Photoisomerization Reaction of Unsymmetrical Azobenzene Disulfide Self-Assembled Monolayers Studied by Surface Plasmon Spectroscopy: Influences of Side Chain Length and Contacting Medium
Photoisomerization Reaction of Unsymmetrical Azobenzene Disulfide Self-Assembled Monolayers Studied by Surface Plasmon Spectroscopy: Influences of Side Chain Length and Contacting Medium
复制标题
表面等离子体光谱研究不对称偶氮苯二硫化物自组装单层光异构反应：侧链长度和接触介质的影响
作者：
K. Tamada;H. Akiyama;T. Wei
报道了用于表面光异构化反应的含偶氮苯的自组装单分子膜(SAM)的特性。光反应自组装膜是由不对称的偶氮苯二硫化物组成的，其中偶氮苯部分的光反应自由体积通过在表面分子水平上稀释50%的染料官能团来保证。利用表面等离子体光谱技术，通过改变光学薄膜的厚度，对光开关反应进行了现场监测。考察了烷基侧链长度和接触介质对光反应的影响。紫外光照射下反式为顺式光异构化反应的谱线明显偏离一级动力学，表明光反应过程中存在空间位阻效应。
We report the characteristics of azobenzene-containing self-assembled monolayers (SAMs) which are designed and synthesized for surface photoisomerization reactions. The photoreactive SAMs were composed of unsymmetrical azobenzene disulfides, in which the free volumes for photoreaction of azobenzene moieties are guaranteed by 50% dilution of dye functions at the molecular level on the surface. The photoswitching reaction was monitored in situ through the change of optical film thickness by means of surface plasmon spectroscopy. The influences of alkyl side chain length and contacting medium on the photoreaction were also investigated. The profile of the trans to cis photoisomerization reaction by UV light irradiation exhibited a clear deviation from first-order kinetics, suggesting a steric hindrance effect on the photoreaction process.