A New Ir-NHC Catalyst for Signal Amplification by Reversible Exchange in D2 O.
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.
Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Peter
P
Spannring
Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Indrek
I
Reile
RWTH Aachen, Institut für Technische und Makromolekulare Chemie, Worringerweg 2, 52074 Aachen, Germany.
Meike
M
Emondts
RWTH Aachen, Institut für Technische und Makromolekulare Chemie, Worringerweg 2, 52074 Aachen, Germany.
Philipp P M
PP
Schleker
Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Niels K J
NK
Hermkens
Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Nick G J
NG
van der Zwaluw
Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Bram J A
BJ
van Weerdenburg
Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Paul
P
Tinnemans
Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Marco
M
Tessari
RWTH Aachen, Institut für Technische und Makromolekulare Chemie, Worringerweg 2, 52074 Aachen, Germany.
Bernhard
B
Blümich
Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Floris P J T
FP
Rutjes
Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands. m.feiters@science.ru.nl.
Martin C
http://orcid.org/0000-0003-0130-835X
MC
Feiters
D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry; D002384:Catalysis; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D017666:Deuterium Oxide / Q000737:chemistry*; D007495:Iridium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000737:chemistry; D014867:Water / Q000737:chemistry
D001672:Biocompatible Materials; D056831:Coordination Complexes; D014867:Water; D009536:Niacinamide; D007495:Iridium; D017666:Deuterium Oxide; C008472:N-methylnicotinamide
SABRE; biocompatible; carbenes; ligand design; parahydrogen; water-soluble