51
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D'Agostino C, Brett GL, Miedziak PJ, Knight DW, Hutchings GJ, Gladden LF, Mantle MD. Understanding the Solvent Effect on the Catalytic Oxidation of 1,4-Butanediol in Methanol over Au/TiO2Catalyst: NMR Diffusion and Relaxation Studies. Chemistry 2012; 18:14426-33. [DOI: 10.1002/chem.201201922] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Indexed: 11/11/2022]
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52
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Sankar M, He Q, Morad M, Pritchard J, Freakley SJ, Edwards JK, Taylor SH, Morgan DJ, Carley AF, Knight DW, Kiely CJ, Hutchings GJ. Synthesis of stable ligand-free gold-palladium nanoparticles using a simple excess anion method. ACS NANO 2012; 6:6600-6613. [PMID: 22769042 DOI: 10.1021/nn302299e] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report a convenient excess anion modification and post-reduction step to the impregnation method which permits the reproducible preparation of supported bimetallic AuPd nanoparticles having a tight particle size distribution comparable to that found for sol-immobilization materials but without the complication of ligands adsorbed on the particle surface. The advantageous features of the modified impregnation materials compared to those made by conventional impregnation include a smaller average particle size, an optimized random alloy composition, and improved compositional uniformity from particle-to-particle resulting in higher activity and stability compared to the catalysts prepared using both conventional impregnation and sol immobilization methods. Detailed STEM combined with EDX analyses of individual particles have revealed that an increase in anion concentration increases the gold content of individual particles in the resultant catalyst, thus providing a method to control/tune the composition of the nanoalloy particles. The improved activity and stability characteristics of these new catalysts are demonstrated using (i) the direct synthesis of hydrogen peroxide and (ii) the solvent-free aerobic oxidation of benzyl alcohol as case studies.
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Alshammari H, Miedziak PJ, Bawaked S, Knight DW, Hutchings GJ. Solvent-free Liquid-phase Oxidation of 1-Hexene using Supported Gold Catalysts. ChemCatChem 2012. [DOI: 10.1002/cctc.201200273] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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54
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Henderson L, Knight DW, Williams AC. An alternative strategy to the Pictet–Spengler method for tetrahydroisoquinoline synthesis: a feasibility study. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.06.091] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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55
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Henderson L, Knight DW, Rutkowski P, Williams AC. Optimised conditions for styrene syntheses using Suzuki–Miyaura couplings and catalyst-ligand-base pre-mixes. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.06.089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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56
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Kotionova T, Lee C, Miedziak PJ, Dummer NF, Willock DJ, Carley AF, Morgan DJ, Knight DW, Taylor SH, Hutchings GJ. Oxidative Esterification of Homologous 1,3-Propanediols. Catal Letters 2012. [DOI: 10.1007/s10562-012-0872-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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57
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bin Saiman MI, Brett GL, Tiruvalam R, Forde MM, Sharples K, Thetford A, Jenkins RL, Dimitratos N, Lopez-Sanchez JA, Murphy DM, Bethell D, Willock DJ, Taylor SH, Knight DW, Kiely CJ, Hutchings GJ. Involvement of Surface-Bound Radicals in the Oxidation of Toluene Using Supported Au-Pd Nanoparticles. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201201059] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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58
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bin Saiman MI, Brett GL, Tiruvalam R, Forde MM, Sharples K, Thetford A, Jenkins RL, Dimitratos N, Lopez-Sanchez JA, Murphy DM, Bethell D, Willock DJ, Taylor SH, Knight DW, Kiely CJ, Hutchings GJ. Involvement of Surface-Bound Radicals in the Oxidation of Toluene Using Supported Au-Pd Nanoparticles. Angew Chem Int Ed Engl 2012; 51:5981-5. [DOI: 10.1002/anie.201201059] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Indexed: 11/08/2022]
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59
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Vetter W, Laure S, Wendlinger C, Mattes A, Smith AWT, Knight DW. Determination of Furan Fatty Acids in Food Samples. J AM OIL CHEM SOC 2012. [DOI: 10.1007/s11746-012-2038-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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60
