# The Evasive Ether: Existence of diethynyl ether?

I tried to find online whether the compound diethynyl ether, $$\ce{HC#COC#CH}$$, exists in a stable state at STP, mainly out of curiosity, but also because it would be interesting to study the properties of a molecule with such interesting characteristics (eg. the very long bent shape, the highly exposed oxygen atom, the potential for multiple different polymerization reactions). However, I spent about 30 minutes scrolling through page after page of search results with only results about diethyl ether, and came up empty-handed. I'm wondering if anyone here has any info/sources/knowledge about this evasive ether. I've included some images to clarify what molecule I'm talking about, as well as to possibly help jog your memory. Any and all information/data about the molecule is appreciated.

• Room-Temperature Chemical Synthesis of C2 by K Miyamotohad a footnote: (21) Diethynyl ether was too unstable to be isolated. See: Serratosa, F. Acetylene 243Diethers: A Logical Entry to Oxocarbons. Acc. Chem. Res. 16, 170–176 (1983) – MaxW Apr 3 '20 at 18:36
• I doubt I've ever seen any molecules with $\ce{R'-C#C-O-C#C-R''}$ group. On the other hand, there are definitely some with sulfur, $\ce{R'-C#C-S-C#C-R''}$. – andselisk Apr 3 '20 at 19:43
• And if acetylenediol. was detected, then this should be quite doable compound. – Mithoron Apr 3 '20 at 22:25

You can find a nice discussion of diethynyl ether and some of its derivatives here:

Ooi, I. H., & Smithers, R. H. (1989). Bis [(trimethylsilyl) ethynyl] ether: a moderately stable C4H2O derivative. The Journal of Organic Chemistry, 54(6), 1479-1480.

https://pubs.acs.org/doi/pdf/10.1021/jo00267a053

They write that "little or nothing is known about diethynyl ether", and they were only able to find theoretical (INDO) calculations in their literature search about the compound, as opposed to actual reports of its synthesis. They do mention that the following authors managed to synthesize a dimethyl derivative, $$\ce{Me-C#C-O-C#C-Me}$$, but reported that it explodes at room temperature (and I infer, from what Ooi and Smithers wrote, that diethynyl ether would be even more unstable):

Brandsma, L., & Arens, J. F. (1962). Chemistry of acetylenic ethers LVI Di‐(alk‐1‐ynyl) ethers and thioethers. Recueil des Travaux Chimiques des Pays‐Bas, 81(6), 510-516.

https://onlinelibrary.wiley.com/doi/abs/10.1002/recl.19620810610

They themselves (Ooi and Smithers) were able to synthesize a di-trimethylsilyl derivative, $$\ce{Me_3Si-C#C-O-C#C-SiMe_3}$$ which, while stable when dissolved in $$\ce{CH_2Cl_2}$$ and stored in a freezer, degrades overnight when stored neat at room temperature.

In summary, for $$\ce{R-C#C-O-C#C-R}$$, larger R's provide added stability:

R = H (diethynyl ether): If it were ever synthesized, it would probably have a very short half-life, except under specalized conditions.

R = Me: Has been synthesized, but explodes at room temperature

R = $$\ce{Me_3Si}$$: Low to moderate stability, as described above. Ooi and Smithers write that the added stability provided by the trimethylsilyl groups "is probably both steric and electronic."