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Other Publications (82)
- Journal of the American Chemical Society
- Chemical Communications (Cambridge, England)
- Chemical Communications (Cambridge, England)
- Journal of the American Chemical Society
- Dalton Transactions (Cambridge, England : 2003)
- Dalton Transactions (Cambridge, England : 2003)
- Nature
- Journal of the American Chemical Society
- Journal of the American Chemical Society
- Journal of the American Chemical Society
- The Journal of Physical Chemistry. B
- Chemical Communications (Cambridge, England)
- Angewandte Chemie (International Ed. in English)
- Journal of the American Chemical Society
- Journal of the American Chemical Society
- Accounts of Chemical Research
- Dalton Transactions (Cambridge, England : 2003)
- Journal of the American Chemical Society
- Angewandte Chemie (International Ed. in English)
- Dalton Transactions (Cambridge, England : 2003)
- Dalton Transactions (Cambridge, England : 2003)
- The Journal of Investigative Dermatology
- Angewandte Chemie (International Ed. in English)
- Angewandte Chemie (International Ed. in English)
- Journal of the American Chemical Society
- Dalton Transactions (Cambridge, England : 2003)
- Organic & Biomolecular Chemistry
- Chemical Communications (Cambridge, England)
- The Journal of Physical Chemistry. B
- Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry
- Dalton Transactions (Cambridge, England : 2003)
- Angewandte Chemie (International Ed. in English)
- Dalton Transactions (Cambridge, England : 2003)
- Chemical Communications (Cambridge, England)
- Dalton Transactions (Cambridge, England : 2003)
- Dalton Transactions (Cambridge, England : 2003)
- Journal of the American Chemical Society
- Nature Chemistry
- Acta Biomaterialia
- Journal of the American Chemical Society
- Nature Chemistry
- Dalton Transactions (Cambridge, England : 2003)
- Dalton Transactions (Cambridge, England : 2003)
- Magnetic Resonance in Chemistry : MRC
- Angewandte Chemie (International Ed. in English)
- Organic & Biomolecular Chemistry
- Dalton Transactions (Cambridge, England : 2003)
- Nature Chemistry
- Dalton Transactions (Cambridge, England : 2003)
- Nature Chemistry
- Nature Chemistry
- Chemical Reviews
- Dalton Transactions (Cambridge, England : 2003)
- Dalton Transactions (Cambridge, England : 2003)
- Dalton Transactions (Cambridge, England : 2003)
- Chemical Communications (Cambridge, England)
- Physical Chemistry Chemical Physics : PCCP
- Angewandte Chemie (International Ed. in English)
- Chemical Communications (Cambridge, England)
- Nature Communications
- Nature Chemistry
- Chemistry (Weinheim an Der Bergstrasse, Germany)
- Dalton Transactions (Cambridge, England : 2003)
- Dalton Transactions (Cambridge, England : 2003)
- Dalton Transactions (Cambridge, England : 2003)
- Chemical Reviews
- Nanoscale
- Dalton Transactions (Cambridge, England : 2003)
- Angewandte Chemie (International Ed. in English)
- Dalton Transactions (Cambridge, England : 2003)
- Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry
- Angewandte Chemie (International Ed. in English)
- Zeitschrift Fur Anorganische Und Allgemeine Chemie
- Nature Chemistry
- Chemical Society Reviews
- Dalton Transactions (Cambridge, England : 2003)
- Dalton Transactions (Cambridge, England : 2003)
- Angewandte Chemie (International Ed. in English)
- Dalton Transactions (Cambridge, England : 2003)
- Nature Chemistry
- CrystEngComm / RSC
- RSC Advances
Articles by Russell E. Morris in JoVE
Other articles by Russell E. Morris on PubMed
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Combined Solid State NMR and X-ray Diffraction Investigation of the Local Structure of the Five-coordinate Silicon in Fluoride-containing As-synthesized STF Zeolite
Journal of the American Chemical Society.
