Aromatic stability of polycyclic compounds
Abstract An additional ring ohanges the stability of a cyclic compound. Aromatic system with condensed additional aromatic ring /e.g benzologuee/ is more stable /more aromatic! if this ring is oondensed to the bond with greater Jt-eleotron bond order, p If additional ring is antiaromatic the lower p the higher abili.' ty is observed. This rule is confirmed by analJis of the REPE and HOMA indices and PPP calculations 4-Variable!. Also bond lengths in polycyclic compounds are discussed.