Bond fission in monocationic frameworks: diverse fragmentation pathways for phosphinophosphonium cations

Area of Science:

• Organophosphorus chemistry
• Gas-phase ion chemistry
• Computational chemistry

Background:

• Phosphinophosphonium cations are novel phosphorus-containing monocations.
• Understanding their gas-phase fragmentation is crucial for fundamental bonding insights.

Purpose of the Study:

• To elucidate the fragmentation pathways of phosphinophosphonium cations.
• To investigate the influence of substituents on P-P and P-C bond cleavage.
• To compare experimental findings with theoretical predictions.

Main Methods:

• Synthesis and characterization of phosphinophosphonium cations.
• Collision-induced dissociation (CID) mass spectrometry.
• Density functional theory (DFT) calculations.

Main Results:

• Experimental evidence for P-P and P-E bond fission and beta-hydride elimination.
• Heterolytic P-P cleavage is more sensitive to substituent changes than homolytic cleavage.
• Beta-hydride elimination increases with steric bulk of the substituent R.
• DFT calculations show good agreement with experimental trends.

Conclusions:

• Phosphinophosphonium cations exhibit both homolytic and heterolytic cleavage pathways.
• These findings challenge simplistic bonding models for monocations.
• The study provides fundamental insights into bonding in phosphorus-containing cations.