Unveiling the reactions of triethylphosphite and its diethylamino substituted derivatives to carbon tetrachloride with a molecular electron density theory perspective

Abstract

A molecular electron density theory study is presented herein for the reactions of triethylphosphite (TEP) and its diethylamino substituted derivatives (DEAP and MEAP) to carbon tetrachloride (CCl4). Analysis of the Electron localization function (ELF) has allowed characterizing the electronic structure of the reagents and the conceptual density functional theory (CDFT) study predicted the polar character of the reactions with the electronic flux from TEP, DEAP and MEAP to CCl4. Analysis of the relative energies along the potential energy surfaces has indicated energetically favoured attack on the chlorine atom of CCl4 relative to that on the carbon atom and the reactions became energetically more facile due to introduction of the electron donating diethylamino substituent. This allowed formulating the heterolytic mechanism of the reactions in which the quick exchange of CCl3- with the chlorine atom takes place for TEP, while the exchange is sloweddown in DEAP and MEAP due to mesomeric stabilization of the phosphonium ion. The ELF and Atoms in molecules (AIM) studies indicated early transition states (TSs) with no new covalent bond formation, and the non-covalent interactions at the interatomic bonding regions of the TSs are analysed from the Independent Gradient Model (IGM) analysis based on the Hirshfield partition of electron density.