17 results on '"Samantha Y. Chong"'
Search Results
2. Three-dimensional protonic conductivity in porous organic cage solids
- Author
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Ming Liu, Linjiang Chen, Scott Lewis, Samantha Y. Chong, Marc A. Little, Tom Hasell, Iain M. Aldous, Craig M. Brown, Martin W. Smith, Carole A. Morrison, Laurence J. Hardwick, and Andrew I. Cooper
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Science - Abstract
Proton conduction is a fundamental process for fuel cell development, but three-dimensional proton conduction in crystalline porous solids is rare. Here, the authors report organic molecular cages in which the structure imposes three-dimensional proton conductivity competing with metal-organic frameworks.
- Published
- 2016
- Full Text
- View/download PDF
3. Reconstructed covalent organic frameworks
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Weiwei Zhang, Linjiang Chen, Sheng Dai, Chengxi Zhao, Cheng Ma, Lei Wei, Minghui Zhu, Samantha Y. Chong, Haofan Yang, Lunjie Liu, Yang Bai, Miaojie Yu, Yongjie Xu, Xiao-Wei Zhu, Qiang Zhu, Shuhao An, Reiner Sebastian Sprick, Marc A. Little, Xiaofeng Wu, Shan Jiang, Yongzhen Wu, Yue-Biao Zhang, He Tian, Wei-Hong Zhu, and Andrew I. Cooper
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Multidisciplinary ,QD - Abstract
Covalent organic frameworks (COFs) are distinguished from other organic polymers by their crystallinity1–3, but it remains challenging to obtain robust, highly crystalline COFs because the framework-forming reactions are poorly reversible4,5. More reversible chemistry can improve crystallinity6–9, but this typically yields COFs with poor physicochemical stability and limited application scope5. Here we report a general and scalable protocol to prepare robust, highly crystalline imine COFs, based on an unexpected framework reconstruction. In contrast to standard approaches in which monomers are initially randomly aligned, our method involves the pre-organization of monomers using a reversible and removable covalent tether, followed by confined polymerization. This reconstruction route produces reconstructed COFs with greatly enhanced crystallinity and much higher porosity by means of a simple vacuum-free synthetic procedure. The increased crystallinity in the reconstructed COFs improves charge carrier transport, leading to sacrificial photocatalytic hydrogen evolution rates of up to 27.98 mmol h−1 g−1. This nanoconfinement-assisted reconstruction strategy is a step towards programming function in organic materials through atomistic structural control.
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- 2022
4. Inherent Ethyl Acetate Selectivity in a Trianglimine Molecular Solid
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Linjiang Chen, Andrew I. Cooper, Mark G. Roper, Rob Clowes, Donglin He, Graeme M. Day, Ming Liu, Katherine McKie, Marc A. Little, Chengxi Zhao, and Samantha Y. Chong
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Macrocyclic Compounds ,Ethyl acetate ,dynamic separation ,molecular crystals ,Acetates ,010402 general chemistry ,01 natural sciences ,crystal structure prediction ,Catalysis ,chemistry.chemical_compound ,Adsorption ,Organic chemistry ,Volatile organic compound ,chemistry.chemical_classification ,Ethanol ,Full Paper ,010405 organic chemistry ,Organic Chemistry ,General Chemistry ,Full Papers ,0104 chemical sciences ,Crystal structure prediction ,Solvent ,macrocycles ,chemistry ,Selective adsorption ,selective adsorption ,Solvents ,Selectivity - Abstract
Ethyl acetate is an important chemical raw material and solvent. It is also a key volatile organic compound in the brewing industry and a marker for lung cancer. Materials that are highly selective toward ethyl acetate are needed for its separation and detection. Here, we report a trianglimine macrocycle (TAMC) that selectively adsorbs ethyl acetate by forming a solvate. Crystal structure prediction showed this to be the lowest energy solvate structure available. This solvate leaves a metastable, “templated” cavity after solvent removal. Adsorption and breakthrough experiments confirmed that TAMC has adequate adsorption kinetics to separate ethyl acetate from azeotropic mixtures with ethanol, which is a challenging and energy‐intensive industrial separation., The separation of ethyl acetate from its azeotropic mixtures with ethanol is of great importance in the industrial production of ethyl acetate. Current purification techniques include extractive distillation and azeotropic distillation are energy‐intensive. Guided by crystal structure prediction, a “templating” strategy was used to construct selective binding sites in a trianglimine macrocycle crystal for the solvent molecule. These crystals exhibit inherently high selectivity towards ethyl acetate, reasonable kinetics, and show promise for real‐life, practical dynamic separations.
