کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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178385 | 459040 | 2006 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: The synthesis and complexation study of some novel 3-methoxyphenyl chromenone crown ethers using conductometry The synthesis and complexation study of some novel 3-methoxyphenyl chromenone crown ethers using conductometry](/preview/png/178385.png)
7,8-Dihydroxy-3-(3,4-dimethoxyphenyl)-2H-chromenones, 7,8-dihydroxy-3-(3,5-dimethoxyphenyl)-2H-chromenones and 7,8-dihydroxy-3-(3,4,5-trimethoxyphenyl)-2H-chromenones, o-dihydroxy-3-methoxyphenylcoumarins, were prepared from 2,3,4-trihydroxybenzaldehyde and corresponding methoxyphenylacetic acid in NaOAc/Ac2O, respectively. 3-Methoxyphenyl-7,8-dihydroxy-2H-chromenone reacted with the polyethylene glycol ditosylate or dichloride in CH3CN/alkali carbonate to afford [12]crown-4, [15]crown-5 and [18]crown-6-chromonones.The chromatographically purified novel chromenone crown ethers were identified with IR, 1H NMR, 13C NMR and low and high resolution mass spectroscopy and elemental analysis.Stability constants for the 1:1 complexes of Na+ and K+ with different substituted methoxyphenyl derivatives of coumarino[12]crown-4, coumarino[15]crown-5 and coumarino[18]crown-6 (5a–5i) have been determined by conductometry at 25 °C in a binary solvent, dioxane/water. For all the coumarino crown ether derivatives, the stability constant decreases for K+ ion compared to Na+ ion.The selectivity sequence of these crown ethers in dioxane/water has showed an irregular order with respect to their cavity size.
Journal: Dyes and Pigments - Volume 71, Issue 3, 2006, Pages 161–167