Jul, 2002 |
Pubmed ID: 12083931 The local structure of the [SiO(4/2)F]- unit in fluoride-containing as-synthesized STF zeolite has been experimentally determined by a combination of solid-state NMR and microcrystal X-ray diffraction to be very close to trigonal bipyramidal. Because the fluoride ions are disordered over two sites, the resulting local structure of the [SiO(4/2)F]- unit from a conventional XRD refinement is an average between tetrahedral SiO(4/2) and five-coordinate [[SiO(4/2)F]-, giving an apparent F-Si distance longer than expected. The correct F-Si distance was determined by slow spinning MAS and fast spinning (19)F/(29)Si CP and REDOR solid-state NMR experiments and found to be between 1.72 and 1.79 A. In light of this, the X-ray structure was re-refined, including the disorder at Si3. The resulting local structure of the [SiO(4/2)F]- unit was very close to trigonal bipyramidal with a F-Si distance of 1.744 (6) A, in agreement with the NMR results and the prediction of Density Functional Theory calculations. In addition, further evidence for the existence of a covalent F-Si bond is provided by a (19)F-->(29)Si refocused INEPT experiment. The resonance for the five-coordinate species at -147.5 ppm in the (29)Si spectrum is a doublet due to the (19)F/(29)Si J-coupling of 165 Hz. The peaks in this doublet have remarkably different effective chemical shift anisotropies due to the interplay of the CSA, dipolar coupling, and J-coupling tensors. The distortions from tetrahedral geometry of the neighboring silicon atoms to the five-coordinate Si3 atom are manifested in increased delta(aniso) values. This information, along with F-Si distances measured by (19)F-->(29)Si CP experiments, makes it possible to assign half of the (29)Si resonances to unique tetrahedral sites. As well as determining the local geometry of the [SiO(4/2)F]- unit, the work presented here demonstrates the complementarity of the solid-state NMR and X-ray diffraction techniques and the advantages of using them together.
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Layered Microporous Tin(IV) Bisphosphonates
Dalton Transactions (Cambridge, England : 2003).
Jun, 2007 |
Pubmed ID: 17844661 This article reports the hydrothermal synthesis and characterization of two new series of porous tin(IV) phosphonophenoxyphenylphosphonates with controlled pore size distributions, using as precursor the 4-(4'-phosphonophenoxy)phenyl phosphonic acid, [H2O3P-C6H4]2-O. Supermicroporous solids (S(BET), 300-400 m2 g(-1)) were obtained employing n-alcohol (C1-C6)-water mixtures (solvents ratio 1 : 1), in the presence of hydrofluoric acid. X-Ray powder diffraction shows that these compounds are semi-crystalline and the local environments around the phosphorus and tin elements have been studied by 31P and 119Sn MAS-NMR spectroscopy, respectively. The microstructure (particle sizes and shapes) of these phosphonates has been analyzed by scanning and transmission electron microscopy. This study shows that the microstructures of single-ligand (for instance tin(IV) phenylphosphonate) and cross-linked tin(IV) bisphosphonates are different. Tin(IV) phenylphosphonate crystallizes as micron-sized spheres, theta approximately 1-2 microm, formed by the aggregation of nanospheres, whereas tin(IV) bisphosphonates crystallize as microparticles larger than 20 microm. The textural properties of these porous solids were characterized by N2 and CO2 sorption isotherms. The key result of this work is that maxima of pore size distributions smoothly shift from 12 to 16 angstroms upon increasing the chain length of the alcohol. The microporosity of tin(IV) bisphosphonates is compatible with a double role played by the phosphonate groups acting as a pillar between adjacent layers and as a component of the hybrid organic-inorganic layers.
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Topically Applied Nitric Oxide Induces T-lymphocyte Infiltration in Human Skin, but Minimal Inflammation
The Journal of Investigative Dermatology.
