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# Reticular Chemistry

(Disclaimer, I know very little about chemistry)

Hi folks,

I came across the field of work known as reticular chemistry recently. Reticular chemistry is essentially the study of the systematic construction of three dimensional lattices of ... "stuff". To indicate why this is potentially so important, for instance in the early 1990s polymer chemistry (the construction of a chain of "things"), was already quite well advanced, but there was very little known about systematic and controlled creation of 2d or 3d structures.

The discovery that this sort of thing might be possible seems to be due to one or two others, but the bulk of the work in terms of fleshing out the promise of same seems to have been done by this fellow and his collaborators, whose group has made a systematic series of strides in it since the mid 90s: http://yaghi.berkeley.edu/

I originally came across this work in an announcement of 'extraction of water from desert air' that was mentioned breathlessly in a recent edition of New Scientist (I think?), and was interested in the science behind it: https://news.berkeley.edu/2019/08/27/water-harvester-makes-it-easy-to-quench-your-thirst-in-the-desert/ .

Following up, I came across this video, wherein it was indicated by Omar Yaghi that this sort of thing could be used not only for water extraction, but for carbon dioxide sequestration as well as generation of things like methanol: . He also briefly indicated that more complex things could be done by building on more recent ideas from his group.

Omar Yaghi has also written a book on this sort of form of modern precursor to practical nanotechnology: https://www.amazon.com.au/Introduction-Reticular-Chemistry-Metal-organic-Frameworks/dp/3527345027/ref=sr_1_1?keywords=reticular+chemistry&qid=1565850793&s=books&sr=1-1 , but it is a bit expensive!

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edited December 2019

Chris Goddard said:

"The discovery that this sort of thing might be possible seems to be due to one or two others, but the bulk of the work in terms of fleshing out the promise of same seems to have been done by this fellow and his collaborators, whose group has made a systematic series of strides in it since the mid 90s: http://yaghi.berkeley.edu/"

If you are asking whether anyone able to comment on this forum can contribute, I can add my experiences in doing molecular building block work on lattices. One of the aspects that we were pioneers at in the 1980's involved monitoring the layer-by-layer epitaxial growth of semiconductor crystals. I was in the lab the day that our research group decided to watch the electron signal bouncing off a growing layer and trying to confirm what other researchers had reported as either an experimental artifact or a real measure of the atom deposition rate. In short, the signal would register as each layer of atoms would deposit.

It turned out to be real and I spent the next several years doing experiments and theory specializing in how adatoms would preferentially attach to what are physically represented as atomic-height step edges.

Just so happens that I spotted a physical analogy to this from a winter landscape the other day. In the photo below, note the footprints across the snow and how oak leaves blown by the wind deposit preferentially in the depressions.

Those depressions are the equivalent of low-energy lattice binding sites where the diffusing adatoms will preferentially attach and complete a layer.

The connection perhaps to this reticular chemistry work (which is a new term to me) is the importance of how step edges and bonding sites interact with what are referred to as surfactants which essentially act like catalysts in assisting the bonding and rearrangement of the surface layer. Just by introducing dopant-level concentrations of specific impurities, one can create new lattice symmetries.

This is one of my original schematics that I retrieved which shows how an arsenic adatom (open circle) preferentially attached to a silicon step edge (black circle) was able to transform a single-step layer into a combined single and triple-step symmetry (cross-sectional side view).

We inferred this from diffraction patterns and it was confirmed via STM images by Bringans at Xerox PARC a few years later (top view)

A more recent review article in Nature from 2011 describes how this work has since matured : "Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions" https://www.nature.com/articles/ncomms1470

Reticular structures are less dense in volume than these, which I believe increases the effective surface area where all the catalytic interactions can occur. That I think is the key because dense crystals just won't have the potential surface area that a porous lattice structure allows. Given that, most of the decisions are made by the chemical interactions and all one has under experimental disposal is control over space and time.

I think time is the next frontier as some researchers are trying to control the time spent in catalytic-space (where and when the interactions take place) and relaxation out of that space so any reaction can be reset. This is a dynamic switching between two different energy minima. Paul Dauenhauer recently did a seminar describing his theoretical model -- so far it hasn't been shown in any experiment

paper

When I was involved in this kind of work, it was essentially the start of the nanotechnology revolution and all the progress that came after that. It was apparently inspired by Feynman who gave a talk called "There's Plenty of Room at the Bottom" and gained experimental support by the pioneering work of Cho & Arthur at Bell Labs.

It was in fact John Arthur who we communicated with early on, as he reported on seeing the mysterious electron signals ... it's hazy to me now but he came to our lab and helped us understand what we were measuring. Amazing what is possible but so much luck involved in trying all the possible material interactions.

