摘要
合成了一种新的取代苯并咪唑化合物 ,2 对二甲氨基苯基 5 氟 6 吗啉苯并咪唑 ,采用紫外 可见光谱、荧光光谱及荧光寿命等方法探讨了溶液pH值对该化合物吸收光谱的影响及其与 β 环糊精的作用。结果表明 ,pH >7 0时 ,该化合物在溶液中主要以中性分子状态存在 ,当 3 8<pH <7 0时 ,以中性分子及一价阳离子状态存在 ,且随着溶液 pH值的降低 ,离子状态百分含量增加 ;当 2 76 <pH <3 8时 ,该分子主要以一价离子状态存在 ,且随着pH值的继续降低 ,一价离子状态与二价离子状态并存 ,并逐渐向二价离子状态转化。该化合物是一种灵敏的荧光探针 ,在酸性条件下与H+ 结合 ,具有较强的pH依赖性。在 pH =9 5 0时 ,与 β 环糊精有较强烈的相互作用 ,并形成 1∶1的包合物 ,结合常数为 (1 0 2± 0 0 4 )× 10 3 mol·L-1。
A new potential pharmaceutical compound, 2-(4-dimethylaminophenyl)-5-fluoro-6-(morpholin-4-yl)-1H-benzimidazole (4) was synthesized. The effect of the pH value of aqueous solution on the absorption spectrum of compound 4 and its interaction with beta-cyclodextrin (beta-CD) were investigated by UV-Vis spectrum, steady-state fluorescence and time-resolved spectroscopic measurements. The results indicate that compound 4 mainly exists in neutral molecular state when pH value of the aqueous phase is above 7.0. In the pH range from 7.0 to 3.8 the neutral molecular state and protonated univalent cationic form coexist. As the pH value decreases, the content of univalent cationic form increases. When 2.76 < pH < 3.8, the protonated univalent cationic form is the predominant species. With further decrease of the pH value, the univalent cation is protonated by another H+ to form a bivalent cation, and both univalent and bivalent cations coexist in the solution. The steady-state fluorescence and time-resolved spectroscopic measurements revealed that compound 4 is a sensitive molecular probe. The interaction of compound 4 and beta-CD is very strong. The guest: host ratio of inclusion complex between compound 4 and beta-CD formed in the aqueous solution (pH = 9.50) is 1:1, and the association constant was determined to be (1.02 +/- 0.04) X 10(3) mol(.)L(-1).
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2004年第5期588-591,共4页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金(20171005)资助项目
