Intramolecular <i>sp</i>²-<i>sp</i>³ Disequalization of Chemically Identical Sulfonamide Nitrogen Atoms: Single Crystal X-Ray Diffraction Characterization, Hirshfeld Surface Analysis and DFT Calculations of <i>N</i>-Substituted Hexahydro-1,3,5-Triazines

Abstract

In this manuscript, the synthesis and single crystal X-ray diffraction characterization of four N-substituted 1,3,5-triazinanes are reported along with a detailed analysis of the noncovalent interactions observed in the solid state architecture to these compounds, focusing on C–H···π and C–H···O H-bonding interactions. These noncovalent contacts have been characterized energetically by using DFT calculations and also by Hirshfeld surface analysis. In addition, the supramolecular assemblies have been characterized using the quantum theory of “atoms-in-molecules” (QTAIM) and molecular electrostatic potential (MEP) calculations. The XRD analysis revealed a never before observed feature of the crystalline structure of some molecules: symmetrically substituted 1,3,5-triazacyclohexanes possess two chemically identical sulfonamide nitrogen atoms in different sp2 and sp3-hybridizations.

Keywords

• triazinane
• 1,3,5-Triazacyclohexane
• Hirshfeld surface analysis
• DFT study
• H-bonding
• C–H···π interaction