Phosphide delivery to a cyclotrisilene.

Area of Science:

• Organosilicon Chemistry
• Main Group Chemistry
• Inorganic Chemistry

Background:

• Cyclic trisilenes are silicon analogues of cyclic alkenes.
• The 2-phosphaethynolate anion (PCO-) is a unique heterocumulene with rich reactivity.
• Understanding the reactivity of low-valent silicon compounds is crucial for developing new synthetic methodologies.

Purpose of the Study:

• To investigate the reaction between the 2-phosphaethynolate anion (PCO-) and a cyclic trisilene.
• To characterize the products formed from this reaction.
• To explore the subsequent transformations of the initial adduct.

Main Methods:

• Reaction of PCO- with cSi3(Tip)4 (Tip = 2,4,6-triisopropylphenyl).
• Spectroscopic characterization of the resulting bicyclo[1.1.1]pentan-2-one analogue ([P(CO)Si3(Tip)4](-); 1).
• Photolytic decarbonylation of compound 1.

Main Results:

• The reaction resulted in the net activation of P-C and Si-Si multiple bonds.
• A novel heteroatomic bicyclo[1.1.1]pentan-2-one analogue (1) was synthesized.
• Photolytic decarbonylation of 1 led to the formation of a cyclobutene anion congener with allylic character.

Conclusions:

• The reaction demonstrates a formal addition of a phosphide and carbonyl across the Si-Si double bond of trisilene.
• The study showcases the utility of PCO- as a versatile building block in low-valent silicon chemistry.
• The observed photolytic decarbonylation provides a pathway to new silicon-containing cyclic structures.