Feb, 2008 |
Pubmed ID: 17914444 Nitric oxide (NO) plays an important role in the cutaneous response to UV radiation and in cutaneous inflammation. The presence of inducible NO synthase protein in a number of inflammatory dermatoses, coupled with the induction of an intense cutaneous inflammatory infiltrate following topical application of the NO donor-acidified nitrite (NO2(-)), has set the paradigm of NO being an inflammatory mediator in human skin. Using zeolite NO (Ze-NO), a chemically inert, pure NO donor, we have shown that NO per se produces little inflammation. Biologically, relevant doses of Ze-NO induce a dermal CD4-positive T-cell infiltrate and IFN-gamma secretion. In contrast acidified nitrite, releasing equal quantities of NO (measured by dermal microdialysis and cutaneous erythema), induces an intense epidermal infiltrate of macrophages with a similar dermal infiltrate of CD3-, CD4-, CD8-, and CD68-positive cells and neutrophils. Suction blisters were created in Ze-NO-treated and control skin. IFN-gamma, but not IL-4, was detected in Ze-NO-treated skin (mean control 0.1+/-0.07 pg mg(-1) protein, mean IFN-gamma 0.6+/-0.4 pg mg(-1) protein). We suggest that the potent inflammation induced by acidified NO2(-) is secondary to the release of additional mediators.
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Gas Storage in Nanoporous Materials
Angewandte Chemie (International Ed. in English).
2008 |
Pubmed ID: 18459091 Gas storage in solids is becoming an ever more important technology, with applications and potential applications ranging from energy and the environment all the way to biology and medicine. Very highly porous materials, such as zeolites, carbon materials, polymers, and metal-organic frameworks, offer a wide variety of chemical composition and structural architectures that are suitable for the adsorption and storage of many different gases, including hydrogen, methane, nitric oxide, and carbon dioxide. However, the challenges associated with designing materials to have sufficient adsorption capacity, controllable delivery rates, suitable lifetimes, and recharging characteristics are not trivial in many instances. The different chemistry associated with the various gases of interest makes it necessary to carefully match the properties of the porous material to the required application.
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Hydrogen-bond-directing Effect in the Ionothermal Synthesis of Metal Coordination Polymers
Dalton Transactions (Cambridge, England : 2003).
Aug, 2008 |
Pubmed ID: 18648702 Four new cobalt coordination polymers, (EMIm)[Co2(TMA-H)2(44bpy)3]Br 1, (EMIm)[Co(TMA-H)(44bpy)2](44bpy)Br 2, (EMIm)[Co(TMA)(Im-H)]3 and (EMIm)2[Co(TMA)2(TED-H2)] 4, were prepared from 1-ethyl-3-methyl imidazolium bromide (EMIm-Br). All the compounds have similar two-dimensional cobalt trimesate (TMA) coordination layers but different three-dimensional supramolecular architectures that contain one of three potentially ditopic amines, 4,4'-bipyridine (44bpy), imidazole (Im-H) and triethylenediamine (TED). Two-fold interpenetration of hydrogen-bonding networks was found for 1, 2 and 4. The coordination layers of 1 and 2 are neutral while 3 and 4 have anionic molecular assemblies. The use of organic amines, that act as supramolecular bridging ligands, introduces hydrogen-bond-directing effects in the ionothermal synthesis of metal coordination polymers. Hydrogen bonding helps to align the packing between the coordination layers and control the formation of 3D supramolecular networks. In 1, hydrogen bonds between the ionic species within the channels direct the alignment of non-directional electrostatic interactions between EMIm+ and Br(-) ions, which is a rare case of a hydrogen-bond-templating effect of ionic liquids in ionothermal synthesis.
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Synthesis of Functional Cubes from Octavinylsilsesquioxane (OVS)
Organic & Biomolecular Chemistry.
