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Topic: Organic conductor from terephthaldehyde?  (Read 3563 times)

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Offline shelanachium

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Organic conductor from terephthaldehyde?
« on: November 10, 2008, 05:27:24 PM »
Anyone fancy trying to make a new 'organic metal'? Can't try it at home myself, I live in rented property, I have to do all my chemistry in my head!

When ethanolic benzaldehyde is treated with CN- as a catalyst we get 'benzoin' C6H5CH(OH)COC6H5. This is readily oxidised to the dione 'benzil' C6H5COCOC6H5. In very strong base benzoin gives the enediolate [C6H5CO=COC6H5]2-, with a full -ve charge on each O atom.

If we were to use terephthaldehyde - para-HCOC6H4CHO, we should obtain a linear polymer [-CH(OH)COC6H4-]n, oxidisable to [-COCOC6H4-]n, and converted by very strong base to the poly(enediolate), also with a full -ve charge on each O atom.

However, all possible intermediates between poly(dione) and the poly(enediolate) should be obtainable, with the negative charge extensively delocalised; only weak base would be needed for lower negative charge densities as when the enediolate structure alternates with the dione structure, and the net charge per O atom is -1/2, as in carboxylate ions. Increase the proportion of dione units and decrease that of enediolate units, and the net charge becomes less than -1/2 per O atom and the polyanion a weaker base, stable in neutral or even acidic solutions (alpha-diones are unstable to strong base).

The number of electrons removed from or added to the polyanion should vary between wide limits, and electrons are free to move along the chain. Therefore solid salts of polyanions obtained by partial oxidation of the 'polyterephthaloin' polymer in basic solution should be 1-dimensional organic conductors.

Anyone fancy a go?

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