Full metadata record
DC Field | Value | Language |
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dc.contributor.author | 엄익환 | - |
dc.date.accessioned | 2016-08-28T12:08:02Z | - |
dc.date.available | 2016-08-28T12:08:02Z | - |
dc.date.issued | 2011 | - |
dc.identifier.issn | 0253-2964 | - |
dc.identifier.other | OAK-7816 | - |
dc.identifier.uri | https://dspace.ewha.ac.kr/handle/2015.oak/221822 | - |
dc.description.abstract | Pseudo-first-order rate constants (k obsd) have been measured spectrophotometrically for nucleophilic substitution reactions of 3,4-dinitrophenyl diphenylphosphinothioate 9 with alkali metal ethoxides (EtOM, M = Li, Na, K) in anhydrous ethanol at 25.0 ± 0.1 °C. The plot of k obsd vs. [EtOM] is linear for the reaction of 9 with EtOK. However, the plot curves downwardly for those with EtOLi and EtONa while it curves upwardly for the one with EtOK in the presence of 18-crown-6-ether (18C6). Dissection of k obsd into k EtO- and k EtOM (i.e., the second-order rate constant for the reaction with dissociated EtO - and ion-paired EtOM, respectively) has revealed that the reactivity increases in the order k EtOLi < k EtONa < k EtO- ≈ k EtOK < k EtOK/18C6, indicating that the reaction is inhibited by Li + and Na + ions but is catalyzed by 18C6-crowned K + ion. The reactivity order found for the reactions of 9 contrasts to that reported previously for the corresponding reactions of 1, i.e., k EtOLi > k EtONa < k EtOK > k EtO- ≈ k EtOK/18C6, indicating that the effect of changing the electrophilic center from P=O to P=S on the role of M + ions is significant. A four-membered cyclic transition-state has been proposed to account for the M + ion effects found in this study, e.g., the polarizable sulfur atom of the P=S bond in 9 interacts strongly with the soft 18C6-crowned K + ion while it interacts weakly with the hard Li + and Na + ions. | - |
dc.language | English | - |
dc.title | Alkali metal ion catalysis and inhibition in nucleophilic substitution reactions of 3,4-Dinitrophenyl diphenylphosphinothioate with alkali metal ethoxides in anhydrous ethanol: Effect of changing electrophilic center from P=O to P=S | - |
dc.type | Article | - |
dc.relation.issue | 7 | - |
dc.relation.volume | 32 | - |
dc.relation.index | SCI | - |
dc.relation.index | SCIE | - |
dc.relation.index | SCOPUS | - |
dc.relation.index | KCI | - |
dc.relation.startpage | 2423 | - |
dc.relation.lastpage | 2427 | - |
dc.relation.journaltitle | Bulletin of the Korean Chemical Society | - |
dc.identifier.doi | 10.5012/bkcs.2011.32.7.2423 | - |
dc.identifier.wosid | WOS:000293202900046 | - |
dc.identifier.scopusid | 2-s2.0-79960487512 | - |
dc.author.google | An J.-S. | - |
dc.author.google | Namkoong G. | - |
dc.author.google | Kang J.-S. | - |
dc.author.google | Um I.-H. | - |
dc.contributor.scopusid | 엄익환(7006725706;6506759437) | - |
dc.date.modifydate | 20230411105538 | - |