Dec, 2008 |
Pubmed ID: 19039377 Octavinylsilsesquioxane, (CH(2)CH)(8)Si(8)O(12), a cubic molecule with vinyl groups at each vertex, has been elaborated to give a series of potential starting materials for nanohybrid synthesis. Terminal bromophenyl groups were introduced onto the surface of octavinylsilsesquioxane either by cross-metathesis or hydrosilylation to give fully bromide substituted POSS A, POSS B and POSS C; the last two were further capped with trimethylsilylacetylene by Sonogashira coupling to produce POSS D and POSS E, showing interesting potential for more useful end group functionalisation. Heck coupling with iodobenzene was used to make the simple phenyl terminated dendrimer POSS F. Cross-metathesis of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)styrene with octavinylsilsesquioxane afforded POSS G with eight aryl borate groups on its periphery, suitable for use as a starting material in Suzuki coupling. Finally, POSS H has been functionalized with 8 benzyl chloride groups via Grubbs coupling, allowing further substitutions by nucleophiles.
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Early Stage Reversed Crystal Growth of Zeolite A and Its Phase Transformation to Sodalite
Journal of the American Chemical Society.
Dec, 2009 |
Pubmed ID: 19919054 Microstructural analysis of the early stage crystal growth of zeolite A in hydrothermal synthetic conditions revealed a revised crystal growth route from surface to core in the presence of the biopolymer chitosan. The mechanism of this extraordinary crystal growth route is discussed. In the first stage, the precursor and biopolymer aggregated into amorphous spherical particles. Crystallization occurred on the surface of these spheres, forming the typical cubic morphology associated with zeolite A with a very thin crystalline cubic shell and an amorphous core. With a surface-to-core extension of crystallization, sodalite nanoplates were crystallized within the amorphous cores of these zeolite A cubes, most likely due to an increase of pressure. These sodalite nanoplates increased in size, breaking the cubic shells of zeolite A in the process, leading to the phase transformation from zeolite A to sodalite via an Ostwald ripening process. Characterization of specimens was performed using scanning electron microscopy and transmission electron microscopy, supported by other techniques including X-ray diffraction, solid-state NMR, and N(2) adsorption/desorption.
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Induction of Chiral Porous Solids Containing Only Achiral Building Blocks
Nature Chemistry.
May, 2010 |
Pubmed ID: 20414234 In many areas of chemistry the synthesis of chiral compounds is a target of increasing importance. They play a vital role in biological function and in many areas of society and science, including biology, medicine, biotechnology, chemistry and agriculture. Many pharmaceutical molecules, like their biological targets, are chiral and it is therefore easy to understand the growing demand for efficient methods of producing enantiomerically pure compounds. This is equally true for the preparation of chiral solids, which have potential applications in asymmetric catalysis, chiral separations and the like. In this Review we will consider recent progress and future potential in the development of methods for the preparation of chirally pure solids, in particular where the building blocks of the structure are achiral themselves. We will discuss strategies for the synthesis of both inorganic (for example, zeolites) and inorganic-organic hybrid (for example, metal organic framework) chiral porous solids.
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Protecting Group and Switchable Pore-discriminating Adsorption Properties of a Hydrophilic-hydrophobic Metal-organic Framework
Nature Chemistry.
Apr, 2011 |
Pubmed ID: 21430690 Formed by linking metals or metal clusters through organic linkers, metal-organic frameworks are a class of solids with structural and chemical properties that mark them out as candidates for many emerging gas storage, separation, catalysis and biomedical applications. Important features of these materials include their high porosity and their flexibility in response to chemical or physical stimuli. Here, a copper-based metal-organic framework has been prepared in which the starting linker (benzene-1,3,5-tricarboxylic acid) undergoes selective monoesterification during synthesis to produce a solid with two different channel systems, lined by hydrophilic and hydrophobic surfaces, respectively. The material reacts differently to gases or vapours of dissimilar chemistry, some stimulating subtle framework flexibility or showing kinetic adsorption effects. Adsorption can be switched between the two channels by judicious choice of the conditions. The monoesterified linker is recoverable in quantitative yield, demonstrating possible uses of metal-organic frameworks in molecular synthetic chemistry as 'protecting groups' to accomplish selective transformations that are difficult using standard chemistry techniques.
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Multifunctional Lanthanum Tetraphosphonates: Flexible, Ultramicroporous and Proton-conducting Hybrid Frameworks
Dalton Transactions (Cambridge, England : 2003).
