Screening seven-electron boron-centered radicals for dinitrogen activation

Area of Science:

• Inorganic chemistry
• Computational chemistry
• Catalysis

Background:

• Dinitrogen (N2) activation is crucial for synthesizing nitrogen-containing compounds but challenging due to its strong triple bond.
• Main group species are emerging as alternatives to transition metals for N2 activation.
• The high HOMO-LUMO gap and bond dissociation energy of N2 necessitate efficient activation strategies.

Purpose of the Study:

• To investigate the potential of seven-electron (7e) boron-centered radicals for dinitrogen activation.
• To explore the influence of ligand and substituents on the N2 activation capabilities of boron radicals.
• To elucidate the mechanism of N2 activation by these boron radicals.

Main Methods:

• Density functional theory (DFT) calculations were employed to study N2 activation.
• Thermodynamic analysis of dinitrogen activation by various boron radicals was performed.
• Reaction barriers for N2 activation were calculated for different boron radical systems.

Main Results:

• Boron-centered radicals, particularly those with amine ligands, exhibit favorable thermodynamics for N2 activation.
• Introduction of electron-donating groups on the boron atom significantly lowers reaction barriers.
• Electron transfer from the boron radical to N2's π* orbitals is identified as a key step.

Conclusions:

• Seven-electron boron radicals show promise as effective catalysts for dinitrogen activation.
• Tuning the electronic properties of boron radicals can optimize their N2 activation performance.
• This work opens new avenues for developing main group-based N2 activation catalysts.