A Monomeric Diarylstannanone with a Sn=O Double Bond: Synthesis and Characterization

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Inorganic Synthesis

Background:

• Diarylstannylenes are versatile precursors in organotin chemistry.
• Understanding the reactivity of low-valent main group compounds is crucial for developing new synthetic methodologies.
• The formation and characterization of metal-oxygen double bonds present unique challenges and opportunities.

Purpose of the Study:

• To synthesize a series of diarylstannylenes with varying steric bulk.
• To investigate the oxidation reactions of these diarylstannylenes.
• To characterize the resulting tin-oxygen compounds, particularly focusing on the nature of the Sn=O bond.

Main Methods:

• Synthesis of diarylstannylenes via reaction of SnX₂·dioxane with organolithium reagents.
• Oxidation of diarylstannylenes using N₂O gas.
• Characterization of products using spectroscopic techniques and computational analysis.

Main Results:

• Successfully synthesized diarylstannylenes (EMind)₂Sn, (Eind)₂Sn, and (MPind)₂Sn.
• Oxidation of the less bulky (EMind)₂Sn led to a dioxadistannetane via a stannanone intermediate.
• Oxidation of the bulkier (MPind)₂Sn yielded a monomeric diarylstannanone, (MPind)₂Sn=O, featuring a distinct Sn=O double bond.

Conclusions:

• Steric hindrance plays a critical role in dictating the oxidation pathway of diarylstannylenes.
• A novel monomeric diarylstannanone with a characterized Sn=O double bond was isolated and studied.
• The Sn=O bond in the stannanone is weaker and more polarized than its germanium analog.