Apr, 2012 |
Pubmed ID: 22278089 A new flexible ultramicroporous solid, La(H(5)DTMP)·7H(2)O (1), has been crystallized at room temperature using the tetraphosphonic acid H(8)DTMP, hexamethylenediamine-N,N,N',N'-tetrakis(methylenephosphonic acid). Its crystal structure, solved by synchrotron powder X-ray diffraction, is characterised by a 3D pillared open-framework containing 1D channels filled with water. Upon dehydration, a new related crystalline phase, La(H(5)DTMP) (2) is formed. Partial rehydration of 2 led to La(H(5)DTMP)·2H(2)O (3). These new phases contain highly corrugated layers showing different degrees of conformational flexibility of the long organic chain. The combination of the structural study and the gas adsorption characterization (N(2) and CO(2)) suggests an ultramicroporous flexible framework. NO isotherms are indicative of a strong irreversible adsorption of NO within the pores. Impedance data indicates that 1 is a proton-conductor with a conductivity of 8 × 10(-3) S cm(-1) at 297 K and 98% of relative humidity, and an activation energy of 0.25 eV.
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High-resolution Solid-state 13C NMR Spectroscopy of the Paramagnetic Metal-organic Frameworks, STAM-1 and HKUST-1
Physical Chemistry Chemical Physics : PCCP.
Jan, 2013 |
Pubmed ID: 23202442 Solid-state (13)C magic-angle spinning (MAS) NMR spectroscopy is used to investigate the structure of the Cu(II)-based metal-organic frameworks (MOFs), HKUST-1 and STAM-1, and the structural changes occurring within these MOFs upon activation (dehydration). NMR spectroscopy is an attractive technique for the investigation of these materials, owing to its high sensitivity to local structure, without any requirement for longer-range order. However, interactions between nuclei and unpaired electrons in paramagnetic systems (e.g., Cu(II)-based MOFs) pose a considerable challenge, not only for spectral acquisition, but also in the assignment and interpretation of the spectral resonances. Here, we exploit the rapid T(1) relaxation of these materials to obtain (13)C NMR spectra using a spin-echo pulse sequence at natural abundance levels, and employ frequency-stepped acquisition to ensure uniform excitation of resonances over a wide frequency range. We then utilise selective (13)C isotopic labelling of the organic linker molecules to enable an unambiguous assignment of NMR spectra of both MOFs for the first time. We show that the monomethylated linker can be recovered from STAM-1 intact, demonstrating not only the interesting use of this MOF as a protecting group, but also the ability (for both STAM-1 and HKUST-1) to recover isotopically-enriched linkers, thereby reducing significantly the overall cost of the approach.
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A Solid with a Hierarchical Tetramodal Micro-meso-macro Pore Size Distribution
Nature Communications.
2013 |
Pubmed ID: 23764887 Porous solids have an important role in addressing some of the major energy-related problems facing society. Here we describe a porous solid, α-MnO2, with a hierarchical tetramodal pore size distribution spanning the micro-, meso- and macro pore range, centred at 0.48, 4.0, 18 and 70 nm. The hierarchical tetramodal structure is generated by the presence of potassium ions in the precursor solution within the channels of the porous silica template; the size of the potassium ion templates the microporosity of α-MnO2, whereas their reactivity with silica leads to larger mesopores and macroporosity, without destroying the mesostructure of the template. The hierarchical tetramodal pore size distribution influences the properties of α-MnO2 as a cathode in lithium batteries and as a catalyst, changing the behaviour, compared with its counterparts with only micropores or bimodal micro/mesopores. The approach has been extended to the preparation of LiMn2O4 with a hierarchical pore structure.
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A Family of Zeolites with Controlled Pore Size Prepared Using a Top-down Method
Nature Chemistry.
