CHARACTERIZATION OF 9-(P-SUBSTITUTED BENZYLIDENEHYDRAZONO)FLUORENES

The title azine was obtained by a reaction of the corresponding fluore none hydrazone and p-substituted benzaldehyde. The hydrazone formed fr om the unsymmetrical fluorenone afforded configurational isomers; the E-isomer was thermodynamically more stable than the Z-isomer. The stru cture of the title azines, derived from symmetrical fluorenone, was as signed to be (s-trans/E) form. The azines from unsymmetrical fluorenon e gave isomeric mixtures due to the 9-iminofluorene moiety. The electr onic spectra of these azines show an intramolecular charge transfer; t he red shift beyond 250 nm is observed in the case of 9-[p-(diethylami no)benzylidenehydrazono] compared to the mother azine. 9-[p-(Pentyloxy )benzylidenehydrazono]-2, and some of the homologs possess a liquid-cr ystalline property; the phase-transition temperature of the dinitro co mpound is K (172 degrees C) M(1) (185) M(2) (187) I between the crysta lline and liquid phases.