Mechanistic analysis by NMR spectroscopy: A users guide

Ben‐Tal, Yael; Boaler, Patrick J.; Dale, Harvey J. A.; Dooley, Ruth E.; Fohn, Nicole A.; Gao, Yuan; García‐Domínguez, Andrés; Grant, Katie M.; Hall, Andrew M. R.; Hayes, Hannah L. D.; Kucharski, Maciej M.; Wei, Ran; Lloyd‐Jones, Guy C.

doi:10.1016/j.pnmrs.2022.01.001

Cited by 58 publications

(93 citation statements)

References 307 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This intramolecular competition experiment showed preference for the insertion in the CH over the CH2 as expected for an insertion reaction (Figure 5, E). The determination of primary kinetic isotopic effects (pKIE) was carried out by both intra-and intermolecular competition experiments using D-5c and D2-5c, respectively (Figure 5, F) (45)(46). The result obtained in the intermolecular competition experiment, KIE = 3.6, supports C-H insertion being the turn over limiting step (Figure 5, F); whereas a KIE = 2.0 measured in the intramolecular competition is also in agreement with the C-H insertion being the product determining step (Figure 5, F).…”

Section: Resultsmentioning

confidence: 99%

Remote C(sp3)—H insertion into non-activated bonds: rapid construction of an added-value molecular diverse library

Miguélez

Rodríguez-Arias

Mykhailiuk

et al. 2022

Preprint

View full text Add to dashboard Cite

The synthesis of added-value compounds from raw feedstock materials represents one of the major challenges in synthetic organic chemistry. By using a well-defined intramolecular C—H insertion reaction, it is possible to transform a number of raw feedstock compounds into a library of molecularly complex and diverse compounds. In addition, these compounds display a C—Br bond amenable for further functionalization. A preliminary mechanistic study supports the participation of an elusive gold (I) vinylidene complex as key intermediate of the reaction. The most salient feature of this methodology is the ability to functionalize in a predictable way non-activated C—H bonds without any sort of electronic, geometric or conformational bias.

show abstract

Section: Resultsmentioning

confidence: 99%

Remote C(sp3)—H insertion into non-activated bonds: rapid construction of an added-value molecular diverse library

Miguélez

Rodríguez-Arias

Mykhailiuk

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Reaction monitoring by NMR spectroscopy provides unique chemical insight. [1][2][3] Online monitoring by flow NMR is a powerful method that makes it possible to analyse reactions carried out in relevant experimental conditions. [4][5][6][7][8][9][10][11] It has notably been shown that reaction kinetics as measured in an NMR tube may not be representative of what happens in a round-bottomed flask with stirring.…”

Section: Introductionmentioning

confidence: 99%

“…[20] DOSY experiments rely on a diffusion-induced signal attenuation that results from the application of pulsed magnetic-field gradients, and on the acquisition of several consecutive sub-experiments with different gradient intensities. Recent examples of DOSY experiments in the context of online monitoring by flow NMR relied on a stopped-flow acquisition, [21] and to our knowledge such methods were never used on flow 1 .…”

Section: Introductionmentioning

confidence: 99%

Online Reaction Monitoring with Fast and Flow‐Compatible Diffusion NMR Spectroscopy

Marchand

Mishra

Bernard

et al. 2022

Chemistry A European J

View full text Add to dashboard Cite

Online monitoring by flow NMR spectroscopy is a powerful approach to study chemical reactions and processes, which can provide mechanistic understanding, and drive optimisations. However, some of the most useful methods for mixture analysis and reaction monitoring are not directly applicable in flow conditions. This is the case of classic diffusion‐ordered NMR spectroscopy (DOSY) methods, which can be used to separate the spectral information for mixture's components. We describe a fast and flow‐compatible diffusion NMR experiment that makes it possible to collect accurate diffusion data for samples flowing at up to 3 mL/min. We use it to monitor the synthesis of a Schiff base with a flow‐tube with a time resolution of approximately 2 minutes. The one‐shot flow‐compatible diffusion NMR described here open many avenues for reaction monitoring applications.

show abstract

“…These experiments are described in every physical chemistry textbook 5,6 and millions of students have conducted these experiments in laboratories, using methodologies that have barely changed in over 100 years. Kinetic data can be collected using a wide range of experimental methods, including multinuclear NMR, [7][8][9] UV-Vis spectroscopy, infrared spectroscopy, 10 high performance liquid chromatography, 11,12 mass spectrometry, 13,14 calorimetry, 15 and many others.…”

Section: Introductionmentioning

confidence: 99%

Continuous Addition Kinetic Elucidation: Catalyst and Reactant Order, Rate Constant, and Poisoning from a Single Experiment

Williams

Killeen

Chagunda

et al. 2022

Preprint

View full text Add to dashboard Cite

Kinetic analysis of catalytic reactions is a powerful tool for mechanistic elucidation but is often challenging to perform. Establishing order in a catalyst is achieved by running several reactions at different loadings, which is complicated by the challenge of maintaining consistent run-to-run experimental conditions. We present Continuous Addition Kinetic Elucidation (CAKE), which involves steadily injecting catalyst into the reaction, and following reaction progress over time to generate a plot whose shape is dependent only on the order in reactant and in catalyst. Modelling the curve (using a convenient web tool) allows the catalyst and reactant order to be determined, as well as the rate constant and the amount of any catalyst poison present.

show abstract

Mechanistic analysis by NMR spectroscopy: A users guide

Cited by 58 publications

References 307 publications

Remote C(sp3)—H insertion into non-activated bonds: rapid construction of an added-value molecular diverse library

Remote C(sp3)—H insertion into non-activated bonds: rapid construction of an added-value molecular diverse library

Online Reaction Monitoring with Fast and Flow‐Compatible Diffusion NMR Spectroscopy

Continuous Addition Kinetic Elucidation: Catalyst and Reactant Order, Rate Constant, and Poisoning from a Single Experiment

Contact Info

Product

Resources

About