The α-effect in the SNAr reaction of 1-(4-nitrophenoxy)-2,4-dinitrobenzene with anionic nucleophiles: effects of solvation and polarizability on the α-effect
| العنوان: | The α-effect in the SNAr reaction of 1-(4-nitrophenoxy)-2,4-dinitrobenzene with anionic nucleophiles: effects of solvation and polarizability on the α-effect |
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| المؤلفون: | Erwin Buncel, Hyo-Jin Cho, Julian M. Dust, Ik-Hwan Um, Min-Young Kim |
| المصدر: | Canadian Journal of Chemistry. 93:1109-1114 |
| بيانات النشر: | Canadian Science Publishing, 2015. |
| سنة النشر: | 2015 |
| مصطلحات موضوعية: | chemistry.chemical_compound, chemistry, Nucleophile, Dinitrobenzene, Nucleophilic aromatic substitution, Polarizability, Organic Chemistry, Solvation, Organic chemistry, General Chemistry, Medicinal chemistry, Alpha effect, Catalysis |
| الوصف: | A kinetic study on SNAr reactions of 1-(4-nitrophenoxy)-2,4-dinitrobenzene (1a) with various anionic nucleophiles in 80 mol% water – 20 mol% DMSO at 25.0 °C is reported. The Brønsted-type plot for the reaction of 1a with a series of substituted phenoxides and HOO− results in an excellent linear correlation with βnuc = 1.17. However, OH− exhibits dramatic negative deviation from the Brønsted-type plot, while N3−, C6H5S−, and butane-2,3-dione monoximate (Ox−) deviate positively from linearity. HOO− is 680-fold more reactive than OH− but does not exhibit the α-effect. In contrast, Ox− is 166-fold more reactive than isobasic 4-Cl−C6H4O− and exhibits the α-effect. Differential solvation effects have been suggested to be responsible for the α-effect in this study, i.e., Ox− exhibits the α-effect, since it is 5.7 kcal/mol less strongly solvated than 4-Cl−C6H4O− in the reaction medium, while HOO− does not show the α-effect due to a strong requirement for partial desolvation before nucleophilic attack. The highly enhanced reactivity of polarizable N3− and C6H5S− and extremely decreased reactivity of nonpolarizable OH− are in accord with the hard–soft acid and base principle. |
| تدمد: | 1480-3291 0008-4042 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::30c3b6e42185e4dc09b4a3b4a42cc47a https://doi.org/10.1139/cjc-2015-0073 |
| حقوق: | CLOSED |
| رقم الأكسشن: | edsair.doi...........30c3b6e42185e4dc09b4a3b4a42cc47a |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14803291 00084042 |
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