Metal-organic frameworks (MOFs) are some of the most exciting materials in current science. Their utility and diversity of applications depends on a combination of their chemistry, their framework ...topology and the spatial dimensions of their pores. In this review we concentrate on the chemistry of MOFs. Specifically we bring together many aspects of MOFs that underpin their stability, reactivity and dynamic behaviour within a common theme related to (changes in) metal-ligand bonding. In each area we provide examples to illustrate the behaviour and discuss it in the context of metal lability and coordination changes. Starting with flexible behaviour in which metal-linker bonds undergo deformation rather than cleavage, we then consider coordination changes that lead to open metal sites, changes in framework topology, framework dimensionality or degree of network interpenetration. We show how these changes are linked to development of new properties, including changes in magnetic behaviour, gas adsorption characteristics, construction of composite MOFs and amorphous MOFs, as well as providing new synthetic routes for MOF preparation. We discuss how the lability of the species that make up the MOFs can affect aspects from their synthesis to the possibility of metal and linker exchange reactions that may lead to defects and disorder. The final section reviews hemilability in MOFs, where regions of different chemical behaviour within MOFs can lead to unusual properties, such as self-accelerating and ultraselective adsorption.
Deformation or cleavage/reformation of metal-ligand bonds in MOFs lies at the heart of chemical/thermal stability and dynamic/flexible behaviour, provides avenues for post-synthetic modification, and can enable novel or improved performance for a variety of applications.
Ionothermal synthesis is the use of ionic liquids simultaneously as both the solvent and potential template or structure directing agent in the formation of solids. It directly parallels hydrothermal ...synthesis where the solvent is water. In this feature article I discuss the general features of ionothermal synthesis and how the properties of the synthesis differ from those of other synthetic methodologies. In particular, I will discuss the role of the ionic liquid anion in determining the structure of the synthesised solid, the role of mineralisers such as water and fluoride, and the targeted use of unstable ionic liquids to produce new inorganic and inorganic-organic hybrid materials.
The assembly–disassembly–organization–reassembly (ADOR) process has been used to disassemble a parent zeolite with the UOV structure type and then reassemble the resulting layers into a novel ...structure, IPC‐12. The structure of the material has previously been predicted computationally and confirmed in our experiments using X‐ray diffraction and atomic resolution STEM‐HAADF electron microscopy. This is the first successful application of the ADOR process to a material with porous layers.
A germane assembly: The synthesis of a new zeolite IPC‐12 using the assembly–disassembly–organization–reassembly (ADOR) transformation of a germanosilicate zeolite with the UOV topology is reported.
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Gas Storage in Nanoporous Materials Morris, Russell E; Wheatley, Paul S
Angewandte Chemie (International ed.),
June 23, 2008, Volume:
47, Issue:
27
Journal Article
Peer reviewed
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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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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In the last two decades, the field of metal-organic frameworks (MOFs) has exploded, and MOF nanoparticles in particular are being investigated with increasing interest for various applications, ...including gas storage and separation, water harvesting, catalysis, energy conversion and storage, sensing, diagnosis, therapy, and theranostics. To further pave their way into real-world applications, and to push the synthesis of MOF nanoparticles that are 'safe-and-sustainable-by-design', this tutorial review aims to shed light on the importance of a systematic toxicity assessment. After clarifying and working out the most important terms and aspects from the field of nanotoxicity, the current state-of-the-art of
in vitro
and
in vivo
toxicity studies of MOF nanoparticles is evaluated. Moreover, the key aspects affecting the toxicity of MOF nanoparticles such as their chemical composition, their physico-chemical properties, including their colloidal and chemical stability, are discussed. We highlight the need of more targeted synthesis of MOF nanoparticles that are 'safe-and-sustainable-by-design', and their tailored hazard assessment in the context of their potential applications in order to tap the full potential of this versatile material class in the future.
This tutorial review highlights the key aspects of nanotoxicity and the importance of its systematic assessment for metal-organic framework (MOF) nanoparticles to pave the way towards their potential applications in a safe and sustainable manner.
The hydrothermal synthesis of a zeolite with properties suitable for use in the assembly–disassembly–organization–reassembly (ADOR) process was designed, and a zeolite called SAZ-1 was successfully ...prepared. This zeolite was then used as a parent in the ADOR process, and two new daughter zeolites, IPC-15 and IPC-16, were prepared. The X-ray powder diffraction patterns of the new zeolites match well with those predicted using computational methods. The three materials form an isoreticular series with decreasing pores size from 14-ring to 12-ring to 10-ring.
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The class of highly porous materials called metal-organic frameworks offer many opportunities for applications across biology and medicine. Their wide range of chemical composition makes ...toxicologically acceptable formulation possible, and their high level of functionality enables possible applications as imaging agents and as delivery vehicles for therapeutic agents. The challenges in the area encompass not only the development of new solids but also improvements in the formulation and processing of the materials, including tailoring the morphology and surface chemistry of the frameworks to fit the proposed applications.
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Zeolites are a class of microporous materials with tremendous value for large scale industrial applications such as catalysis, ion exchange, or gas separation. In addition to naturally ocurring ...variants, zeolites are made synthetically using hydrothermal synthesis, requiring temperatures beyond 100 °C and long reaction times up to weeks. Furthermore, specific applications may require more sophisticated synthesis conditions, expensive reagents, or post-synthetic modifications. Some of these issues can be tackled by using the reemerged technique of mechanochemistry. In 2014, Majano
et al.
reviewed the space and outlined several possibilities for the usage of mechanical forces in zeolite chemistry. Since then the field has seen many more publications employing mechanochemical methodology to further and improve the synthesis and properties of zeolite materials. The usage ranges from the activation of raw materials, rendering the synthesis of the widely used catalysts much more economical in terms of duration, atom efficiency, and production of waste, to post-synthetic modification of the materials leading to improved properties for target aplications. We present a short review of the advances that have been reported recently, highlight promising work and important studies, and give a perspective of potential future endeavours.
Recent advances of mechanochemical methods in the field of zeolite science are reviewed and their future potential highlighted.
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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