Noncovalent Interactions of Silatranes and Germatranes with the Surface of Stoichiometric and Hydroxylated 2D Silica.

Analysis of noncovalent interactions formed by the surface of a 2D silica bilayer and atrane molecules, as precursors of functional layers immobilized on a surface of silicatene, was performed. For this purpose, the systems of substituted silatranes and germatranes adsorbed on silicatene surfaces with different amounts of hydroxyl groups (0, 2, 4, and 30 per cell) were simulated by using quantum chemical modeling with periodic boundary conditions and full-electron basis sets. The observation results for interaction energy changes in the systems "atrane molecule-silicatene surface" with increasing silanol number of the silicatene surface can be used to predict the optimal degree of silicatene hydroxylation in order to control the effective progress of atrane deprotection on activated 2D silica materials. In addition to the typical hydrogen bonds, the ability of atranes to form noncovalent O···O and O···Hal interactions was discovered. In these bonds, the oxygen or halogen atoms of atranes act as electron-donor centers in relation to the silicatene oxygen atoms. The observed weakening of the Ge-O covalent bonds in germatranes, on which further deprotection reaction depends, is more manifested than for the Si-O bonds in adsorbed silatranes.