A modular approach to carbene-stabilized diphosphorus species

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• N-heterocyclic Carbene Chemistry

Background:

• N-heterocyclic carbenes (NHCs) are versatile ligands in organometallic chemistry.
• Diphosphorus species with NHC ligands are of interest for their unique bonding and reactivity.
• Controlling the electronic properties and oxidation states of these species is crucial for understanding phosphorus-phosphorus bonding.

Purpose of the Study:

• To synthesize novel heteroleptic N-heterocyclic dicarbene-diphosphorus compounds.
• To investigate the structural and electronic properties of these species across different oxidation states.
• To explore the nature of the phosphorus-phosphorus bond in these compounds.

Main Methods:

• Synthesis of precursor carbene-phosphinidene and carbene-phosphorus trichloride adducts.
• Reduction and oxidation reactions to generate different oxidation states of the diphosphene core.
• X-ray diffraction analysis for structural determination.
• Density Functional Theory (DFT) calculations for electronic structure analysis.

Main Results:

• Successful synthesis of a series of heteroleptic NHC-stabilized diphosphorus compounds.
• Isolation and characterization of neutral, radical cation, and dicationic species.
• Observation of a progressively shortening P-P bond length with increasing positive charge.
• Experimental evidence for a P-P single bond in the neutral species and a P=P double bond in the dicationic species.

Conclusions:

• The study demonstrates the successful preparation of heteroleptic NHC-diphosphorus complexes.
• The P-P bond character can be tuned by varying the oxidation state of the diphosphene core.
• The dicationic species can be described as a diphosphene, supported by structural and computational data.