Collect. Czech. Chem. Commun. 1995, 60, 1081-1093

AM1 Calculations of Spin Distribution in Hydroxyanthrasemiquinones

Martin Breza and Vlasta Brezová

Department of Physical Chemistry, Slovak Technical University, 812 37 Bratislava, Slovak Republic


The AM1 method was used to obtain the optimum geometries of hydroxyanthrasemiquinones. The relation between the spin distribution data obtained by analysis of EPR spectra and by AM1 calculations depends on the position of the C atom within the aromatic skeleton, on its spin density sign and on its position relative to OH substituents. Complete annihilation of higher spin state contaminations is insufficient to eliminate the significant discrepancies between the theoretical and experimental data.