Electronic Structure of Substituted Oxopyrrole and Oxopyrrolinyl

The electronic structure of nine equilibrium pyrrole structures (five molecules and four radicals) has been studied in the framework of the quantum theory of atoms in molecules (QTAIM). Integral characteristics of the electron density of the atomic groups of nine substituted pyrroles were obtained, including charge, volume, and spin density of the unpaired electron in the four radicals. Equal delocalization of free valence between the three ring groups was observed in the compounds with unpaired electron. Intramolecular weak (non-valent) interactions stabilizing the spatial configuration were found in 2-oxo-3-methyl-4-vinylpyrrole, 2-oxo-3-methyl-4-vinylpyrrolinyl, and 3-methyl-4-vinylpyrrole.