Tetrel Bonding along the Pathways of Transsilylation and Alkylation of N-Trimethylsilyl- N-methylacetamide with Bifunctional (Chloromethyl)fluorosilanes.

A quantum chemical study has been carried out on the complexes formed in the first stage of the reaction of (chloromethyl)trifluorosilane with an ambident nucleophile, N-trimethylsilyl- N-methylacetamide, existing in the amide and imidate tautomeric forms. The analysis of molecular electrostatic potential maps of the electrophile molecule revealed the presence of two σ-holes belonging to the Si and C atoms. Each of the two tautomers of the nucleophile form complexes having O···Si, O···C, N···Si, and N···C bonds of different characters. The natural bond orbital and quantum theory of atoms in molecules analyses showed the presence of the O···Si and O···C tetrel bonds or of electrostatic interaction in the complexes with the amide tautomer, depending on the orientation of the components. The imidate tautomer forms a complex with covalent N-Si bond, whereas the N···C bond is very weak. The effect of silicon atom arrangement on the structure of complexes between N-trimethylsilyl- N-methylacetamide and bifunctional silanes ClCHSiX F (X = Me, OMe, Cl, n = 1, 2) and the effect of σ-hole tetrel bonding interactions on the reaction pathways are discussed.