B22-Multimode InfraRed imaging And Microspectroscopy
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Diamond Proposal Number(s):
[13725, 16257, 20906]
Abstract: Synchrotron infrared microspectroscopy has identified with high temporal resolution (down to 0.25 s) the initial events occurring when methanol vapour is contacted with a crystal of zeolite HZSM-5. The first alkenes are generated directly from methoxy groups formed at the acid sites via their deprotonation. These alkenes can either desorb directly or oligomerise and cyclise to form dimethylcyclopentenyl cations. The oligomeric and dimethylcyclopentenyl cations are the first major components of the hydrocar-bon pool that precede aromatic hydrocarbons and lead to indirect alkene formation. This is the first direct observation of these events in real time.
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Jun 2019
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B18-Core EXAFS
B22-Multimode InfraRed imaging And Microspectroscopy
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Kirill
Titov
,
Dmitry
Eremin
,
Alexey S.
Kashin
,
Roberto
Boada Romero
,
Barbara
Souza
,
Chris S.
Kelley
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Diego
Gianolio
,
Giannantonio
Cibin
,
Svemir
Rudic
,
Valentine P
Ananikov
,
Jin-chong
Tan
Diamond Proposal Number(s):
[14902, 17146]
Abstract: A catalytic system based on OX-1 metal-organic framework nanosheets is reported, incorporating catalytically active palladium (Pd) species. The Pd@OX-1 guest@host system is rapidly synthesised via a facile single-pot supramolecular assembly method, with the possibility of controlling the Pd loading. The structures of the re-sulting framework and of the active Pd species before and after catalytic reactions are studied in detail using a wide variety of techniques including synchrotron radiation infrared spectroscopy, inelastic neutron scattering and X-ray absorption spectroscopy. Crystals of the resulting Pd@OX-1 composite material contain predomi-nantly atomic and small cluster Pd species, which selectively reside on benzene rings of the benzenedicarbox-ylate (BDC) linkers. The composites are shown to efficiently catalyse the Suzuki coupling and Heck arylation reactions under a variety of conditions. Pd@OX-1 further shows potential to be recycled for at least five cycles of each reaction as well as an ability to recapture active Pd species during both catalytic reactions.
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Feb 2019
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B18-Core EXAFS
B22-Multimode InfraRed imaging And Microspectroscopy
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Ana L. M.
Batista De Carvalho
,
Adriana P.
Mamede
,
Asha
Dopplapudi
,
Victoria
Garcia Sakai
,
James
Doherty
,
Mark
Frogley
,
Gianfelice
Cinque
,
Peter
Gardner
,
Diego
Gianolio
,
Luis A. E.
Batista De Carvalho
,
M. Paula M.
Marques
Diamond Proposal Number(s):
[14895, 16058]
Abstract: Complementary structural and dynamical information on drug–DNA interplay has been achieved at a molecular level, for Pt/Pd-drugs, allowing a better understanding of their pharmacodynamic profile which is crucial for the development of improved chemotherapeutic agents. The interaction of two cisplatin-like dinuclear Pt(II) and Pd(II) complexes with DNA was studied through a multidisciplinary experimental approach, using quasi-elastic neutron scattering (QENS) techniques coupled with synchrotron-based extended X-ray absorption fine structure (SR-EXAFS) and Fourier-Transform Infrared Spectroscopy-Attenuated Total Reflectance (SR-FTIR-ATR). DNA extracted from drug-exposed human triple negative breast cancer cells (MDA-MB-231) was used, with a view to evaluate the effect of the unconventional antineoplastic agents on this low prognosis type of cancer. The drug impact on DNA's dynamical profile, via its hydration layer, was provided by QENS, a drug-triggered enhanced mobility having been revealed. Additionally, an onset of anharmonicity was detected for dehydrated DNA, at room temperature. Far- and mid-infrared measurements allowed the first simultaneous detection of the drugs and their primary pharmacological target, as well as the drug-prompted changes in DNA's conformation that mediate cytotoxicity. The local environment of the absorbing Pd(II) and Pt(II) centers in the drugs’ adducts with adenine, guanine and glutathione was attained by EXAFS.
