ORCID Profile
0000-0002-5132-5468
Current Organisation
University of York
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Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4CC09696G
Abstract: The reaction of the vinylidene cations trans -[Ru(CCH–C 6 H 2 -2,5-R 2 -4-CCH)Cl(dppm) 2 ] + (R = H, Me) with chloride results in Markovnikov addition of HCl to the terminal alkyne, suggesting the intermediacy of a quinoidal cumulene complex.
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/CH16673
Abstract: The co-crystallisation behaviour of three symmetrical dipyridylacetylacetone ligands (1,3-di(2-pyridyl)-1,3-propanedione (o-bppdH), 1,3-di(3-pyridyl)-1,3-propanedione (m-bppdH), and 1,3-di(4-pyridyl)-1,3-propanedione (p-bppdH)), with the linear halogen-bond donor 1,4-diiodotetrafluorobenzene (1,4-DITFB) has been investigated. The reaction of these components under ambient conditions in a 1 : 1 stoichiometry produced four halogen-bonded assemblies ([o-bppdH·1,4-DITFB, [m-bppdH·1,4-DITFB], [2(m-bppdH)·1,4-DITFB], and [p-bppdH·1,4-DITFB]). The combination of multiple supramolecular interactions including halogen bonding, hydrogen bonding, and π-stacking produces a range of supramolecular architectures, including one-, two-, and three-dimensional motifs. The crystal structure of m-bppdH is also reported.
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: American Chemical Society (ACS)
Date: 07-07-2015
Publisher: Wiley
Date: 03-2006
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B906823F
Abstract: Ionic pi-acidic alkene ligands based on chalcone and benzylidene acetone frameworks have been "doped" into ionic liquids to provide functional reaction media for Pd-catalysed cross-couplings of a cyclohexenyl carbonate with aryl siloxanes that allow simple product isolation, free from Pd (<50 ppm) and ligand contamination.
Publisher: American Chemical Society (ACS)
Date: 09-01-2009
DOI: 10.1021/OM800975W
Publisher: Elsevier BV
Date: 10-2005
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.
Publisher: American Chemical Society (ACS)
Date: 27-01-2022
Publisher: American Chemical Society (ACS)
Date: 18-08-2011
DOI: 10.1021/JA203320Y
Abstract: A study is presented of the thermodynamics of the halogen-bonding interaction of C(6)F(5)I with a series of structurally similar group 10 metal fluoride complexes trans-[Ni(F)(2-C(5)NF(4))(PCy(3))(2)] (2), trans-[Pd(F)(4-C(5)NF(4))(PCy(3))(2)] (3), trans-[Pt(F){2-C(5)NF(2)H(CF(3))}(PR(3))(2)] (4a, R = Cy 4bR = iPr) and trans-[Ni(F){2-C(5)NF(2)H(CF(3))}(PCy(3))(2)] (5a) in toluene solution. (19)F NMR titration experiments are used to determine binding constants, enthalpies and entropies of these interactions (2.4 ≤ K(300) ≤ 5.2 -25 ≤ ΔH(o) ≤ -16 kJ mol(-1) -73 ≤ ΔS(o) ≤ -49 J K(-1) mol(-1)). The data for -ΔH(o) for the halogen bonding follow a trend Ni < Pd < Pt. The fluoropyridyl ligand is shown to have a negligible influence on the thermodynamic data, but the influence of the phosphine ligand is significant. We also show that the value of the spin-spin coupling constant J(PtF) increases substantially with adduct formation. X-ray crystallographic data for Ni complexes 5a and 5c are compared to previously published data for a platinum analogue. We show by experiment and computation that the difference between Pt-X and Ni-X (X = F, C, P) bond lengths is greatest for X = F, consistent with F(2pπ)-Pt(5dπ) repulsive interactions. DFT calculations on the metal fluoride complexes show the very negative electrostatic potential around the fluoride. Calculations of the enthalpy of adduct formation show energies of -18.8 and -22.8 kJ mol(-1) for Ni and Pt complexes of types 5 and 4, respectively, in excellent agreement with experiment.
Publisher: Elsevier BV
Date: 2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B418426B
Abstract: With certain substituent patterns, benzyl benzyl sulfone systems have been found to give unexpectedly high Z-stereoselectivity (up to E:Z = 1:16) in the Meyers variant of the Ramberg-Bäcklund reaction. A range of sulfones, bearing various aryl substituents, were explored to rationalize this unprecedented selectivity for Z-stilbene systems. This high level of double bond stereocontrol has also been utilized in the synthesis of integrastatin nucleus, the core of two highly bioactive anti-HIV compounds.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Adrian Whitwood.