Colossal kinetic isotope effects in proton-coupled electron transfer

Proceedings of the National Academy of Sciences of the United States of America
My Hang V Huynh, Thomas J Meyer

Abstract

The kinetics of reduction of benzoquinone (Q) to hydroquinone (H(2)Q) by the Os(IV) hydrazido (trans-[Os(IV)(tpy)(Cl)(2)(N(H)N(CH(2))(4)O)]-PF(6) = [1]PF(6), tpy = 2,2':6',2"-terpyridine), sulfilimido (trans-[Os(IV)-(tpy)(Cl)(2)(NS(H)-4-C(6)H(4)Me)]PF(6) = [2]PF(6)), and phosphoraniminato (trans-[Os(IV)(Tp)(Cl)(2)(NP(H)(Et)(2))] = [3], Tp(-) = tris(pyrazolyl)-borate) complexes have been studied in 1:1 (vol/vol) CH(3)CN/H(2)O and CH(3)CN/D(2)O (1.0 M in NH(4)PF(6)/KNO(3) at 25.0 +/- 0.1 degrees C). The reactions are first order in both [Q] and Os(IV) complex and occur by parallel pH-independent (k(1)) and pH-dependent (k(2)) pathways that can be separated by pH-dependent measurements. Saturation kinetics are observed for the acid-independent pathway, consistent with formation of a H-bonded intermediate (K(A)) followed by a redox step (k(red)). For the pH-independent pathway, k(1)(H(2)O)/k(1)(D(2)O) kinetic isotope effects are 455 +/- 8 for [1(+)], 198 +/- 6 for [2(+)], and 178 +/- 5 for [3]. These results provide an example of colossal kinetic isotope effects for proton-coupled electron transfer reactions involving nitrogen, sulfur, and phosphorus as proton-donor atoms.

References

Feb 6, 1999·Annual Review of Physical Chemistry·R I Cukier, D G Nocera
Mar 4, 2000·Proceedings of the National Academy of Sciences of the United States of America·M L PaddockM Y Okamura
Apr 20, 2001·Accounts of Chemical Research·S Hammes-Schiffer
Jun 13, 2001·Biochemistry·M M Whittaker, J W Whittaker
Apr 25, 2002·Journal of the American Chemical Society·Nedialka Iordanova, Sharon Hammes-Schiffer
Jan 30, 2003·Journal of the American Chemical Society·Laurie A ReinhardtNigel G J Richards
Apr 15, 2002·Angewandte Chemie·My Hang V Huynh, Thomas J Meyer

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Citations

Feb 10, 2007·Journal of the American Chemical Society·Ryan E CowleyJeremy M Smith
Oct 12, 2010·Journal of the American Chemical Society·Vlad M Iluc, Gregory L Hillhouse
May 14, 2011·Journal of the American Chemical Society·Ryan E CowleyPatrick L Holland
Feb 21, 2013·Journal of the American Chemical Society·Robert N BarnettGary B Schuster
Feb 7, 2014·Journal of the American Chemical Society·Anna Lewandowska-AndralojcEtsuko Fujita
Oct 9, 2012·The Journal of Chemical Physics·M Kryvohuz, R A Marcus
May 4, 2006·Journal of the American Chemical Society·Ian J RhileJames M Mayer
Feb 11, 2016·Journal of the American Chemical Society·Megan N Jackson, Yogesh Surendranath
May 19, 2017·Journal of the American Chemical Society·Ying WangAndrzej Rajca
Dec 7, 2017·Dalton Transactions : an International Journal of Inorganic Chemistry·Jianhui XieTai-Chu Lau
Dec 22, 2019·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·Tetiana HalenovaTatiana Pleteneva
Mar 27, 2020·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·Ana Karković MarkovićStanko Uršić
May 3, 2019·Dalton Transactions : an International Journal of Inorganic Chemistry·Neil C TomsonJames M Boncella
Sep 17, 2020·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·Igor ZlatskiyAnton Syroeshkin
Nov 15, 2007·Chemical Reviews·My Hang V Huynh, Thomas J Meyer
Mar 12, 2008·Inorganic Chemistry·Feng LiuThomas J Meyer
Jan 7, 2021·Journal of the American Chemical Society·Robin TyburskiLeif Hammarström

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