Synthesis And Spectral Characterization Of Trizao Pigments Used For OPC

With the aim of studying the relation between the photoelectric performance and substitution effect when the substituted naphthol AS act as the coupling ingredients, three triazo-typed pigments were synthesized, using triphenylamine triazo as a bridge. Moreover, with the considering of 1,8-naphthalimides' structure of push-draw electron, and their excellent photochemical stability, 3- hydroxy group were introduced and they are acted as coupling ingredients, coupled with triphenylamine triazo, so another three triazo- typed pigments were synthesized with different performance from the former.4,4',4"-trinitrophenylamine was synthesized ,in which 4-chloric-nitrobenzene was replaced by 4-fluoric-nitrobenzene and anhydrous K2CO3 worked as a component catching acid, and it was reduced by hydrogenation catalyzed by Pd/C to produce 4,4',4"- tri amino phenylamine. Through salting, dehydrating, condensing and neutralizing, the naphthol AS were prepared. Otherwise, 3-hydroxy-1,8-naphthalimides were synthesized from 1,8-naphthalic anhydride via the reaction of sulfonating,alkaline fusion and imination. Six trizao-typed pigments were obtained by 4,4',4"-triaminophenylamine hexazonium salt coupled with the above-mentioned two kinds of coupling ingredients. The products were proved by IR, MALDI-TOFMS, Elemental analysis and UV spectra and were characterized by X-ray diffraction patterns.The solution UV spectra indicate that the six compounds' absorbance range from 500nm to 720nm, and λ_ab^max is about 610nm,with ε >10⁴. Their absorbance range from 350nm to700nm, and λ_ab^max is about 510nm in the solid-state UV spectra. The difference between theUV spectra and the solid-state UV spectra results from the hydroxy-azo/hydrazone tautomerism. In addition, the latter three compounds are more soluble than the former three ones, which may lead to spread pigments more easily in making CGL(carrier generating layer) that can help to reduce noise. The X-ray diffraction patterns indicate these pigments are all small crystallite sizes, which are expected to have high photoconductivity. In the same time, the compounds' thermo-stability is illuminated by DSC and TG-SDTA thermo- analysis with the decomposed temperature exceeds 300℃.