Solvent Dependence of Absorption and Fluorescence Spectra of Piroxicam. A Possible Intramolecular Proton Transfer in the Excited State = Piroxicam의 흡수 및 형광 스첵트럼의 용매에 대한 의존성. 여기상태에서 가능한 분자간의 프로톤 전이

다국어 초록 (Multilingual Abstract)

The spectral properties of piroxicam in different solvents are similar to those of its skeletal precursor, HMBDC. The maximum absorption and emission wavelengths strongly depend on the hydrogen bonding ability of the solvent, and it is shown that intramolecular hydrogen bonding between the OH and the ortho carbonyl group of the parent benzothiazine ring plays an important role in the solvent-dependence of their spectroscopic properties. The fluorescence spectra in aprotic nonpolar solvent exhibit abnormally large Stokes-shifted (∼9,000㎝^-1) emission bands in contrast to the spectra in water. In ethanol, dual emission bands with two different fractional components of lifetimes have been observed. These results suggest that the abnormally red-shifted emission is attributed to the proton transferred form of an intramolecularly hydrogen-bonded closed conformer.