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)diquinoxalino2,3-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.