Comment Source:Chris Goddard said: > "The discovery that this sort of thing might be possible seems to be due to one or two others, but the bulk of the work in terms of fleshing out the promise of same seems to have been done by this fellow and his collaborators, whose group has made a systematic series of strides in it since the mid 90s: http://yaghi.berkeley.edu/" If you are asking whether anyone able to comment on this forum can contribute, I can add my experiences in doing molecular building block work on lattices. One of the aspects that we were pioneers at in the 1980's involved monitoring the layer-by-layer epitaxial growth of semiconductor crystals. I was in the lab the day that our research group decided to watch the electron signal bouncing off a growing layer and trying to confirm what other researchers had reported as either an experimental artifact or a real measure of the atom deposition rate. In short, the signal would register as each layer of atoms would deposit. It turned out to be real and I spent the next several years doing experiments and theory specializing in how adatoms would preferentially attach to what are physically represented as atomic-height step edges. Just so happens that I spotted a physical analogy to this from a winter landscape the other day. In the photo below, note the footprints across the snow and how oak leaves blown by the wind deposit preferentially in the depressions. ![](https://imagizer.imageshack.com/img922/2183/H81ypl.jpg) Those depressions are the equivalent of low-energy lattice binding sites where the diffusing adatoms will preferentially attach and complete a layer. The connection perhaps to this reticular chemistry work (which is a new term to me) is the importance of how step edges and bonding sites interact with what are referred to as *surfactants* which essentially act like catalysts in assisting the bonding and rearrangement of the surface layer. Just by introducing dopant-level concentrations of specific impurities, one can create new lattice symmetries. This is one of my original schematics that I retrieved which shows how an *arsenic* adatom (open circle) preferentially attached to a *silicon* step edge (black circle) was able to transform a single-step layer into a combined single and triple-step symmetry (cross-sectional side view). ![](https://imagizer.imageshack.com/img923/6171/lIQ9cV.gif) We inferred this from diffraction patterns and it was confirmed via STM images by Bringans at Xerox PARC a few years later (top view) ![](https://imagizer.imageshack.com/img924/6361/zLsro5.gif) A more recent review article in Nature from 2011 describes how this work has since matured : "Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions" https://www.nature.com/articles/ncomms1470 Reticular structures are less dense in volume than these, which I believe increases the effective surface area where all the catalytic interactions can occur. That I think is the key because dense crystals just won't have the potential surface area that a porous lattice structure allows. Given that, most of the decisions are made by the chemical interactions and all one has under experimental disposal is control over space and time. I think time is the next frontier as some researchers are trying to control the time spent in catalytic-space (where and when the interactions take place) and relaxation out of that space so any reaction can be reset. This is a dynamic switching between two different energy minima. Paul Dauenhauer recently did a seminar describing his theoretical model -- so far it hasn't been shown in any experiment https://youtu.be/f11lQmFewwk [paper](https://chemrxiv.org/articles/Catalytic_Resonance_Theory_Parallel_Reaction_Pathway_Control/10271090) When I was involved in this kind of work, it was essentially the start of the nanotechnology revolution and all the progress that came after that. It was apparently inspired by Feynman who gave a talk called ["There's Plenty of Room at the Bottom"](http://calteches.library.caltech.edu/1976/1/1960Bottom.pdf) and gained experimental support by the pioneering work of Cho & Arthur at Bell Labs. ![](https://imagizer.imageshack.com/img922/7768/mExUGh.gif) It was in fact John Arthur who we communicated with early on, as he reported on seeing the mysterious electron signals ... it's hazy to me now but he came to our lab and helped us understand what we were measuring. Amazing what is possible but so much luck involved in trying all the possible material interactions. 
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2.

Thanks for sharing!

[My group was involved in] monitoring the layer-by-layer epitaxial growth of semiconductor crystals [...]

That sounds intriguing - the 1980s would have been quite an amazing time to have been working in that industry, when personal computers were just - or yet - to become a common consumer item, and the internet-to-be was still just ARPANET.

If you are asking whether anyone able to comment on this forum can contribute [...]

My main motivation was just to share information, as Reticular Chemistry looks to me (as an interested layperson) like a fascinating and growing area. Also, even though this area is of course far broader, there also appear to be a number of promising applications of this sort of thing to mitigating climate change, such as carbon capture and sequestration, which is potentially highly important in terms of strategy.

Comment Source:Thanks for sharing! >[My group was involved in] monitoring the layer-by-layer epitaxial growth of semiconductor crystals [...] That sounds intriguing - the 1980s would have been quite an amazing time to have been working in that industry, when personal computers were just - or yet - to become a common consumer item, and the internet-to-be was still just ARPANET. >If you are asking whether anyone able to comment on this forum can contribute [...] My main motivation was just to share information, as Reticular Chemistry looks to me (as an interested layperson) like a fascinating and growing area. Also, even though this area is of course far broader, there also appear to be a number of promising applications of this sort of thing to mitigating climate change, such as carbon capture and sequestration, which is potentially highly important in terms of strategy.
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3.

