S-alkylation of soft scorpionates.

Rajeev Rajasekharan-Nair, Dean Moore, Kirsten Chalmers, Dawn Wallace, Louise M Diamond, Lisa Darby, David R Armstrong, John Reglinski, Mark D Spicer

WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.

Chemistry (Weinheim an der Bergstrasse, Germany) 2013 Feb 11

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The alkylation reactions of soft scorpionates are reported. The hydrotris(S-alkyl-methimazolyl)borate dications (alkyl = methyl, allyl, benzyl), which were prepared by the reaction of Tm(Me) anion and primary alkyl halides, have been isolated and structurally characterised. The reaction is, however, not universally successful. DFT analysis of these alkylation reactions (C=S versus B-H alkylation) indicates that the observed outcome is driven by kinetic factors. Extending the study to incorporate alternative imine thiones (mercaptobenzothiazole, bz; thiazoline, tz) led to the structural characterisation of di[aquo-μ-aquohydrotris(mercaptobenzothiazolyl)boratosodium], which contains sodium atoms in the κ(3)-S,S,S coordination mode. Alkylation of Na[Tbz] and Na[tzTtz] leads to decomposition resulting in the formation of the simple S-alkylated heterocycles. The analysis of the species involved in these reactions shows an inherent weakness in the B-N bond in soft scorpionates, which has implications for their use in more advanced chemistry. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Citation

Rajeev Rajasekharan-Nair, Dean Moore, Kirsten Chalmers, Dawn Wallace, Louise M Diamond, Lisa Darby, David R Armstrong, John Reglinski, Mark D Spicer. S-alkylation of soft scorpionates. Chemistry (Weinheim an der Bergstrasse, Germany). 2013 Feb 11;19(7):2487-95