Researchers at KAUST have devised a novel approach to metal-organic framework (MOF) design, drawing inspiration from a centuries-old architectural method. This innovative technique holds promise for customizing nanoscale windows within MOFs, potentially revolutionizing applications in gas separation and the medical field.
The genesis of this breakthrough lies in an ancient technique employed for crafting arched stone windows. This time-honored approach has inspired a fresh methodology for shaping nanoscale windows in porous functional materials known as metal-organic frameworks (MOFs).
The process leverages a molecular adaptation of an architectural arch-forming concept referred to as a “centering formwork” template. This template precisely guides the creation of MOFs with predetermined shapes and sizes for their pore windows. The MOFs produced through this method encompass a spectrum, ranging from materials with narrow windows suitable for gas separation to larger-windowed structures with remarkable oxygen-adsorption capabilities, holding promise for medical applications.
Aleksandr Sapianik, a postdoctoral researcher in Mohamed Eddaoudi’s team, emphasizes the challenge of achieving precise control over structure formation in new designs. In the realm of reticular chemistry, which involves assembling molecular building blocks into porous crystalline materials like MOFs, the centering formwork concept offers the sought-after precision.
The research commenced with a zeolite-like MOF (ZMOF), typically characterized by pentagonal windows framed by building blocks called supertetrahedra (ST). Sapianik explains that their objective was to manipulate the arrangement of ST units, departing from the familiar topology.
To achieve this, the team devised centering structure-directing agents (cSDAs) designed for controlling the alignment of ST units, ultimately yielding ZMOF windows of new shapes and sizes. One set of cSDAs, engineered to reduce the angle between adjoining ST units, resulted in smaller windows, while another set, designed to widen this angle, produced larger windows.
Marina Barsukova, another postdoctoral researcher in Eddaoudi’s team, underscores the significance of MOF pore size and volume in their applications. The team’s creation, Fe-sod-ZMOF-320, boasting large windows, exhibited the highest known oxygen adsorption capacity among MOFs. This property holds importance in the medical and aerospace sectors, potentially enhancing oxygen storage and transport. Additionally, these ZMOFs demonstrated favorable characteristics for storing methane and hydrogen, both of which have potential as fuels. Meanwhile, other ZMOFs in the family, featuring narrow windows, displayed potential for the separation of molecular mixtures.
Vincent Guillerm, a research scientist in Eddaoudi’s group, highlights the multiple advantages offered by the cSDA concept in enhancing MOF performance. This approach subdivides large windows into smaller ones, which initial findings suggest could be valuable for chemical separations. It also augments the internal pore surface, improving gas storage, and fortifies the MOF framework, enhancing material stability.
In the words of Mohamed Eddaoudi, the architect behind this innovative approach, “The centering approach we have developed is another powerful strategy in the repertoire of reticular chemistry, offering great potential for made-to-order MOFs for applications in energy security and environmental sustainability.”
Reference: “Face-directed assembly of tailored isoreticular MOFs using centring structure-directing agents” by Marina Barsukova, Aleksandr Sapianik, Vincent Guillerm, Aleksander Shkurenko, Aslam C. Shaikh, Prakash Parvatkar, Prashant M. Bhatt, Mickaele Bonneau, Abdulhadi Alhaji, Osama Shekhah, Salvador R. G. Balestra, Rocio Semino, Guillaume Maurin and Mohamed Eddaoudi, 2 October 2023, Nature Synthesis. DOI: 10.1038/s44160-023-00401-8
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Frequently Asked Questions (FAQs) about MOF Nanoscale Windows
What is the significance of the ancient architectural technique mentioned in the text?
The ancient architectural technique, used for constructing arched stone windows, has inspired a novel method for shaping nanoscale windows in metal-organic frameworks (MOFs). It provides a precise template for controlling the formation of MOFs with predetermined shapes and sizes, opening up possibilities for various applications.
What are metal-organic frameworks (MOFs)?
Metal-organic frameworks (MOFs) are porous materials composed of metal ions or clusters connected by organic ligands. They have a highly ordered structure with regularly spaced pores, making them suitable for a wide range of applications, including gas separation, storage, and catalysis.
How does the centering formwork concept apply to MOF design?
The centering formwork concept, inspired by architectural techniques, is adapted to the molecular level to guide the formation of MOFs with specific pore window shapes and sizes. This concept allows precise control over the structure of MOFs, enabling tailored designs for various applications.
What are some potential applications of MOFs with tailored nanoscale windows?
MOFs with tailored nanoscale windows have diverse applications. They can be used for gas separation, medical applications due to their excellent oxygen adsorption capacity, storage of gases like methane and hydrogen, and chemical separations. They also hold promise in sectors like energy security and environmental sustainability.
How do centering structure-directing agents (cSDAs) influence MOF window size?
Centering structure-directing agents (cSDAs) are designed to control the alignment of supertetrahedra (ST) units in MOFs. Some cSDAs reduce the angle between ST units, resulting in smaller windows, while others widen the angle, producing larger windows. This manipulation allows for the customization of MOF window sizes.
What advantages do cSDAs offer in enhancing MOF performance?
cSDAs offer multiple benefits for MOF performance. They partition large windows into smaller ones, potentially aiding chemical separations. Additionally, they increase the internal pore surface area, improving gas storage, and strengthen the MOF framework, enhancing material stability.
Why is the oxygen adsorption capacity of MOFs important?
High oxygen adsorption capacity in MOFs is significant, especially in medical and aerospace industries, as it can increase oxygen storage efficiency and enable the development of smaller cylinders for easier transport. This property can have critical implications for oxygen supply and storage in various applications.
How can tailored MOFs contribute to environmental sustainability?
Tailored MOFs, created using precise design techniques like the centering formwork concept, can be customized for specific applications in energy security and environmental sustainability. They can potentially enhance the efficiency of processes related to gas storage, separation, and catalysis, thus contributing to sustainable practices.
3 comments
MOFs, what r they? Need explain more plz.
Woah, cool stuff bout ancient arch & MOFs. Need 2 dig more.
Oxygen adsorption, critical 4 many, very interestin!