Obenaus Utz, Althoff-Ospelt Gerhard, Lang Swen, Himmelmann Robin, Hunger Michael
Institute of Chemical Technology, University of Stuttgart, 70550, Stuttgart, Germany.
Solid-State NMR Application, Bruker BioSpin GmbH, Silberstreifen 4, 76287, Rheinstetten, Germany.
Chemphyschem. 2017 Mar 3;18(5):455-458. doi: 10.1002/cphc.201601227. Epub 2017 Jan 23.
The present work introduces a novel method for the selective detection of H NMR anti-phase signals caused by the pairwise incorporation of parahydrogen into olefins on noble-metal-containing catalysts. Via a two-dimensional (2D) nutation NMR experiment, the anti-phase signals of hyperpolarized H nuclei are separated due to their double nutation frequency compared to that of thermally polarized H nuclei. For demonstrating this approach, parahydrogen induced polarization (PHIP) was achieved via the hydrogenation of propene with parahydrogen on platinum-containing silica and investigated by in situ H MAS NMR spectroscopy under continuous-flow conditions, that is, the hydrogenation reaction was performed inside the magnet of the NMR spectrometer. The 2D nutation NMR experiment described in the present work is useful for the separation of overlapping anti-phase and in-phase signals due to hyperpolarized and thermally polarized H nuclei, respectively, which is important for research in the field of heterogeneous catalysis.
本工作介绍了一种新颖的方法，用于选择性检测由仲氢成对掺入含贵金属催化剂上的烯烃所引起的¹H NMR反相信号。通过二维（2D）章动NMR实验，与热极化¹H核相比，超极化¹H核的反相信号因其双倍章动频率而被分离。为证明此方法，通过在含铂二氧化硅上用仲氢对丙烯进行氢化实现了仲氢诱导极化（PHIP），并在连续流动条件下通过原位¹H MAS NMR光谱进行研究，即氢化反应在NMR光谱仪的磁体内部进行。本工作中描述的二维章动NMR实验分别有助于分离由于超极化和热极化¹H核引起的重叠反相和同相信号，这对于多相催化领域的研究很重要。
