Why do N-heterocyclic carbenes and silylenes activate white phosphorus differently?

Tibor Szilvási, Tamás Veszprémi

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We explored the possible reaction of three model carbenes and two model silylenes with white phosphorus leading to insertion, bis-adduct, and tris-adduct products. The energetics of the calculated mechanisms are in accordance with the experimental observations explaining key features like carbene-P4 ratio-dependent reactivity of carbonyl decorated bisamidocarbene and cyclic alkyl-amino carbene. The analysis of the bonding motif of C-P and Si-P bonds in the key intermediate revealed the importance of double-bond and donor-acceptor resonance structures. We found correlation between the σ-donor and π-acceptor strength of investigated carbenes and silylenes and their reactivity with white phosphorus. The combination of low σ-donor and high π-acceptor strength in N-heterocyclic silylene (NHSi) indicated the instability of the key intermediate, bis-adduct, and tris-adduct products and the stability of the insertion product, while high σ-donor and low π-acceptor strength of N-heterocyclic carbene (NHC) resulted in reversed stability order of the previous compounds explaining the different reaction of NHC and NHSi with white phosphorus. Donor-stabilized silylene (DSSi) has high σ-donor and low π-acceptor strength similar to NHC supporting their similar reactivity and the difference between NHSi and DSSi.

Original languageEnglish
Pages (from-to)1335-1342
Number of pages8
JournalStructural Chemistry
Volume26
Issue number5-6
DOIs
Publication statusPublished - Dec 1 2015

Keywords

  • Carbene
  • DFT
  • Reaction mechanism
  • Silylene
  • Small molecule activation
  • White phosphorus

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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