Transferring the properties of molecular receptors to the carbon surface in hybrid materials: The crucial role of porous texture

This paper analyzes the influence of the textural parameters of the parent active carbon support (AC) on the characteristics of AC/organic-receptor hybrid materials. It is shown that neither the surface area nor the pore volume are key factors, but a polymodal distribution of pores, improving the accessibility of the porous network, is critical in the amount of anchored receptors. The receptor adsorption on poorly connected porous networks blocks the access to inner parts of the porosity, decreasing the yield of functionalization. Moreover, the textural properties of the parent AC are not only crucial in the amount of fixed receptors, but also on the complexation behaviour of the AC/receptor materials. Hybrid materials based on AC having a polymodal distribution of pores increase the metal adsorption capacity compared to the original AC, while those with restricted porosity do not improve the adsorption behaviour of the AC, despite of having a significant amount of fixed receptors. These results allow us to conclude that an important part of the adsorbed receptors in the narrow porosity are forced to adopt spatial configurations inadequate to coordinate the metal ions. These findings are important as they open new perspectives in the design of new hybrid materials.

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► Irreversible anchorage of pyrimidine derivatives on carbons for metal complexation.
► The topology of the network is crucial in the functionalization of the surface.
► Good connectivity of the porous network is more important than surface area.
► The topology of the network also influences the behaviour of molecular receptors.
► Receptors in narrow pores cannot coordinate metal ions due to steric factors.