Comparative investigation of ±σ–hole interactions of carbon-containing molecules with Lewis bases, acids and di-halogens

Abstract

Herein, the potentiality of carbon-containing molecules (W–C–F3, where W is a withdrawing atom or group) to interact with Lewis bases (B), Lewis acids (A) and σ–hole-containing molecules (X2) with W–C···B/A/X2 angle of 180° was reported. −σ–hole and +σ–hole terminologies were implemented to describe the interactions of W–C–F3 with nucleophilic and electrophilic sites, respectively. To characterize such interactions, quantum mechanical calculations including geometrical optimization, ±σ–hole test, interaction energy calculation, quantum theory of atoms in molecules (QTAIM) and noncovalent interaction (NCI) index calculation were performed at MP2/aug-cc-pVTZ(PP) level of theory. The results showed (1) the electrostatic potentiality of the W–C–F3 molecules to favorably interact with Lewis bases and acids, (2) the dependency of ±σ–hole interaction energies on the σ–hole size of the tetrel atom and (3) descending of interaction energies in the order W–C–F3···B > W–C–F3···X2 > W–C–F3···A. QTAIM, and NCI calculations revealed the noncovalent nature of the ±σ–hole interactions. Further, an investigation on F–C–X3 model was carried out to highlight the emerging role of X3 atoms in ±σ–hole interactions. Comprising of the findings, the most favorable interaction energies were denoted when the F–C–X3 interact with X2 molecules compared to those with B and A molecules.