The Bis(ferrocenyl)phosphenium Ion Revisited

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Phosphorus Chemistry

Background:

• The bis(ferrocenyl)phosphenium ion ([Fc2P]+) was previously identified as a unique donor-free divalent phosphenium ion.
• Understanding the electronic and structural properties of phosphenium ions is crucial for their application in synthesis.

Purpose of the Study:

• To investigate the molecular and electronic structure of the bis(ferrocenyl)phosphenium ion ([Fc2P]+).
• To determine the influence of intramolecular interactions on the Lewis acidity of [Fc2P]+.
• To explore the complex formation of [Fc2P]+ with Lewis bases.

Main Methods:

• Computational analysis of molecular and electronic structure.
• Examination of intramolecular Fe-P contacts.
• Reaction studies with Lewis bases PPh3 and IPr.

Main Results:

• The [Fc2P]+ ion displays significant intramolecular Fe-P contacts.
• These Fe-P contacts are primarily electrostatic and attenuate the Lewis acidity of the phosphenium center.
• [Fc2P]+ successfully forms stable donor-acceptor complexes with PPh3 and IPr.

Conclusions:

• Intramolecular Fe-P interactions play a key role in modulating the reactivity of [Fc2P]+.
• The [Fc2P]+ ion, despite its divalent nature, exhibits Lewis acidity and can act as a Lewis acid in complex formation.
• The findings provide insights into the fundamental chemistry of phosphenium ions and their potential applications.