Phosphinimine-substituted boranes and borenium ions

Area of Science:

• Organometallic Chemistry
• Boron Chemistry
• Phosphorus Chemistry

Background:

• Phosphinimines (R3PNSiMe3) are versatile ligands in coordination chemistry.
• Boranes are electron-deficient compounds with diverse reactivity.
• Understanding the interplay between phosphinimine ligands and boranes is crucial for developing new synthetic methodologies.

Purpose of the Study:

• To synthesize novel phosphinimine-substituted boranes.
• To investigate the steric and electronic factors influencing product formation (monomeric vs. dimeric).
• To explore the preparation of borenium ion salts from these novel compounds.

Main Methods:

• Reaction of phosphinimines (R = t-Bu, Cy, Et, Ph) with various chloro and fluoroboranes.
• Characterization of products using spectroscopic techniques and X-ray diffraction.
• Synthesis of borenium ion salts via reaction with MeOTf.

Main Results:

• A series of phosphinimine-substituted boranes were successfully synthesized via Me3SiX elimination.
• Steric and electronic factors were identified as key determinants for monomeric or dimeric product formation.
• Lewis acid-mediated exchange of Si-bonded methyl groups for chloro-substituents was observed.
• Novel borenium ion salts were prepared from the phosphinimine-substituted boranes.

Conclusions:

• The study established a new route to phosphinimine-substituted boranes and borenium ions.
• Steric bulk and electronic properties of substituents significantly influence the outcome of reactions with boranes.
• The characterized compounds offer potential for further applications in catalysis and materials science.