5 ms·

The read cube link doesn't work for me. I kind of get the weirdness of the result and the usefulness of silanes. But nothing explains what you have to do with

The read cube link doesn't work for me. I kind of get the weirdness of the result and the usefulness of silanes. But nothing explains what you have to do with potassium tert-butoxide to get this to work. That may be why some comments remark on the irritation -- no specifics. If I could access the paper I probably still could not understand the process but maybe someone could translate it into lay speak. Also the potential for new chemistry seems extremely interesting but again the specifics are missing. I guess we are talking about the same old quantum mechanics, so what would be new -- some larger scale effect that no one every realized was implied by the physics? Or what?

jedharris 12y ago
The interviews are helpful but only deepen the mystery. They say that the reactions are so easy they can be carried out at room temperature in introductory college chemistry (albeit at Cal Tech). And potassium tert-butoxide is apparently cheap and common. So what exactly did this team discover? Apparently the basic recipe can be varied to cover a huge range of applications. What are the key new ideas common to all these recipes that make them work?
- subnaught 12y ago
  To answer the previous comment, there is no special preparation of the potassium t-butoxide necessary. The reaction itself is indeed quite simple to carry out. (In fact, this is one of the things that makes the research significant.) The achievement of the researchers was simply to find this reaction, which they did in part by paying attention to some early results that others may have not noticed or chosen to ignore. Right now, the "key new idea" is simply that this is possible. But because the reaction is so general (i.e. it works on a wide variety of substrates) and so unexpected, it's clear that some new unifying ideas are just around the corner.
  - jedharris 12y ago
    Not being a bench chemist I have no sense of what "the reaction" is, even looking at the paper. Could you describe it?
    - refurb 12y ago
      Heteroaromatic silanes (rings made mostly of carbon but also include a non-carbon atom like nitrogen) are useful synthetic intermediates (you can use them to make other molecules). In the past, you usually made them using precious metal catalysts (really expensive metals like rhodium; the reactions are easy to screw up). The metal atom basically inserts between the ring and a hydrogen (the outside of the rings are covered in hydrogens). You then added a silane source and it would displace the metal complex (through a pretty complex pathway) to get your desired product (the original ring with a silicon atom where a hydrogen used to be). This new method creates the exact same product. However, instead of using a precious metal catalyst, you can just add this really common base (potassium t-butoxide) and your silicon source and "poof!" the reaction is complete. No expensive reagents! What makes this so science-news worthy is that I don't think anyone would have guessed this would have worked. A good analogy would be a really complex math problem. Folks can solve it, but it's a lengthy and complex proof. Suddenly someone comes by and says "just take the cosine and divide by 9" and you realize that this super simple approach works better than anything else.
      - biot 12y ago
        Sounds a bit like how Feynman diagrams changed finding solutions to quantum problems from lengthy, complex math equations into simple doodles.
      - jedharris 12y ago
        Thanks! The description of the old complex way was helpful.
- kbetz 12y ago
  So as some other comments say, we discovered that this reaction was a thing at all! Once you put everything together, it happens very simply, in an easy setup, but no one had put together this setup because it's so unlikely and, according to old chemical knowledge, impossible. It's hard to describe just how much this goes against the grain of 100 years of chemical history, which all tell us that precious (transition) metal catalysts are absolutely necessary for these types of seemingly difficult transformations. This is like - to make a complicated pastry with layers and bubbles and flakes, it's a crazy bakery process, right, complicated and most people can't do it. But what if I told you to make the most complicated pastry, all you had to do was add salt and stir it up in a big bowl and poof - your pastry would be there? You'd laugh at me and say I didn't know anything about pastry-making. The thing is, in this case, it's right - a potassium salt can indeed do this, which goes against this big assumption that chemists have been making for a very long time: that transition metal catalysts (the middle block of the periodic table) are the ONLY things that can do this type of chemistry. So to answer your last question, the key new idea is "earth-abundant catalysis" - or the fact that we can do these complicated reactions with very, very simple, cheap, and common reagents - maybe the way that Nature itself does chemistry!
jedharris 12y ago
OK, found a library with the subscription, and the key sentence in the paper seems to be: We observed that the combination of a bulky basic anion (that is, Ot-Bu, trimethylsilanolate or bis(trimethylsilyl)amide) and, importantly, a potassium countercation led to the desired C–Si bond formation. But I don't understand it at all. Lay speak translation needed.
- deleted 12y ago
  [deleted]
- kbetz 12y ago
  Hi there, I'm Kerry - one of the researchers who wrote the paper. Basically, you have a molecule with a bunch of carbons bonded to hydrogens - like R-C-H (where R is the rest of your molecule). Then you mix in our catalyst (K-OtBu, the potassium tert-butoxide catalyst) and a silicon compound (let's say Si-H) and then stir it up, and you get your final product: R-C-Si-H! A very simple explanation for what is no doubt an extremely complex mechanism. A bit about the specifics of that quote - so we don't know the specific way this catalyst works, just that it works (we're working on finding it out!!) But we've observed several important things - and one of them is that the potassium ion in that potassium tert butoxide salt is absolutely necessary for the reaction to go. Analagous ions like Sodium or Lithium (going up the periodic table) don't work AT ALL. You NEED this potassium ion - which has never been seen before in chemistry, really. You'd expect sodium and lithium to maybe work less well, but to not work at all? Something weird's going on. Let me know if I didn't answer your question - I can probably get a bit too technical sometimes, habit really :(
  - jedharris 12y ago
    That really helps. Thanks very much.
jedharris 12y ago
These replies are great and the picture is getting clearer, but now I wonder... The linked article describes Anton Toutov as struggling to get the basic reaction figured out, being ready to give up, finally getting it to work well, etc. But this doesn't fit the underlying simplicity of the reaction. Kudos to Anton for noticing the oddity and figuring out what was going on, but was there really a heroic struggle or was that journalistic license?

jedharris 12y ago

The interviews are helpful but only deepen the mystery. They say that the reactions are so easy they can be carried out at room temperature in introductory college chemistry (albeit at Cal Tech). And potassium tert-butoxide is apparently cheap and common. So what exactly did this team discover? Apparently the basic recipe can be varied to cover a huge range of applications. What are the key new ideas common to all these recipes that make them work?

subnaught 12y ago
To answer the previous comment, there is no special preparation of the potassium t-butoxide necessary. The reaction itself is indeed quite simple to carry out. (In fact, this is one of the things that makes the research significant.) The achievement of the researchers was simply to find this reaction, which they did in part by paying attention to some early results that others may have not noticed or chosen to ignore. Right now, the "key new idea" is simply that this is possible. But because the reaction is so general (i.e. it works on a wide variety of substrates) and so unexpected, it's clear that some new unifying ideas are just around the corner.
- jedharris 12y ago
  Not being a bench chemist I have no sense of what "the reaction" is, even looking at the paper. Could you describe it?
  - refurb 12y ago
    Heteroaromatic silanes (rings made mostly of carbon but also include a non-carbon atom like nitrogen) are useful synthetic intermediates (you can use them to make other molecules). In the past, you usually made them using precious metal catalysts (really expensive metals like rhodium; the reactions are easy to screw up). The metal atom basically inserts between the ring and a hydrogen (the outside of the rings are covered in hydrogens). You then added a silane source and it would displace the metal complex (through a pretty complex pathway) to get your desired product (the original ring with a silicon atom where a hydrogen used to be). This new method creates the exact same product. However, instead of using a precious metal catalyst, you can just add this really common base (potassium t-butoxide) and your silicon source and "poof!" the reaction is complete. No expensive reagents! What makes this so science-news worthy is that I don't think anyone would have guessed this would have worked. A good analogy would be a really complex math problem. Folks can solve it, but it's a lengthy and complex proof. Suddenly someone comes by and says "just take the cosine and divide by 9" and you realize that this super simple approach works better than anything else.
    - biot 12y ago
      Sounds a bit like how Feynman diagrams changed finding solutions to quantum problems from lengthy, complex math equations into simple doodles.
    - jedharris 12y ago
      Thanks! The description of the old complex way was helpful.
kbetz 12y ago
So as some other comments say, we discovered that this reaction was a thing at all! Once you put everything together, it happens very simply, in an easy setup, but no one had put together this setup because it's so unlikely and, according to old chemical knowledge, impossible. It's hard to describe just how much this goes against the grain of 100 years of chemical history, which all tell us that precious (transition) metal catalysts are absolutely necessary for these types of seemingly difficult transformations. This is like - to make a complicated pastry with layers and bubbles and flakes, it's a crazy bakery process, right, complicated and most people can't do it. But what if I told you to make the most complicated pastry, all you had to do was add salt and stir it up in a big bowl and poof - your pastry would be there? You'd laugh at me and say I didn't know anything about pastry-making. The thing is, in this case, it's right - a potassium salt can indeed do this, which goes against this big assumption that chemists have been making for a very long time: that transition metal catalysts (the middle block of the periodic table) are the ONLY things that can do this type of chemistry. So to answer your last question, the key new idea is "earth-abundant catalysis" - or the fact that we can do these complicated reactions with very, very simple, cheap, and common reagents - maybe the way that Nature itself does chemistry!

jedharris 12y ago

OK, found a library with the subscription, and the key sentence in the paper seems to be: We observed that the combination of a bulky basic anion (that is, Ot-Bu, trimethylsilanolate or bis(trimethylsilyl)amide) and, importantly, a potassium countercation led to the desired C–Si bond formation. But I don't understand it at all. Lay speak translation needed.

deleted 12y ago
[deleted]
kbetz 12y ago
Hi there, I'm Kerry - one of the researchers who wrote the paper. Basically, you have a molecule with a bunch of carbons bonded to hydrogens - like R-C-H (where R is the rest of your molecule). Then you mix in our catalyst (K-OtBu, the potassium tert-butoxide catalyst) and a silicon compound (let's say Si-H) and then stir it up, and you get your final product: R-C-Si-H! A very simple explanation for what is no doubt an extremely complex mechanism. A bit about the specifics of that quote - so we don't know the specific way this catalyst works, just that it works (we're working on finding it out!!) But we've observed several important things - and one of them is that the potassium ion in that potassium tert butoxide salt is absolutely necessary for the reaction to go. Analagous ions like Sodium or Lithium (going up the periodic table) don't work AT ALL. You NEED this potassium ion - which has never been seen before in chemistry, really. You'd expect sodium and lithium to maybe work less well, but to not work at all? Something weird's going on. Let me know if I didn't answer your question - I can probably get a bit too technical sometimes, habit really :(
- jedharris 12y ago
  That really helps. Thanks very much.

jedharris 12y ago

These replies are great and the picture is getting clearer, but now I wonder... The linked article describes Anton Toutov as struggling to get the basic reaction figured out, being ready to give up, finally getting it to work well, etc. But this doesn't fit the underlying simplicity of the reaction. Kudos to Anton for noticing the oddity and figuring out what was going on, but was there really a heroic struggle or was that journalistic license?