Nitrenium ion analogues of nonclassical carbocations: cyclopropylnitrenium, allylnitrenium, and azetidenium ions and mechanisms for their interconversion.

Abstract

Cyclopropylnitrenium 3S, allylnitreium 6S, and azetidenium (i.e., the nitrogen analogue of cyclobutylcarbenium) ions were examined using density functional theory and a complete basis set method. Similarly to the carbon analogues, the singlet states of these species have several local minima with nonclassical bonding. Structures characterized include 3S, an N analogue of the bisected cyclopropylcarbinyl cation, 11S, an N analogue of the bicyclobutonium ion, and 6S, an unsymmetric 2-azidinylcarbinyl cation.