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Jan 2019
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B22-Multimode InfraRed imaging And Microspectroscopy
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Diamond Proposal Number(s):
[11395, 8920]
Abstract: The design and characterisation of rectifying terahertz detectors, based on InGaAs zero-bias Schottky diodes, is reported. These uncooled devices offer a spectral detection range from tens of GHz to above 3 THz, high response speed, and the prospect of low cost for mass production and arrayed implementation. We describe the airbridged semiconductor devices, their incorporation into waveguide mounts and quasi-optical substrate lens / planar antenna structures. Noise equivalent powers of 5 pW/Hz1/2 at 100 GHz, increasing to 50 pW/Hz1/2 at 300 GHz been achieved, along with rise and fall times of tens of picoseconds. We shall discuss examples of the use of the detectors: characterising a picosecond transistor-based source, spectrally narrow and broad band sources in the laboratory and coherent THz synchrotron radiation in the range 0.15 to 1.4 THz at the MIRIAM beamline B22 on the Diamond Light Source. The latter radiation was emitted from bunches of electrons circulating in the Diamond storage ring operating in THz-dedicated low-alpha mode. Spectral information on coherent synchrotron radiation originating from a single bunch of electrons is obtained, as well as the usefulness of this for spectroscopy, is evaluated.
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Jan 2019
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B22-Multimode InfraRed imaging And Microspectroscopy
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Open Access
Abstract: In September 2017, the International Workshop on Infrared Microscopy and Spectroscopy with Accelerator-based Sources (WIRMS) paid its first visit to the UK. Organized by Diamond Light Source, a vibrant international community came together for four packed days among the spires of the historical Worcester College of Oxford University to discuss the latest developments in infrared (IR) microscopy, spectroscopy including Terra Hertz (THz), and imaging by synchrotron radiation (SR) and free electron lasers (FELs).
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Nov 2018
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B22-Multimode InfraRed imaging And Microspectroscopy
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Jack
Humby
,
Oguarabau
Benson
,
Gemma L.
Smith
,
Stephen P.
Argent
,
Ivan
Da Silva
,
Yongqiang
Cheng
,
Svemir
Rudic
,
Pascal
Manuel
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Lucy K.
Saunders
,
Inigo
Vitorica-yrezabal
,
George F. S.
Whitehead
,
Timothy L.
Easun
,
William
Lewis
,
Alexander J.
Blake
,
Anibal J.
Ramirez-cuesta
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[13666]
Open Access
Abstract: In order to develop new porous materials for applications in gas separations such as natural gas upgrading, landfill gas processing and acetylene purification it is vital to gain understanding of host-substrate interactions at a molecular level. Herein we report a series of six isoreticular metal-organic frameworks (MOFs) for selective gas adsorption. These materials do not incorporate open metal sites and thus provide an excellent platform to investigate the effect of the incorporation of ligand functionality via amide and alkyne groups on substrate binding. By reducing the linker length of our previously reported MFM-136, we report much improved CO2/CH4 (50:50) and CO2/N¬2 (15:85) selectivity values of 20.2 and 65.4, respectively (1 bar and 273 K), in the new amide-decorated MOF, MFM-126. The CO2 separation performance of MFM-126 has been confirmed by dynamic breakthrough experiments. In situ inelastic neutron scattering and synchrotron FT-IR microspectroscopy were employed to elucidate dynamic interactions of adsorbed CO2 molecules within MFM-126. Upon changing the functionality to an alkyne group in MFM-127, the CO2 uptake decreases but the C2H2 uptake increases by 68%, leading to excellent C2H2/CO2 and C2H2/CH4 selectivities of 3.7 and 21.2, respectively. Neutron powder diffraction enabled the direct observation of the preferred binding domains in MFM-126 and MFM-127, and, to the best of our knowledge, we report the first example of acetylene binding to an alkyne moiety in a porous material, with over 50% of the acetylene observed within MFM-127 displaying interactions (<4 Å) with the alkyne functionality of the framework.
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Oct 2018
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B22-Multimode InfraRed imaging And Microspectroscopy
Detectors
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Abstract: Using a range of zero-biased InGaAs Schottky diode detectors, terahertz coherent synchrotron radiation emitted by individual electron bunches has been detected. The source was the UK's Diamond Light Source synchrotron operating in low-alpha THz mode. Detected signals have a FWHM of <50 picoseconds, and a spectral bandwidth of 0.2 – 3 THz. Due to the sensitivity, high linearity and fast recovery of the detectors, we were able to record the THz emission from a series of bunches over several synchrotron round trips.
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Oct 2018
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B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
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Lei
Li
,
Ivan
Da Silva
,
Daniil I.
Kolokolov
,
Xue
Han
,
Jiangnan
Li
,
Gemma
Smith
,
Yongqiang
Cheng
,
Luke L.
Daemen
,
Christopher G.
Morris
,
Harry G. W.
