摘要
测试了3,3-双(N-辛基-2-甲基吲哚)邻苯二甲内酯荧烷(ck-16)在显色前后的^(13)C NMR谱图,揭示了其显色前后的结构变化及其显色机理。利用紫外可见吸收光谱法研究了ck-16在乙醇溶液中与不同显色剂作用后的光谱性质,测定了其与常用显色剂间的络合比和不稳定常数,并进一步研究了外界条件的改变对ck-16在乙醇溶液中与特定显色剂作用后显色性能的影响。研究发现,亲电阳离子进攻ck-16荧烷分子的苯酞环,使苯酞环断裂,推电子的N原子和吸电子的羰基O原子之间建立π电子迁移通道使分子显色。在乙醇介质中,ck-16与不同显色剂作用后具有不同的显色效果;对路易斯酸和有机弱酸这两类显色剂而言,ck-16与所测的四种显色剂(Fe Cl_3、草酸、Cu Cl_2、水杨酸)均以1∶1的形式络合,ck-16与Fe^(3+)的不稳定常数最小,结合最稳定,草酸其次,与Cu^(2+)的相近,ck-16与水杨酸的结合最弱;在乙醇中,放置时间对ck-16/Fe Cl_3和ck-16/H_2C_2O_4两个体系的吸光度影响不大,但两体系表现出随水含量变化不同的敏感性,ck-16/Fe Cl_3体系具有比ck-16/H_2C_2O_4体系更为灵敏和快速的水致褪色性能。
The structures of dye 3,3＇-bis（1-n-octyl-2-methylindol-3-yl）phthalide（ck-16） in coloring and decoloring states were analyzed by ^13C NMR. The chromogenic properties of ck-16 interacted with different color developers in ethyl alcohol were studied by UV-visible spectroscopy. The composition ratio and instability constant of the complexes composed of ck-16 and the color developers were measured. Furthermore, the effect of external conditions on the absorbance at λmax of the system was investigated. ^13C NMR results show that the delocalized bonds formed between electron donor（N） and acceptor（O） atoms lead to ring cleavage of the phthalide to a carboxylate as a colored form. The chromogenic properties of ck-16 vary with different color developers. When the molar ratio of ck-16 to four color developers（FeCl3, oxalic acid, CuCl2 and salicylic acid） are all 1：1, the combination between ck-16 with Fe^3＋ is the most stable, followed by oxalic acid and Cu^2＋. Among the four color developers, the combination between ck-16 with salicylic acid is the most instable. The time has little influence on the absorbance at λmax of ck-16/FeCl3 and ck-16/H2C2O4. However, different sensibility is observed when water is added. The ck-16/FeCl3 fades more rapidly with water than ck-16/H2C2O4, and exhibits potential application as water sensitive recording or copying materials.
出处
《应用化学》
CAS
CSCD
北大核心
2015年第12期1437-1447,共11页
Chinese Journal of Applied Chemistry
基金
国家自然科学基金(21175086)
山西大学人才建设项目(205533801001)资助~~
关键词
荧烷染料
显色剂
显色性能
紫外可见光谱
fluorane
color developer
chromogenic properties
UV-Vis spectrum
