Heterometathesis of diphosphanes (R₂P-PR₂) with dichalcogenides (R'E-ER', E = O, S, Se, Te)

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Computational Chemistry

Background:

• Exploration of heterometathesis reactions involving P-P and E-E bonds (E = Se, S, O, Te).
• Understanding the reactivity patterns and mechanistic pathways of these transformations.

Purpose of the Study:

• To investigate the experimental and computational aspects of R2P-PR2 reacting with R'E-ER' to form R2P-ER'.
• To elucidate the factors governing the reactivity and selectivity of these heterometathesis reactions.

Main Methods:

• Experimental synthesis and characterization of novel phosphorus-chalcogen compounds.
• X-ray crystallography for structural determination.
• Density Functional Theory (DFT) calculations to study reaction mechanisms and thermodynamics.

Main Results:

• Rapid and quantitative formation of Ph2P-SePh from Ph2P-PPh2 and PhSe-SePh, consistent with a radical mechanism.
• Synthesis and characterization of various Ar2P-SeR compounds.
• Reactions with dichalcogenides (E=S, Se) are favorable, while E=Te and E=O show kinetic limitations or require specific conditions (UV irradiation for O-O).
• DFT calculations predict thermodynamic favorability for E=O, S, Se but not E=Te.

Conclusions:

• Heterometathesis reactions with R'E-ER' are efficient for E=S and Se, proceeding via radical pathways.
• Reactions with R'O-OR' are kinetically controlled and can be initiated by UV light.
• The observed reactivity trends are explained by a combination of thermodynamic and kinetic factors elucidated by DFT calculations.