水杨酰苯胺衍生物分子内电荷/质子转移荧光  

Intramolecular Charge Transfer and Proton Transfer Fluorescence of Salicylanilides

作　　者：张煊[1] 郭琳[1] 江云宝[1] 

机构地区：[1]厦门大学化学系,现代分析科学教育部重点实验室,厦门361005

出　　处：《物理化学学报》2004年第F08期930-935,共6页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(20175020);福建省自然科学基金(D0220001);教育部优秀青年教师奖励计划(2001);德国大众基金(I/77072)资助项目~~

摘　　要：将苯甲酰苯胺(BA)类电荷转移(CT)反应基团耦合到具有激发态分子内质子转移(ESIPT)反应通道的水杨酸(SA)分子中,设计合成了苯胺对/间位取代的水杨酰苯胺及其羟基甲基化衍生物邻甲氧基苯甲酰苯胺,考察了环己烷、乙醚、乙腈和甲醇中两类水杨酰苯胺衍生物吸收光谱和荧光光谱的溶剂效应和取代基效应.结果表明,水杨酰苯胺的荧光为SA-型质子转移(PT)荧光,对取代基的依赖性较小;当电子给体苯胺基的给电子能力提高时,如N-甲基水杨酰苯胺分子,其荧光为BA-型CT荧光.而羟基甲基化后的衍生物邻甲氧基苯甲酰苯胺则表现出与BA类似的荧光光谱特性,具有明显的取代基效应.认为水杨酰苯胺衍生物的激发态存在着相互竞争的BA-型CT和SA-型PT通道,二者可经苯胺基上取代基的电子效应调控.The intramolecular charge transfer(CT)reaction known to occur in benzanilide(BA)derivatives was coupled to salicylic acid(SA)for understanding the substituent e ffect on the proton transfer fluorescence in comparison with that on the CT fluore scence.A series of salicylanilides1,in which the SA structural framewor k was incorporated in the electron acc eptor moiety of the BA-like CT fluoro phore,were designed and their absor ption and fluorescence spectra were investigated in aprotic solvents CHX,DEE,and ACN and a protic solvent MeOH.It was found that 1exhibited a long-wavelength emission at 470nm in CHX that scarcely shifted when solvent changed from DEE to ACN of increasing polarity,whereas it drastically sh ifted to blue at ca 430nm in protic sol -vent MeOH.It was therefore made clea r that the emission of 1was different from that of benzanilide,the latter be-ing highly sensitive to solvent pola rity.With2,the o-OH methylated derivatives of 1,long-wavelength fluores-cence emission with similar solvent dependence to that of benzanilides was observed.These facts suggested t hat the emission from1originated from the SA-like PT state while that of 2from the BA-like CT state.The sub-stituent effect on the emission of 1and2with p-or m-substituent at the anilino phenyl r ing was examined.Re-sults showed that,whereas the emission of 1scarcely varied,that of 2dramatically shifted to the blue wit h increas-ing electron-withdrawing ability o f the substituent.The emission energies of 2in CHX were found to be correlated linearly to the Hammett constants of the substituents with a slope of +0.378eV,close to +0.361eV observed for benzanilides.It was concluded that the emission of 1originated from the PT state that showed practically no de-pendence on solvent polarity and sub stituent at the proton acceptor moie ty.

关 键 词：苯甲酰苯胺 水杨酰苯胺 电荷转移 质子转移 取代基效应 溶剂效应 

分 类 号：O625[理学—有机化学]