Use of electrostatic potentials to study non-bonded intramolecular interactions in 1,8-disubstituted naphthalenes with carbonyl groups as electrophilic substituents

Ab initio Self-Consistent Field molecular orbital calculations were carried out on seven 1,8-disubstituted naphthalene compounds to probe the non-bonded intramolecular interactions between electrophilic and nucleophilic substituents located at the 1 and 8 positions. The electrophilic substituents were characterized by the C=O group with the carbonyl carbon as the electrophilic center. The nucleophilic substituents were amino [(CH₃)₂N-], methoxy (CH₃O-) and hydroxy (-OH) groups. The nature of the intramolecular interaction was probed by calculating the molecular electrostatic potential on the molecular surface adjacent to the substituents. Differences in net atomic charges and surface molecular electrostatic potentials with and without an adjacent substituent showed the presence of significant non-bonded interactions between the electrophilic and nucleophilic centers in these compounds.