Isolation of a Lewis acid-base stabilized stannanone.

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Inorganic Synthesis

Background:

• Stabilizing multiple bonds in heavier elements presents significant synthetic challenges.
• Ylide-substituted stannylenes are precursors to stannones, but isolation of monomeric forms is difficult.
• Previous attempts using cyano-substituted ylides resulted in dimeric stannoxanes.

Purpose of the Study:

• To synthesize and characterize a monomeric diylide-substituted stannanone.
• To investigate the role of ylide substituents in stabilizing the Sn=O bond.
• To explore the electronic structure and bonding characteristics of the isolated stannanone.

Main Methods:

• Synthesis via oxidation of a stannylene precursor.
• Characterization using spectroscopic (NMR, IR, Mass Spectrometry), crystallographic (X-ray diffraction), and computational (DFT) methods.
• Comparative study using different ylide substituents (cyano vs. thiophosphinoyl).

Main Results:

• Successful isolation and characterization of a monomeric stannanone stabilized by a thiophosphinoyl ylide.
• The thiophosphinoyl group provided steric bulk and P=S coordination for stabilization.
• Computational analysis revealed a highly polarized Sn-O bond with significant charge separation and minimal pi-bonding.

Conclusions:

• Substituent design is crucial for stabilizing formal multiple bonds in heavy main group elements.
• The thiophosphinoyl moiety effectively stabilizes the monomeric stannanone, overcoming challenges seen with cyano-substituted ylides.
• The study provides insights into the challenges and strategies for synthesizing and stabilizing unusual bonding arrangements in organotin compounds.