Parahydrogen is used to give efficient NMR detection of array of amines, amides, alcohols, carboxylates, carbonates, and phosphates.

Hyperpolarisation methods that premagnetise agents such as pyruvate are currently receiving significant attention because they produce sensitivity gains that allowd isease tracking and interrogation of cellular metabolism by magnetic resonance.Here,wecommunicate how signal amplification by reversible exchange (SABRE) can providestrong 13 Cpyruvate signal enhancements in seconds through the formation of the novel polarisation transfer catalyst [Ir(H) 2 (h 2 -pyruvate)-(DMSO)(IMes)].B yh arnessing SABRE, strong signals for [1-13 C]-and [2-13 C]pyruvate in addition to along-lived singlet state in the [1,2-13 C 2 ]form are readily created;the latter can be observed five minutes after the initial hyperpolarisation step. We also demonstrate how this development may help with future studies of chemical reactivity.

Hyperpolarisation methods that premagnetise agents such as pyruvate are currently receiving significant attention because they produce sensitivity gains that allowd isease tracking and interrogation of cellular metabolism by magnetic resonance.Here,wecommunicate how signal amplification by reversible exchange (SABRE) can providestrong 13 Cpyruvate signal enhancements in seconds through the formation of the novel polarisation transfer catalyst [Ir(H) 2 (h 2 -pyruvate)-(DMSO)(IMes)].B yh arnessing SABRE, strong signals for [1-13 C]-and [2-13 C]pyruvate in addition to along-lived singlet state in the [1,2-13 C 2 ]form are readily created;the latter can be observed five minutes after the initial hyperpolarisation step. We also demonstrate how this development may help with future studies of chemical reactivity.

Iridium N-heterocyclic carbene (NHC) complexes catalyse the para-hydrogen-induced hyperpolarization process, Signal Amplification by Reversible Exchange (SABRE). This process transfers the latent magnetism of para-hydrogen into a substrate, without changing its chemical identity, to dramatically improve its nuclear magnetic resonance (NMR) detectability. By synthesizing and examining over 30 NHC containing complexes, here we rationalize the key characteristics of efficient SABRE catalysis prior to using appropriate catalyst-substrate combinations to quantify the substrate’s NMR detectability. These optimizations deliver polarizations of 63% for 1H nuclei in methyl 4,6-d2-nicotinate, 25% for 13C nuclei in a 13C2-diphenylpyridazine and 43% for the 15N nucleus of pyridine-15N. These high detectability levels compare favourably with the 0.0005% 1H value harnessed by a routine 1.5 T clinical MRI system. As signal strength scales with the square of the number of observations, these low cost innovations offer remarkable improvements in detectability threshold that offer routes to significantly reduce measurement time.

SABRE catalysts [Ir(H)2(η2-pyruvate)(sulfoxide)(NCH) transfer magnetisation from para-hydrogen to pyruvate yielding hyperpolarised 13C NMR signals enhanced by >2000-fold. Properties of the catalyst control efficiency.

Para-hydrogen achieves the hyperpolarisation of amines via SABRE.

Fluorinated ligands have a variety of uses in chemistry and industry, but it is their medical applications as 18F‐labelled positron emission tomography (PET) tracers where they are most visible. In this work, we illustrate the potential of using 19F‐containing ligands as future magnetic resonance imaging (MRI) contrast agents and as probes in magnetic resonance spectroscopy studies by significantly increasing their magnetic resonance detectability through the signal amplification by reversible exchange (SABRE) hyperpolarization method. We achieve 19F SABRE polarization in a wide range of molecules, including those essential to medication, and analyze how their steric bulk, the substrate loading, polarization transfer field, pH, and rate of ligand exchange impact the efficiency of SABRE. We conclude by presenting 19F MRI results in phantoms, which demonstrate that many of these agents show great promise as future 19F MRI contrast agents for diagnostic investigations.

Signal amplification by reversible exchange (SABRE) is shown to allow access to strongly enhanced 1H NMR signals in a range of substrates in aqueous media. To achieve this outcome, phase‐transfer catalysis is exploited, which leads to less than 1.5×10−6 mol dm−3 of the iridium catalyst in the aqueous phase. These observations reflect a compelling route to produce a saline‐based hyperpolarized bolus in just a few seconds for subsequent in vivo MRI monitoring. The new process has been called catalyst separated hyperpolarization through signal amplification by reversible exchange or CASH‐SABRE. We illustrate this method for the substrates pyrazine, 5‐methylpyrimidine, 4,6‐d 2‐methyl nicotinate, 4,6‐d 2‐nicotinamide and pyridazine achieving 1H signal gains of approximately 790‐, 340‐, 3000‐, 260‐ and 380‐fold per proton at 9.4 T at the time point at which phase separation is complete.