"That sounds intriguing - the 1980s would have been quite an amazing time to have been working in that industry, when personal computers were just - or yet - to become a common consumer item, and the internet-to-be was still just ARPANET."

Interesting that as I was finishing up, the internet was gearing up and the PC guys downstairs were developing software such as POPmail and the Gopher internet protocol.

This was at Shepherd labs on the U Minnesota campus. We were on the 4th floor and the microcomputer center was on the 1st floor.

"The center was in Shepherd Labs, a hulking cement building built like a tank in 1968 on the U’s Minneapolis campus, with concrete floors and no windows. Early on, it was used for NASA materials research. “There were pipes with strange fluids running through them,” Lindner recalls."

As it turns out the Gopher protocol -- which was about the only way to surf the internet initially -- lost out to WWW because the UMN decided to impose licensing fees on the software

"Eventually, though, the U did want some money — for itself. At GopherCon ’93, Yen announced that for-profit Gopher users would need to pay the U a licensing fee: hundreds or thousands of dollars, depending on the size and nature of their business. Many users felt betrayed. In the open-source computing spirit of the day, they had contributed code to Gopher, helping the team keep up with the times. Now they were being asked to pony up."

That was the end of Gopher. The saga was also recounted by Tim Berners-Lee here in this TED Radio Hour interview https://www.npr.org/transcripts/449180060

RAZ: The University wanted to charge people to use its system to navigate the Internet. And by charging money, the University had signaled that Gopher would be proprietary, a completely closed system. And this was fundamentally different from Tim's idea for the World Wide Web.

BERNERS-LEE: The crucial thing about the World Wide Web actually is the URLs. So for the thing to work, anybody anywhere who ran a computer that had some information which should be available to other people should make up one of these URLs for each document. That is a massive ask. You can't ask that and also ask other things. You can't say, you must use my particular type of computer. You can't say, you must use my particular browser. You can't say, and you must pay me 0.001 cents per click when everybody clicks on it.

RAZ: Which is why the moment the University of Minnesota announced it would charge money for Gopher...

BERNERS-LEE: At that point, the Gopher traffic on the Internet dropped off.

RAZ: Wow.

Comment Source:> "That sounds intriguing - the 1980s would have been quite an amazing time to have been working in that industry, when personal computers were just - or yet - to become a common consumer item, and the internet-to-be was still just ARPANET." Interesting that as I was finishing up, the internet was gearing up and the PC guys downstairs were developing software such as POPmail and the Gopher internet protocol. https://www.minnpost.com/business/2016/08/rise-and-fall-gopher-protocol/ This was at Shepherd labs on the U Minnesota campus. We were on the 4th floor and the microcomputer center was on the 1st floor. > ![](https://www.minnpost.com/wp-content/uploads/sites/default/files/attachments/08ShepherdLabs960.jpg) > "The center was in Shepherd Labs, a hulking cement building built like a tank in 1968 on the U’s Minneapolis campus, with concrete floors and no windows. Early on, it was used for NASA materials research. “There were pipes with strange fluids running through them,” Lindner recalls." As it turns out the Gopher protocol -- which was about the only way to surf the internet initially -- lost out to WWW because the UMN decided to impose licensing fees on the software > "Eventually, though, the U did want some money — for itself. At GopherCon ’93, Yen announced that for-profit Gopher users would need to pay the U a licensing fee: hundreds or thousands of dollars, depending on the size and nature of their business. Many users felt betrayed. In the open-source computing spirit of the day, they had contributed code to Gopher, helping the team keep up with the times. Now they were being asked to pony up." That was the end of Gopher. The saga was also recounted by Tim Berners-Lee here in this TED Radio Hour interview https://www.npr.org/transcripts/449180060 > RAZ: *The University wanted to charge people to use its system to navigate the Internet. And by charging money, the University had signaled that Gopher would be proprietary, a completely closed system. And this was fundamentally different from Tim's idea for the World Wide Web.* > BERNERS-LEE: *The crucial thing about the World Wide Web actually is the URLs. So for the thing to work, anybody anywhere who ran a computer that had some information which should be available to other people should make up one of these URLs for each document. That is a massive ask. You can't ask that and also ask other things. You can't say, you must use my particular type of computer. You can't say, you must use my particular browser. You can't say, and you must pay me 0.001 cents per click when everybody clicks on it.* > RAZ: *Which is why the moment the University of Minnesota announced it would charge money for Gopher...* > BERNERS-LEE: *At that point, the Gopher traffic on the Internet dropped off.* > RAZ: *Wow.*