I19-Small Molecule Single Crystal Diffraction
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Peter
Rought
,
Christopher
Marsh
,
Simona
Pili
,
Ian P.
Silverwood
,
Victoria
Garcia Sakai
,
Ming
Li
,
Martyn
Brown
,
Stephen P.
Argent
,
Inigo
Vitorica-yrezabal
,
George
Whitehead
,
Mark R.
Warren
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[13650, 12517]
Open Access
Abstract: Three multi-carboxylic acid functionalised ligands have been designed, synthesised and utilised to synthesise the new barium-based MOFs, MFM-510, -511, and -512, which show excellent stability to water-vapour. MFM-510 and MFM-511 show moderate proton conductivities (2.1 x10-5 and 5.1 x10-5 S cm-1, respectively) at 99RH% and 298 K, attributed to the lack of free protons or hindered proton diffusion within the framework structures. In contrast, MFM-512, which incorporates a pendant carboxylic acid group directed into the pore of the framework, shows a two orders of magnitude enhancement in proton conductivity (2.9 x10-3 S cm-1). Quasi-elastic neutron scattering (QENS) suggests that the proton dynamics of MFM-512 are mediated by “free diffusion inside a sphere” confirming that incorporation of free carboxylic acid groups within the pores of MOFs is an efficient albeit a synthetically challenging strategy to improve proton conductivity.
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Nov 2018
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[14341]
Abstract: We report a record-high SO2 adsorption capacity of 12.3 mmol g–1 in a robust porous material, MFM-601, at 298 K and 1.0 bar. SO2 adsorption in MFM-601 is fully reversible and highly selective over CO2 and N2. The binding domains for adsorbed SO2 and CO2 molecules in MFM-601 have been determined by in situ synchrotron X-ray diffraction experiments, giving insights at the molecular level to the basis of the observed high selectivity.
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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
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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I11-High Resolution Powder Diffraction
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Simona
Pili
,
Peter
Rought
,
Daniil I.
Kolokolov
,
Longfei
Lin
,
Ivan
Da Silva
,
Yongqiang
Cheng
,
Christopher
Marsh
,
Ian P.
Silverwood
,
Victoria
García-sakai
,
Ming
Li
,
Jeremy J.
Titman
,
Lyndsey
Knight
,
Luke L.
Daemen
,
Anibal J.
Ramirez-cuesta
,
Chiu C.
Tang
,
Alexander G.
Stepanov
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[13247]
Abstract: Owing to their inherent pore structure, porous metal-organic frameworks (MOFs) can undergo post-synthetic modification, such as loading extra-framework proton carriers. However, strategies for improving the proton conductivity for non-porous MOFs are largely lacking, although increasing numbers of non-porous MOFs exhibit promising proton conductivities. Often, high humidity is required for non-porous MOFs to achieve high conductivities, but to date no clear mechanisms have been experimentally identified. Here we describe the new materials MFM-550(M), [M(HL1)], (H4L1 = biphenyl-4,4'-diphosphonic acid; M = La, Ce, Nd, Sm, Gd, Ho), MFM-550(Ba), [Ba(H2L1)], and MFM-555(M), [M(HL2)], (H4L2 = benzene-1,4-diphosphonic acid; M = La, Ce, Nd, Sm, Gd, Ho), and report enhanced proton conductivities in these non-porous materials by (i) replacing the metal ion to one with a lower oxidation state, (ii) reducing the length of the organic ligand, and (iii) introducing additional acidic protons on MOF surface. Increased framework proton density in these materials can lead to an enhancement in proton conductivity of up to four orders of magnitude. Additionally, we report a comprehensive investigation using in situ 2H NMR and neutron spectroscopy, coupled with molecular dynamic modelling, to elucidate the role of humidity in assembling interconnected networks for proton hopping. This study constructs a relationship between framework proton density and the corresponding proton conductivity in non-porous MOFs, and directly explains the role of both surface protons and external water in assembling the proton conducting pathways.
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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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B22-Multimode InfraRed imaging And Microspectroscopy
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Nicholas M.
Jacques
,
Peter R. E.
Rought
,
Detlev
Fritsch
,
Mathew
Savage
,
Harry G. W.
Godfrey
,
Lei
Li
,
Tamoghna
Mitra
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Sihai
Yang
,
Martin
Schroder
Diamond Proposal Number(s):
[17709]
Abstract: The binding domains within a mixed matrix membrane (MMM) that is selective for CO2 comprising MFM-300(Al) and the polymer 6FDA-Durene-DABA have been established via in situ synchrotron IR microspectroscopy. The MOF crystals are fully accessible and play a critical role in the binding of CO2, creating a selective pathway to promote permeation of CO2 within and through the MMM. This study reveals directly the molecular mechanism for the overall enhanced performance of this MMM in terms of permeability, solubility and selectivity for CO2.
