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Selective Anion Incarceration and Extraction by Nanojars (NSF-funded: CHE-1404730 and CHE-1808554)
One of the major research directions pursued in the Mezei group involves a class of large (~2 nm), supramolecular/coordination aggregates of the formula [anion⊂{CuII(OH)(R-pz)}n] (anion = SO42–, CO32–, PO43– and other small inorganic oxoanions with 2− or 3− charge; pz = pyrazolate, C3H3N2; R = functional group; n = 26−36), termed nanojars. Each nanojar is based on a combination of three or four [Cu(OH)(pz)]x rings (x = 6−14, except 11), which wrap around the incarcerated anion using a multitude of hydrogen bonds and completely isolate the anion from the surrounding medium. Nanojars selectively incarcerate anions with large hydration energies (over anions with small hydration energies) and allow for the unprecedented extraction of such anions from aqueous solutions into aliphatic hydrocarbons. The reversible, pH-dependent assembly-disassembly of nanojars has been exploited for the extraction and recycling of toxic anions, such as chromate and arsenate.

Molecularly Woven Materials
Strength, lightness and non-brittleness are crucial features of some materials used in everyday life. For certain specialized applications, extreme strength is required while lightness and non-brittleness are still desirable. The challenge to combine all these properties into one material is not trivial, since very tough materials are usually heavy and/or brittle. By analogy to macroscopic woven materials, such as textiles and ropes, we believe that materials woven at the molecular level should be the ultimate choice featuring extreme strength while being lightweight and non-brittle. In creating these novel materials, we exploit coordination chemistry and ligand design, using building blocks with intertwined strands that are subsequently “sewn” together on the molecular level.

Functional Supramolecular Architectures

Rotaxanes and catenanes – supramolecules that contain mechanically interlocked components – are the focus of increased attention in recent years due to their potential for being developed into molecular devices and machines. Examples of such rotaxane- or catenane-based devices include molecular shuttles, elevators, muscles, nanovalves, information storage devices and components for molecular electronics such as molecular switches and single-molecule transistors. We are interested in engineering more complex molecular machinery by assembling two or more such devices into discrete supramolecular entities. We are also pursuing the incorporation of rotaxanes into 3-dimensional architectures in order to prepare functional materials with controllable pore sizes and shapes.