Jul, 2013 |
Pubmed ID: 23787755 The properties of zeolites, and thus their suitability for different applications, are intimately connected with their structures. Synthesizing specific architectures is therefore important, but has remained challenging. Here we report a top-down strategy that involves the disassembly of a parent zeolite, UTL, and its reassembly into two zeolites with targeted topologies, IPC-2 and IPC-4. The three zeolites are closely related as they adopt the same layered structure, and they differ only in how the layers are connected. Choosing different linkers gives rise to different pore sizes, enabling the synthesis of materials with predetermined pore architectures. The structures of the resulting zeolites were characterized by interpreting the X-ray powder-diffraction patterns through models using computational methods; IPC-2 exhibits orthogonal 12- and ten-ring channels, and IPC-4 is a more complex zeolite that comprises orthogonal ten- and eight-ring channels. We describe how this method enables the preparation of functional materials and discuss its potential for targeting other new zeolites.
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A New Family of Two-dimensional Zeolites Prepared from the Intermediate Layered Precursor IPC-3P Obtained During the Synthesis of TUN Zeolite
Chemistry (Weinheim an Der Bergstrasse, Germany).
Oct, 2013 |
Pubmed ID: 24038214 The crystallization of zeolite TUN with 1,4-bis(N-methylpyrrolidinium)butane as template proceeds through an intermediate, designated IPC-3P, following the Ostwald rule of successive transformations. This apparently layered transient product has been thoroughly investigated and found to consist of MWW monolayers stacked without alignment in register, that is, disordered compared with MCM-22P. The structure was confirmed based on X-ray diffraction and high-resolution (HR)TEM analysis. The layered zeolite precursor IPC-3P can be swollen and pillared affording a combined micro- and mesoporous material with enhanced Brunauer-Emmett-Teller (BET) surface area (685 m(2) g(-1) ) and greater accessibility of Brønsted acid sites for bulky molecules. This mesoporous material was probed with 2,6-di-tert-butylpyridine (DTBP). IPC-3P and its modification create a new layered zeolite sub-family belonging to the MWW family. FTIR data indicate that (Al)MWW materials MCM-22 and IPC-3 with Si/Al ratios greater than 20 exhibit a lower relative ratio of Brønsted to Lewis acid sites than MCM-22 (with Si/Al ratios of around 13), that is, less than 2 versus more than 3, respectively. This is maintained even upon pillaring and warrants further exploration of materials like IPC-3P with a higher Al content. The unique XRD features of IPC-3P indicating misaligned stacking of layers and distinct from MCM-22P, are also seen in other MWW materials such as EMM-10P, hexamethonium-templated (HM)-MCM-22, ITQ-30, and UZM-8 suggesting the need for more detailed study of their identity and properties.
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Structural Diversity in Hybrid Vanadium(IV) Oxyfluorides Based on a Common Building Block
Dalton Transactions (Cambridge, England : 2003).
Jan, 2014 |
Pubmed ID: 24129339 There are only limited reports on vanadium(iv) oxyfluorides (VOFs) with extended crystal structures. Here we expand and enrich the list of existing VOFs with a series of 14 new materials "VOF-n (n = 1-14)" prepared using ionothermal and solvothermal synthesis methods. All of these materials arise from the condensation of a dimeric structural motif. These VOFs can be classified into three groups depending on their key structural features; layer structures: VOF-1"[HN2C7H6][V2O2F5]", VOF-2"[HN2C4H4][V2O2F5]", VOF-3"[HN2C3H4][V2O2F5]" and VOF-4"V2(N2C4H4)O2F4", ladder like structures: VOF-5"[NH4(HN2C3H4)][V2O2F6]", VOF-6"[K(HN2C3H4)][V2O2F6]", VOF-7"[HNH2CH2CH3][VOF3]", VOF-8"[HN2C7H6][VOF3]", VOF-9"[H2N2C4H6][V2O2F6]", VOF-10"β-RbVOF3", VOF-11"α-KVOF3", VOF-12"β-KVOF3", VOF-13"[H2(NH2)2(CH2)2][V2O2F6]", and a chain structure: VOF-14"[H2N2C6H12][V2O2F7]". The crystal structures of VOF-n are presented, and their synthetic and structural relationships are discussed.
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The Effect of Pressure on the Post-synthetic Modification of a Nanoporous Metal-organic Framework
Nanoscale.