- Published
- 2021
5. Covalent Organic Framework Nanosheets Embedding Single Cobalt Sites for Photocatalytic Reduction of Carbon Dioxide
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Andrew I. Cooper, Reiner Sebastian Sprick, Linjiang Chen, Zhiwei Fu, Samantha Y. Chong, Rasmita Raval, Xiao-Feng Wu, Matthew Bilton, Xue Wang, Lirong Zheng, Chengxi Zhao, Lunjie Liu, Xiaoyan Wang, and Fiona McBride
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General Chemical Engineering ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Reduction (complexity) ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Covalent bond ,Carbon dioxide ,Materials Chemistry ,Photocatalysis ,QD ,0210 nano-technology ,Cobalt ,Covalent organic framework - Abstract
Covalent organic framework nanosheets (CONs), fabricated from twodimensional covalent organic frameworks (COFs), present a promising strategy for incorporating atomically distributed catalytic metal centers into well-defined pore structures with desirable chemical environments. Here, a series of CONs was synthesized by embedding single cobalt sites that were then evaluated for photocatalytic carbon dioxide reduction. A partially fluorinated, cobalt-loaded CON produced 10.1 μmol carbon monoxide with a selectivity of 76%, over 6 hours irradiation under visible light (TON = 28.1), and a high external quantum efficiency (EQE) of 6.6% under 420 nm irradiation in the presence of an iridium dye. The CONs appear to act as a semiconducting support, facilitating charge carrier transfer between the dye and the cobalt centers, and this results in a performance comparable with that of the state-of-the-art heterogeneous catalysts in the literature under similar conditions. The ultrathin CONs outperformed their bulk counterparts in all cases, suggesting a general strategy to enhance the photocatalytic activities of COF materials.
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- 2020
6. A stable covalent organic framework for photocatalytic carbon dioxide reduction
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Xiaoyan Wang, Gaia Neri, Reiner Sebastian Sprick, Lunjie Liu, Xue Wang, Linjiang Chen, Andrew I. Cooper, Anastasia Vogel, Xiaobo Li, Adrian M. Gardner, Alexander J. Cowan, Rob Clowes, Matthew Bilton, Samantha Y. Chong, and Zhiwei Fu
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Chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Rhenium ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,7. Clean energy ,0104 chemical sciences ,Catalysis ,Chemical engineering ,13. Climate action ,Photocatalysis ,QD ,0210 nano-technology ,Selectivity ,Platinum ,Electrochemical reduction of carbon dioxide ,Syngas ,Covalent organic framework - Abstract
Photocatalytic conversion of CO2 into fuels is an important challenge for clean energy research and has attracted considerable interest. Here we show that tethering molecular catalysts - a rhenium complex, [Re(bpy)(CO)3Cl] - together in the form of a crystalline covalent organic framework (COF) affords a heterogeneous photocatalyst with a strong visible light absorption, a high CO2 binding affinity, and ultimately an improved catalytic performance over its homogeneous Re counterpart. The COF incorporates bipyridine sites, allowing for ligation of the Re complex, into a fully π-conjugated backbone that is chemically robust and promotes light-harvesting. A maximum rate of 1040 μmol g-1 h-1 for CO production with 81% selectivity was measured. CO production rates were further increased up to 1400 μmol g-1 h-1, with an improved selectivity of 86%, when a photosensitizer was added. Addition of platinum resulted in production of syngas, hence, the co-formation of H2 and CO, the chemical composition of which could be adjusted by varying the ratio of COF to platinum. An amorphous analog of the COF showed significantly lower CO production rates, suggesting that crystallinity of the COF is beneficial to its photocatalytic performance in CO2 reduction.
