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Thiolate alkylation in tripod zinc complexes: a comparative kinetic study.

Michael Rombach·Jan Seebacher·Mian Ji·Guofang Zhang·Guosen He·Mohamed M Ibrahim·Boumahdi Benkmil·Heinrich Vahrenkamp
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Abstract

The biologically relevant alkylations of the thiolate ligands in tripod zinc thiolates by methyl iodide were studied kinetically. Five tripod ligands of the pyrazolyl/thioimidazolyl borate type were employed, offering N3, N2S, NS2, and S3 donor sets. For each of them, the ethyl-, benzyl-, phenyl-, and p-nitrophenylthiolate zinc complexes were investigated, yielding a total of 20 second-order rate constants. The comparison of these rate constants shows three effects: (1) the electronic effect among the thiolates, i.e., the ethanethiolates react about 3 orders of magnitude faster than the p-nitrophenylthiolates; (2) the steric effect among the pyrazolylborates, i.e., the phenyl-substituted ones react about 2 orders of magnitude faster than the tert-butyl-substituted ones; and (3) the strong acceleration by the sulfur donors in the tripods, reaching 4 orders of magnitude between the reaction times of the (N3)Zn-SR and (S3)Zn-SR complexes.

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AlkylationIndicators and ReagentsKineticsLigandsSulfhydryl CompoundsSulfurZincComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't

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Michael Rombach, Jan Seebacher, Mian Ji, Guofang Zhang, Guosen He, Mohamed M Ibrahim, Boumahdi Benkmil, Heinrich Vahrenkamp. 2006-05-29. Thiolate alkylation in tripod zinc complexes: a comparative kinetic study.. https://doi.org/10.1021/ic060301v

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