I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[34797]
Open Access
Abstract: MOF@COF composites have emerged as a promising class of engineered materials with unique functionalities, combining the high porosity and tunability of metal-organic frameworks (MOFs) with the chemical and mechanical stability of covalent-organic frameworks (COFs). While their advantageous properties are well-recognized, their structural intricacies and the nature of the interfacial interactions remain insufficiently explored. In this study, a Fe-MOF@COF composite is presented, exhibiting dual functionalities for the efficient removal of organic pollutants from water. The enhanced performance is attributed to the unique properties of the MOF-COF interface, where synergistic interactions between the two porous materials play a critical role. Advanced synchrotron techniques were employed to probe interfacial interactions at the atomic and molecular levels. These findings underscore the potential of Fe-MOF@COF composite as a highly effective material for water remediation, providing deeper insights into their structural behavior and interfacial properties.
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Aug 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Chumei
Ye
,
Lauren N.
Mchugh
,
Pierre
Florian
,
Ruohan
Yu
,
Celia
Castillo-Blas
,
Celia
Chen
,
Arad
Lang
,
Yuhang
Dai
,
Jingwei
Hou
,
David A.
Keen
,
Sian E.
Dutton
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[35405]
Open Access
Abstract: Hybrid organic-inorganic perovskites (HOIPs) have garnered significant attention for their crystalline properties, yet recent findings reveal that they can also form liquid and glassy phases, offering an alternative platform for understanding non-crystalline materials. In this study, we present a detailed investigation into the structural dynamics of the melting and glass formation process of a two-dimensional (2D) HOIP, (S−(−)−1-(1−naphthyl)ethylammonium)2PbBr4. Compared to its crystalline counterpart, the glass exhibits superior mechanical properties, including higher Young’s modulus and hardness. Our structural studies reveal that the liquid and glass formed from the 2D HOIP exhibit network-forming behaviour, featuring limited short-range order within individual octahedra, partial retention of metal-halide-metal connectivity between neighbouring octahedra, and residual structural correlations mediated by organic cations. We then combine in situ variable-temperature X-ray total scattering experiments, terahertz far-infrared absorption spectroscopy and solid-state nuclear magnetic resonance techniques to study the melting mechanism and the nature of the HOIP liquid obtained. Our results deepen the understanding of the structural evolution and property relationships in HOIP glasses, providing a foundation for their potential applications in advanced phase-change material technologies.
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Aug 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[29957]
Open Access
Abstract: The development of metal-organic framework (MOF) crystal-glass composites (CGCs) has been hindered by the scarcity of MOF glass matrices with low glass transition temperatures (Tgs). Here, we investigate a CGC consisting of a low-Tg MOF glass, (agZIF-UC-7) and UiO-66. Powder X-ray diffraction and stability tests in phosphate buffer saline solution showed UiO-66 was stabilised in the glass matrix. Additionally, the composite exhibited enhanced dye uptake and gas adsorption relative to agZIF-UC-7.
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Jul 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Celia
Castillo-Blas
,
Montaña J.
García
,
Ashleigh M.
Chester
,
Matjaž
Mazaj
,
Shaoliang
Guan
,
Georgina P.
Robertson
,
Ayano
Kono
,
James M. A.
Steele
,
Luis
León-Alcaide
,
Bruno
Poletto-Rodrigues
,
Philip A.
Chater
,
Silvia
Cabrera
,
Andraž
Krajnc
,
Lothar
Wondraczek
,
David A.
Keen
,
Jose
Alemán
,
Thomas
Bennett
Diamond Proposal Number(s):
[29957]
Open Access
Abstract: Metal–organic framework (MOF) composites are proposed as solutions to the mechanical instability of pure MOF materials. Here, we present a new compositional series of recently discovered MOF–crystalline inorganic glass composites. In this case, formed by the combination of a photocatalytic titanium MOF (MIL-125-NH2) and a phosphate-based glass (20%Na2O–10%Na2SO4–70%P2O5). This new family of composites has been synthesized and characterized using powder X-ray diffraction, thermal gravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and X-ray total scattering. Through analysis of the pair distribution function extracted from X-ray total scattering data, the atom–atom interactions at the MOF–glass interface are described. Nitrogen and carbon dioxide isotherms demonstrate good surface area values despite the pelletization and mixing of the MOF with a dense inorganic glass. The catalytic activity of these materials was investigated in the photooxidation of amines to imines, showing the retention of the photocatalytic effectiveness of the parent pristine MOF.
