Journal of Physical Chemistry A vol:108 issue:18 pages:4059-4068
The theoretical study of azonine (C8NH9) and its N-substituted derivatives presents a new view on the azonine chemistry. Azonine is characterized as a molecule with very specific aromatic properties: interaction with surrounding H2O molecules and alkali ions and substitution of the N-H hydrogen distorts the planarity of,,, This distortion is such that the aromaticity remains. N-Methylazonine is characterized as nonplanar the ring and the global minimum structures of the alkali salts have the metal residing on top of the distorted ring (cation-pi interaction). These findings explain the experimentally known H-1 NMR spectra, UV-vis spectra, and thermal stability studies. The study also includes the reaction paths from azonine to cis- and trans-8,9-dihydroindole, and suggests that the trans isomer could be formed by proper kinetic control. The vibrational spectrum of azonines, analyzed with the potential energy distribution approach, is presented for the first time.