نبذة مختصرة : In-situ NMR spectroscopic analysis of homogeneous reactions is an essential tool for mechanistic analysis in organic and organometallic chemistry. However, rapid non-equilibrium reactions, that are initiated by mixing, require specialized approaches. We report herein on a study of the factors that ensure quantitative results in a recently-developed technique for stopped-flow NMR spectroscopy. The influence of some of the key parameters on quantitation is studied by 19F NMR spectroscopic analysis of the kinetics and activation parameters for the base-catalyzed protodeboronation of highly-reactive polyfluorinated arylboronic acids, with half-lives as low as 0.1 seconds. The effects of spin relaxation, pre-magnetization, heat-transfer versus reaction enthalpy, and mixing-efficiency are analyzed in detail. We also compare and contrast choice of pulse angle, interscan delay, and use of pseudo real-time by interleaving, as means to achieve an optimal balance between temporal resolution and sensitivity.
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