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Haider MH, Dummer NF, Zhang D, Miedziak P, Davies TE, Taylor SH, Willock DJ, Knight DW, Chadwick D, Hutchings GJ. Rubidium- and caesium-doped silicotungstic acid catalysts supported on alumina for the catalytic dehydration of glycerol to acrolein. J Catal 2012. [DOI: 10.1016/j.jcat.2011.11.004] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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61
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Hall SR, Collins AM, Wood NJ, Ogasawara W, Morad M, Miedziak PJ, Sankar M, Knight DW, Hutchings GJ. Biotemplated synthesis of catalytic Au–Pd nanoparticles. RSC Adv 2012. [DOI: 10.1039/c2ra01336c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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62
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Brett GL, Miedziak PJ, Dimitratos N, Lopez-Sanchez JA, Dummer NF, Tiruvalam R, Kiely CJ, Knight DW, Taylor SH, Morgan DJ, Carley AF, Hutchings GJ. Oxidative esterification of 1,2-propanediol using gold and gold-palladium supported nanoparticles. Catal Sci Technol 2012. [DOI: 10.1039/c1cy00254f] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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63
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Hasbi Ab Rahim M, He Q, Lopez-Sanchez JA, Hammond C, Dimitratos N, Sankar M, Carley AF, Kiely CJ, Knight DW, Hutchings GJ. Gold, palladium and gold–palladium supported nanoparticles for the synthesis of glycerol carbonate from glycerol and urea. Catal Sci Technol 2012. [DOI: 10.1039/c2cy20288c] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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64
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W. Knight D, W. T. Smith A. Optimized Syntheses of the Furan Fatty Acids F5 and F6 Featuring Convertion of a β-Iodofuran into a β-Methylfuran in a Single Operation. HETEROCYCLES 2012. [DOI: 10.3987/com-11-s(p)63] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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65
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Griffiths-Jones (née Haskins) CM, Knight DW. A total synthesis of (±)-α-cyclopiazonic acid using a cationic cascade as a key step. Tetrahedron 2011. [DOI: 10.1016/j.tet.2011.08.094] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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66
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Brett GL, He Q, Hammond C, Miedziak PJ, Dimitratos N, Sankar M, Herzing AA, Conte M, Lopez-Sanchez JA, Kiely CJ, Knight DW, Taylor SH, Hutchings GJ. Selective oxidation of glycerol by highly active bimetallic catalysts at ambient temperature under base-free conditions. Angew Chem Int Ed Engl 2011; 50:10136-9. [PMID: 21990249 PMCID: PMC3644171 DOI: 10.1002/anie.201101772] [Citation(s) in RCA: 198] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 07/18/2011] [Indexed: 11/10/2022]
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67
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Brett GL, He Q, Hammond C, Miedziak PJ, Dimitratos N, Sankar M, Herzing AA, Conte M, Lopez-Sanchez JA, Kiely CJ, Knight DW, Taylor SH, Hutchings GJ. Selective Oxidation of Glycerol by Highly Active Bimetallic Catalysts at Ambient Temperature under Base-Free Conditions. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201101772] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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68
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Sankar M, Nowicka E, Tiruvalam R, He Q, Taylor SH, Kiely CJ, Bethell D, Knight DW, Hutchings GJ. Controlling the Duality of the Mechanism in Liquid‐Phase Oxidation of Benzyl Alcohol Catalysed by Supported Au–Pd Nanoparticles. Chemistry 2011; 17:6524-32. [DOI: 10.1002/chem.201003484] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 02/12/2011] [Indexed: 11/07/2022]
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69
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Barsby RW, Salan U, Knight DW, Hoult JR. Feverfew Extracts and Parthenolide Irreversibly Inhibit Vascular Responses of the Rabbit Aorta. J Pharm Pharmacol 2011; 44:737-40. [PMID: 1360525 DOI: 10.1111/j.2042-7158.1992.tb05510.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Abstract
Samples prepared from chloroform extracts of fresh leaves of feverfew (Tanacetum parthenium) strongly inhibited responses of rabbit aortic rings to phenylephrine, 5-hydroxytryptamine, thromboxane mimetic U46619 (9,11-dideoxy-11α,9α-epoxy-methano-PGF2α), and angiotensin II, but the inhibition to contractions induced by potassium depolarization was much less. The inhibition was concentration- and time-dependent, non-competitive, and irreversible, and also occurred in endothelium-denuded preparations. The feverfew extracts also caused a progressive loss of tone of pre-contracted aortic rings and appeared to impair the ability of acetylcholine to induce endothelium-dependent relaxations of the tissue. These effects were mimicked by a purified preparation of an α-methylenebutyrolactone, parthenolide, obtained from the extract. Our results demonstrate a nonspecific and potentially toxic response to feverfew on the vasculature.
