Ab initio MO computation of ionization potentials of small benzenoid hydrocarbons and their -SO3Na, -SO3H, and -SO3- substituted compounds

STO-3G calculations on benzene, naphthalene, phenanthrene, anthracene, pyre ne and their -SO3Na, -SO3H, and -SO3- substituted compounds were carried ou t. The calculated values for ionization potential Of -SO3Na substituted com pounds are close to those of the corresponding hydrocarbons with benzene be ing the only exception. On the contrary, the calculated ionization potentia ls of -SO3- substituted compounds are very small in comparison with those o f the corresponding neutral compounds. The highest occupied molecular orbit al (HOMO) of sodium pyrenesulfonate comprises almost p(pi) atomic orbitals of conjugated hydrocarbon skeleton and is similar to that of pyrene. The HO MO of pyrenesulfonate anion is quite different from that of pyrene. Ionizat ion potential of sodium pyrenesulfonate in water was discussed based on the se results. (C) 2001 Elsevier Science B.V. All rights reserved.