伞形花内酯的荧光量子产率与电离常数  

Fluorescence Quantum Yield and Ionization Constant of Umbelliferone

作　　者：张珺[1] 刘翠格[1] 魏永巨[1] 

机构地区：[1]河北师范大学化学与材料科学学院,石家庄050016

出　　处：《化学通报》2011年第10期957-960,共4页Chemistry

基　　金：国家自然科学基金项目(20675025;20975029)资助

摘　　要：研究了伞形花内酯在不同酸度下的荧光光谱,测量了荧光量子产率和电离常数。伞形花内酯有2种荧光型体,分别存在于弱酸性和弱碱性溶液中。在pH 3～6的溶液中,伞形花内酯以中性分子型体存在,最大激发波长λex=325nm,最大发射波长λem=455nm;在pH 9～10.5的溶液中,伞形花内酯主要以阴离子型体存在,λex/λem=367nm/455nm。以硫酸奎宁为参比,测得pH 5.49时分子型体在激发波长325nm的荧光量子产率为0.81,pH 9.49时阴离子型体在激发波长367nm的荧光量子产率为0.91。用pH-荧光法测得7-羟基质子的电离常数pKa=7.61。Fluorescence spectra of umbelliferone under different acidity were studied,and its fluorescence quantum yield and ionization constant were measured.There are two fluorescent species of umbelliferone existing in weak acidic and weak alkaline solutions,respectively.In acidic solutions of pH 3~6,umbelliferone exists as neutral molecular form with maximum excitation wavelength at λex= 325 nm and emission wavelength at λem= 455 nm;while in alkaline solutions of pH 9~10.5,umbelliferone exist as anion form with λex / λem= 367 nm / 455 nm.Using quinine bisulphate as a reference,fluorescence quantum yield of the molecular form under pH 5.49 and at λex= 325 nm was measured to be 0.81;fluorescence quantum yield of the anion form under pH 9.49 and at λex= 367 nm was measured to be 0.91.By pH-fluorescence method,ionization constant of 7-hydroxy proton of umbelliferone was measured to be pKa = 7.61.

关 键 词：伞形花内酯 荧光光谱 荧光量子产率 电离常数 

分 类 号：O621.13[理学—有机化学]