Owing to the increasing level of attention focused on the preservation of the environment, there is a growing need for novel multi-functional materials that can meet the increasing demands from society on water resources and pollution remediation. Porous organic polymers (POPs) composed of light elements that possess high specific surface areas, large pore volume, and multiple functionalities are good candidate to fulfil the requirements. In particular, porous covalent organic polymers (COPs) are a promising class because of their ultrahigh hydrothermal stabilities and high yielding synthetic polymer chemistry. Very recently we reported the successful synthesis of a first-in-class calix[4]arene-based porous covalent polymer and tested its adsorption ability toward oil, organic solvents, and dyes. The calix[4]arene-based porous polymer can selectively absorb up to seven times its weight of oil from oil/water mixtures. From aqueous solutions, it can adsorb both anionic and cationic dyes in under 15 minutes. Its uptake capacity is significantly higher than those of the most adsorbent materials reported to date, including commercial activated carbon. With these positive results and the known advantages of porous organic polymers as adsorbents, we decided to design a series of hyper-cross-linked π-bond-rich porous covalent polycalix[4]arenes, for I2 adsorption. We enriched the polymers with arenes and alkynes, which are known to endow materials with high surface area and high I2 affinity. Furthermore, because the phenols of calix[4]arenes are easily lithiated and because alkali metal ions such as Li+ are known to enhance adsorption properties of materials by providing sites for charge induced dipolar and quadrupolar electrostatic interactions, we synthesized the corresponding series of lithiated polymers by exposing them to n-butyl lithium at low temperature. We found that both types of polymers (as synthesized and lithiated) performed well as I2 adsorbents. For all application, the polymers can be easily regenerated using mild washing procedures and reused several times with no loss of absorption efficiency.

Multi-functional porous calix[n]arene-based materials

256th National Meeting (2018)

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