Shiraishi Yasuhiro, Yamamoto Kohei, Sumiya Shigehiro, Hirai Takayuki
Research Center for Solar Energy Chemistry, and Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan.
Phys Chem Chem Phys. 2014 Jun 28;16(24):12137-42. doi: 10.1039/c3cp55478c.
Design of optical molecular probes for selective detection of aromatic thiols has attracted much attention. Although several types of probes have been proposed, all of them exhibit colorimetric or fluorometric response via irreversible reaction with aromatic thiols and cannot be reused. Here we report that a spiropyran dye is the first example of a reusable chemosensor for aromatic thiols. A colorless spiropyran dye () dissolved in aqueous media containing aromatic thiols is selectively isomerized to the colored merocyanine form in the dark. In contrast, visible light irradiation of the merocyanine form promotes successful reversion to the colorless spirocyclic form. Kinetic absorption analysis and ab initio calculations of the transition states revealed that this colorimetric response in the dark is ascribed to the decrease in activation energy for isomerization via the nucleophilic interaction between the aromatic thiol and the olefinic carbon of the dye.
用于选择性检测芳香硫醇的光学分子探针的设计备受关注。尽管已经提出了几种类型的探针，但它们都通过与芳香硫醇的不可逆反应表现出比色或荧光响应，并且不能重复使用。在此我们报告，螺吡喃染料是用于芳香硫醇的可重复使用化学传感器的首个实例。溶解在含有芳香硫醇的水性介质中的无色螺吡喃染料（）在黑暗中选择性地异构化为有色部花青形式。相比之下，部花青形式的可见光照射促使其成功地逆转为无色螺环形式。动力学吸收分析和过渡态的从头算计算表明，这种在黑暗中的比色响应归因于通过芳香硫醇与染料的烯碳之间的亲核相互作用使异构化的活化能降低。
