Abstract
The hydrogenation of alkynes and alkenes using a Shrock-Osborn catalysts was followed in-situ with dissolution dynamic nuclear polarization (dDNP) NMR. Natural abundance and 13C labeled dimethyl acetylenedicarboxylate was hyperpolarized prior to hydrogenation using (1,4-bis{diphenylphosphino}butane)(2,5-norbornadiene) rhodium(I) perchlorate, [Rh(NBD)(DPPB)]ClO4. The increased signal-to-noise ratio of dDNP compared to conventional 13C NMR allowed real-time detection of substrate and products as well as the modeling of the hydrogenation kinetics. The build-up of an intermediate was observed during interruption in hydrogen flow, substantiating the current view of the reaction mechanism. Selective inversion of the carbonyl NMR signal of the substrate was applied to demonstrate unequivocally that the new peak appearing in the spectrum originates from a reaction intermediate. The scope of the dDNP method for following reaction dynamics in real time was further demonstrated by substrate competition experiments.
Original language | English |
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Journal | The Journal of Physical Chemistry Part C |
Volume | 123 |
Issue number | 15 |
Pages (from-to) | 9949-9956 |
Number of pages | 8 |
ISSN | 1932-7447 |
DOIs | |
Publication status | Published - 2019 |