View : 18 Download: 0
Mechanistic assessment of S NAr displacement of halides from 1-Halo-2,4-dinitrobenzenes by selected primary and secondary amines: Brønsted and Mayr analyses
- Mechanistic assessment of S NAr displacement of halides from 1-Halo-2,4-dinitrobenzenes by selected primary and secondary amines: Brønsted and Mayr analyses
- Um I.-H.; Im L.-R.; Kang J.-S.; Bursey S.S.; Dust J.M.
- Ewha Authors
- SCOPUS Author ID
- Issue Date
- Journal Title
- Journal of Organic Chemistry
- vol. 77, no. 21, pp. 9738 - 9746
- SCI; SCIE; SCOPUS
- Pseudo-first-order rate constants (k obsd) have been measured spectrophotometrically for nucleophilic substitution reactions of 1-X-2,4-dinitrobenzenes (1a-d, X = F, Cl, Br, I) with various primary and secondary amines in MeCN and H 2O at 25.0 ± 0.1 °C. The plots of k obsd vs [amine] curve upward for reactions of 1a (X = F) with secondary amines in MeCN. In contrast, the corresponding plots for the other reactions of 1b-d with primary and secondary amines in MeCN and H 2O are linear. The Brønsted-type plots for reactions of 1a-d with a series of secondary amines are linear with β nuc = 1.00 for the reaction of 1a and 0.52 ± 0.01 for those of 1b-d. Factors governing reaction mechanisms (e.g., solvent, halogen atoms, H-bonding interactions, amine types) have been discussed. Kinetic data were also analyzed in terms of the Mayr nucleophilicity parameter for the amines with each aromatic substrate. Provisional Mayr electrophilicity parameter (E) values for 1-X-2,4-dinitrobenzenes have been determined: E = ?14.1 for X = F, E = ?17.6 for X = Cl and Br, and E = ?18.3 for X = I. These values are consistent with the range and order of E values for heteroaromatic superelectrophiles and normal 6-? aromatic electrophiles. © 2012 American Chemical Society.
- Appears in Collections:
- 자연과학대학 > 화학·나노과학전공 > Journal papers
- Files in This Item:
There are no files associated with this item.
- RIS (EndNote)
- XLS (Excel)
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.