Aromaticity and Electron Density of Hypericin

J Nat Prod. 2019 Aug 23;82(8):2106-2115. doi: 10.1021/acs.jnatprod.8b00872. Epub 2019 Jul 26.

Abstract

The influence of the substituents on the geometry of the central ring system of hypericin has been analyzed. Substitution that causes flattening of the hypericin central rings is connected with introducing the aromatic character of the empty rings. All the hypericin rings have an aromatic character illustrated by the Harmonic Oscillator Measure of Aromaticity (HOMA), Nucleus Independent Chemical Shift (NICS), Fluctuation Index (FLU), and Ellipticity Index (EL) indices. Quantum Theory of Atoms in Molecules (QTAIM) and Natural Bond Orbital (NBO) analyses performed on 7,14-dihydrophenanthro[1,10,9,8-opqra]perylene, its substituted analogues, and hypericin show an influence of this substitution on electron density of the central rings.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anthracenes
  • Electrons
  • Molecular Structure
  • Perylene / analogs & derivatives*
  • Perylene / chemistry
  • Quantum Theory

Substances

  • Anthracenes
  • Perylene
  • hypericin