I know that ZIFs (Zeolitic imidazolate frameworks) are a class of MOFs (Metal Organic Frameworks) but what is so special about ZIFs that encouraged scientists to open a class for these structures?
Dear Abdolazim Hasseli you can find the answer to your question in the Wikipedia entry on the topic "Zeolitic imidazolate framework". It has a paragraph entitled "ZIFS vs MOFs". In the end, ZIFs are a subgroup of MOFs.
In this paragraph it is stated that "While ZIFs are a subset of the MOF hybrids that combine organic and metal frameworks to create hybrid microporous and crystalline structures, they are much more restricted in their structure. Similar to MOFs, most ZIF properties are largely dependent on the properties of the metal clusters, ligands, and synthesis conditions in which they were created. Perhaps the most important difference is the ZIFs' hydrophobic properties and water stability."
https://en.wikipedia.org/wiki/Zeolitic_imidazolate_framework
Frank T. Edelmann
Thank you. I have already seen the Wikipedia but you see, there are many MOFs with their own different properties but they don't have their own classes like ZIFs.
I am looking for some important feature that ZIFs have (if there is really one!) urging scientists to put ZIFs in a special class.
Dear Abdolazim Hasseli please find attached a useful review article entitled "Zeolitic imidazolate framework materials: recent progress in synthesis and applications". In this article it s stated that "Their intrinsic porous characteristics, abundant functionalities as well as exceptional thermal and chemical stabilities have led to a wide range of potential applications for various ZIF materials." Moreover, "Their attractive and potential applications in gas separation, catalysis, sensing and electronic devices, and drug delivery in the past years are discussed and reviewed". I hope this will provide you with some answers to your question.
A large portion of changing linkers included adding functional groups with various polarities and symmetries to the imidazolate ligands to alter the ZIFs carbon dioxide adsorption ability without changing the transitional-metal cations. Compare this to MOFs, which have a much larger degree of variety in the types of their building units.
Because ZIFs tend to resemble the crystalline framework of zeolites, their thermal and chemical stability are higher than those of other MOFs, allowing them to work at a wider range in temperatures, making them suitable to chemical processes.
Perhaps the most important difference is the ZIFs' hydrophobic properties and water stability. A main issue with zeolites and MOFs, to a certain extent, was their adsorption of water along with CO2. Water vapor is often found in carbon-rich exhaust gases, and MOFs would absorb the water, lowering the amount of CO2 required to reach saturation. MOFs are also less stable in moist and oxygen-rich environments due to metal-oxygen bonds performing hydrolysis. ZIFs, however, have nearly identical performance in dry vs humid conditions, showing much higher CO2 selectivity over water, allowing the adsorbent to store more carbon before saturation is reached
Sagar Varangane Thank you so much, please! can you help me by pasting the title of the paper to support your above answer
I think the best search for this query may be via googling, e.g., file:///C:/Users/malib/Downloads/crystals-11-01422.pdf
and too many other items can be find via googling it.
Zeolitic imidazolate frameworks (ZIFs) and metal-organic frameworks (MOFs) are both classes of porous materials made up of metal ions or clusters connected by organic linkers. The major difference between the two is the composition of the metal ions and the organic linkers. ZIFs are composed of metal ions from the group of zinc and imidazolate linkers, while MOFs can be composed of a wide range of metal ions, such as zinc, cobalt, and aluminum, and various types of organic linkers.
ZIFs were discovered as a distinct class of MOFs due to their unique properties, such as high thermal stability, high gas adsorption capacity, and high selectivity for specific gases. They are also more robust than other MOFs, which makes them more suitable for industrial applications. Furthermore, ZIFs exhibit less water uptake and have a more uniform pore size distribution compared to other MOFs.
It is possible to identify the difference between ZIFs and MOFs by using X-ray diffraction (XRD) and infrared spectroscopy (IR). XRD can help to identify the crystal structure of the material, while IR can help to identify the organic linkers and metal ions present in the material. Additionally, NMR spectroscopy can be used to identify the metal ions.
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