''meta''-Diethynylbenzene dianion
 Meta-diethynylbenzene dianion | |
.png) The compound C 6H 4(C 3HO 2) 2 used for the synthesis of Meta-diethynylbenzene dianion | |
| Names | |
|---|---|
| IUPAC name
Meta-diethynylbenzene dianion | |
| Properties | |
| C 6H 4C2− 4 | |
| Hazards | |
| Main hazards | Extremely corrosive |
| Related compounds | |
Related bases |
Ortho-diethynylbenzene dianion |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
The meta-diethynylbenzene dianion is a structural isomer of the ortho-diethynylbenzene dianion. The meta-diethynylbenzene dianion is not as strong as ortho-diethynylbenzene dianion, but it is still the second-strongest superbase. Like the ortho-diethynylbenzene dianion, the meta-diethynylbenzene dianion exists in the gas state, contrary to the other bases and superbases which exist in the solution state. In the meta-diethynylbenzene dianion, the two negatively charged ethynyl (−C
2H−
2) groups are bonded to the first and third carbon atoms of the benzene ring. But in the ortho-diethynylbenzene dianion, the ethynyl groups are bonded to the first and second carbon atoms of the benzene ring. Like Ortho-diethynylbenzene dianion, Meta-diethynylbenzene dianion has no known use.
Synthesis
- Step 1
- A sample of meta-C6H4(C3HO2)2 is taken.
- Step 2
- In this next step, the parent compound is subjected through electrospray ionization (ESI) and consequently, loses two Hydrogen atoms and therefore, acquires a charge of −2. The new compound's chemical formula is [C6H4(C3O2)2]2−
- Step 3
- The ionized parent compound [C6H4(C3O2)2]2− is subjected to collision-induced dissociation (CID), because of which, one of the carboxylate anion loses a Carbon dioxide molecule to become [C6H4(C5O2)]2−.
- Step 4
- The meta-[C6H4(C3O2)2]2− compound is again subjected to collision-induced dissociation, because of which, the other carboxylate anion loses the other Carbon dioxide molecule and becomes meta-[C6H4(C5O2)]2−
- Step 5
- Therefore, the meta-diethynylbenzene dianion [C6H4(C2)2]2− is formed, having lost, in total, two hydrogen atoms and two molecules of carbon dioxide.
The same process can generate either ortho-diethynylbenzene dianion and Meta-diethynylbenzene dianion depending on which isomer of the original compound is used.
Summary
![{\displaystyle {\ce {\overset {}{C6H4(C3HO2)2->[{\ce {ESI}}][][C6H4(C3O2)2]^{2-}->[{\ce {CID}}][][C6H4(C5O2)]^{2-}->[{\ce {CID}}][][C6H4(C2)2]^{2-}}}}}](../I/m/bf7de91dbcf70c24e9de1511a18dc02290a6e159.svg)
The compound after the first stage of collision-induced dissociation having lost a carbon dioxide molecule and retaining the negative charge.
meta-[C
6H
4(C
5O
2)]2− is subjected to collision-induced dissociation for the second time losing another Carbon dioxide molecule but retaining the negative charge. Thus, the compound, Meta-diethynylbenzene dianion is formed.
See also
List of the other isomers
References
Poad, Berwyck L. J.; Reed, Nicholas D.; Hansen, Christopher S.; Trevitt, Adam J.; Blanksby, Stephen J.; Mackay, Emily G.; Sherburn, Michael S.; Chan, Bun; Radom, Leo (12 January 2018). "Preparation of an ion with the highest calculated proton affinity: ortho -diethynylbenzene dianion". Chemical Science. 7 (9). doi:10.1039/C6SC01726F. Retrieved 12 January 2018.