A New Ir‐NHC Catalyst for Signal Amplification by Reversible Exchange in D 2 O

作者：Peter Spannring, Indrek Reile, Meike Emondts, P. Philipp M. Schleker, Niels K. J. Hermkens, Nick G. J. van der Zwaluw, Bram J. A. van Weerdenburg, Paul Tinnemans, Marco Tessari, Bernhard Blümich, Floris P. J. T. Rutjes, Martin C. Feiters · 发表于：Chemistry - A European Journal · 年份：2016 · DOI：10.1002/chem.201601211 · 被引用次数：84 · 研究领域：Advanced NMR Techniques and Applications、N-Heterocyclic Carbenes in Organic and Inorganic Chemistry、Magnetism in coordination complexes

NMR signal amplification by reversible exchange (SABRE) has been observed for pyridine, methyl nicotinate, N-methylnicotinamide, and nicotinamide in D2 O with the new catalyst [Ir(Cl)(IDEG)(COD)] (IDEG=1,3-bis(3,4,5-tris(diethyleneglycol)benzyl)imidazole-2-ylidene). During the activation and hyperpolarization steps, exclusively D2 O was used, resulting in the first fully biocompatible SABRE system. Hyperpolarized (1) H substrate signals were observed at 42.5 MHz upon pressurizing the solution with parahydrogen at close to the Earth's magnetic field, at concentrations yielding barely detectable thermal signals. Moreover, 42-, 26-, 22-, and 9-fold enhancements were observed for nicotinamide, pyridine, methyl nicotinate, and N-methylnicotinamide, respectively, in conventional 300 MHz studies. This research opens up new opportunities in a field in which SABRE has hitherto primarily been conducted in CD3 OD. This system uses simple hardware, leaves the substrate unaltered, and shows that SABRE is potentially suitable for clinical purposes.