In situ synthesis of hexakis(alkoxy)diquinoxalino[2,3-a:2',3'-c]phenazines: mesogenic phase transition of the electron-deficient discotic compounds.
2,3,8,9,14,15-Hexakis(alkoxy)diquinoxalino[2,3-a:2',3'-c]phenazines with alkyl side chains varying from 6 to 12 carbon atoms were readily synthesized by the condensation of hexaketocyclohexane with the respective 1,2-bisalkoxy-4,5-diaminobenzene. Polarization microscopy and DSC studies showed all these compounds to exhibit a very wide mesophase range of over 150 degrees C. An interesting D(hd) to D(rd) transition was observed for the octyl derivative 3b, as determined by X-ray diffraction measurements. The hexyl derivative showed three reduction potentials, suggesting that the HATN core maintained its electron-deficient characteristic and considered suitable as an n-doped discotic-liquid crystalline material. Incorporation of six alkoxy chains did not override the electron deficiency of the HATN core.
Ong
Chi Wi
CW
Department of Chemistry, National Sun Yat Sen University, Kaoshiung, Taiwan 804. cong@mail.nsysu.edu.tw
Liao
Su-Chih
SC
Chang
Tsu Hsing
TH
Hsu
Hsiu-Fu
HF