|Budget Amount *help
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1995 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1994 : ¥1,900,000 (Direct Cost : ¥1,900,000)
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.