新しい二重蛍光現象を利用した微視的粘度・圧力センサーの開発

本文研究了多种新合成的芳香羧酸酯和酰胺类化合物的荧光行为，揭示了由相邻的大块酯或酰胺基团之间的空间位阻诱导的新型双荧光的详细机理。本研究的主要成果如下：1)首先，合成了多种新型的具有大量烷基的苯甲酸酯和酰胺。2)采用荧光仪、单光子计数技术和荧光各向异性测量等方法研究了这些高拥塞酯类和酰胺类化合物的荧光行为。我们发现酯类在330- 390nm区域表现出双重荧光，而酰胺类则完全不发出荧光，并且相邻的大块酯基之间的空间位阻导致了旋转势垒产生的双重荧光。3)发现的双荧光行为被认为是有用的微粘度传感器，例如，在胶束中，因为双荧光峰的相对强度不依赖于溶剂极性，而只依赖于溶剂粘度。同样的化合物也被证明是在1-5000 atm范围内的良好的原位压力传感器。4)非常有趣的是，烷基苯聚羧酸酯和携带手性烷基的酰胺被用作手性增敏剂用于环烯烃的对映分化几何光异构反应，获得了良好的光学产率。

Fluorescence behavior of a variety of newly synthesized aromatic carboxylic esters and amides has been examined in order to reveal the detailed mechanism of novel dual fluorescence induced by steric hindrance between the adjacent bulky ester or amide groups. The results obtained by this research may be summarized as follows :1) First, a wide variety of novel benzenecarboxylic esters and amides possessing bulky alkyl groups were synthesized.2) Fluorescence behavior of these highly congested esters and amides was examined by means of fluorimeter, single photon counting technique, and fluorescence anisotropy measurement. We found that the esters exhibit dual fluorescence in the region 330-390 nm, while the amides do not fluoresce at all, and also that the steric hindrance between the adiacent bulky ester groups causes the dual fluorescence arising from the rotational barrier.3) The dual fluorescence behavior found was found to be useful as a microviscosity sensor, for example, in micelles, since the relative intensity of dual fluorescence peaks does not depend on solvent polarity but only on solvent viscosity. The same compounds were also demonstrated to be good in situ pressure sensors between the range of 1-5000 atm.4) Quite interestingly, the alkyl benzenepolycarboxylates and amides carrying chiral alkyl groups were employed as chiral sensitizer in enantiodifferentiating geometrical photoisomerizations of cycloalkenes to give good to excellent optical yields.