DFT and QTAIM study of the tetra-tert-butyltetraoxa[8]circulene regioisomers structure

The recently synthesized tetra-tert-butyltetraoxa[8]circulene regioisomers characterized by unusual solution-state aggregation behavior are calculated at the density functional theory (DFT) level with the quantum theory of atoms in molecules (QTAIMs) approach to the electron density distribution analysis. The presence of stabilizing intramolecular hydrogen bonds and hydrogen–hydrogen interactions in the studied molecules is predicted and the energies of these interactions are estimated with QTAIM. Occurrence of the CH⋯O bonds is detected by the single-crystal X-ray analysis for two regioisomers, obtained in high purity.