کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1237240 | 968886 | 2010 | 5 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: UV absorption and keto–enol tautomerism equilibrium of methoxy and dimethoxy 1,3-diphenylpropane-1,3-diones UV absorption and keto–enol tautomerism equilibrium of methoxy and dimethoxy 1,3-diphenylpropane-1,3-diones](/preview/png/1237240.png)
UV absorption spectra of 1,3-diphenylpropane-1,3-dione (1), its three methoxy derivatives (2–4) and its six dimethoxy derivatives (5–10) in various solvents dissolved were collected. The keto–enol tautomerism equilibrium constant was calculated with 1H NMR. The position of the methoxy group in 1,3-diphenylpropane-1,3-dione was shown to have an influence on the molecule's UV absorption spectrum and the keto–enol tautomerism equilibrium constant. The methoxy group in the para position increases the absorption of radiation in the UV-A range. A shift to the keto form in the keto–enol tautomerism equilibrium is experienced by compounds with methoxy groups in ortho position. When two methoxy groups are present, the influence of their position is cumulative.
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 75, Issue 2, February 2010, Pages 925–929