کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1235914 | 1495287 | 2007 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: 2-Phenoxathiinyl-5-phenyloxazole and 5-phenoxathiinyl-2-phenyloxazole derivatives: Experimental and theoretical study of emission properties 2-Phenoxathiinyl-5-phenyloxazole and 5-phenoxathiinyl-2-phenyloxazole derivatives: Experimental and theoretical study of emission properties](/preview/png/1235914.png)
The absorption and emission spectra in cyclohexane and methanol of the title phenoxathiinyl-phenyloxazole derivatives are presented and discussed. Comparing to the unsubstituted diphenyloxazole (PPO), the experimental results show a bathochromic shift of the emission band, a significant dependence of the maximum on the solvent polarity and a drastic decrease of the fluorescence quantum yield. Semiempirical MO calculations (AM1) in both the ground and excited states support the experimental findings. A charge transfer from the phenoxathiin fragment to the oxazole ring is predicted in the excited state explaining the solvatochromism of the compounds. The values for the singlet–triplet gap, 3500–5000 cm−1 point to an enhanced probability of intersystem crossing (ISC) non-radiative deactivation processes, in agreement with the low fluorescence quantum yields.
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 66, Issues 4–5, April 2007, Pages 1165–1170