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.
| Original language | English |
|---|---|
| Pages (from-to) | 2079-2090 |
| Number of pages | 12 |
| Journal | ACS Catalysis |
| Volume | 9 |
| Issue number | 3 |
| Early online date | 22 Jan 2019 |
| DOIs | |
| Publication status | Published - 1 Mar 2019 |
Keywords
- kinetics
- NMR spectroscopy
- reaction monitoring
- transfer hydrogenation
- transition metal catalysis
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
Cite this
Kinetics of Asymmetric Transfer Hydrogenation, Catalyst Deactivation, and Inhibition with Noyori Complexes As Revealed by Real-Time High-Resolution FlowNMR Spectroscopy. / Hall, Andrew M.R.; Dong, Peilong; Codina, Anna; Lowe, John P.; Hintermair, Ulrich.
In: ACS Catalysis, Vol. 9, No. 3, 01.03.2019, p. 2079-2090.Research output: Contribution to journal › Article
}
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
JF - ACS Catalysis
SN - 2155-5435
IS - 3
ER -