Description of heteroaromaticity on the basis of pi-electron density anisotropy

作者：Firouzi Rohoullah^*; Ardani Sahar Sharifi

来源：Physical Chemistry Chemical Physics, 2014, 16(23): 11538-11548.

DOI：10.1039/c4cp01125b

It is demonstrated that there is a direct connection between aromaticity and the anisotropy of the pi-electron density on planes parallel to the molecular ring. The electron density anisotropy on the plane is measured through the ratio of the in-plane Hessian eigenvalues associated with the eigenvectors lying in the plane. Computations on a wide-ranging set of well-characterized monocyclic systems containing heteroatoms validate the correlation between this one-electron density-based descriptor and aromaticity; in aromatic compounds, the in-plane Hessian eigenvalues are degenerate (or near degenerate) and the anisotropy of the pi-electron density is undirected, whereas the results for antiaromatic rings are reversed and the degeneracy of the eigenvalues completely disappears. This finding is in line with our very recent study on [n] annulenes and provides further evidence that the anisotropy of the pi-electron density should be considered as a new manifestation of aromaticity.

• 出版日期2014