B22-Multimode InfraRed imaging And Microspectroscopy
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Diamond Proposal Number(s):
[13725, 16257, 18680, 20906]
Abstract: Operando synchrotron infrared microspectroscopy (OIMS) was used to study the conversion of methanol over coffin-shaped HZSM-5 crystals of different sizes: large (∼250 × 80 × 85 μm3), medium (∼160 × 60 × 60 μm3) and small (∼55 × 30 × 30 μm3). The induction period, for direct alkene formation by deprotonation of surface methoxy groups, was found to decrease with decreasing crystal size and with increasing reaction temperature. Experiments with a continuous flow of dimethylether showed that evolution of the hydrocarbon pool and indirect alkene formation is also strongly dependent on crystal size. These measurements suggest that the hydrocarbon pool formation and indirect alkene generation should be almost instantaneous at reaction temperatures used in practical catalysis with crystal sizes typically ∼1 μm3.
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Mar 2020
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B22-Multimode InfraRed imaging And Microspectroscopy
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Open Access
Abstract: Broadband infrared nanospectroscopy with Synchrotron Radiation, via the atomic force microscope detection of photothermal expansion, was first demonstrated at the MIRIAM beamline of Diamond in 2016. Since then, the system has undergone significant developments and has been available to users in collaboration since January 2018. Continuous nano-FTIR spectra are so-far achieved with useful signal-to-noise in the 4000 – 800 wavenumber region and at around 100 nm spatial resolution (depending on sample geometry and thermal diffusion at the modulation frequency of the IR beam), for soft materials like single biological cells and polymers. Here we briefly describe the nanospectroscopy system and evaluate the performances through comparison of measured data for typical samples with theoretical expectations. Noise levels are shown to be cantilever thermal-noise limited at the first contact resonance currently employed, whilst signal levels are consistent with expectations for the focussed IR power density available from the IR beamline and using sinusoidal modulation of the beam tuned to the contact resonance frequency. Finally, planned enhancements of the performance, including access to higher cantilever contact resonances to reduce noise and increase spatial resolution, are discussed.
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Feb 2020
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B22-Multimode InfraRed imaging And Microspectroscopy
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Barbara E.
Souza
,
Lorenzo
Donà
,
Kirill
Titov
,
Paolo
Bruzzese
,
Zhixin
Zeng
,
Yang
Zhang
,
Arun S.
Babal
,
Annika F.
Moeslein
,
Mark D.
Frogley
,
Magda
Wolna
,
Gianfelice
Cinque
,
Bartolomeo
Civalleri
,
Jin-chong
Tan
Diamond Proposal Number(s):
[14902, 20281]
Abstract: Nanocomposites comprising metal organic frameworks (MOFs) embedded in a polymeric matrix are promising carriers for drug delivery applications. While understanding the chemical and physical transformations of MOFs during the re-lease of confined drug molecules is challenging, this is central to devising better ways for controlled release of therapeutic agents. Herein we demonstrate the efficacy of synchrotron microspectroscopy to track the in situ release of 5-fluorouracil (5-FU) anticancer drug molecules from a drug@MOF/polymer composite (5-FU@HKUST-1/polyurethane). Using experimental time-resolved infrared spectra jointly with newly developed density functional theory calculations, we reveal the detailed dynamics of vibrational motions underpinning the dissociation of 5-FU bound to the framework of HKUST-1 upon water exposure. We discover that HKUST-1 creates hydrophilic channels within the hydrophobic polyurethane matrix hence helping to tune drug release rate. The synergy between a hydrophilic MOF with a hydrophobic polymer can be harnessed to engineer a tunable nanocomposite that alleviates the unwanted burst effect commonly encountered in drug delivery.
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Jan 2020
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B22-Multimode InfraRed imaging And Microspectroscopy
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Diamond Proposal Number(s):
[17743]
Open Access
Abstract: Photoacoustic spectroscopy (PAS) measures the photon absorption spectrum of a sample through detection of the acoustic wave generated by the photothermal effect as one modulates the intensity of the incident radiation at each wavelength. We have recently demonstrated the implementation of PAS in a microscopy configuration with mid-infrared radiation (microPAS). In the present work, we describe the performance of microPAS using synchrotron radiation (SR) in diffraction-limited spectromicroscopy and imaging experiments. Spectra were obtained for polystyrene beads, polypropylene fibres, and single fibres of human hair. SR produced microPAS spectra of much higher intensity as compared with those obtained using conventional mid- and near-infrared sources. For hair samples, the penetration depth of mid-infrared light, even with bright SR, is significantly shorter than the probed sample thickness at very low modulation frequencies resulting in saturated PAS spectra. In contrast, microPAS spectra of polymer beads were in general of much better quality than those obtained with conventional sources. We also demonstrated the capability to collect line profiles and line spectra at diffraction limited spatial resolution. The microPAS spectra of beads appear free from appreciable bandshape distortions arising from the real part of the refractive index of the sample. This observation confirms microPAS as an absorption-only technique and establishes it as a valuable new tool in the microspectroscopic analysis of particulates and of samples with a complex topography.
