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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 16, Number 6
BKCSDE 16(6)
June 20, 1995 

The Isoparametricity and Non-interaction Phenomena in the Reactions of Benzyl Benzenesulfonates with Anilines
Igor V. Shpanko, Seung Il Kim, Han Joong Koh, Ikchoon Lee*
The nucleophilic substitution reactions of benzyl benzenesulfonates with anilines have been studied in dimethylsulfoxide-tetrahydrofuran mixtures (1:3 and in part 1:1, v/v) with varying substituents in the nucleophile (X), substrate (Y) and leaving group (Z). Total second-order interactions between variable factors provide experimental evidence for the isoparametricity phenomenon : at the isoparametric points (IPPs),{σX},&^{σY} and &^{T} (isokinetic temperature) the rate of nucleophilic displacement does not change with variation in substituents Y,i.e. ρY=0 ; after passing through these IPPs, the order of reactivity for the substrate is reversed. Significant third-order interaction (QXYT=-1.66) provides realization of the non-interaction phenomenon : at critical values of &^{σY(XT)} = 0.08 and &^{σX(YT)} =-0.26 corresponding second-order interactions between temperature and substituents X(QXT) as well as substituents Y(QYT) vanish ; after passing through these critical values the sign reversals for QXT and QYT are observed. The first-and second-order sensitivity coefficients as well as the IPPs were used for characterization of the transition state structure.
534 - 538
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