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- 2020
7. Oriented Two‐Dimensional Porous Organic Cage Crystals
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Shan Jiang, Qilei Song, Alan Massey, Samantha Y. Chong, Linjiang Chen, Shijing Sun, Tom Hasell, Rasmita Raval, Easan Sivaniah, Anthony K. Cheetham, and Andrew I. Cooper
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oriented molecular crystals ,porous organic cages ,010405 organic chemistry ,Communication ,crystal defects ,separation membranes ,Microporous Materials ,General Medicine ,010402 general chemistry ,01 natural sciences ,Communications ,0104 chemical sciences - Abstract
The formation of two‐dimensional (2D) oriented porous organic cage crystals (consisting of imine‐based tetrahedral molecules) on various substrates (such as silicon wafers and glass) by solution‐processing is reported. Insight into the crystallinity, preferred orientation, and cage crystal growth was obtained by experimental and computational techniques. For the first time, structural defects in porous molecular materials were observed directly and the defect concentration could be correlated with crystal growth rate. These oriented crystals suggest potential for future applications, such as solution‐processable molecular crystalline 2D membranes for molecular separations.
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- 2017
8. Computationally-Guided Synthetic Control over Pore Size in Isostructural Porous Organic Cages
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Andrew I. Cooper, Tom Hasell, Daniel Holden, Rob Clowes, Linjiang Chen, Marc A. Little, Angeles Pulido, Ben M. Alston, Graeme M. Day, Maciej Haranczyk, Samantha Y. Chong, Michael E. Briggs, Anna G. Slater, and Paul S. Reiss
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Chemistry ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Cocrystal ,0104 chemical sciences ,Crystal structure prediction ,Crystal ,lcsh:Chemistry ,chemistry.chemical_compound ,Crystallography ,Molecular geometry ,Chemical engineering ,lcsh:QD1-999 ,Chemical Sciences ,Isostructural ,0210 nano-technology ,Porosity ,Topology (chemistry) ,Methyl group ,Research Article - Abstract
The physical properties of 3-D porous solids are defined by their molecular geometry. Hence, precise control of pore size, pore shape, and pore connectivity are needed to tailor them for specific applications. However, for porous molecular crystals, the modification of pore size by adding pore-blocking groups can also affect crystal packing in an unpredictable way. This precludes strategies adopted for isoreticular metal–organic frameworks, where addition of a small group, such as a methyl group, does not affect the basic framework topology. Here, we narrow the pore size of a cage molecule, CC3, in a systematic way by introducing methyl groups into the cage windows. Computational crystal structure prediction was used to anticipate the packing preferences of two homochiral methylated cages, CC14-R and CC15-R, and to assess the structure–energy landscape of a CC15-R/CC3-S cocrystal, designed such that both component cages could be directed to pack with a 3-D, interconnected pore structure. The experimental gas sorption properties of these three cage systems agree well with physical properties predicted by computational energy–structure–function maps., The pore size in a molecular crystal, CC3α, is narrowed by introducing methyl groups without disrupting the crystal packing, in line with energy−structure−function maps for these porous crystals.
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- 2017
9. Synthesis of a Large, Shape-Flexible, Solvatomorphic Porous Organic Cage
- Author
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Samantha Y. Chong, Kim E. Jelfs, Andrew I. Cooper, Rob Clowes, Baiyang Teng, Michael E. Briggs, Tom Hasell, and Marc A. Little
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Materials science ,010405 organic chemistry ,Imine ,Solid-state ,General Chemistry ,Microporous material ,Crystal structure ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,Quantitative Biology::Other ,0104 chemical sciences ,law.invention ,Condensed Matter::Soft Condensed Matter ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,law ,Physics::Atomic and Molecular Clusters ,General Materials Science ,Crystallization ,Cage ,Porosity - Abstract
[Image: see text] Porous organic cages have emerged over the last 10 years as a subclass of functional microporous materials. However, among all of the organic cages reported, large multicomponent organic cages with 20 components or more are still rare. Here, we present an [8 + 12] porous organic imine cage, CC20, which has an apparent surface area up to 1752 m(2) g(–1), depending on the crystallization and activation conditions. The cage is solvatomorphic and displays distinct geometrical cage structures, caused by crystal-packing effects, in its crystal structures. This indicates that larger cages can display a certain range of shape flexibility in the solid state, while remaining shape persistent and porous.
