Resonance energy per pi-electron (REPE) of azaarenes were calculated b
y Aihara's theory of resonance energy (TRE). Consequently, it was show
n that the REPE values for the cationic species not having the carbon,
or nitrogen atom with the highest approximate superdelocalizability (
Sr'(E)) in the parent skeleton were more unstable than those of their
parent skeleton. Some correlations seem to exist between the REPE valu
es for the cationic species not having the atom with the highest value
of (Sr'(E)) in parent skeleton and carcinogenic activity. Other types
of correlations can be assumed in the case of carbazoles 7H-benzo[g]p
yrido[2,3-a]carbazole (14), 13H-dibenzo[a]pyrido[3,2-i]carbazole (17),
and 7H-benzo[c]pyrido[2,3-g]carbazole (20) although there are some ex
ceptions, i.e., 7H-benzo[g]pyrido[3,2-a]carbazole (15) and 7H-dibenzo[
c,g]carbazole (18). The bond-order affected carcinogenicity induction
in some ways as well.