A rod-like phenolic π-conjugated polymer with pillar[5]arene units in its main chain

- A π-conjugated polymer containing pillar[5]arenes in its main chain was prepared.
- The phenolic π-conjugated polymer showed high thermal stability.
- The phenolic π-conjugated polymer showed selective gas adsorption property.

A new rigid rod-like phenolic π-conjugated polymer containing pillar[5]arene units in its main chain was prepared. First, a pillar[5]arene-containing π-conjugated polymer was prepared by Pd-catalyzed copolymerization of 4,4'-diphenyldiboronic acid with a pillar[5]arene bearing two triflate moieties in one hydroquinone unit and eight ethoxy groups in the other units. Then, deprotection of the ethyl moieties using BBr3 gave a rigid rod-like phenolic π-conjugated polymer. The phenolic polymer showed high thermal stability, with a 10 wt% loss temperature (T10) of 300 °C in a nitrogen atmosphere, which is higher than that of a pillar[5]arene containing 10 phenolic moieties (T10 = 164 °C). Moreover, the phenolic π-conjugated polymer showed selective gas adsorption properties: it was highly selective for the adsorption of CO2, but did not take up N2 or methane.

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