茜素在不同pH值的甲醇溶液中的存在形式  

Existence Forms of Alizarin in Methanol Solution with Different pH Values

作　　者：黎雅琴 胡玉江 刘汉广[2] 高超[1] 熊金艳 田迪 洪少力 李伟[1] LI Yaqin;HU Yujiang;LIU Hanguang;GAO Chao;XIONG Jinyan;TIAN Di;HONG Shaoli;LI Wei(Hubei Key Laboratory of Biomass Fiber and Eco-dyeing&Finishing,College of Chemistry and Chemical Engineering,Wuhan Textile University,Wuhan 430073,China;PetroChina Tarim Oilfield Company,Korla 841000,China)

机构地区：[1]武汉纺织大学化学化工学院生物质纤维与生态染整湖北省重点实验室,湖北武汉430073 [2]中国石油塔里木油田分公司,新疆库尔勒841000

出　　处：《化学与生物工程》2023年第9期27-34,共8页Chemistry & Bioengineering

基　　金：国家自然科学基金项目(22204123)。

摘　　要：为了探究茜素在不同pH值的甲醇溶液中的存在形式,设计了9种结构,利用时间依赖密度泛函(TDDFT)方法模拟了茜素的紫外可见吸收光谱和荧光发射光谱,并与不同pH值下的实验光谱进行了比较;通过检验模拟光谱与实验光谱的一致性,确定了茜素在不同pH值下的存在形式。结果表明,在酸性条件下,茜素以a_G_1和a_G_4的分子形式存在;在碱性条件下,茜素以b_G_1、b_G_4和c_G的阴离子形式存在;在基态上,a_G_3不稳定,转变为a_G_4;在激发态上,a_E_3不稳定,转变为a_E_1;在激发态上,通过荧光发射光谱和TDDFT计算证实了质子在1位羟基和9位羧基之间的转移;茜素的紫外可见吸收光谱和荧光发射光谱主要来源于分子内电荷转移。In order to explore the existence forms of Alizarin in methanol solution with different pH values,we designed nine structures,calculated UV-Vis absorption spectra and fluorescence emission spectra by time-dependent density functional theory(TDDFT)method and compared with the experimental spectra at different pH values.By checking the consistency between the simulated and experimental spectra,the reasonable existence forms of Alizarin at different pH values were confirmed.Under the acidic condition,Alizarin exists in the molecular form of a_G_1 and a_G_4;under the basic condition,Alizarin exists in the anion forms of b_G_1,b_G_4,and c_G.On the ground state,a_G_3 is unstable and is transformed to a_G_4;on the excited state,a_E_3 is unstable and is transformed to a_E_1.On the excited state,the proton transfer between 1-position hydroxyl and 9-position carboxyl can be confirmed by fluorescence emission spectra and TDDFT calculations.The UV-Vis absorption spectra and fluorescence emission spectra of Alizarin mainly originate from intra-molecular charge transfer.

关 键 词：茜素 结构 紫外可见吸收光谱 荧光发射光谱 TDDFT 

分 类 号：TQ610.1[化学工程—精细化工] O657.3[理学—分析化学]