High surface area conjugated microporous polymers: The importance of reaction solvent choice

The choice of reaction solvent has a major influence on the surface area and pore volume in conjugated microporous polymer (CMP) networks synthesized by Sonogashira-Hagihara palladium-catalyzed cross-coupling chemistry of aromatic dibromo monomers with 1,3,5-triethynylbenzene. Four solvents were evaluated for these reactions: N,N-dimethylformamide (DMF), 1,4-dioxane, tetrahydrofuran (THF), and toluene. Networks synthesized in DMF tend to exhibit the highest surface areas (up to 1260 m2/g), whereas those synthesized in toluene have on average significantly lower surface areas and pore volumes. By judicious choice of reaction solvent, microporous materials can be prepared which combine high surface area with a variety of functional groups of interest in applications such as gas storage, molecular separations, and catalysis.