【摘要】 用2-羟基-1-萘甲醛和含杂环胺合成出7种席夫碱,利用IR和1HNMR对其结构进行了表征。利用UV-Vis和IR研究了光致变色的性能,并且探讨了变色性能与化合物结构的关系。结果表明:虽然这7种席夫碱的亚胺基团的邻位都具有羟基,但只有2-羟基萘甲醛缩2-胺基-3-甲基吡啶和2-羟基萘甲醛缩5-甲基噻唑表现出光致变色的性能。在经历了波长为365 nm的紫外光辐射之后,2-羟基萘甲醛缩2-胺基-3-甲基吡啶的紫外光谱中λ<400 nm的吸收谱带中的吸收峰的强度都不同程度降低了;2-羟基萘甲醛缩5-甲基噻唑在498 nm处出现新的吸收峰,并且随着紫外光照射时间的延长,该新吸收峰和2-羟基萘甲醛缩2-胺基-3-甲基吡啶在592 nm处的吸收峰都逐渐增强,说明光致变色的性能是由于烯醇亚胺-酮胺构型互变异构导致的。红外光谱检测结果显示,2-羟基萘甲醛缩2-胺基-3-甲基吡啶、2-羟基萘甲醛缩5-甲基噻唑在经历了紫外光辐射后,羟基氢的伸缩振动的吸收峰急剧减弱以至消失不见,而两者在1 686、1 730 cm-1处分别出现新的小的羰基伸缩振动吸收峰,此外红外光谱中指纹区的吸收也发生了比较明显的变化,这些都进一步说明烯醇亚胺-酮胺的互变异构。比较这7种席夫碱的结构可知,化合物的吡啶环上亚胺基团的邻位或者噻唑环上连接有供电子基团时,表现出光致变色性能的可能性较大。更多还原

【Abstract】 Seven Schiff bases were synthesized by using the reaction of 2-hydroxy-1-naphthaldehyde with heterocyclic amines. The compounds were characterized by IR spectra and1 HNMR. The photochromism of the compounds were investigated by IR and UV-Vis spectra. The relationship between photochromism and the structures were also explored. Although there was oxhydryl at ortho-position of imine group in all the seven compounds molecules,only( 2-hydroxylnaphthaldehyde)-imino-3-methy-lpyridine( HNIMP) and( 2-hydroxylnaphthaldehyde)-imino-5-methyl-thiazole( HNIMT), showed photochromism. Undergoing UV irradiation,the UVVis absorptions peak intensity of a band of HNIMT or HNIMP at λ < 400 nm decreased. A new band of HNIMT at λ > 400 nm appeared,and the absorbance of which and the band at592 nm of HNIMP gradually increased with the radiation time,so the photochromism of HNIMP and HNIMT were caused by the tautomerism between enol-imine and keto-amine. IR spectra showed that the peak of the hydroxyl-H stretching vibration of HNIMP and HNIMT shrunk with the UV radiation time,and a new band appeared at 1 686 and1 730 cm-1of HNIMP and HNIMT respectively. In addition,certain absorptions at fingerprint region changed,all signed of HNIMP and HNIMP undergoing tautomerism. By comparison of the structures of the seven Schiff bases,with methyl on the pyridine ring at ortho-position of imine group or electron-donating substituent on the thiazole ring,the compound is comparatively easy to exhibit photochromism.更多还原