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- 2019
10. Core-Shell Crystals of Porous Organic Cages
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Linjiang Chen, Andrew I. Cooper, David C. Calabro, Edward W. Corcoran, Shan Jiang, Rob Clowes, Yi Du, Samantha Y. Chong, Tom Hasell, and Marco Marcello
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Materials science ,core–shell crystals ,Nuclear Theory ,Shell (structure) ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Porous Crystals ,Catalysis ,Adsorption selectivity ,Core shell ,surface hydrophobicity ,Physics::Atomic and Molecular Clusters ,Molecule ,adsorption selectivity ,Porosity ,Chemical composition ,Communication ,porous cage crystals ,General Chemistry ,021001 nanoscience & nanotechnology ,Communications ,0104 chemical sciences ,Chemical engineering ,0210 nano-technology ,Selectivity - Abstract
The first examples of core–shell porous molecular crystals are described. The physical properties of the core–shell crystals, such as surface hydrophobicity, CO2 /CH4 selectivity, are controlled by the chemical composition of the shell. This shows that porous core–shell molecular crystals can exhibit synergistic properties that out‐perform materials built from the individual, constituent molecules.
- Published
- 2018
11. Near-ideal xylene selectivity in adaptive molecular pillar[n]arene crystals
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Fumiyasu Sakakibara, Samantha Y. Chong, Angeles Pulido, Graeme M. Day, Feihe Huang, Andrew I. Cooper, Kecheng Jie, Frédéric Blanc, Yujuan Zhou, Tomoki Ogoshi, Marc A. Little, Ashlea R. Hughes, Ming Liu, and Andrew Stephenson
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Sorbent ,010405 organic chemistry ,Xylene ,General Chemistry ,Nuclear magnetic resonance spectroscopy ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,Article ,0104 chemical sciences ,Crystal structure prediction ,chemistry.chemical_compound ,Crystallography ,Colloid and Surface Chemistry ,Adsorption ,chemistry ,Structural isomer ,Selectivity ,Conformational isomerism - Abstract
The energy-efficient separation of alkylaromatic compounds is a major industrial sustainability challenge. The use of selectively porous extended frameworks, such as zeolites or metal–organic frameworks, is one solution to this problem. Here, we studied a flexible molecular material, perethylated pillar[n]arene crystals (n = 5, 6), which can be used to separate C8 alkylaromatic compounds. Pillar[6]arene is shown to separate para-xylene from its structural isomers, meta-xylene and ortho-xylene, with 90% specificity in the solid state. Selectivity is an intrinsic property of the pillar[6]arene host, with the flexible pillar[6]arene cavities adapting during adsorption thus enabling preferential adsorption of para-xylene in the solid state. The flexibility of pillar[6]arene as a solid sorbent is rationalized using molecular conformer searches and crystal structure prediction (CSP) combined with comprehensive characterization by X-ray diffraction and 13C solid state NMR spectroscopy. The CSP study, which takes into account the structural variability of pillar[6]arene, breaks new ground in its own right and showcases the feasibility of applying CSP methods to understand and ultimately to predict the behaviour of soft, adaptive molecular crystals.
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- 2018
12. Computational modelling of solvent effects in a prolific solvatomorphic porous organic cage
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Samantha Y. Chong, Marc A. Little, David P. McMahon, James T. A. Jones, Graeme M. Day, Andrew I. Cooper, and Andrew Stephenson
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Lattice energy ,Thermogravimetric analysis ,Materials science ,Solvation ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Crystal structure prediction ,law.invention ,Solvent ,Chemical physics ,law ,Physical and Theoretical Chemistry ,Solvent effects ,Crystallization ,0210 nano-technology ,Porosity - Abstract
Crystal structure prediction methods can enable the in silico design of functional molecular crystals, but solvent effects can have a major influence on relative lattice energies sometimes thwarting predictions. This is particularly true for porous solids, where solvent included in the pores can have an important energetic contribution. Here we present a Monte Carlo solvent insertion procedure for predicting the solvent filling of porous structures from crystal structure prediction landscapes, tested using a highly solvatomorphic porous organic cage molecule, CC1. We use this method to rationalise the fact that the predicted global energy minimum structure for CC1 is never observed from solvent crystallisation. We also explain the formation of three different solvatomorphs of CC1 from three structurally-similar chlorinated solvents. Calculated solvent stabilisation energies are found to correlate with experimental results from thermogravimetric analysis, suggesting a future computational framework for a priori materials design that includes solvation effects.
