Sterically crowded thioamides: deviations from planarity as determined by X-ray structure analyses and quantum chemical calculations

Abstract

The structures of selected thiobenzamides and some corresponding benzamides with two more or less bulky N-substituents have been studied by single-crystal X-ray diffraction analyses. The planarity of the thioamide moiety, i.e., the internal rotation about the Ar-CS and the C-N bond as well as the bending of the two N-substituents versus the thioamide plane, was determined from the data. The experimental data were corroborated by quantum chemical calculations of molecular ensembles in the crystal and, in particular, by Hirshfeld surface analysis.