Coplanarity in the backbones of ladder-type oligo(p-phenylene) homologues and derivatives.
p-Tolyl-substituted ladder-type oligo(p-phenylene)s containing three, four, and five phenylene rings were readily synthesized. The uniform aryl substitution of these systems allowed us to determine the coplanarity of the pi-conjugated backbones crystallographically. The intramolecular annulations eliminate almost all of the conformational disorder and enhance the degree of pi-conjugation of the backbones, resulting in significant red shifts in the absorption and emission maxima and lower oxidation potentials in the higher homologues. [structure: see text]
Wong
Ken-Tsung
KT
Department of Chemistry, National Taiwan University, Taipei 106, Taiwan. kenwong@ntu.edu.tw
Chi
Liang-Chen
LC
Huang
Shih-Chiang
SC
Liao
Yuan-Li
YL
Liu
Yi-Hung
YH
Wang
Yu
Y