Kinetics of Asymmetric Transfer Hydrogenation, Catalyst Deactivation, and Inhibition with Noyori Complexes As Revealed by Real-Time High-Resolution FlowNMR Spectroscopy

Andrew M.R. Hall, Peilong Dong, Anna Codina, John P. Lowe, Ulrich Hintermair

Research output: Contribution to journalArticle

Abstract

Catalytic hydrogen transfer from basic isopropyl alcohol to aryl ketones mediated by [(arene)(TsDPEN)RuCl] complexes has been investigated by operando 1 H NMR spectroscopy using a recirculating flow setup. Selective excitation pulse sequences allowed fast and quantitative monitoring of the key [(mesitylene)(TsDPEN)RuH] intermediate during catalysis, which is shown to interact with both substrates by polarization transfer experiments. Comparison of reaction profiles with catalyst speciation traces in conjunction with reaction progress kinetic analysis using variable time normalization and kinetic modeling showed the existence of two independent catalyst deactivation/inhibition pathways: whereas excess base exerted a competitive inhibition effect on the unsaturated catalyst intermediate, the active hydride suffered from an inherent first-order decay that is not evident in early stages of the reaction where turnover is fast. Isotopic labeling revealed arene loss to be the entry point into deactivation pathways to Ru nanoparticles via hydride-bridged intermediates.

LanguageEnglish
Pages2079-2090
Number of pages12
JournalACS Catalysis
Volume9
Issue number3
Early online date22 Jan 2019
DOIs
StatusPublished - 1 Mar 2019

Keywords

  • kinetics
  • NMR spectroscopy
  • reaction monitoring
  • transfer hydrogenation
  • transition metal catalysis

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

Cite this

@article{4a8260b401f84334a1e35562a9fa6b6a,
title = "Kinetics of Asymmetric Transfer Hydrogenation, Catalyst Deactivation, and Inhibition with Noyori Complexes As Revealed by Real-Time High-Resolution FlowNMR Spectroscopy",
abstract = "Catalytic hydrogen transfer from basic isopropyl alcohol to aryl ketones mediated by [(arene)(TsDPEN)RuCl] complexes has been investigated by operando 1 H NMR spectroscopy using a recirculating flow setup. Selective excitation pulse sequences allowed fast and quantitative monitoring of the key [(mesitylene)(TsDPEN)RuH] intermediate during catalysis, which is shown to interact with both substrates by polarization transfer experiments. Comparison of reaction profiles with catalyst speciation traces in conjunction with reaction progress kinetic analysis using variable time normalization and kinetic modeling showed the existence of two independent catalyst deactivation/inhibition pathways: whereas excess base exerted a competitive inhibition effect on the unsaturated catalyst intermediate, the active hydride suffered from an inherent first-order decay that is not evident in early stages of the reaction where turnover is fast. Isotopic labeling revealed arene loss to be the entry point into deactivation pathways to Ru nanoparticles via hydride-bridged intermediates.",
keywords = "kinetics, NMR spectroscopy, reaction monitoring, transfer hydrogenation, transition metal catalysis",
author = "Hall, {Andrew M.R.} and Peilong Dong and Anna Codina and Lowe, {John P.} and Ulrich Hintermair",
year = "2019",
month = "3",
day = "1",
doi = "10.1021/acscatal.8b03530",
language = "English",
volume = "9",
pages = "2079--2090",
journal = "ACS Catalysis",
issn = "2155-5435",
publisher = "American Chemical Society",
number = "3",

}

TY - JOUR

T1 - Kinetics of Asymmetric Transfer Hydrogenation, Catalyst Deactivation, and Inhibition with Noyori Complexes As Revealed by Real-Time High-Resolution FlowNMR Spectroscopy

AU - Hall, Andrew M.R.

AU - Dong, Peilong

AU - Codina, Anna

AU - Lowe, John P.

AU - Hintermair, Ulrich

PY - 2019/3/1

Y1 - 2019/3/1

N2 - Catalytic hydrogen transfer from basic isopropyl alcohol to aryl ketones mediated by [(arene)(TsDPEN)RuCl] complexes has been investigated by operando 1 H NMR spectroscopy using a recirculating flow setup. Selective excitation pulse sequences allowed fast and quantitative monitoring of the key [(mesitylene)(TsDPEN)RuH] intermediate during catalysis, which is shown to interact with both substrates by polarization transfer experiments. Comparison of reaction profiles with catalyst speciation traces in conjunction with reaction progress kinetic analysis using variable time normalization and kinetic modeling showed the existence of two independent catalyst deactivation/inhibition pathways: whereas excess base exerted a competitive inhibition effect on the unsaturated catalyst intermediate, the active hydride suffered from an inherent first-order decay that is not evident in early stages of the reaction where turnover is fast. Isotopic labeling revealed arene loss to be the entry point into deactivation pathways to Ru nanoparticles via hydride-bridged intermediates.

AB - Catalytic hydrogen transfer from basic isopropyl alcohol to aryl ketones mediated by [(arene)(TsDPEN)RuCl] complexes has been investigated by operando 1 H NMR spectroscopy using a recirculating flow setup. Selective excitation pulse sequences allowed fast and quantitative monitoring of the key [(mesitylene)(TsDPEN)RuH] intermediate during catalysis, which is shown to interact with both substrates by polarization transfer experiments. Comparison of reaction profiles with catalyst speciation traces in conjunction with reaction progress kinetic analysis using variable time normalization and kinetic modeling showed the existence of two independent catalyst deactivation/inhibition pathways: whereas excess base exerted a competitive inhibition effect on the unsaturated catalyst intermediate, the active hydride suffered from an inherent first-order decay that is not evident in early stages of the reaction where turnover is fast. Isotopic labeling revealed arene loss to be the entry point into deactivation pathways to Ru nanoparticles via hydride-bridged intermediates.

KW - kinetics

KW - NMR spectroscopy

KW - reaction monitoring

KW - transfer hydrogenation

KW - transition metal catalysis

UR - http://www.scopus.com/inward/record.url?scp=85061544917&partnerID=8YFLogxK

U2 - 10.1021/acscatal.8b03530

DO - 10.1021/acscatal.8b03530

M3 - Article

VL - 9

SP - 2079

EP - 2090

JO - ACS Catalysis

T2 - ACS Catalysis

JF - ACS Catalysis

SN - 2155-5435

IS - 3

ER -