AM1 Study of a β-carboline set. Part II: pyrrole-N deprotonated species

Abstract

We report a semiempirical AM1 study of the structural properties and potential reactivity of several indole-N deprotonated β-carbolines with different degrees of aromaticity. The influence of methylation on the non-indole nitrogen atom has also been studied. Geometrical parameters, deprotonation enthalpies and static reactivity indices have been examined. In order to analyse the effect of annellation, some model compounds including those with only a few condensed rings have also been studied. The anionic data have then been used as ionic probes for the aromatic stabilizations of the annellated rings. Annellation effects are in general well reproduced by the AM1 semiempirical method.