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Mar 2018
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B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
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Xinran
Zhang
,
Ivan
Da Silva
,
Harry G. W.
Godfrey
,
Samantha K.
Callear
,
Sergey A.
Sapchenko
,
Yongqiang
Cheng
,
Inigo J.
Vitorica-yrezabal
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Chiu C.
Tang
,
Carlotta
Giacobbe
,
Catherine
Dejoie
,
Svemir
Rudic
,
Anibal J.
Ramirez-cuesta
,
Melissa A.
Denecke
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[14341, 14938]
Abstract: During the nuclear waste disposal process, radioactive iodine in fission product can be released. The widespread implementation of sustainable nuclear energy thus requires the development of efficient iodine stores that have simultaneously high capacity, stability and more importantly, storage density (and hence minimised system volume). Here, we report high I2 adsorption in a series of robust porous metal-organic materials, MFM-300(M) (M = Al, Sc, Fe, In). MFM-300(Sc) exhibits fully reversible I2 uptake of 1.54 g g-1 and its structure remains completely unperturbed upon inclusion/removal of I2. Direct observation and quantification of the adsorption, binding domains and dynamics of guest I2 molecules within these hosts have been achieved using XPS, TGA-MS, high resolution synchrotron X-ray diffraction, pair distribution function analysis, Raman, terahertz and neutron spectroscopy, coupled with density functional theory modelling. These complimentary techniques reveal a comprehensive understanding on the host-I2 and I2-I2 binding interaction at a molecular level. The initial binding site of I2 in MFM-300(Sc), I2I, is located near the bridging hydroxyl group of the [ScO4(OH)2] moiety [I2I···H–O = 2.263(9) Å] with an occupancy of 0.268. I2II is located interstitially between two phenyl rings of neighbouring ligand molecules [I2II···phenyl ring = 3.378(9) and 4.228(5) Å]. I2II is 4.565(2) Å from the hydroxyl group with an occupancy of 0.208. Significantly, at high I2 loading an unprecedented self-aggregation of I2 molecules into triple-helical chains within the confined nano-voids has been observed at crystallographic resolution, leading to a highly efficient packing of I2 molecules with an exceptional I2 storage density of 3.08 g cm-3 in MFM-300(Sc).
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Oct 2017
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I11-High Resolution Powder Diffraction
I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[9443, 9444, 13650, 15833]
Abstract: Natural gas (methane, CH4) is widely considered as a promising energy carrier for mobile applications. Maximising the storage capacity is the primary goal for the design of future storage media. Here we report the CH4 storage properties in a family of isostructural (3,24)-connected porous materials, MFM-112a, MFM-115a and MFM-132a with different linker backbone functionalisation. Both MFM-112a and MFM-115a show excellent CH4 uptakes of 236 and 256 cm3 (STP) cm–3 (v/v) at 80 bar and room temperature, respectively. Significantly, MFM-115a displays an exceptionally high deliverable CH4 capacity of 208 v/v between 5 and 80 bar at room temperature, making it among the best performing MOFs for methane storage. We also synthesized the partially deuterated versions of the above materials and applied solid-state 2H NMR spectroscopy to show that these three frameworks contain molecular rotors which exhibit motion in fast, medium and slow regimes, respectively. In situ neutron powder diffraction studies on the binding sites for CD4 within MFM-132a and MFM-115a reveal that the primary binding site is located within the small pocket enclosed by the [(Cu2)3(isophthalate)3] window and three anthracene/phenyl panels. The open Cu(II) sites are the secondary/tertiary adsorption sites in these structures. Thus, we obtained direct experimental evidence showing that a tight cavity can generate a stronger binding affinity to gas molecules than open metal sites. Solid-state 2H NMR and neutron diffraction studies reveal that it is the combination of optimal molecular dynamics, pore geometry and size, and favourable binding sites that leads to the exceptional and different methane uptakes in these materials.
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Aug 2017
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I19-Small Molecule Single Crystal Diffraction
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Iñigo J.
Vitórica-yrezábal
,
Daniel Florin
Sava
,
Grigore A.
Timco
,
Martyn S.
Brown
,
Mathew
Savage
,
Harry G. W.
Godfrey
,
Florian
Moreau
,
Martin
Schroeder
,
Flor
Siperstein
,
Lee
Brammer
,
Sihai
Yang
,
Martin P.
Attfield
,
Joseph J. W.
Mcdouall
,
Richard E. P.
Winpenny
Abstract: The {Cr8} metallacrown [CrF(O2CtBu)2]8, containing a F-lined internal cavity, shows high selectivity for CO2 over N2. DFT calculations and absorption studies support the multiple binding of F-groups to the C-center of CO2 (C⋅⋅⋅F 3.190(9)–3.389(9) Å), as confirmed by single-crystal X-ray diffraction.
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May 2017
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