Nitroso group transfer from N-nitrososulfonamides to thiolate ions. Intrinsic reactivity
摘要:
The nitroso group transfer from N-nitrososulfonamides to thiolate ions was studied. Based on the results, the reaction rate is strongly dependent on the nature of the leaving group (alpha(1g) approximate to -1.30), but virtually independent of the basicity of the thiol (beta(nuc) approximate to 0-10)This dependence is ascribed to the presence of a nucleophile desolvation equilibrium (beta(d)) that is followed by the attack of the thiolate ion on the nitroso group (beta'(nuc)) via a concerted mechanism. The equilibrium constants for the loss of a nitroso group from a nitrosothiol and an N-nitrososulfonarni de were used to obtain the equilibrium constants for the different reactions involved. By using rate-equilibrium correlations, the parameters alpha(norm)(1g) ,beta(d), and beta('norm)(nuc) were obtained. (c) 2006 Elsevier Ltd. All rights reserved.
Cation-anion combination reactions. 21. Reactions of thiolate ions, cyanide ion, and amines with cations and carbonyl compounds in dimethyl sulfoxide solution
Kinetics of extremely fast ligand-exchange reactions with methylmercury(II)-nitrothiophenolate complexes: rate-equilibria correlations
作者:Gerhard Geier、Hugo Gross
DOI:10.1016/s0020-1693(00)90373-6
日期:1989.2
S-donors can also initiate directly the ligand-exchangereactions. The rate constants for the thiophenols are always smaller than those for the thiophenolates. The reactivity of the protonated S-donors is strongly dependent on the nature of the ligand to be displaced. Several features of the reaction mechanisms involved and their relevance for the transport of CH3Hg(II) in natural systems are discussed.
Mechanism of reactions of N-(methoxymethyl)-N,N-dimethylanilinium ions with nucleophilic reagents
作者:Barry L. Knier、William P. Jencks
DOI:10.1021/ja00542a021
日期:1980.10
weak interactions with the entering and leaving groups. Secondary ..cap alpha..-deuterium isotope effects for the second-order reactions range from (k/subH//k/sub D/)/D = 0.99 for fluoride ion to 1.18 for iodide ion. Solvolysis and the second-order reaction with n-propylamine exhibit values of ..delta..S/sup + +/ = -1.2 and -2.1 cal K/sup -1/ mol/sup -1/, respectively, and display similarmore » changes
Detection and kinetic characterization of S<sub>N</sub>V intermediates. Reactions of thiomethoxybenzylidene Meldrum's acid with thiolate ions, alkoxide ions, OH<sup>-</sup>, and water in aqueous DMSO
作者:Claude F Bernasconi、Rodney J Ketner、Xin Chen、Zvi Rappoport
DOI:10.1139/v99-009
日期:1999.6.1
The reaction of thiomethoxybenzylidene Meldrum'sacid (5-SMe) with thiolate and alkoxide ion nucleophiles is shown to proceed by the two-step addition-elimination SNV mechanism in which the tetrahedral intermediate accumulates to detectable levels. For the reactions with thiolate ions, rate constants for nucleophilicaddition (k1RX), its reverse (k-1RX), and for conversion of the intermediate to products
Imidinium ions, ArNCNR2+, were generated in aqueoussolution from the solvolysis of fluoro and chloro formamidines at pH 9.3 and 25 °C. Rate constants for the hydration of five imidinium ions were determined from a kinetic analysis of their trapping by thiolacetate anion, CH3COS-, in the presence of a pool of competing fluoride anion, and a rate constant of kAcS− = 5 × 109 M-1 s-1 for diffusion-controlled
Unraveling Structure−Reactivity Relationships in S<sub>N</sub>V Reactions: Kinetics of the Reactions of Methoxybenzylidenemalononitrile, 2-(Methylthiobenzylidene)-1,3-indandione, 2-(Benzylthiobenzylidene)-1,3-indandione, and Methyl β-Methylthio-α-nitrocinnamate with OH<sup>-</sup> and Thiolate Ions in Aqueous DMSO
作者:Claude F. Bernasconi、Rodney J. Ketner、Mark L. Ragains、Xin Chen、Zvi Rappoport
DOI:10.1021/ja003536t
日期:2001.3.1
The kinetics of the title reactions were determined in 50% DMSO-50% water (v/v) at 20 degrees C; n-BuS-, HOCH2CH2S-, and MeO2CCH2S- were used as thiolateions. The reactions with the thiolateions gave rise to two separate kinetic processes. The first refers to rapid, reversible attachment of RS- to the substrate leading to a tetrahedral intermediate (k1RS), k(-1)RS, the second to the conversion of