Tetrel Interactions from an Interacting Quantum Atoms Perspective

Abstract

Tetrel bonds, the purportedly non-covalent interaction between a molecule that contains an atom of group 14 and an anion or (more generally) an atom or molecule with lone electron pairs, are under intense scrutiny. In this work, we perform an interacting quantum atoms (IQA) analysis of several simple complexes formed between an electrophilic fragment (A) (CH3F, CH4, CO2, CS2, SiO2, SiH3F, SiH4, GeH3F, GeO2, and GeH4) and an electron-pair-rich system (B) (NCH, NCO-, OCN-, F-, Br-, CN-, CO, CS, Kr, NC-, NH3, OC, OH2, SH-, and N3-) at the aug-cc-pvtz coupled cluster singles and doubles (CCSD) level of calculation. The binding energy ( E bind AB ) is separated into intrafragment and inter-fragment components, and the latter in turn split into classical and covalent contributions. It is shown that the three terms are important in determining E bind AB , with absolute values that increase in passing from electrophilic fragments containing C, Ge, and Si. The degree of covalency between A and B is measured through the real space bond order known as the delocalization index ( δ AB ). Finally, a good linear correlation is found between δ AB and E xc AB , the exchange correlation (xc) or covalent contribution to E bind AB .

Contributions of IQA electron correlation in understanding the chemical bond and non-covalent interactions

“…The details of our approach have been exhaustively explained in previous publications [32,[41][42][43][44][45]. The IQA method has been developed for over two decades, and was initially applied mainly at Hartree-Fock level [31], but was more recently made compatible with density functional theory [38,46,47]. So far there are two methods to account for electron correlation within the Interacting Quantum Atoms [31, 38,[46][47][48][49] (IQA) paradigm: the 6D and the 3D Electrostatic Potential (ESP) integration models.…”

“…The IQA method has been developed for over two decades, and was initially applied mainly at Hartree-Fock level [31], but was more recently made compatible with density functional theory [38,46,47]. So far there are two methods to account for electron correlation within the Interacting Quantum Atoms [31, 38,[46][47][48][49] (IQA) paradigm: the 6D and the 3D Electrostatic Potential (ESP) integration models. The 6D integration approach was the original partition scheme proposed by our group [50] and generates intra-atomic and interatomic terms…”

The Activation Strain Model in the Light of Real Space Energy Partitions

“…Indeed, although charge transfer is non-zero, the overall interaction between the non-overlapping fragment densities is globally destabilizing. An interesting point regards the so-called exchange-repulsion [63,64] IQA energy, defined as XR ϵ E xr…”

Engineering Crystals Using sp3‐C Centred Tetrel Bonding Interactions

“…[9] To date, an otable absentee amongt he non-metal elements that have been rationally exploited as s-hole donor is carbon, [1b, 10] which is ubiquitouslyp resent in synthetic chemistry and of central importance to life. Carbon-centred interactions with carbonyls are well established, [11] and interactions between (coordinated) acetonitrile, [12] carbonm onoxide [13] and carbon dioxide [14] with appropriate acceptors have also been reported. However, these involve sp 2 -o rs p-hybridized carbon atoms that do not align with the definition of a s-hole interaction (but rather some type of p-interaction).I nterestingly,p olar interactions with sp 3 -hybridized carbon atoms can persist with methylg roups in crystal structures.…”