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Dec 2019
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B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
I12-JEEP: Joint Engineering, Environmental and Processing
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Harry G. W.
Godfrey
,
Lydia
Briggs
,
Xue
Han
,
William J. F.
Trenholme
,
Christopher
Morris
,
Mathew
Savage
,
Louis
Kimberley
,
Oxana
Magdysyuk
,
Michael
Drakopoulos
,
Claire A.
Murray
,
Chiu C.
Tang
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[11278]
Open Access
Abstract: Understanding the mechanism of assembly and function of metal-organic frameworks (MOFs) is important for the development of practical materials. Herein, we report a time-resolved diffraction analysis of the kinetics of formation of a robust MOF, MFM-300(Fe), which shows high adsorption capacity for CO2 (9.55 mmol g−1 at 293 K and 20 bar). Applying the Avrami-Erofe’ev and the two-step kinetic Finke-Watzky models to in situ high-energy synchrotron X-ray powder diffraction data obtained during the synthesis of MFM-300(Fe) enables determination of the overall activation energy of formation (50.9 kJ mol−1), the average energy of nucleation (56.7 kJ mol−1), and the average energy of autocatalytic growth (50.7 kJ mol−1). The synthesis of MFM-300(Fe) has been scaled up 1000-fold, enabling the successful breakthrough separations of the CO2/N2 mixture in a packed-bed with a selectivity for CO2/N2 of 21.6. This study gives an overall understanding for the intrinsic behaviors of this MOF system, and we have determined directly the binding domains and dynamics for adsorbed CO2 molecules within the pores of MFM-300(Fe).
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Nov 2019
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B22-Multimode InfraRed imaging And Microspectroscopy
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Arun S.
Babal
,
Lorenzo
Donà
,
Matthew R.
Ryder
,
Kirill
Titov
,
Abhijeet K.
Chaudhari
,
Zhixin
Zeng
,
Chris S.
Kelley
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Bartolomeo
Civalleri
,
Jin-chong
Tan
Diamond Proposal Number(s):
[14902]
Abstract: Research on the broadband dielectric response of metal-organic frameworks (MOFs) is an emergent field that could yield exciting device applications, such as smart optoelectronics, terahertz sensors, high-speed telecommunications and microelectronics. Hitherto, a detailed understanding of the physical mechanisms controlling the frequency-dependent dielectric and optical behavior of MOFs is lacking because a large number of studies have focused only on static dielectric constants. Herein we employed high-resolution spectroscopic techniques in combination with periodic ab initio density functional theory (DFT) calculations to establish the different polarization processes for a porous copper-based MOF, termed HKUST-1. We used alternating current measurements to determine its dielectric response between 4 Hz and 1.5 MHz where orientational polarization is predominant, while synchrotron infrared (IR) reflectance was used to probe the far-IR, mid-IR, and near-IR dielectric response across the 1.2 THz to 150 THz range (ca. 40 – 5000 cm-1) where vibrational and optical polarizations are principal contributors to its dielectric permittivity. We demonstrate the role of pressure on the evolution of broadband dielectric response, where THz vibrations reveal distinct blue and red shifts of phonon modes from structural deformation of the copper paddle-wheel and the organic linker, respectively. We also investigated the effect of temperature on dielectric constants in the MHz region pertinent to microelectronics, to study temperature-dependent dielectric losses via dissipation in an alternating electric field. The DFT calculations offer insights into the physical mechanisms responsible for dielectric transitions observed in the experiments and enable us to explain the frequency shifts phenomenon detected under pressure. Together, the experiments and theory have enabled us to glimpse into the complex dielectric response and mechanisms underpinning a prototypical MOF subject to pressure, temperature, and vast frequencies.
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Nov 2019
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B22-Multimode InfraRed imaging And Microspectroscopy
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Xinchen
Kang
,
Kai
Lyu
,
Lili
Li
,
Jiangnan
Li
,
Louis
Kimberley
,
Bin
Wang
,
Lifei
Liu
,
Yongqiang
Cheng
,
Mark D.
Frogley
,
Svemir
Rudic
,
Anibal J.
Ramirez-cuesta
,
Robert A. W.
