Hydrogen-Bonded Dialkylcarboxamide Cations and Their Dihalogenohalogenates

Molecular geometry, electron structure and thermodynamic parameters for a representative group of tertiary amides and bis(amide)hydrogen cations were computed by density functional theory at ωB97X-V/dgdzvp//ωB97X/dgdzvp level, trihalide salts of these cations were synthesized, and NMR manifestations of short hydrogen bond in these cations were experimentally demonstrated. With a vocabulary of computational techniques, a number of intramolecular noncovalent interactions such as H···O···H, C–H···O, C–H···H–C were revealed, and the role of these interaction in the stabilization of hemiprotonated amides and their saline forms evaluated.