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Mar 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[29957]
Open Access
Abstract: We report the solvent-free synthesis of a crystalline heterometallic imidazolate derivative with formula [Fe1Zn2(im)6(Him)2], designated MUV-25, incorporating both iron and zinc. The structure imposes strict positional constraints on the metal centres due to the lattice containing distinct geometric coordination sites, tetrahedral and octahedral. As a consequence, each metal is exclusively directed to its specific coordination site, ensuring precise spatial organization within the lattice. Atom locations were meticulously monitored utilizing X-ray diffraction (single crystal and total scattering) and XAS techniques, demonstrating that the tetrahedral sites are occupied exclusively by zinc, and the octahedral sites are occupied by iron. This combination of metal centres results, upon heating, in a structural phase transformation to the zni topology at a very low temperature. Further heating causes the melting of the solid, yielding a heterometallic MOF-derived glass. The methodology lays the groundwork for tailoring crystalline structures to advance the development of novel materials capable of melting and forming glasses upon cooling.
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Mar 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Shichun
Li
,
Chao
Ma
,
Jingwei
Hou
,
Shuwen
Yu
,
Aibing
Chen
,
Juan
Du
,
Philip A.
Chater
,
Dean S.
Keeble
,
Zhihua
Qiao
,
Chongli
Zhong
,
David A.
Keen
,
Yu
Liu
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[20038]
Open Access
Abstract: Crystalline metal-organic frameworks (MOFs) exhibit enormous potential application in gas separation, thanks to their highly porous structures and precise pore size distributions. Nevertheless, the inherent limitations in mechanical stability of crystalline MOFs cause challenges in processing MOF powders into bulky structures, particularly for membrane filtrations. Melt-quenched MOF glasses boast excellent processability due to liquid-like properties. However, the melting process diminishes the inherent porosity, leading to reduced gas adsorption capacities and lower gas diffusion coefficients. In this work, we demonstrated that enhancing the porosity of MOF glasses is achievable through topological engineering on the crystalline precursors. Crystalline zeolitic imidazolate frameworks (ZIFs) with large 12-membered rings pores, including AFI and CAN topology, were synthesized by using both structure-directing agents and mixed organic ligands. The large pores are partially preserved in the melt-quenched glass as evidenced by high-pressure CO2 absorption at 3000 kPa. The agAFI-[Zn(Im)1.68(bIm)0.32] glass was then fabricated into self-supported membranes, which shows high gas separation performance, for example, CO2 permeance of 3.7 × 104 GPU with a CO2/N2 selectivity of 14.8.
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Feb 2025
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Emily V.
Shaw
,
Celia
Castillo Blas
,
Timothy
Lambden
,
Beatriz
De Santos
,
Bethan
Turner
,
Giulio I.
Lampronti
,
Joonatan E. M.
Laulainen
,
Georgina
Robertson
,
Ashleigh M.
Chester
,
Chumei
Ye
,
Shaoliang
Guan
,
Joshua
Karlsson
,
Valentina
Martinez
,
Ivana
Brekalo
,
Bahar
Karadeniz
,
Silvia
Cabrera
,
Lauren N.
Mchugh
,
Krunoslav
Užarević
,
Jose
Aleman
,
Alberto
Fraile
,
Rachel C
Evans
,
Paul
Midgley
,
David A.
Keen
,
Xavier
Moya
,
Thomas D.
Bennett
Open Access
Abstract: In this work, we investigated the response of the metal-organic framework MIL-125-NH2 to ball-milling. Both localised and bulk analyses revealed that prolongued ball-milling results in a complete loss of long-range structural order. Investigation of this disorder revealed partial retention of the local bonding of the secondary building unit, suggesting structure collapse progressed primarily through metal-linker bond breakage. We explored the photocatalytic performance of the materials, and examined the materials’ band gap using UV-Vis reflectance spectroscopy.
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Feb 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Bikash Kumar
Shaw
,
Lucia
Corti
,
Joshua M.
Tuffnell
,
Celia
Castillo-Blas
,
Patrick
Schlachta
,
Georgina P.
