0
$\begingroup$

I was reading about a zwitter ion and I had a thought that is the same possible for an acidic and basic groups. Like a very long carbon chain with a basic group and an acidic group on either sides, I am guessing it’d be called amphoteric but amphoteric compounds themselves do not contain acidic and basic group, so is it possible to synthesis one? And if it is done already what is it called?

$\endgroup$
0

1 Answer 1

8
$\begingroup$

There is no reason why basic and acidic groups could not coexist being attached to different carbons of the carbon chain, when they can coexist on the same carbon of aminoacids $\ce{H2N-CHR-COOH}$, occuring free or condensed in proteins in living cells.

These aminoacids exchange protons via $\ce{H+(aq)}$, forming zwitterions $\ce{H3N^{+}-CHR-COO-}$, neutralizing themselves.

For longer chains, consider e.g. $\ce{H2N-(CH2)_n-COOH}$ with an acidic and a basic group at the ends (simple example is GABA, $\gamma$-aminobutyric acid, a natural neurotransmitter where $n=3$). similarly as above, in water solution they would exist as zwittterions. In strongly acidic/basic solutions, only amino/carboxy group would have charge, respectively.

For $n=5$, it is epsilon-aminokaproic acid with an acidic and a basic group. Its cyclical lactam with amidic bond $\ce{-CO-NH-}$ is used as the monomer for the original polyamide Silon $\ce{[-NH-(CH2)_5-CO-]_n}$, with more simple production, compared to the Nylon-66. It was produced in the post-WW-II Czechoslovakia. For the curiosity, it was invented by famous Czech organic chemist Otto Wichterle, who invented also soft contact lenses.

Analogically, the above occurs for other acidic and basic groups, e.g.: $\ce{R1-NH-R2-SO3H ->[H2O]R1-NH2^{+}-R2-SO3-}$.

$\endgroup$
4

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.