Quantum-mechanical investigation of tetrel bond characteristics based on the point-of-charge (PoC) approach

Abstract

The point-of-charge (PoC) approach was employed to investigate the characteristics of the tetrel bond from an electrostatic perspective. W-T-XYZ···B nomenclature was suggested where T is a tetrel atom, W is the atom along the σ-hole extension, B is a Lewis base, and X, Y, and Z are three atoms on the same side of the σ-hole. Quantum-mechanical calculations were carried out on F-T-F systems (where T = C, Si, Ge, or Sn) at the MP2/aug-cc-pVTZ level of theory, with PP functions for Ge and Sn atoms. The tetrel bond strength was estimated via the molecular stabilization energy. Tetrel bond strength was found to increase with increasing PoC negativity (i.e., Lewis basicity) and the electronegativity of the W atom. Moreover, the effects of the T···PoC distance, the W-T···PoC angle, and the aqueous medium on the tetrel bond strength were also investigated. Correlations between tetrel bond strength and several atomic and molecular descriptors such as the natural charge on the tetrel atom, E, and the p-orbital contribution to W-T bond hybridization were observed. Contrary to expectations, the tetrel bond strength in F-C-X increased as the electronegativity of X decreased. The σ-node criteria for the studied molecules were also introduced and discussed. The ability of these molecules to simultaneously form more than one tetrel bond was examined via the σ-hole test. In conclusion, the tetrel bond strength was found to be governed by the strengths of (i) the attractive electrostatic interaction of the Lewis base with the σ-hole, (ii) the attractive/repulsive interaction between the Lewis base and the X, Y, and Z atoms, and (iii) the van der Waals interaction between the Lewis base and the X, Y, and Z atoms. Graphical Abstract Characterization of tetrel bond using the Point-of-Charge (PoC) approach.

A Computational Investigation of Unconventional Lone‐Pair Hole Interactions of Group V–VIII Elements

“…With the PoC approach, the σ‐hole test was proposed to examine the ability of a σ‐atom‐containing molecule to form bonds of the tetrel, chalcogen, and halogen types. Similarly, the lp‐hole test was introduced in this study to ascertain whether molecules containing lp‐hole have the ability to participate in favorable electrostatic interactions with Lewis bases via the lp‐hole.…”

“…MEP and V s,max calculations were carried out at the same level of geometry optimization. To precisely locate the maximum electrostatic potential of an lp‐hole, the stabilization energy surface of the XYZ side of the molecule was scanned using Point‐of‐Charge (PoC) approach . A PoC of −0.01 au was adopted at 2.0 Å from the σ‐atom as illustrated in Figure ii.…”

σ-Hole and Lone-Pair Hole Interactions in Chalcogen-Containing Complexes: A Comparative Study

“…The value of the employed PoC to investigate the Chal···PoC distance effect was made equal to the one used in optimization. The strength of the σ-hole and lp hole interactions was estimated in terms of the molecular stabilization energy ( E stablization ) according to the following equation: 12 , 13 , 18 , 34 , 35 …”

“…The σ-hole and lp hole interactions will first be investigated from the electrostatic perspective via the point-of-charge (PoC) approach. 12 , 13 , 18 , 34 , 35 In addition, the PoC approach will be utilized to precisely define lp, lp hole, and σ-hole locations. Moreover, the Lewis basicity effect on the strength of the σ-hole and lp hole interactions will be also examined.…”

±π‐Hole Interactions: A Comparative Investigation Based on Boron‐Containing Molecules

“…Furthermore, the B⋅⋅⋅PoC distance effect on the given electrostatic interactions was studied through distances ranging from 2.5 Å to 5.0 Å along x‐axis with step size of 0.1 Å and X‐B⋅⋅⋅PoC angle of 90° (see Figure 1). The strength of the π‐hole interaction was estimated in terms of molecular stabilization energy ( E stablization ) according to the following equation: [21,28a, 19a, 17, 19b, 28b] …”