Robertson
,
Lauren
Mchugh
,
Adam F.
Sapnik
,
Sebastian A.
Hallweger
,
Philip A.
Chater
,
Gregor
Kieslich
,
David A.
Keen
,
Sian E.
Dutton
,
Frédéric
Blanc
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[20038]
Open Access
Abstract: ABX3-type hybrid organic–inorganic structures have recently emerged as a new class of meltable materials. Here, by the use of phenylphosphonium derivatives as A cation, we study liquid- and glass-forming behavior of a new family of hybrid structures, (RPh3P)[Mn(dca)3] (R = Me, Et, Ph; dca = dicyanamide). These new compounds melt at 196–237 °C (Tm) and then vitrify upon cooling to room temperature, forming glasses. In situ glass formation of this new family of materials was probed on a large scale using a variable-temperature PXRD experiment. Structure analyses of the crystalline and the glasses were carried out by solid-state nuclear magnetic resonance spectroscopy and synchrotron X-ray total scattering techniques for using the pair distribution function. The mechanical properties of the glasses produced were evaluated showing promising durability. Thermal and electrical conductivities showed low thermal conductivities (κ ∼ 0.07–0.09 W m–1 K–1) and moderate electrical conductivities (σ ∼ 10–4–10–6 S m–1) at room temperature, suggesting that by the precise control of the A cation, we can tune meltable hybrid structures from moderate conductors to efficient thermal insulators. Our results raise attention on the practical use of this new hybrid material in applications including, e.g., photovoltaic devices to prevent light-deposited heat (owing to low κRT), energy harvesting thermoelectric, etc., and advance the structure–property understanding.
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Dec 2024
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I15-1-X-ray Pair Distribution Function (XPDF)
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Abstract: DUT-67 is a Zr-based metal–organic framework (MOF) that incorporates thiophene dicarboxylic acid linkers. In this study, we observed that DUT-67 underwent a striking structural order–disorder transition upon a dynamic heating process. We established a correlation between thermal responses and structural changes in DUT-67 during heating through both calorimetric analysis and structural characterization at various length scales. It was discovered that the chemical integrity of the DUT-67 linkers remained intact during heating. The morphology of DUT-67 was preserved after structural changes, while 50% of its porosity was retained, increasing the apparent density of the framework. The chemical changes caused by the heating were directly related to desolvation. The atomic pair distribution function analyses revealed that the structural disordering process occurred during heating. This was supported by a notable decrease in correlations between neighboring clusters, indicating a loss of structural order. The structural reordering in DUT-67 was found to involve multiple thermally induced phase transitions and then amorphization. The amorphous form of DUT-67 preserved both the high porosity and the functionality observed in its original crystalline state. This study implies that it is possible to find inherently unstable MOF structures for order–disorder engineering for creating new functionalities.
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Aug 2024
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I15-1-X-ray Pair Distribution Function (XPDF)
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Vahid
Nozari
,
Ayda Nemati Vesali
Azar
,
Roman
Sajzew
,
Celia
Castillo-Blas
,
Ayano
Kono
,
Martin
Oschatz
,
David A.
Keen
,
Philip A.
Chater
,
Georgina P.
Robertson
,
James M. A.
Steele
,
Luis
León-Alcaide
,
Alexander
Knebel
,
Christopher W.
Ashling
,
Thomas D.
Bennett
,
Lothar
Wondraczek
Diamond Proposal Number(s):
[29957]
Open Access
Abstract: Metal-organic framework (MOF) composite materials containing ionic liquids (ILs) have been proposed for a range of potential applications, including gas separation, ion conduction, and hybrid glass formation. Here, an order transition in an IL@MOF composite is discovered using CuBTC (copper benzene-1,3,5-tricarboxylate) and [EMIM][TFSI] (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide). This transition – absent for the bare MOF or IL – provides an extended super-cooling range and latent heat at a capacity similar to that of soft paraffins, in the temperature range of ≈220 °C. Structural analysis and in situ monitoring indicate an electrostatic interaction between the IL molecules and the Cu paddle-wheels, leading to a decrease in pore symmetry at low temperature. These interactions are reversibly released above the transition temperature, which reflects in a volume expansion of the MOF-IL composite.
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Jul 2024
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