Introduction of a Disulfide Bond as a Key Element of Acyclic Bis-Thiourea-Type Anion Receptors
作者:Kentaro Tomita、Toshio Ishioka、Akira Harata
DOI:10.1246/bcsj.20130267
日期:2014.3.15
This article shows that a difference in the building blocks of the molecular framework, C–C to S–S, results in a significant influence on its optical properties. Acyclic anion receptors, bis2-[3-(substituted)thioureido]ethyl} disulfides were newly synthesized, and their optical properties in response to complex formation with an acetate ion were compared with those of a hexamethylene framework between two thioureido groups. Quantum chemical calculations suggested that receptors fold their molecular framework around disulfide because of the presence of the intramolecular hydrogen bonding between two N,N′-disubstituted thioureas. The complex of the receptor and the acetate ion with 1:1 stoichiometry consists of the coordination of two thioureido groups to the acetate via hydrogen bonds. This complex formation is accompanied by a dissociation of intramolecular hydrogen bonding and rotation of one side of the thioureido group. These circumstances of conformational changes in the molecular framework functioned by switching on and off the excimer fluorescence of the 1-pyrenylmethyl derivative.
本文表明,分子框架的组成部分(C-C 到 S-S)的差异对其光学性质产生重大影响。新合成了无环阴离子受体双2-[3-(取代)硫脲基]乙基}二硫化物,并将其响应与乙酸根离子形成络合物的光学性质与两个硫脲基之间的六亚甲基骨架的光学性质进行了比较。量子化学计算表明,由于两个 N,N'-二取代硫脲之间存在分子内氢键,受体将其分子框架折叠在二硫键周围。受体和乙酸根离子按 1:1 化学计量形成的复合物由两个硫脲基通过氢键与乙酸根配位组成。这种复合物的形成伴随着分子内氢键的解离和硫脲基一侧的旋转。分子框架中构象变化的这些情况通过打开和关闭 1-芘基甲基衍生物的准分子荧光来发挥作用。