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arXiv · 2105.05657

Time- and Site-Resolved Kinetic NMR: Real-Time Monitoring of Off-Equilibrium Chemical Dynamics by 2D Spectrotemporal Correlations

Michael J. Jaroszewicz·Mengxiao Liu·Jihyun Kim·Guannan Zhang·Yaewon Kim·Christian Hilty·Lucio Frydman
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Abstract

Nuclear magnetic resonance (NMR) spectroscopy provides detailed information pertaining to dynamic processes through line-shape changes, which have been traditionally limited to equilibrium conditions. However, there is a wealth of information to be gained by studying chemical reactions under off-equilibrium conditions -- e.g., in states that arise upon mixing reactants that subsequently undergo chemical changes -- and in monitoring the formation of reaction products in real time. Herein, we propose and demonstrate a time-resolved kinetic NMR experiment that combines rapid mixing techniques, continuous flow, and single-scan spectroscopic imaging methods, leading in unison to a new 2D spectro-temporal NMR correlation which provides high-quality kinetic information of off-equilibrium dynamics. These kinetic 2D NMR spectra possess a spectral dimension conveying with high resolution the individual chemical sites, correlated with a time-independent, steady-state spatial axis that delivers unique information concerning temporal changes along the chemical reaction coordinate. A comprehensive description of the kinetic and spectroscopic features associated to these spectro-temporal NMR analyses is presented, factoring in the rapid-mixing, the flow and the spectroscopic NMR imaging. An experimental demonstration of this method's novel aspects was carried out using an enzymatically catalyzed reaction, leading to site- and time-resolved kinetic NMR data that are in excellent agreement with control experiments and literature values.

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Michael J. Jaroszewicz, Mengxiao Liu, Jihyun Kim, Guannan Zhang, Yaewon Kim, Christian Hilty, Lucio Frydman. 2021-05-12. Time- and Site-Resolved Kinetic NMR: Real-Time Monitoring of Off-Equilibrium Chemical Dynamics by 2D Spectrotemporal Correlations. https://doi.org/10.1038/s41467-022-28304-w

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