Tridentate Lewis acids with phenyl substituted 1,3,5-trisilacyclohexane backbones

Area of Science:

• Organosilicon Chemistry
• Lewis Acid Chemistry
• Supramolecular Chemistry

Background:

• 1,3,5-Trisilacyclohexane derivatives offer a versatile scaffold for developing novel functional molecules.
• The introduction of ethynyl groups provides reactive handles for further chemical transformations.
• Tridentate Lewis acids are crucial in catalysis and materials science due to their unique coordination properties.

Purpose of the Study:

• To synthesize and characterize a novel 1,3,5-trisilacyclohexane skeleton functionalized with ethynyl groups.
• To explore the functionalization of this scaffold into tridentate Lewis acids.
• To investigate the reactivity of the ethynyl groups towards hydroboration and metalation.

Main Methods:

• Synthesis of the 1,3,5-trisilacyclohexane skeleton with ethynyl substituents.
• Hydroboration reaction using bis(pentafluorophenyl)borane (HB(C6F5)2).
• Metalation reactions with gallium organyls (GaR3, R = Me, Et).
• Characterization using elemental analysis, NMR spectroscopy (1H, 13C, 29Si), and IR spectroscopy.
• X-ray crystallography for structural determination of key derivatives.

Main Results:

• Successful synthesis of the [CH2Si(Ph)(C2H)]3 core structure.
• Formation of the ethenylborane derivative {CH2Si(Ph)[C2H2B(C6F5)2]}3 via hydroboration.
• Synthesis of gallium derivatives {CH2Si(Ph)[C2Ga(R)2]}3 (R = Me, Et) through metalation.
• Structural elucidation of various derivatives, including all-cis and cis-trans isomers, confirming the molecular architecture.

Conclusions:

• The 1,3,5-trisilacyclohexane framework is a viable platform for creating functionalized tridentate Lewis acids.
• The ethynyl groups serve as effective sites for introducing boron and gallium moieties, leading to new organometallic compounds.
• The characterized compounds possess potential for applications in areas requiring directed Lewis acidity and tailored electronic properties.