Apr, 2014 |
Pubmed ID: 24603846 Here we report four post-synthetic modifications, including the first ever example of a high pressure-induced post-synthetic modification, of a porous copper-based metal-organic framework. Ligand exchange with a water ligand at the axial metal site occurs with methanol, acetonitrile, methylamine and ethylamine within a single-crystal and without the need to expose a free metal site prior to modification, resulting in significant changes in the pore size, shape and functionality. Pressure experiments carried out using isopropylalcohol and acetaldehyde, however, results in no ligand exchange. By using these solvents as hydrostatic media for high-pressure single-crystal X-ray diffraction experiments, we have investigated the effect of ligand exchange on the stability and compressibility of the framework and demonstrate that post-synthetic ligand exchange is very sensitive to both the molecular size and functionality of the exchanged ligand. We also demonstrate the ability to force hydrophilic molecules into hydrophobic pores using high pressures which results in a pressure-induced chemical decomposition of the Cu-framework.
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From Double-four-ring Germanosilicates to New Zeolites: in Silico Investigation
Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry.
Oct, 2014 |
Pubmed ID: 25048804 To date, the majority of zeolites have been prepared by the solvothermal route using organic structure directing agents. Two new zeolites with structural codes PCR and OKO were recently prepared from UTL germanosilicate by removal of the double-four ring (D4R) connecting the dense two-dimensional layers [Nature Chem. 2013, 5, 628]. The corresponding experimental protocol, Assembly-Disassembly-Organization-Reassembly (ADOR), is explored in this contribution with an in silico investigation. The structure and properties of hypothetical zeolites that could be obtained from zeolites with IWW, IWV, IWR, ITR, and ITH topologies using the ADOR protocol are reported based on a computational investigation. A total of 20 new structures are presented together with their characteristics.
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Exploiting Chemically Selective Weakness in Solids As a Route to New Porous Materials
Nature Chemistry.
May, 2015 |
Pubmed ID: 25901815 Weakness in a material, especially when challenged by chemical, mechanical or physical stimuli, is often viewed as something extremely negative. There are countless examples in which interesting-looking materials have been dismissed as being too unstable for an application. But instability with respect to a stimulus is not always a negative point. In this Perspective we highlight situations where weakness in a material can be used as a synthetic tool to prepare materials that, at present, are difficult or even impossible to prepare using traditional synthetic approaches. To emphasize the concept, we will draw upon examples in the field of nanoporous materials, concentrating on metal-organic frameworks and zeolites, but the general concepts are likely to be applicable across a wide range of materials chemistry. In zeolite chemistry, there is a particular problem with accessing hypothetical structures that this approach may solve.
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Water Based Scale-up of CPO-27 Synthesis for Nitric Oxide Delivery
Dalton Transactions (Cambridge, England : 2003).
Dec, 2015 |
Pubmed ID: 26616891 The applicability of water-based reflux and room temperature synthesis processes for the production of CPO-27 MOFs, suitable for NO delivery applications, is investigated. NO adsorption, storage and release performance of products obtained under reflux conditions are comparable to those of equivalent samples synthesised from traditional solvothermal methods at small scale. Products obtained from room temperature processes show lower NO release capability, although the quantities that are released are still more than adequate for biomedical applications. Results also reveal differences for the first time in NO uptake, storage and release depending on whether Zn, Ni or Mg is employed. The results indicate that while the crystallinity of CPO-27(Zn) and CPO-27(Mg) is not affected by moving to lower temperature methods, the crystallinity of CPO-27(Ni) is reduced. Particle morphology and size is also affected. The low temperature processes are successfully demonstrated at 20 L and 100 L scale and the main problems encountered during scale-up are outlined. The 100 L scale is in itself an appropriate production scale for some niche biomedical products. Indeed, results indicate that this synthesis approach is suitable for commercial production of MOFs for this application field. We also confirm that BET surface area from nitrogen adsorption at 77 K is not a good indicator for successful adsorption of NO.
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