Popping and Locking: Balanced Rigidity and Porosity of Zeolitic Imidazolate Frameworks for High-Productivity Methane Purification.

Zeolitic imidazolate frameworks (ZIFs) hold great promise in carbon capture, owing to their structural designability and functional porosity. However, intrinsic linker dynamics limit their pressure-swing adsorption application to biogas upgrading and methane purification. Recently, a functionality-locking strategy has shown feasibility in suppressing such dynamics.

A Hydrogen-Bonded Organic Framework Equipped with a Molecular Nanovalve.

The concept of a molecular nanovalve is applied to a synthesized biocompatible hydrogen-bonded organic framework (HOF), termed RSS-140, to load, trap, and subsequently release an antioxidant on command. Specifically, we exploit the pore windows of RSS-140 (i.e.

Calcium l-Malate and d-Tartarate Frameworks as Adjuvants for the Sustainable Delivery of a Fungicide.

Agrichemical adjuvants that combine a highly selective, efficient, and active mode of operation are critically needed to realize a more sustainable approach to their usage. Herein, we report the synthesis and full characterization of two new metal-organic frameworks (MOFs), termed UPMOF-1 and UPMOF-2, that were constructed from eco-friendly Ca ions and naturally occurring, low-molecular weight plant acids, l-malic and d-tartaric acid, respectively. Upon structural elucidation of both MOFs, a widely used fungicide, hexaconazole (Hex), was loaded on the structures, reaching binding affinities of -5.

Engaging Early-Career Scientists in Global Policy-Making.

Pressing global challenges, such as climate change, the COVID-19 pandemic, or antibiotic resistance, require coordinated international responses guided by evidence-informed decisions. For this purpose, it is critical that scientists engage in providing insights during the decision-making process. However, the mechanisms for the engagement of scientists in policy-making are complex and vary internationally, which often poses significant challenges to their involvement.

ZIF-90 nanoparticles modified with a homing peptide for targeted delivery of cisplatin.

To improve the selective delivery of cisplatin (Cis) to cancer cells, we report and establish the significance of active, targeting drug delivery nanosystems for efficient treatment of lung cancer. Specifically, pH-responsive nano-sized zeolitic imidazolate framework (nZIF-90) was synthesized, post-synthetically modified with an Arg-Gly-Asp peptide motif (RGD@nZIF-90), a known cancer cell homing peptide, and loaded with a large amount of Cis (RGD@Cis⊂nZIF-90). RGD@Cis⊂nZIF-90 was shown to be highly stable under physiological conditions (pH = 7.

Environmentally adaptive MOF-based device enables continuous self-optimizing atmospheric water harvesting.

Harvesting water vapor from desert, arid environments by metal-organic framework (MOF) based devices to deliver clean liquid water is critically dependent on environment and climate conditions. However, reported devices have yet been developed to adapt in real-time to such conditions during their operation, which severely limits water production efficiency and unnecessarily increases power consumption. Herein, we report and detail a mode of water harvesting operation, termed 'adaptive water harvesting', from which a MOF-based device is proven capable of adapting the adsorption and desorption phases of its water harvesting cycle to weather fluctuations throughout a given day, week, and month such that its water production efficiency is continuously optimized.

Dissolution and Biological Assessment of Cancer-Targeting Nano-ZIF-8 in Zebrafish Embryos.

Cancer-targeting nanotherapeutics offer promising opportunities for selective delivery of cytotoxic chemotherapeutics to cancer cells. However, the understanding of dissolution behavior and safety profiles of such nanotherapeutics is scarce. In this study, we report the dissolution profile of a cancer-targeting nanotherapeutic, gemcitabine (GEM) encapsulated within RGD-functionalized zeolitic imidazolate framework-8 (GEM⊂RGD@nZIF-8), in dissolution media having pH = 6.

Surface peptide functionalization of zeolitic imidazolate framework-8 for autonomous homing and enhanced delivery of chemotherapeutic agent to lung tumor cells.

Chemotherapeutic agents used in treating certain cancer types operate in a non-selective manner tending to accumulate in normal, healthy tissue when high doses are used. To mitigate the toxicity effect resulting from this, there is an urgent need to develop active nano delivery systems capable of regulating optimal doses specifically to cancer cells without harming adjacent normal cells. Herein, we report a versatile nanoparticle - zeolitic imidazolate framework-8 (nZIF-8) - that is loaded with a chemotherapeutic agent (gemcitabine; GEM) and surface-functionalized with an autonomous homing system (Arg-Gly-Asp peptide ligand; RGD) via a straightforward, one-pot solvothermal reaction.

Novel Porous Organic Polymer for the Concurrent and Selective Removal of Hydrogen Sulfide and Carbon Dioxide from Natural Gas Streams.

