Radical Trianions of Isopyrenes
SummaryThe radical trianions derived from acepleiadylene (l), dicyclopenta[eA kllheptalene (2) and dicyclohepta[cd, gh]-pentalene (3) are described. Whereas the hyperfine data of 13; and Z3; are consistent with the predictions of an HMO-McLachlan-procedure, the corresponding data of 33; substantially differ from the calculated values. The spin distribution in 337 is polarized by the counterions in such a way, that the hyperfine data of this radical trianion no longer reflect theDZh-symmetry of the neutral compound3 and the radical anion 3;. In addition, the interaction of the charged organic ion 33: with the counterions influences the energy of the low-lying antibonding molecular orbitals LUMO (lowest unoccupied molecular orbital) and NLUMO (next lowest unoccupied molecular orbital). The passage from a looser ion pair (33:/3Li+) to a tighter ion pair (33T/3Na', 33T/3Kt) causes a change in the orbital sequence of LUMO and NLUMO.