Capture of Singlet Oxygen Modulates Host-Guest Behavior of Coordination Cages.

The anthracene panels of two tetrahedral M L cages, where M =Co or Fe , were found to react with photogenerated singlet oxygen ( O ) in a hetero-Diels-Alder reaction. ESI-MS analysis showed the cobalt(II) cages to undergo complete transformation of all anthracene panels into endoperoxides, whereas the iron(II) congeners underwent incomplete conversion. The reaction was found to be partially reversible in the case of the 1-Fe cage.

Hetero-Diels-Alder Reaction between Singlet Oxygen and Anthracene Drives Integrative Cage Self-Sorting.

A ZnL pseudocube containing anthracene-centered ligands, a ZnL' tetrahedron with a similar side length as the cube, and a trigonal prism ZnLL' were formed in equilibrium from a common set of subcomponents. Hetero-Diels-Alder reaction with photogenerated singlet oxygen transformed the anthracene-containing "L" ligands into endoperoxide "L" ones and ultimately drove the integrative self-sorting to form the trigonal prismatic cage ZnLL' exclusively. This ZnLL' structure lost dioxygen in a retro-Diels-Alder reaction after heating, which resulted in reversion to the initial ZnL + ZnL' ⇌ 2 × ZnLL' equilibrating system.

Rapid and Efficient Removal of Perfluorooctanoic Acid from Water with Fluorine-Rich Calixarene-Based Porous Polymers.

On account of its nonbiodegradable nature and persistence in the environment, perfluorooctanoic acid (PFOA) accumulates in water resources and poses serious environmental issues in many parts of the world. Here, we present the development of two fluorine-rich calix[4]arene-based porous polymers, and , and demonstrate their utility for the efficient removal of PFOA from water. These materials featured Brunauer-Emmett-Teller (BET) surface areas of up to 450 m g, which is slightly lower than their nonfluorinated counterparts (up to 596 m g).

Calix[4]arene-Based Porous Organic Nanosheets.

Calixarenes are a common motif in supramolecular chemistry but have rarely been incorporated in structurally well-defined covalent 2D materials. Such a task is challenging, especially without a template, because of the nonplanar configuration and conformational flexibility of the calixarene ring. Here, we report the first-of-a-kind solvothermal synthesis of a calix[4]arene-based 2D polymer (CX4-NS) that is porous, covalent, and isolated as few-layer thick (3.

Porous Polycalix[4]arenes for Fast and Efficient Removal of Organic Micropollutants from Water.

Organic micropollutants are hazards to the environment and human health. Conventional technologies are often inefficient at removing them from wastewater. For example, commercial activated carbon (AC) exhibits slow uptake rates, limited capacities, and is costly to regenerate.