ani-cAAC on a multigram scale.
• Synthesized anionic selenium adducts and an Ani-cAAC gold complex, showcasing reactivity.

Conclusions:

• Borane-substituted Ani-cAACs represent a novel class of ligands with tunable electronic properties.
• These ligands possess a unique combination of negative charge, large steric bulk, and adaptable electronic characteristics.
• The ease of synthesis and versatile properties make these Ani-cAACs promising building blocks for future chemical applications.