Metal-organic frameworks (MOFs) have emerged as a new type of porous materials for diverse applications. Most open MOFs reported to date are microporous (pore sizes <2 nm), and only a small fraction of MOFs with ordered mesoscale domains (2-50 nm) is reported. This tutorial review covers recent advances in the field of mesoporous MOFs (mesoMOFs), including their design and synthesis, porosity activation and surface modification, and potential applications in storage and separation, catalysis, drug delivery and imaging. Their specificities are dependent on the pore shape, size, and chemical environments of the cages or channels. The relationship between the structures and functions is discussed. The future outlook for the field is discussed in the context of current challenges in applications of mesoporous materials.
Owing to the potential applications in technological areas such as gas storage, catalysis, separation, sensing and nonlinear optics, tremendous efforts have been devoted to the development of porous metal-organic frameworks (MOFs) over the past ten years. Homochiral porous MOFs are particularly attractive candidates as heterogeneous asymmetric catalysts and enantioselective adsorbents and separators for production of optically active organic compounds due to the lack of homochiral inorganic porous materials such as zeolites. In this review, we summarize the recent research progress in homochiral MOF materials, including their synthetic strategy, distinctive structural features and latest advances in asymmetric heterogeneous catalysis and enantioselective separation.
The self-assembly of enantiopure pyridyl-functionalized metallosalan units affords a homochiral helicate cage, [Zn(8)L(4)Cl(8)], in which the optical rotation of each ligand is increased by a factor of 10 upon coordination. The octanuclear cage featuring a chiral amphiphilic cavity exhibits enantioselective luminescence enhancement by amino acids in solution. The cage exists in two different crystalline polymorphic forms that possess porous structures built of helicate cages interconnected by 1D channels or pentahedral cages and have the ability to separate small racemic molecules by adsorption but with different enantioselectivities.
The discovery of new gigantic molecules formed by self‐assembly and crystal growth is challenging as it combines two contingent events; first is the formation of a new molecule, and second its crystallization. Herein, we construct a workflow that can be followed manually or by a robot to probe the envelope of both events and employ it for a new polyoxometalate cluster, Na6[Mo120Ce6O366H12(H2O)78]⋅200 H2O (1) which has a trigonal‐ring type architecture (yield 4.3 % based on Mo). Its synthesis and crystallization was probed using an active machine‐learning algorithm developed by us to explore the crystallization space, the algorithm results were compared with those obtained by human experimenters. The algorithm‐based search is able to cover ca. 9 times more crystallization space than a random search and ca. 6 times more than humans and increases the crystallization prediction accuracy to 82.4±0.7 % over 77.1±0.9 % from human experimenters.
The synthesis of chiral polyoxometalates (POMs) is a challenge because of the difficulty to induce the formation of intrinsically chiral metal-oxo frameworks. Herein we report the stereoselective synthesis of a series of gigantic chiral Mo Blue (MB) POM clusters 1–5 that are formed by exploiting the synergy between coordinating lanthanides ions as symmetry breakers to produce MBs with chiral frameworks decorated with amino acids ligands; these promote the selective formation of enantiopure MBs. All the compounds share the same framework archetype, based on {Mo124Ce4}, which forms an intrinsically chiral Δ or Λ configurations, controlled by the configurations of functionalized chiral amino acids. The chirality and stability of 1–5 in solution are confirmed by circular dichroism, 1H NMR, and electrospray ion mobility–mass spectrometry studies. In addition, the framework of the {Mo124Ce4} MB not only behaves as a host able to trap a chiral {Mo8} cluster that is not accessible by traditional synthesis but also promotes the transformation of tryptophan to kynurenine in situ. This work demonstrates the potential and applicability of our synthetic strategy to produce gigantic chiral POM clusters capable of host–guest chemistry and selective synthetic transformations.
Inspired by the high efficiency and specificity of enzymes in living systems, the development of artificial catalysts intrinsic to the key features of enzyme has emerged as an active field. Recent advances in supramolecular chemistry have shown that supramolecular coordination cages, built from non-covalent coordination bonds, offer a diverse platform for enzyme mimics. Their inherent confined cavity, analogous to the binding pocket of an enzyme, and the facile tunability of building blocks are essential for substrate recognition, transition-state stabilization, and product release. In particular, the combination of chirality with supramolecular coordination cages will undoubtedly create an asymmetric microenvironment for promoting enantioselective transformation, thus providing not only a way to make synthetically useful asymmetric catalysts, but also a model to gain a better understanding for the fundamental principles of enzymatic catalysis in a chiral environment. The focus here is on recent progress of supramolecular coordination cages for asymmetric catalysis, and based on how supramolecular coordination cages function as reaction vessels, three approaches have been demonstrated. The aim of this review is to offer researchers general guidance and insight into the rational design of sophisticated cage containers for asymmetric catalysis.
We describe the synthesis, structure, self-assembly, solution chemistry, and mass spectrometry of two new gigantic decameric molybdenum blue wheels, {Mo200Ce12} (1) and {Mo100Ce6} (2), by building block rearrangement of the tetradecameric {Mo154} framework archetype and control of the architecture's curvature in solution from the addition of Ce(III). The assembly of 1 and 2 could be directed accordingly by adjusting the ionic strength and acidity of the reaction mixture. Alternatively, the dimeric cluster {Mo200Ce12} could be transformed directly to the monomeric species {Mo100Ce6} upon addition of a potassium salt. ESI-ion mobility mass spectra were successfully obtained for both {Mo200Ce12} and {Mo100Ce6}, which is the first report in molybdenum blue chemistry thereby confirming that the gigantic clusters are stable in solution and that ion mobility measurements can be used to characterize nanoscale inorganic molecules.
Stroke is the world's leading cause of disability with limited brain repair treatments which effectively improve long-term neurological deficits. The neuroinflammatory responses persist into the late repair phase of stroke and participate in all brain repair elements, including neurogenesis, angiogenesis, synaptogenesis, remyelination and axonal sprouting, shedding new light on post-stroke brain recovery. Resident brain glial cells, such as astrocytes not only contribute to neuroinflammation after stroke, but also secrete a wide range of trophic factors that can promote post-stroke brain repair. Alternatively, activated microglia, monocytes, and neutrophils in the innate immune system, traditionally considered as major damaging factors after stroke, have been suggested to be extensively involved in brain repair after stroke. The adaptive immune system may also have its bright side during the late regenerative phase, affecting the immune suppressive regulatory T cells and B cells. This review summarizes the recent findings in the evolving role of neuroinflammation in multiple post-stroke brain repair mechanisms and poses unanswered questions that may generate new directions for future research and give rise to novel therapeutic targets to improve stroke recovery.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
334 Leonard St
Brooklyn, NY 11211
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.