CC BY-NC 3.0 UnportedBara-Estaún, AlejandroLyall, Catherine L.Lowe, John P.Pringle, Paul G.Kamer, Paul C. J.Franke, RobertHintermair, Ulrich2022-02-082022-02-082021https://oa.tib.eu/renate/handle/123456789/7974https://doi.org/10.34657/7015The hydroformylation of 1-hexene with 12 bar of 1 : 1 H2/CO in the presence of the catalytic system [Rh(acac)(CO)2]/PPh3 was successfully studied by real-time multinuclear high-resolution FlowNMR spectroscopy at 50 °C. Quantitative reaction progress curves that yield rates as well as chemo- and regioselectivities have been obtained with varying P/Rh loadings. Dissolved H2 can be monitored in solution to ensure true operando conditions without gas limitation. 31P{1H} and selective excitation 1H pulse sequences have been periodically interleaved with 1H FlowNMR measurements to detect Rh–phosphine intermediates during the catalysis. Stopped-flow experiments in combination with diffusion measurements and 2D heteronuclear correlation experiments showed the known tris-phosphine complex [RhH(CO)(PPh3)3] to generate rapidly exchanging isomers of the bis-phosphine complex [Rh(CO)2(PPh3)2] under CO pressure that directly enter the catalytic cycle. A new mono-phosphine acyl complex has been identified as an in-cycle reaction intermediate.enghttps://creativecommons.org/licenses/by-nc/3.0/540HydroformylationIsomersPhosphorus compoundsReaction intermediatesReaction ratesRhodium compoundsSpectroscopic analysisChemo-and regioselectivitiesDiffusion measurementsHeteronuclear correlationPhosphine complexReaction progressSelective excitationsSpectroscopic studiesStopped flow experimentsRhodium metallographyArticle