Godfrey
,
Nicholas
Jacques
,
Xinran
Zhang
,
Pascal
Manuel
,
Mark D.
Frogley
,
Claire A.
Murray
,
Anibal J.
Ramirez-cuesta
,
Gianfelice
Cinque
,
Chiu C.
Tang
,
Alexander G.
Stepanov
,
Sihai
Yang
,
Martin
Schroder
Diamond Proposal Number(s):
[14564, 15970]
Open Access
Abstract: Modulation of pore environment is an effective strategy to optimize guest binding in porous materials. We report the post-synthetic modification of the charge distribution in a charged metal-organic framework, MFM-305-CH3, [Al(OH)(L)]Cl, [(H2L)Cl = 3,5-dicarboxy-1-methylpyridinium chloride] and its effect on guest binding. MFM-305-CH3 shows a distribution of cationic (methylpyridinium) and anionic (chloride) centers and can be modified to release free pyridyl N-centres by thermal demethylation of the 1-methylpyridinium moiety to give the neutral isostructural MFM-305. This leads simultaneously to enhanced adsorption capacities and selectivities (two parameters that often change in opposite directions) for CO2 and SO2 in MFM-305. The host-guest binding has been comprehensively investigated by in situ synchrotron X-ray and neutron powder diffraction, inelastic neutron scattering, synchrotron infrared and 2H NMR spectroscopy and theoretical modelling to reveal the binding domains of CO2 and SO2 in these materials. CO2 and SO2 binding in MFM-305-CH3 is shown to occur via hydrogen bonding to the methyl and aromatic-CH groups, with a long range interaction to chloride for CO2. In MFM-305 the hydroxyl, pyridyl and aromatic C-H groups bind CO2 and SO2 more effectively via hydrogen bonds and dipole interactions. Post-synthetic modification via dealkylation of the as-synthesised metal-organic framework is a powerful route to the synthesis of materials incorporating active polar groups that cannot be prepared directly.
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Oct 2018
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B22-Multimode InfraRed imaging And Microspectroscopy
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Diamond Proposal Number(s):
[9614]
Open Access
Abstract: The aqueously altered CM carbonaceous chondrite meteorites can be used to investigate the nature and transport of volatiles in the early solar system. We present the preliminary results of an effort to collect 2D infrared (IR) spectral maps from the matrix and fine-grained rims (FGRs) of material that surround chondrules and inclusions in the Murchison CM2 meteorite using synchrotron IR micro-spectroscopy. The main features in mid-IR spectra of the matrix and FGRs occur at ∼3500 cm-1 and ∼1000 cm-1 and are attributed to -OH/H2O and Si-O bonds in phyllosilicates and anhydrous silicates. Minor features in the spectra are attributed to organic species (3000–2800 cm-1), CO2 (2400 – 2000 cm-1), and carbonates (1500 – 1380 cm-1). In both the matrix and FGRs we observe correlations between the -OH/H2O and phyllosilicate/silicate features confirming that phyllosilicates dominate the mineralogy. This is consistent with previous studies showing that Murchison contains ∼70 vol% phyllosilicates following aqueous alteration on an asteroid parent body. The presence of anhydrous silicates in the matrix indicates that the alteration was heterogeneous at the micron-scale and that the reactions did not reach completion. We highlight a possible correlation between the phyllosilicates and organic species in the matrix, supporting the hypothesis that phyllosilicates may have played an important role in the formation and preservation of simple organic molecules and compounds. In the FGRs variations in the distribution of the phyllosilicate minerals cronstedtite and Mg-serpentine/saponite likely reflect differences in the local geochemical conditions during aqueous alteration on the asteroid.
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Sep 2018
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B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
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Martin
Schroder
,
Harry
Godfrey
,
Ivan
Da Silva
,
Lydia
Briggs
,
Joe
Carter
,
Christopher
Morris
,
Mathew
Savage
,
Timothy
Easun
,
Pascal
Manuel
,
Claire
Murray
,
Chiu
Tang
,
Mark
Frogley
,
Gianfelice
Cinque
,
Sihai
Yang
Diamond Proposal Number(s):
[15972, 13666]
Abstract: MFM‐300(Al) shows reversible uptake of NH3 (15.7 mmol g‐1 at 273 K and 1.0 bar) over 50 cycles with an exceptional packing density of 0.62 g cm‐3 at 293 K. In situ neutron powder diffraction and synchrotron FTIR micro‐spectroscopy on ND3@MFM‐300(Al) confirms reversible H/D site exchange between the adsorbent and adsorbate, representing a new type of adsorption interaction.
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Aug 2018
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