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类化合物的荧光行为，以揭示空间位阻引起的新型双荧光的详细机理。本研究取得的成果可概括如下：1)合成了一系列具有大分子烷基的新型苯羧酸酯和酰胺类化合物。2)用荧光仪、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度酯类和酰胺类化合物的荧光行为。我们发现，在330-390 nm区域，酯类化合物表现出双重荧光，而酰胺类化合物则根本不发光，而且绝热大分子酯基之间的空间位阻导致了来自旋转势垒的双重荧光。3)双重荧光行为被发现用作微粘度传感器，例如，在胶束中，因为双重荧光峰的相对强度不取决于溶剂的极性，而只取决于溶剂的粘度。同样的化合物也被证明在1-5000大气压范围内是良好的原位压力传感器。4)有趣的是，烷基苯多羧酸酯和含手性烷基的酰胺作为手性增敏剂用于环烯类化合物的几何光致异构化反应，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.