Geometrical Structures and Magnetic Properties of Trinaphtho[abc,ghi,mno][18]annulene and its congeners

Abstract

Pariser–Parr–Pople-type SCF MO and semiempirical magnetic-susceptibility calculations show that trinaphtho[ abc,ghi,mno]- and two kinds of triazuleno[ abc,ghi,mno][18]annulenes have large diamagnetic susceptibilities and aromatic-islands structures in which three naphthalenes or three azulenes are linked by three olefinic bridges, whereas tripentaleno[ abc,ghi,mno]- and triheptaleno[ abc,ghi,mno][18]annulenes have small diamagnetic susceptibilities and polyolefine structures where bond alternations are distributed all over their molecular planes.