Nitrogen-Based Lewis Acids Derived from Phosphonium Diazo Cations.

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Catalysis

Background:

• Diaryl diazabutadiene cations are nitrogen-containing compounds with potential applications in catalysis.
• Understanding their electronic properties and reactivity is crucial for developing new synthetic methodologies.

Purpose of the Study:

• To investigate the Lewis acidity and electron-accepting capabilities of diaryl diazabutadiene cations.
• To explore the reactivity of these cations with phosphine ligands and their potential in small molecule activation.

Main Methods:

• Synthesis of diaryl diazabutadiene cations with varying phosphine ligands.
• Characterization of the resulting compounds using spectroscopic techniques.
• Electrochemical reduction studies to determine electron-accepting properties.
• Investigation of the reaction with diphenyl disulfide (PhSSPh) to assess small molecule cleavage.

Main Results:

• The study synthesized novel diaryl diazabutadiene cations, confirming their Lewis acidity at the nitrogen atoms.
• Electron reduction studies revealed the ability of these cations to act as one- or two-electron acceptors.
• The combination of a bulky phosphine and a diaryl diazabutadiene cation demonstrated Frustrated Lewis Pair (FLP) activity, cleaving diphenyl disulfide.

Conclusions:

• Diaryl diazabutadiene cations exhibit significant Lewis acidity and can function as potent one- or two-electron acceptors.
• These cations, particularly when paired with bulky phosphines, show promise as Frustrated Lewis Pairs for activating small molecules like disulfides.