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- 2018
13. Reticular synthesis of porous molecular 1D nanotubes and 3D networks
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Samantha Y. Chong, Xiao-Feng Wu, C. Morgan, Marc A. Little, Angeles Pulido, Tom Hasell, Andrew I. Cooper, Rob Clowes, Kim E. Jelfs, Linjiang Chen, Ge Cheng, Michael E. Briggs, Anna G. Slater, Graeme M. Day, Daniel Holden, and The Royal Society
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ORGANIC NANOTUBES ,Chemistry, Multidisciplinary ,General Chemical Engineering ,Supramolecular chemistry ,CAGE COMPOUNDS ,Nanotechnology ,010402 general chemistry ,01 natural sciences ,DESIGN ,Porosity ,Quantitative Biology::Biomolecules ,Science & Technology ,CONSTRUCTION ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,General Chemistry ,AGGREGATION ,FRAMEWORK ,0104 chemical sciences ,HYDROGEN-BONDS ,Physical Sciences ,Reticular connective tissue ,SEPARATION ,CRYSTAL-STRUCTURE PREDICTION ,CAVITIES ,03 Chemical Sciences - Abstract
Synthetic control over pore size and pore connectivity is the crowning achievement for porous metal-organic frameworks. The same level of control has not been achieved for molecular crystals, which are not defined by strong, directional intermolecular coordination bonds. Hence, molecular crystallization is inherently less predictable than framework crystallization, and there are fewer examples of ‘reticular synthesis’, where multiple building blocks can be assembled according to a common assembly motif. Here, we apply a chiral recognition strategy to a new family of tubular covalent cages, TCC1–TCC3, to create both 1-D porous nanotubes and 3-D, diamondoid pillared porous networks in a targeted way. The diamondoid networks are analogous to metal-organic frameworks prepared from tetrahedral metal nodes and linear, difunctional organic linkers. The crystal structures can be rationalized by computational lattice energy searches, which provide an in silico screening method to evaluate candidate molecular building blocks. These results are a blueprint for applying the ‘node and strut’ principles of reticular synthesis to molecular crystals.
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- 2017
14. Separation of rare gases and chiral molecules by selective binding in porous organic cages
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Andrew I. Cooper, Jon G. Bell, Linjiang Chen, Raymond Noel, Samantha Y. Chong, Jose Busto, Adam Kewley, Praveen K. Thallapally, Michael E. Briggs, Tom Hasell, Daniel Holden, Denis M. Strachan, Paul S. Reiss, Marc A. Little, K. Mark Thomas, Andrew Stephenson, Jian Liu, Kim E. Jelfs, Jayne A. Armstrong, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Chen, Linjiang, Reiss, Paul, Chong, Sam, Holden, Daniel, Jelfs, Kim, Hasell, Tom, Little, Marc, Kewley, Adam, Briggs, Michael, Stephenson, Andrew, Thomas, K. Mark, Armstrong, Jayne A., Bell, Jon, Busto, Jose, Noel, Raymond, Liu, Jian, Strachan, Denis M., Thallapally, Praveen K., and Cooper, Andy
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Chemistry ,[CHIM.ORGA]Chemical Sciences/Organic chemistry ,Mechanical Engineering ,Krypton ,Enantioselective synthesis ,chemistry.chemical_element ,General Chemistry ,Condensed Matter Physics ,Xenon ,Chemical engineering ,Mechanics of Materials ,Molecule ,General Materials Science ,Metal-organic framework ,Enantiomer ,Selectivity ,Porosity - Abstract
The separation of molecules with similar size and shape is an important technological challenge. For example, rare gases can pose either an economic opportunity or an environmental hazard and there is a need to separate these spherical molecules selectively at low concentrations in air. Likewise, chiral molecules are important building blocks for pharmaceuticals, but chiral enantiomers, by definition, have identical size and shape, and their separation can be challenging. Here we show that a porous organic cage molecule has unprecedented performance in the solid state for the separation of rare gases, such as krypton and xenon. The selectivity arises from a precise size match between the rare gas and the organic cage cavity, as predicted by molecular simulations. Breakthrough experiments demonstrate real practical potential for the separation of krypton, xenon and radon from air at concentrations of only a few parts per million. We also demonstrate selective binding of chiral organic molecules such as 1-phenylethanol, suggesting applications in enantioselective separation.