Dryfe
,
Buxing
Han
,
Sihai
Yang
,
Martin
Schroder
Diamond Proposal Number(s):
[19171]
Open Access
Abstract: Incorporation of mesopores and active sites into metal-organic framework (MOF) materials to uncover new efficient catalysts is a highly desirable but challenging task. We report the first example of a mesoporous MOF obtained by templated electrosynthesis using an ionic liquid as both electrolyte and template. The mesoporous Cu(II)-MOF MFM-100 has been synthesised in 100 seconds at room temperature, and this material incorporates crystal defects with uncoupled Cu(II) centres as evidenced by confocal fluorescence microscopy and electron paramagnetic resonance spectroscopy. MFM-100 prepared in this way shows exceptional catalytic activity for the aerobic oxidation of alcohols to produce aldehydes in near quantitative yield and selectivity under mild conditions, as well as having excellent stability and reusability over repeated cycles. The catalyst-substrate binding interactions have been probed by inelastic neutron scattering. This study offers a simple strategy to create mesopores and active sites simultaneously via electrochemical formation of crystal defects to promote efficient catalysis using MOFs.
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Oct 2019
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B22-Multimode InfraRed imaging And Microspectroscopy
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Gemma L.
Smith
,
Jennifer E.
Eyley
,
Xue
Han
,
Xinran
Zhang
,
Jiangnan
Li
,
Nicholas M.
Jacques
,
Harry G. W.
Godfrey
,
Stephen P.
Argent
,
Laura J.
Mccormick Mcpherson
,
Simon J.
Teat
,
Yongqiang
Cheng
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Sarah
Day
,
Chiu C.
Tang
,
Timothy L.
Easun
,
Svemir
Rudic
,
Anibal J.
Ramirez-cuesta
,
Sihai
Yang
,
Martin
Schroeder
Abstract: Emissions of SO2 from flue gas and marine transport have detrimental impacts on the environment and human health, but SO2 is also an important industrial feedstock if it can be recovered, stored and transported efficiently. Here we report the exceptional adsorption and separation of SO2 in a porous material, [Cu2(L)] (H4L = 4′,4‴-(pyridine-3,5-diyl)bis([1,1′-biphenyl]-3,5-dicarboxylic acid)), MFM-170. MFM-170 exhibits fully reversible SO2 uptake of 17.5 mmol g−1 at 298 K and 1.0 bar, and the SO2 binding domains for trapped molecules within MFM-170 have been determined. We report the reversible coordination of SO2 to open Cu(ii) sites, which contributes to excellent adsorption thermodynamics and selectivities for SO2 binding and facile regeneration of MFM-170 after desorption. MFM-170 is stable to water, acid and base and shows great promise for the dynamic separation of SO2 from simulated flue gas mixtures, as confirmed by breakthrough experiments.
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Oct 2019
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B22-Multimode InfraRed imaging And Microspectroscopy
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F.
Domenici
,
A.
Capocefalo
,
F.
Brasili
,
A.
Bedini
,
C.
Giliberti
,
R.
Palomba
,
I.
Silvestri
,
S.
Scarpa
,
S.
Morrone
,
G.
Paradossi
,
M. D.
Frogley
,
G.
Cinque
Diamond Proposal Number(s):
[8055]
Open Access
Abstract: Ultrasound (US) induced transient membrane permeabilisation has emerged as a hugely promising tool for the delivery of exogenous vectors through the cytoplasmic membrane, paving the way to the design of novel anticancer strategies by targeting functional nanomaterials to specific biological sites. An essential step towards this end is the detailed recognition of suitably marked nanoparticles in sonoporated cells and the investigation of the potential related biological effects. By taking advantage of Synchrotron Radiation Fourier Transform Infrared micro-spectroscopy (SR-microFTIR) in providing highly sensitive analysis at the single cell level, we studied the internalisation of a nanoprobe within fibroblasts (NIH-3T3) promoted by low-intensity US. To this aim we employed 20 nm gold nanoparticles conjugated with the IR marker 4-aminothiophenol. The significant Surface Enhanced Infrared Absorption provided by the nanoprobes, with an absorbance increase up to two orders of magnitude, allowed us to efficiently recognise their inclusion within cells. Notably, the selective and stable SR-microFTIR detection from single cells that have internalised the nanoprobe exhibited clear changes in both shape and intensity of the spectral profile, highlighting the occurrence of biological effects. Flow cytometry, immunofluorescence and murine cytokinesis-block micronucleus assays confirmed the presence of slight but significant cytotoxic and genotoxic events associated with the US-nanoprobe combined treatments. Our results can provide novel hints towards US and nanomedicine combined strategies for cell spectral imaging as well as drug delivery-based therapies.
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Aug 2019
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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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