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Miedziak P, Sankar M, Dimitratos N, Lopez-Sanchez JA, Carley AF, Knight DW, Taylor SH, Kiely CJ, Hutchings GJ. Oxidation of benzyl alcohol using supported gold–palladium nanoparticles. Catal Today 2011. [DOI: 10.1016/j.cattod.2010.10.028] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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71
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Kesavan L, Tiruvalam R, Ab Rahim MH, bin Saiman MI, Enache DI, Jenkins RL, Dimitratos N, Lopez-Sanchez JA, Taylor SH, Knight DW, Kiely CJ, Hutchings GJ. Solvent-Free Oxidation of Primary Carbon-Hydrogen Bonds in Toluene Using Au-Pd Alloy Nanoparticles. Science 2011; 331:195-9. [PMID: 21233383 DOI: 10.1126/science.1198458] [Citation(s) in RCA: 517] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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72
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Bawaked S, He Q, Dummer NF, Carley AF, Knight DW, Bethell D, Kiely CJ, Hutchings GJ. Selective oxidation of alkenes using graphite-supported gold-palladium catalysts. Catal Sci Technol 2011. [DOI: 10.1039/c1cy00122a] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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73
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Hammond C, Lopez-Sanchez JA, Hasbi Ab Rahim M, Dimitratos N, Jenkins RL, Carley AF, He Q, Kiely CJ, Knight DW, Hutchings GJ. Synthesis of glycerol carbonate from glycerol and urea with gold-based catalysts. Dalton Trans 2011; 40:3927-37. [DOI: 10.1039/c0dt01389g] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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74
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Griffiths PC, Knight DW, Morgan IR, Ford A, Brown J, Davies B, Heenan RK, King SM, Dalgliesh RM, Tomkinson J, Prescott S, Schweins R, Paul A. Gelation or molecular recognition; is the bis-(α,β-dihydroxy ester)s motif an omnigelator? Beilstein J Org Chem 2010; 6:1079-88. [PMID: 21160568 PMCID: PMC3002023 DOI: 10.3762/bjoc.6.123] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2010] [Accepted: 11/02/2010] [Indexed: 11/23/2022] Open
Abstract
Understanding the gelation of liquids by low molecular weight solutes at low concentrations gives an insight into many molecular recognition phenomena and also offers a simple route to modifying the physical properties of the liquid. Bis-(α,β-dihydroxy ester)s are shown here to gel thermoreversibly a wide range of solvents, raising interesting questions as to the mechanism of gelation. At gelator concentrations of 5-50 mg ml⁻¹, gels were successfully formed in acetone, ethanol/water mixtures, toluene, cyclohexane and chloroform (the latter, albeit at a higher gelator concentration). A range of neutron techniques - in particular small-angle neutron scattering (SANS) - have been employed to probe the structure of a selection of these gels. The universality of gelation in a range of solvent types suggests the gelation mechanism is a feature of the bis-(α,β-dihydroxy ester) motif, with SANS demonstrating the presence of regular structures in the 30-40 Å range. A correlation between the apparent rodlike character of the structures formed and the polarity of the solvent is evident. Preliminary spin-echo neutron scattering studies (SESANS) indicated the absence of any larger scale structures. Inelastic neutron spectroscopy (INS) studies demonstrated that the solvent is largely unaffected by gelation, but does reveal insights into the thermal history of the samples. Further neutron studies of this kind (particularly SESANS and INS) are warranted, and it is hoped that this work will stimulate others to pursue this line of research.
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NajeebUllah M, Knight DW, Munawar MA, Yaseen M, Vincenzo F. Corrigendum to ‘A microwave-assisted synthesis of triphenodioxazines [TPDOs]’ [Tetrahedron 66(2010) 6761–6764]. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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