Magnetic properties of dicyclopentapyrenes and their congeners

The magnetic susceptibilities for dicyclopentapyrenes, dicyclopentanthanthrenes, and their congeners have been examined by use of the modified London-Hoarau method in the framework of the Wheland-Mann-type SCF MO approximation. Dicyclopenta[cd, mn]pyrene is calculated to be more diamagnetic than dicyclopenta[cd, jk]pyrene and dicyclopenta[cd, fg]pyrene. This agrees with the experimental data. Further, the calculated results have suggested that the presence or absence of perimeter delocalization contributes to the magnetic properties of the molecules. (C) 1997 Elsevier Science Ltd.