Exceedingly facile Ph−X activation (X=Cl, Br, I) with ruthenium(II) : Arresting kinetics, autocatalysis, and mechanisms
Abstract
[(Ph3P)3Ru(L)(H)2] (where L=H2 (1) in the presence of styrene, Ph3P (3), and N2 (4)) cleave the Ph[BOND]X bond (X=Cl, Br, I) at RT to give [(Ph3P)3RuH(X)] (2) and PhH. A combined experimental and DFT study points to [(Ph3P)3Ru(H)2] as the reactive species generated upon spontaneous loss of L from 3 and 4. The reaction of 3 with excess PhI displays striking kinetics which initially appears zeroth order in Ru. However mechanistic studies reveal that this is due to autocatalysis comprising two factors: 1) complex 2, originating from the initial PhI activation with 3, is roughly as reactive toward PhI as 3 itself; and 2) the Ph[BOND]I bond cleavage with the just-produced 2 gives rise to [(Ph3P)2RuI2], which quickly comproportionates with the still-present 3 to recover 2. Both the initial and onward activation reactions involve PPh3 dissociation, PhI coordination to Ru through I, rearrangement to a η2-PhI intermediate, and Ph[BOND]I oxidative addition.
Citation
Miloserdov , F M , McKay , D , Muñoz , B K , Samouei , H , Macgregor , S A & Grushin , V V 2015 , ' Exceedingly facile Ph−X activation (X=Cl, Br, I) with ruthenium(II) : Arresting kinetics, autocatalysis, and mechanisms ' , Angewandte Chemie International Edition , vol. 54 , no. 29 , pp. 8466–8470 . https://doi.org/10.1002/anie.201501996
Publication
Angewandte Chemie International Edition
Status
Peer reviewed
ISSN
1521-3773Type
Journal article
Rights
© 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Description
The ICIQ Foundation and The Spanish Government (Grant CTQ2011-25418 and the Severo Ochoa Excellence Accreditation 2014-2018 SEV-2013-0319) are thankfully acknowledged for support of this work. F.M.M. is grateful to the Government of Spain (MICINN) for the FPI Ph.D. Scholarship (BES-2012-054922). S.A.M. and D.M. thank the EPSRC for support through award EP/J010677/1.Collections
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