AROMATICITY OF SUBSTITUTED CYCLOPROPENES - A THEORETICAL-STUDY

The aromaticity of several heterosubstituted cyclopropenes and corresp onding protonated forms was investigated using ab initio calculations at the G2-MP2 level of theory, topological charge density, and NBO ana lysis. It was shown that according to geometric, energetic, charge den sity, and magnetic criteria these systems are remarkably aromatic, esp ecially the protonated forms. It was shown that the aromatic delocaliz ation of double bond in the cyclopropene ring can be well modeled usin g a three-center two-electron bond in the framework of NBO analysis pr oposed by Reed and Weinhold.