Natural gas sweetening currently requires multistep, complex separation processes to remove the acid gas contaminants, carbon dioxide and hydrogen sulfide. In addition to being widely recognized as energy inefficient and cost-intensive, the effectiveness of this conventional process also suffers considerably because of limitations of the sorbent materials it employs. Herein, we report a new porous organic polymer, termed KFUPM-5, that is demonstrated to be effective in the concurrent separation of both hydrogen sulfide and carbon dioxide from a mixed gas stream at ambient conditions.

Unraveling the Structural Dynamics of an Enzyme Encapsulated within a Metal-Organic Framework.

Herein, we detail an atomic-level investigation of the cutinase enzyme encapsulated within a model metal-organic framework (MOF) platform using quantum mechanics calculations and molecular dynamics simulations. Cutinase, when encapsulated in an isoreticularly expanded MOF-74 (cutinase@IRMOF-74-VI), was proven to maintain its structural stability at temperatures that would otherwise denature the enzyme in its unprotected native state. Hydrogen bonding and salt bridge interactions, most notably involving arginine residues at the surface of the enzyme, were critical for stabilizing cutinase within the pore channels of IRMOF-74-VI.

An Ultrasensitive and Selective Metal-Organic Framework Chemosensor for Palladium Detection in Water.

A new europium-based metal-organic framework, termed KFUPM-3, was constructed using an allyloxy-functionalized linker. As a result of coordinative interactions between the allyloxy moieties and Pd, highly selective changes in both the absorption and emission spectra of KFUPM-3 were observed. Accordingly, KFUPM-3 was demonstrated to have an ultrasensitive Pd detection limit (44 ppb), regenerative properties without loss in performance, detection of palladium in different oxidation states and in the presence of other competitor metal ions, and fully functional sensing capabilities over a wide pH range.

Building a Global Culture of Science-The Vietnam Experience.

We detail the lessons learned, challenges, achievements, and outlook in building a chemistry research center in Vietnam. Through the principles of "global science", we provide specific insight into the process behind establishing an internationally-competitive research program-a model that is scalable and adaptable to countries beyond Vietnam. Furthermore, we highlight the prospects for success in advancing global science education, research capacity building, and mentorship.

Publisher Correction: The role of reticular chemistry in the design of CO reduction catalysts.

In the version of this Perspective originally published, the titles of the references were missing; the online versions have now been amended to include them.

The role of reticular chemistry in the design of CO reduction catalysts.

The problem with current state-of-the-art catalysts for CO photo- or electroreduction is rooted in the notion that no single system can independently control, and thus optimize, the interplay between activity, selectivity and efficiency. At its core, reticular chemistry is recognized for its ability to control, with atomic precision, the chemical and structural features (activity and selectivity) as well as the output optoelectronic properties (efficiency) of porous, crystalline materials. The molecular building blocks that are in a reticular chemist's toolbox are chosen in such a way that the structures are rationally designed, framework chemistry is performed to integrate catalytically active components, and the manner in which these building blocks are connected endows the material with the desired optoelectronic properties.

New Metal-Organic Frameworks for Chemical Fixation of CO.

A novel series of two zirconium- and one indium-based metal-organic frameworks (MOFs), namely, MOF-892, MOF-893, and MOF-894, constructed from the hexatopic linker, 1',2',3',4',5',6'-hexakis(4-carboxyphenyl)benzene, were synthesized and fully characterized. MOF-892 and MOF-893 are two new exemplars of materials with topologies previously unseen in the important family of zirconium MOFs. MOF-892, MOF-893, and MOF-894 exhibit efficient heterogeneous catalytic activity for the cycloaddition of CO, resulting in a cyclic organic carbonate formation with high conversion, selectivity, and yield under mild conditions (1 atm CO, 80 °C, and solvent-free).

Tuning the Interplay between Selectivity and Permeability of ZIF-7 Mixed Matrix Membranes.

Nanoparticles of zeolitic imidazolate framework-7 (nZIF-7) were blended with poly(ether imide) (PEI) to fabricate a new mixed-matrix membrane (nZIF-7/PEI). nZIF-7 was chosen in order to demonstrate the power of postsynthetic modification (PSM) by linker exchange of benzimidazolate to benzotriazolate for tuning the permeability and selectivity properties of a resulting membrane (PSM-nZIF-7/PEI). These two new membranes were subjected to constant volume, variable pressure gas permeation measurements (H, N, O, CH, CO, CH, and CH), in which unique gas separation behavior was observed when compared to the pure PEI membrane.

Mixed-Metal Zeolitic Imidazolate Frameworks and their Selective Capture of Wet Carbon Dioxide over Methane.

