Comparison of σ‐/π‐Hole Tetrel Bonds between TH₃F/F₂TO and H₂CX (X=O, S, Se)

Abstract Several σ‐hole and π‐hole tetrel‐bonded complexes with a base H 2 CX (X=O, S, Se) have been studied, in which TH 3 F (T=C−Pb) and F 2 TO (T=C and Si) act as the σ‐hole and π‐hole donors, respectively. Generally, these complexes are combined with a primary tetrel bond and a weak H‐bond. Only one minimum tetrel‐bonded structure is found for TH 3 F, whereas two minima tetrel‐bonded complexes for some F 2 TO. H 2 CX is favorable to engage in the π‐hole complex with F 2 TO relative to TH 3 F in most cases, and this preference further expands for the Si complex. Particularly, the double π‐hole complex between F 2 SiO and H 2 CX (X=S and Se) has an interaction energy exceeding 500 kJ/mol, corresponding to a covalent‐bonded complex with the huge orbital interaction and polarization energy. Both the σ‐hole interaction and the π‐hole interaction are weaker for the heavier chalcogen atom, while the π‐hole interaction involving F 2 TO (T=Ge, Sn, and Pb) has an opposite change. Both types of interactions are electrostatic in nature although comparable contributions from dispersion and polarization are respectively important for the weaker and stronger interactions.

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