ORCID Profile
0000-0002-9788-6615
Current Organisation
University of York
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Publisher: American Chemical Society (ACS)
Date: 08-11-2018
DOI: 10.1021/JACS.8B10923
Publisher: American Chemical Society (ACS)
Date: 23-01-2023
DOI: 10.1021/JACS.2C12642
Publisher: Wiley
Date: 19-07-2017
Publisher: Wiley
Date: 15-11-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CY01214H
Abstract: The catalytic signal lification by reversible exchange process is used widely to improve the magnetic resonance detectability of small molecules by hyperpolarisation.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CP02844F
Abstract: More than 4% net 1 H-polarisation is created, in seconds, that is detectable for over 2 minutes.
Publisher: Wiley
Date: 15-11-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2DT12057G
Abstract: Density functional theory has been used to provide atomic-level detail on the structures of metal hydride intermediates that have previously been proposed in the hydrogenation of phenylacetylene using Ru(3)(CO)(10)(PPh(3))(2). Based on a comparison of energetic data along with computed chemical shifts and coupling constants, we suggest that the detected species share a Ru(3)(μ-H)(μ-H) motif, with two distinct bridging hydride sites, rather than the terminal hydride proposed previously. The work illustrates how theory can be used as a complement to spectroscopy to enhance the accuracy of deductions, and to provide a basis for future rational design of second generation catalysts.
Publisher: American Chemical Society (ACS)
Date: 10-09-2014
DOI: 10.1021/JA5077525
Abstract: Aromatic hydrogenation is a challenging transformation typically requiring alkali or transition metal reagents and/or harsh conditions to facilitate the process. In sharp contrast, the aromatic heterocycle 2,4,6-tri-tert-butyl-1,3,5-triphosphabenzene is shown to be reduced under 4 atm of H2 to give [3.1.0]bicylo reduction products, with the structure of the major isomer being confirmed by X-ray crystallography. NMR studies show this reaction proceeds via a reversible 1,4-H2 addition to generate an intermediate species, which undergoes an irreversible suprafacial hydride shift concurrent with P-P bond formation to give the isolated products. Further, para-hydrogen experiments confirmed the addition of H2 to triphosphabenzene is a bimolecular process. Density functional theory (DFT) calculations show that facile distortion of the planar triphosphabenzene toward a boat-conformation provides a suprafacial combination of vacant acceptor and donor orbitals that permits this direct and uncatalyzed reduction of the aromatic molecule.
Publisher: Wiley
Date: 25-01-2018
DOI: 10.1002/MRC.4703
Publisher: Wiley
Date: 07-03-2022
DOI: 10.1002/MRM.29166
Abstract: Enabling drug tracking (distribution/specific pathways) with magnetic resonance spectroscopy requires manipulation (via hyperpolarization) of spin state populations and targets with sufficiently long magnetic lifetimes to give the largest possible window of observation. Here, we demonstrate how the proton resonances of a group of thienopyridazines (with known anticancer properties), can be lified using the para‐hydrogen ( p ‐H 2 ) based signal lification by reversible exchange (SABRE) hyperpolarization technique. Thienopyridazine isomers, including a 2 H version, were synthesized in house. Iridium‐based catalysts dissolved in a methanol‐ d 4 solvent facilitated polarization transfer from p ‐H 2 gas to the target thienopyridazines. Subsequent SABRE 1 H responses of hyperpolarized thienopyridazines were completed (400 MHz NMR). Pseudo‐singlet state approaches were deployed to extend magnetic state lifetimes. Proof of principle spectral‐spatial images were acquired across a range of field strengths (7T‐9.4T MRI). 1 H‐NMR signal enhancements of −10,130‐fold at 9.4T (~33% polarization) were achieved on thieno[2,3‐ d ]pyridazine (T[2,3‐ d ]P), using SABRE under optimal mixing/field transfer conditions. 1 H T 1 lifetimes for the thienopyridazines were ~18‐50 s. Long‐lived state approaches extended the magnetic lifetime of target proton sites in T[2,3‐ d ]P from an average of 25‐40 seconds. Enhanced in vitro imaging (spatial and chemical shift based) of target T[2,3‐ d ]P was demonstrated. Here, we demonstrate the power of SABRE to deliver a fast and cost‐effective route to hyperpolarization of important chemical motifs of anticancer agents. The SABRE approach outlined here lays the foundations for realizing continuous flow, hyperpolarized tracking of drug delivery athways.
Publisher: Proceedings of the National Academy of Sciences
Date: 04-04-2017
Abstract: The study of molecules and materials is of great significance to both science and human welfare. The noninvasive techniques of NMR and MRI reflect two of the most important methods to study them. However, both of these approaches are insensitive, and hyperpolarization methods to improve sensitivity are needed to access new applications. The hyperpolarization approach signal lification by reversible exchange is used to produce a signal that is 100,000 times larger than that which would be seen on a routine clinical MRI scanner under Boltzmann equilibrium conditions. By revealing the broad scope of this approach we demonstrate its potential for the future diagnostic detection of metabolites, drugs, and many other small molecules.
Publisher: Wiley
Date: 12-2017
Publisher: Wiley
Date: 27-11-2018
Abstract: The hyperpolarization technique, Signal Amplification by Reversible Exchange (SABRE), has the potential to improve clinical diagnosis by making molecular magnetic resonance imaging in vivo a reality. Essential to this goal is the ability to produce a biocompatible bolus for administration. We seek here to determine how the identity of the catalyst and substrate affects the cytotoxicity by in vitro study, in addition to reporting how the use of biocompatible solvent mixtures influence the polarization transfer efficiency. By illustrating this across five catalysts and 8 substrates, we are able to identify routes to produce a bolus with minimal cytotoxic effects.
Publisher: Wiley
Date: 14-11-2017
Abstract: Despite the successful use of isoniazid, rif icin, pyrazinamide and ethambutol in the treatment of tuberculosis (TB), it is a disease of growing global concern. We illustrate here a series of methods that will dramatically improve the magnetic resonance imaging (MRI) detectability of nineteen TB-relevant agents. We note that the future probing of their uptake and distribution in vivo would be expected to significantly enhance their efficacy in disease treatment. This improvement in detectability is achieved by use of the parahydrogen based SABRE protocol in conjunction with the
Publisher: Springer Science and Business Media LLC
Date: 12-10-2018
DOI: 10.1038/S41467-018-06766-1
Abstract: 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 1 H nuclei in methyl 4,6- d 2 -nicotinate, 25% for 13 C nuclei in a 13 C 2 -diphenylpyridazine and 43% for the 15 N nucleus of pyridine- 15 N. These high detectability levels compare favourably with the 0.0005% 1 H 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.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Simon Duckett.