Full metadata record
DC Field | Value | Language |
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dc.contributor.author | 엄익환 | - |
dc.date.accessioned | 2016-08-28T11:08:01Z | - |
dc.date.available | 2016-08-28T11:08:01Z | - |
dc.date.issued | 2006 | - |
dc.identifier.issn | 0022-3263 | - |
dc.identifier.other | OAK-3158 | - |
dc.identifier.uri | https://dspace.ewha.ac.kr/handle/2015.oak/219669 | - |
dc.description.abstract | In a study of the solvent effect on the α-effect, second-order rate constants (kNu-) have been determined spectrophotometrically for reactions of a series of substituted phenyl acetates with butan-2,3-dione monoximate (Ox-, α-nucleophile) and p-chlorophenoxide (p-ClPhO-, reference nucleophile) in DMSO-H2O (DMSO = dimethyl sulfoxide) mixtures of varying compositions at 25.0 ± 0.1 °C. The magnitude of the α-effect, kOX-/k p-ClPhO-, increases as the DMSO content in the medium increases up to 40-50 mol %, reaching 500, one of the largest α-effect values, and then decreases on further addition of DMSO, resulting in a bell-shaped α-effect profile regardless of the nature of the substrates. The magnitude of the α-effect is found to be significantly dependent on the substrates (or, more quantitatively, on βnuc). Thus, βnuc is an important predictor of the magnitude of the α-effect. The bell-shaped α-effect profile found in the present system is attributed to the differential change in the sensitivity of the medium effect on the Ox - and p-ClPhO- systems but not due to a change in the reaction mechanism or to a drastic change in the basicity of the two nucleophiles on addition of DMSO to the medium. Through application of calorimetric measurements of ground-state solvation combined with the diagnostic βnuc values, it is shown that the transition-state effect is more dominant than the ground-state effect as the origin of the α-effect in the present system. © 2006 American Chemical Society. | - |
dc.language | English | - |
dc.title | Solvent effect on the α-effect: Ground-state versus transition-state effects; a combined calorimetric and kinetic investigation | - |
dc.type | Article | - |
dc.relation.issue | 3 | - |
dc.relation.volume | 71 | - |
dc.relation.index | SCI | - |
dc.relation.index | SCIE | - |
dc.relation.index | SCOPUS | - |
dc.relation.startpage | 915 | - |
dc.relation.lastpage | 920 | - |
dc.relation.journaltitle | Journal of Organic Chemistry | - |
dc.identifier.doi | 10.1021/jo051823f | - |
dc.identifier.wosid | WOS:000235101100008 | - |
dc.identifier.scopusid | 2-s2.0-32144451129 | - |
dc.author.google | Um I.-H. | - |
dc.author.google | Hwang S.-J. | - |
dc.author.google | Buncel E. | - |
dc.contributor.scopusid | 엄익환(7006725706;6506759437) | - |
dc.date.modifydate | 20230411105538 | - |