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

研究了一系列新合成的芳香族羧酸酯和酰胺的荧光行为，以揭示由相邻的大体积酯或酰胺基团之间的空间位阻引起的新型双荧光的详细机理。主要研究结果如下：1）合成了一系列新型的具有大体积烷基结构的苯甲酸酯和苯甲酸酰胺; 2）利用荧光计、单光子计数技术和荧光各向异性测量等手段研究了这些高稠合的苯甲酸酯和苯甲酸酰胺的荧光行为。我们发现，酯在330-390 nm区域显示出双重荧光，而酰胺根本不发荧光，并且还发现己二烯基庞大酯基团之间的空间位阻导致由旋转势垒引起的双重荧光。3）发现的双重荧光行为被发现可用作微粘度传感器，例如，在胶束中，因为双荧光峰的相对强度不取决于溶剂极性而仅取决于溶剂粘度。同样的化合物也被证明是良好的原位压力传感器在1-5000 atm.4）非常有趣的是，烷基苯多羧酸酯和酰胺携带手性烷基作为手性敏化剂在环烯烃的对映体区分几何光异构化，得到良好的优异的光学产率。

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.