水杨酸-2′-乙基己基酯在胶束中的增溶位点

考察了阳离子、非离子和阴离子表面活性剂存在下水杨酸-2′-乙基己基酯(EHS)的吸收光谱和激发态分子内质子转移(ESIPT)荧光光谱.结果表明,EHS可增溶在胶束中,2′-乙基己基碳链朝向胶束内核,而水杨酸基朝向胶束-水界面;胶柬环境有利于EHS分子对紫外光的吸收和分子内氢键的形成,从而使ESIPT荧光显著增强,激发态分子以发射可见光和非辐射去活化方式衰减;并根据EHS和表面活性剂分子的结构和大小,解释了EHS分子在胶束中的结合位点,荧光猝灭和酯水解的光谱测量进一步为此结合位点提供了佐证.

Location of Solubilization of 2'-ethylhexyl Salicylate in Micelles

Absorption and excited state intramolecular proton transfer(ESIPT)fluorescence of 2'-ethylhexyl salicylate(EHS)were examined in the presence of cationic,non-ionic,and anionic snrfactants.It was found that linear EHS molecule was solubilized in micelles with its flexible hydrophobic 2'-ethylhexyl chain toward the micellar core and with its rigid salicylate moiety toward the micelle-water interface.The UV absorbance of EHS was improved and intramolecular hydrogen bonding formation of EHS was favored,resulting in greatly enhanced ESIPT fluorescence. The excited EHS molecules decay via visible luminescence and non-radiative deactivation.The binding sites of EHS in micelles were explained at a molecular level in terms of molecular structures and sizes of EHS and surfactants. Dynamic fluorescence quenching and spectral measurements of ester hydrolysis of EHS provide further evidences for the binding sites of EHS in different micelles.