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Merging Gradient‐Based Methods to Improve Benchtop NMR Spectroscopy: A New Tool for Flow Reaction Optimization
Author(s) -
Kunjir Shrikant,
RodriguezZubiri Mireia,
Coeffard Vincent,
Felpin FrançoisXavier,
Giraudeau Patrick,
Farjon Jonathan
Publication year - 2020
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202000573
Subject(s) - context (archaeology) , resolution (logic) , protonation , spectrometer , chemistry , spectral resolution , flow (mathematics) , analytical chemistry (journal) , flow chemistry , pulse sequence , spectroscopy , sensitivity (control systems) , solvent , spectral line , nuclear magnetic resonance spectroscopy , nuclear magnetic resonance , computational physics , computer science , organic chemistry , physics , optics , catalysis , electronic engineering , mechanics , ion , paleontology , quantum mechanics , astronomy , artificial intelligence , biology , engineering
Emerging low cost, compact NMR spectrometers that can be connected in‐line to a flow reactor are suited to study reaction mixtures. The main limitation of such spectrometers arises from their lower magnetic field inducing a reduced sensitivity and a weaker spectral resolution. For enhancing the spectral resolution, the merging of Pure‐Shift methods recognized for line narrowing with solvent elimination schemes was implemented in the context of mixtures containing protonated solvents. One more step was achieved to further enhance the resolution power on compact systems, thanks to multiple elimination schemes prior to Pure‐Shift pulse sequence elements. For the first time, we were able to remove up to 6 protonated solvent signals simultaneously by dividing their intensity by 500 to 1700 with a concomitant spectral resolution enhancement for signals of interest from 9 to 12 as compared to the standard 1D 1 H. Then, the potential of this new approach was shown on the flow synthesis of a complex benzoxanthenone structure.