Determination of long-range scalar 1H–1H coupling constants responsible for polarization transfer in SABRE

Eshuis, Nan; Aspers, Ruud L. E. G.; Weerdenburg, Bram J. A. van; Feiters, Martin C.; Rutjes, Floris P. J. T.; Wijmenga, Sybren S.; Tessari, Marco

doi:10.1016/j.jmr.2016.01.012

Cited by 54 publications

(70 citation statements)

References 43 publications

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“…We conclude, therefore, that 1a has polarization acceptor sites that are too magnetically isolated from the hydride ligands of the catalyst for effective SABRE transfer. In contrast, forms 1b-1g all possess a proton adjacent to nitrogen, and based on the recent study by Eshuis et al (37), the relative position of the ortho proton to the ring substituent is unlikely to affect its coupling with the hydride ligand in the catalyst. They should therefore all receive polarization at a similar rate and hence the poor performance of 1c under SABRE must be a consequence of rapid relaxation.…”

Section: Resultsmentioning

confidence: 98%

Delivering strong ¹ H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange

Rayner

Burns

Olaru

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

128

207

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Hyperpolarization turns typically weak NMR and MRI responses into strong signals so that ordinarily impractical measurements become possible. The potential to revolutionize analytical NMR and clinical diagnosis through this approach reflect this area's most compelling outcomes. Methods to optimize the low-cost parahydrogen-based approach signal amplification by reversible exchange with studies on a series of biologically relevant nicotinamides and methyl nicotinates are detailed. These procedures involve specific 2 H labeling in both the agent and catalyst and achieve polarization lifetimes of ca. 2 min with 50% polarization in the case of methyl-4,6-d 2 -nicotinate. Because a 1.5-T hospital scanner has an effective 1 H polarization level of just 0.0005% this strategy should result in compressed detection times for chemically discerning measurements that probe disease. To demonstrate this technique's generality, we exemplify further studies on a range of pyridazine, pyrimidine, pyrazine, and isonicotinamide analogs that feature as building blocks in biochemistry and many disease-treating drugs.

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Section: Resultsmentioning

confidence: 98%

Delivering strong ¹ H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange

Rayner

Burns

Olaru

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

128

207

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“…We note that Tessari et al further developed the co‐ligand approach to enable analyte quantification at low loadings 28. Additionally, the efficiency of the SABRE effect is PTF dependant as a consequence of the matching conditions that must be met between the chemical shift and coupling values within the catalyst 2, 29. It is therefore usual to quote optimal PTF values when reporting data in a similar way to quoting absorption maxima in UV spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

Harnessing polarisation transfer to indazole and imidazole through signal amplification by reversible exchange to improve their NMR detectability

Fekete

Rayner

Green

et al. 2017

Magnetic Reson in Chemistry

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The signal amplification by reversible exchange (SABRE) approach has been used to hyperpolarise the substrates indazole and imidazole in the presence of the co‐ligand acetonitrile through the action of the precataysts [IrCl(COD)(IMes)] and [IrCl(COD)(SIMes)]. 2H‐labelled forms of these catalysts were also examined. Our comparison of the two precatalysts [IrCl(COD)(IMes)] and [IrCl(COD)(SIMes)], coupled with 2H labelling of the N‐heterocyclic carbene and associated relaxation and polarisation field variation studies, demonstrates the critical and collective role these parameters play in controlling the efficiency of signal amplification by reversible exchange. Ultimately, with imidazole, a 700‐fold1H signal gain per proton is produced at 400 MHz, whilst for indazole, a 90‐fold increase per proton is achieved. The co‐ligand acetonitrile proved to optimally exhibit a 190‐fold signal gain per proton in these measurements, with the associated studies revealing the importance the substrate plays in controlling this value. Copyright © 2017 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd.

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“…[14] Additional experimental details are provided in the Supporting Information (SI). When B T is roughly matched to the spin-spin coupling ( J H-H ) between nascent parahydrogen-derived hydride protons on the metal center, [4b, 15] a coherent polarization transfer from hydride protons to the protons of the substrate molecule occurs (Figure 2c)--in accord with conventional SABRE of N-heterocycles. [3, 16] Once polarization transfer occurs on the Ir-hexacoordinate complex, the HP substrate molecules and hydride hydrogens exchange with free substrate and parahydrogen in solution, allowing the SABRE hyperpolarization cycle to continue as it reaches the maximum hyperpolarization level at steady state (which typically occurs in seconds).…”

mentioning

confidence: 84%

NMR Signal Amplification by Reversible Exchange of Sulfur‐Heterocyclic Compounds Found In Petroleum

et al. 2016

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NMR hyperpolarization via Signal Amplification by Reversible Exchange (SABRE) was employed to investigate the feasibility of enhancing the NMR detection sensitivity of sulfur-heterocycles (specifically 2-methylthiophene and dibenzothiophenes), a family of compounds typically found in petroleum and refined petroleum products. SABRE hyperpolarization of sulfur-heterocycles (conducted in seconds) offers potential advantages of providing structural information about sulfur-containing contaminants in petroleum, thereby informing petroleum purification and refining to minimize sulfur content in refined products such as gasoline. Moreover, NMR spectroscopy sensitivity gains endowed by hyperpolarization potentially allows for performing structural assays using inexpensive, low-magnetic-field (ca. 1 T) high-resolution NMR spectrometers ideally suited for industrial applications in the field.

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Determination of long-range scalar 1H–1H coupling constants responsible for polarization transfer in SABRE

Cited by 54 publications

References 43 publications

Delivering strong ¹ H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange

Delivering strong ¹ H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange

Harnessing polarisation transfer to indazole and imidazole through signal amplification by reversible exchange to improve their NMR detectability

NMR Signal Amplification by Reversible Exchange of Sulfur‐Heterocyclic Compounds Found In Petroleum

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Determination of long-range scalar 1H–1H coupling constants responsible for polarization transfer in SABRE

Cited by 54 publications

References 43 publications

Delivering strong 1 H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange

Delivering strong 1 H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange

Harnessing polarisation transfer to indazole and imidazole through signal amplification by reversible exchange to improve their NMR detectability

NMR Signal Amplification by Reversible Exchange of Sulfur‐Heterocyclic Compounds Found In Petroleum

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Delivering strong ¹ H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange

Delivering strong ¹ H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange