Sciencemadness Discussion Board

Deprotonated alkyne stability

Triflic Acid - 24-1-2021 at 16:00

I plan to make some metal deprotonated alkyne metal salts. I don't want these to explode, so I was wondering if a deprotonating something like 1-hexyne would still be explosive. Maybe the long side chain would make it a little less explosive? I couldn't find any information about this online.

DraconicAcid - 24-1-2021 at 16:26

I'm not sure what factors make them more explosive. I've made and used AgCCPh and AgCCCO2Et, and found them stable, but the latter did detonate on a friend of mine without warning.

Triflic Acid - 24-1-2021 at 19:01

@DraconicAcid is AgCCPh water/air stable? Also, how did you make the AgCCPh? Did you start from Phenylacetylene?

[Edited on 25-1-2021 by Triflic Acid]

DraconicAcid - 24-1-2021 at 19:03

I'm pretty sure I made it from aqueous (ammoniacal) solution, so probably. I stored it in air, but I seem to recall it being photosensitive.

Triflic Acid - 24-1-2021 at 19:07

Well, photosensitive is expected with silver, but the fact that it is water stable is good. Also, is AgCCPh soluble in water? Do you by any chance remember the prep you followed? If you can't I plan to make it by deprotonating Phenylacetylene with Na. Phenylacetylene can be made with molten KOH and bromostyrene. I guess bromostyrene can be made from styrene. How do I make styrene?

[Edited on 25-1-2021 by Triflic Acid]

DraconicAcid - 24-1-2021 at 19:29

No, it's not soluble in water. I believe I mixed phenylacetylene into a solution of silver nitrate in a mixture of aqueous ammonia and methanol, which gave an immediate precipitate. However, that was 25 years ago.

Styrene can be make by cracking polystyrene- that prep has been mentioned several times on this forum.

https://books.google.ca/books?id=uMEwAAAAYAAJ&pg=PA832&a...

[Edited on 25-1-2021 by DraconicAcid]

Triflic Acid - 26-1-2021 at 22:17

Just a question, but does adding phenylacetylene to a metal nitrate always give the phenylactylenide? I want to do this for metals like Mn, Fe, Cu, and Ni. Would these phenylactylenides be non-explosive + stable to air and water + insoluble?

DraconicAcid - 26-1-2021 at 22:31

Quote: Originally posted by Triflic Acid  
Just a question, but does adding phenylacetylene to a metal nitrate always give the phenylactylenide? I want to do this for metals like Mn, Fe, Cu, and Ni. Would these phenylactylenides be non-explosive + stable to air and water + insoluble?


No, I think it's fairly specific to silver (and Cu(I)?) because it's insoluble. If you were to react silver phenylacetylide with, say, and aqueous solution of iron(II) bromide, I suspect you'd get phenylacetylene, silver bromide, and iron(II) hydroxide. if you did the same reaction under anhydrous conditions, you might get the desired metal phenylacetylides, but I have no idea how stable they'd be.

The nickel(II) phenylacetylide (or something similar) has been made- it's an oligomeric material, soluble in benzene, that will polymerize phenylacetylene.

https://books.google.ca/books?id=l4RJ8k44fZQC&pg=PA30&am...


Dialkynylzinc is also known, and is a reagent for adding an alkynyl group to a ketone. Stable in ether/hydrocarbon solvents, and made by reacting a terminal alkyne with diethylzinc.
[Edited on 27-1-2021 by DraconicAcid]

[Edited on 27-1-2021 by DraconicAcid]

Triflic Acid - 27-1-2021 at 12:52

So, if I wanted to make a whole bunch of these, I would have to add anhydrous metal salts to sodium phenylacetylineide in something like THF?

njl - 27-1-2021 at 15:32

Pretty much all depends on solubility and solvent compatibility.

Triflic Acid - 30-1-2021 at 13:02

I might just be bad at searching the internet, but I can't find a single source about these metal phenylacetleneides. Where did you find that paper DragonicAcid? Also, I can make the phenylacetyleneide by combining sodium metal with phenylacetylene, right?

DraconicAcid - 30-1-2021 at 13:33

I just googled "nickel phenyacetylide", etc. It might be your spelling of phenylacetylide that's tripping you up.

Yes, sodium phenylacetylide in THF with an anhydrous metal salt is probably your best bet. I think sodium metal and phenylacetylene will work, but I don't have any experience with that. I've made the silver phenylacetylide, and I seem to recall deprotonating the alkyne with a Grignard or alkyllithium a couple of times.