A presynthesized, square planar copper imidazole complex, [Cu(imidazole)4](NO3)2, was utilized as a precursor in the synthesis of a new series of zeolitic imidazolate frameworks, termed ZIF-202, -203, and -204. The structures of all three members were solved by single-crystal X-ray diffraction analysis, which revealed ZIF-203 and -204 having successfully integrated square planar units within the backbones of their respective frameworks. As a result of this unit, the structures of both ZIF-203 and -204 were found to adopt unprecedented three-dimensional nets, namely, ntn and thl, respectively.

A Titanium-Organic Framework as an Exemplar of Combining the Chemistry of Metal- and Covalent-Organic Frameworks.

A crystalline material with a two-dimensional structure, termed metal-organic framework-901 (MOF-901), was prepared using a strategy that combines the chemistry of MOFs and covalent-organic frameworks (COFs). This strategy involves in situ generation of an amine-functionalized titanium oxo cluster, Ti6O6(OCH3)6(AB)6 (AB = 4-aminobenzoate), which was linked with benzene-1,4-dialdehyde using imine condensation reactions, typical of COFs. The crystal structure of MOF-901 is composed of hexagonal porous layers that are likely stacked in staggered conformation (hxl topology).

Three-Dimensional Metal-Catecholate Frameworks and Their Ultrahigh Proton Conductivity.

A series of three-dimensional (3D) extended metal catecholates (M-CATs) was synthesized by combining the appropriate metal salt and the hexatopic catecholate linker, H6THO (THO(6-) = triphenylene-2,3,6,7,10,11-hexakis(olate)) to give Fe(THO)·Fe(SO4) (DMA)3, Fe-CAT-5, Ti(THO)·(DMA)2, Ti-CAT-5, and V(THO)·(DMA)2, V-CAT-5 (where DMA = dimethylammonium). Their structures are based on the srs topology and are either a 2-fold interpenetrated (Fe-CAT-5 and Ti-CAT-5) or noninterpenetrated (V-CAT-5) porous anionic framework. These examples are among the first catecholate-based 3D frameworks.

An azobenzene-containing metal-organic framework as an efficient heterogeneous catalyst for direct amidation of benzoic acids: synthesis of bioactive compounds.

An azobenzene-containing zirconium metal-organic framework was demonstrated to be an effective heterogeneous catalyst for the direct amidation of benzoic acids in tetrahydrofuran at 70 °C. This finding was applied to the synthesis of several important, representative bioactive compounds.

Synthesis and Selective CO2 Capture Properties of a Series of Hexatopic Linker-Based Metal-Organic Frameworks.

Four crystalline, porous metal-organic frameworks (MOFs), based on a new hexatopic linker, 1',2',3',4',5',6'-hexakis(4-carboxyphenyl)benzene (H6CPB), were synthesized and fully characterized. Interestingly, two members of this series exhibited new topologies, namely, htp and hhp, which were previously unseen in MOF chemistry. Gas adsorption measurements revealed that all members exhibited high CO2 selectivity over N2 and CH4.

Tailoring the Optical Absorption of Water-Stable Zr(IV)- and Hf(IV)-Based Metal-Organic Framework Photocatalysts.

New Zr(IV)- and Hf(IV)-based metal-organic framework photocatalysts, termed VNU-1 and VNU-2 (where VNU = Vietnam National University), were synthesized and their resulting structures fully characterized. By employing a highly π-conjugated linker, namely 1,4-bis(2-[4-carboxyphenyl]ethynyl)benzene, the optical absorption properties were effectively red-shifted into the visible light region. This strategy, coupled with the high water stability of the materials, led to enhanced MOF-driven photocatalytic degradation, under ultraviolet-visible light, of organic dye pollutants commonly found in wastewater.

The Development of Global Science.

How do we build research capacity throughout the world and capture the great human potential? To us, the answer is rather straightforward: the time-honored tradition of scientific mentoring must be practiced on a wider scale across borders. Herein, we detail the necessity for expanding mentorship to a global scale and provide several important principles to be considered when designing, planning, and implementing programs and centers of research around the world.

Introduction of functionality, selection of topology, and enhancement of gas adsorption in multivariate metal-organic framework-177.

Metal-organic framework-177 (MOF-177) is one of the most porous materials whose structure is composed of octahedral Zn4O(-COO)6 and triangular 1,3,5-benzenetribenzoate (BTB) units to make a three-dimensional extended network based on the qom topology. This topology violates a long-standing thesis where highly symmetric building units are expected to yield highly symmetric networks. In the case of octahedron and triangle combinations, MOFs based on pyrite (pyr) and rutile (rtl) nets were expected instead of qom.