5 ms·

Sounds like an artificial zeolite. https://en.m.wikipedia.org/wiki/Zeolite https://en.m.wikipedia.org/wiki/Zeolite

jkqwzsoo 6y ago
It's a MOF (metal-organic framework). Basically a metal ion or metal cluster linked (nodes) together with organic molecules (linkers or struts). Some of them are even stable in aqueous solutions (like UiO-66). Typically, the linker-metal bond is via a carboxylic acid, and the metal node is something like... Zr, Ce, Hf, Ti, Fe, Cu, Co, Mn, Al, etc. etc. They've been the gold standard for gas sorption and hydrogen-car promises for at least 17 years. The actual term MOF was apparently first used in 95[0]. While there are a lot of things that can affect the synthesis (metal concentration, metal precursor, metal:linker ratio, solvent choice, presence or absence of water, modulators, synthesis temperature), the synthesis of MOFs is usually about tuning what goes into the pot. Then its shake-n-bake and MOF comes out a day later (solvothermal method). So, it's an easy synthesis if you know what to load into your reaction vessel. While continuous synthesis is a harder, I think it's a lot more immediately scalable than porous aromatic frameworks (PAFs). This work is combining some of the advantages of MOF (high specific surface area, regular structure, easy synthesis) with some of the advantages of PAFs (even higher specific surface area). You can see the linker they use on PDF page 5 of the supplementary online material[1]. The hexadentate structure is large and is reminiscent of PAFs like PAF-1[2], which are known for having very high specific surface area. This is because the aryl group has a high specific surface area. By making the linker very large and bulky, they're reducing the contribution of the metal nodes to the specific surface area by having a greater volume fraction of (lightweight) aromatic linker. However, while PAFs usually (always? I'm not a PAF person) have an SP3 carbon center (and thus a tetrahedral symmetry), this linker is kind of shaped like a paddle wheel with three paddles (or a trigonal prism, if you access the Science article and see Fig. 1). Thus, while PAFs are typically in a diamond-like net (dia [3]), this MOF is in a acs net[4]. [0] https://www.nature.com/milestones/milecrystal/full/milecrystal22.html https://www.nature.com/milestones/milecrystal/full/milecryst... [1] https://science.sciencemag.org/content/sci/suppl/2020/04/15/368.6488.297.DC1/aaz8881_Chen_SM.pdf https://science.sciencemag.org/content/sci/suppl/2020/04/15/... [2] dx.doi.org/10.1039/C4MH00163J, http://www.rsc.org/suppdata/mh/c4/c4mh00163j/c4mh00163j1.pdf http://www.rsc.org/suppdata/mh/c4/c4mh00163j/c4mh00163j1.pdf [3] http://rcsr.anu.edu.au/nets/dia http://rcsr.anu.edu.au/nets/dia [4] http://rcsr.anu.edu.au/nets/acs http://rcsr.anu.edu.au/nets/acs Fun fact: Most MOFs are named after the research institution that found them first. This one is named NU-1500 for Northwestern University, where Farha is. The UiO-series are named after Universitet i Oslo, the HKUST series is named for Hong Kong University of Science and Technology, the MIL series is named for Material Insitute Lavoisier.
- lowdose 6y ago
  Thank you for your explanation & links, much appreciated.

It's a MOF (metal-organic framework). Basically a metal ion or metal cluster linked (nodes) together with organic molecules (linkers or struts). Some of them are even stable in aqueous solutions (like UiO-66). Typically, the linker-metal bond is via a carboxylic acid, and the metal node is something like... Zr, Ce, Hf, Ti, Fe, Cu, Co, Mn, Al, etc. etc. They've been the gold standard for gas sorption and hydrogen-car promises for at least 17 years. The actual term MOF was apparently first used in 95[0]. While there are a lot of things that can affect the synthesis (metal concentration, metal precursor, metal:linker ratio, solvent choice, presence or absence of water, modulators, synthesis temperature), the synthesis of MOFs is usually about tuning what goes into the pot. Then its shake-n-bake and MOF comes out a day later (solvothermal method). So, it's an easy synthesis if you know what to load into your reaction vessel. While continuous synthesis is a harder, I think it's a lot more immediately scalable than porous aromatic frameworks (PAFs). This work is combining some of the advantages of MOF (high specific surface area, regular structure, easy synthesis) with some of the advantages of PAFs (even higher specific surface area). You can see the linker they use on PDF page 5 of the supplementary online material[1]. The hexadentate structure is large and is reminiscent of PAFs like PAF-1[2], which are known for having very high specific surface area. This is because the aryl group has a high specific surface area. By making the linker very large and bulky, they're reducing the contribution of the metal nodes to the specific surface area by having a greater volume fraction of (lightweight) aromatic linker. However, while PAFs usually (always? I'm not a PAF person) have an SP3 carbon center (and thus a tetrahedral symmetry), this linker is kind of shaped like a paddle wheel with three paddles (or a trigonal prism, if you access the Science article and see Fig. 1). Thus, while PAFs are typically in a diamond-like net (dia [3]), this MOF is in a acs net[4]. [0] https://www.nature.com/milestones/milecrystal/full/milecrystal22.html https://www.nature.com/milestones/milecrystal/full/milecryst... [1] https://science.sciencemag.org/content/sci/suppl/2020/04/15/368.6488.297.DC1/aaz8881_Chen_SM.pdf https://science.sciencemag.org/content/sci/suppl/2020/04/15/... [2] dx.doi.org/10.1039/C4MH00163J, http://www.rsc.org/suppdata/mh/c4/c4mh00163j/c4mh00163j1.pdf http://www.rsc.org/suppdata/mh/c4/c4mh00163j/c4mh00163j1.pdf [3] http://rcsr.anu.edu.au/nets/dia http://rcsr.anu.edu.au/nets/dia [4] http://rcsr.anu.edu.au/nets/acs http://rcsr.anu.edu.au/nets/acs Fun fact: Most MOFs are named after the research institution that found them first. This one is named NU-1500 for Northwestern University, where Farha is. The UiO-series are named after Universitet i Oslo, the HKUST series is named for Hong Kong University of Science and Technology, the MIL series is named for Material Insitute Lavoisier.

lowdose 6y ago
Thank you for your explanation & links, much appreciated.