- Published
- 2014
15. Molecular Dynamics Simulations of Gas Selectivity in Amorphous Porous Molecular Solids
- Author
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Maciej Haranczyk, Shan Jiang, Samantha Y. Chong, Abbie Trewin, Daniel Holden, Tom Hasell, Kim E. Jelfs, and Andrew I. Cooper
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Diffraction ,Chemistry ,Nanotechnology ,General Chemistry ,Biochemistry ,Catalysis ,Amorphous solid ,Molecular dynamics ,Colloid and Surface Chemistry ,Molecular solid ,Volume (thermodynamics) ,Chemical physics ,Gaseous diffusion ,Molecule ,Porosity - Abstract
Some organic cage molecules have structures with protected, internal pore volume that cannot be in-filled, irrespective of the solid-state packing mode: that is, they are intrinsically porous. Amorphous packings can give higher pore volumes than crystalline packings for these materials, but the precise nature of this additional porosity is hard to understand for disordered solids that cannot be characterized by X-ray diffraction. We describe here a computational methodology for generating structural models of amorphous porous organic cages that are consistent with experimental data. Molecular dynamics simulations rationalize the observed gas selectivity in these amorphous solids and lead to insights regarding self-diffusivities, gas diffusion trajectories, and gas hopping mechanisms. These methods might be suitable for the de novo design of new amorphous porous solids for specific applications, where "rigid host" approximations are not applicable.
- Published
- 2013
16. Tuning of gallery heights in a crystalline 2D carbon nitride network
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Andrew I. Cooper, Markus Antonietti, Michael J. Bojdys, Samantha Y. Chong, James T. A. Jones, Yaroslav Z. Khimyak, and Arne Thomas
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Materials science ,Renewable Energy, Sustainability and the Environment ,Potassium bromide ,Inorganic chemistry ,Intercalation (chemistry) ,Halide ,Ammonium fluoride ,General Chemistry ,chemistry.chemical_compound ,Crystallography ,chemistry ,Bromide ,ddc:540 ,General Materials Science ,ddc:530 ,Imide ,Eutectic system ,Triazine - Abstract
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich. This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively. Poly(triazine imide)—a 2D layered network—can be obtained as an intercalation compound with halides from the ionothermal condensation of dicyandiamide in a eutectic salt melt. The gallery height of the intercalated material can be tuned via the composition of the eutectic melt and by post-synthetic modification. Here, we report the synthesis of poly(triazine imide) with intercalated bromide ions (PTI/Br) from a lithium bromide and potassium bromide salt melt. PTI/Br has a hexagonal unit-cell (P63cm (no. 185); a = 8.500390(68) Å, c = 7.04483(17) Å) that contains two layers of imide-bridged triazine (C3N3) units stacked in an AB-fashion as corroborated by solid-state NMR, FTIR spectroscopy and high-resolution TEM. By comparison with a recently reported material PTI/Li+Cl−, prepared from a LiCl/KCl eutectic, the layer-stacking distance in the analogous bromide material was expanded from 3.38 Å to 3.52 Å – an exceptionally large spacing for an aromatic, discotic system (cf. graphite 3.35 Å). Subsequent treatment of PTI/Br with concentrated ammonium fluoride yields poly(triazine imide) with intercalated fluoride ions (PTI/F) (P63/m (no. 176); a = 8.4212(4) Å, c = 6.6381(5) Å) as a statistical phase mix with PTI/Br. Fluoride intercalation leads to a contraction of the gallery height to 3.32 Å, demonstrating that the gallery height is synthetically tuneable in these materials.
- Published
- 2013
17. Combined optimization using cultural and differential evolution: application to crystal structure solution from powder diffraction data.
- Author
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Samantha Y. Chong and Maryjane Tremayne
- Published
- 2006
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