Carbene-stabilized phosphenium oxides and sulfides

Area of Science:

• Organophosphorus chemistry
• Main group chemistry
• Carbene chemistry

Background:

• Oxo- and thiooxophosphenium species ([R(2)P(+)=X], X=O, S) are highly reactive and elusive intermediates.
• Intermolecular stabilization of such species has been challenging.
• Carbene donors, such as N-heterocyclic carbenes (NHC) and diaminocyclopropenylidenes (BAC), are known to stabilize reactive species.

Purpose of the Study:

• To isolate and characterize carbene→chalcogenophosphenium adducts.
• To investigate the nature of the carbene-chalcogenophosphenium bond.
• To explore the intermolecular stabilization of oxo- and thiooxophosphenium species.

Main Methods:

• Isolation and full characterization of carbene→chalcogenophosphenium adducts.
• Experimental confirmation of dative bond character via nucleophilic displacement with chloride.
• Ligand exchange reactions to demonstrate carbene donor mobility.
• Density Functional Theory (DFT) calculations to analyze bonding and dissociation modes.

Main Results:

• Successful isolation and characterization of novel carbene→chalcogenophosphenium adducts.
• Experimental evidence confirmed the dative nature of the R(2)C:→P(+)(X)Ph(2) bond.
• Nucleophilic displacement of carbene donors and ligand exchange reactions were achieved.
• DFT calculations supported a heterolytic dissociation preference, consistent with a dative bond.

Conclusions:

• Carbene donors effectively stabilize elusive oxo- and thiooxophosphenium species through adduct formation.
• The carbene→chalcogenophosphenium interaction is characterized by a dative bond.
• These findings provide a new avenue for studying and utilizing reactive phosphorus-chalcogen species.