Cavitands can be smoothly derivatized by CuAAC chemistry to incorporate ligand species at the upper rim. These species can coordinate metal species in a number of different conformations, leading to self-assembly. The metal-coordination confers water solubility on the cavitands, and the iron-bound species are capable of catalytic C – H oxidations of fluorene under mild conditions.

A new selective hydrocarbon oxidation heterogeneous catalyst has been developed by tethering an iron-coordinated cavitand to the surfaces of a SBA-15 mesoporous material. The resulting material was shown to catalyze the oxidation of cyclic hydrocarbons at room temperature and to be quite robust and easily recyclable. The role of the cavitand scaffold is to prevent the catalytic Fe ions from interacting directly with the silica surface and to provide a controlled environment for reversible redox catalysis. An induction period is required for the activation of the catalyst, during which a change in coordination of the iron ions to the tethered cavitand takes place.

Hemiprotonated dimers of cytosine derivatives, implicated in the formation of the i-motif of DNA, have been created in solution and the gas phase. The mechanism of dimerization has been analyzed by mass spectrometry and multidimensional NMR spectroscopy.

Functionalized cavitands have been shown to self-fold via coordination of Fe(II) salts and effect catalytic C-H oxidation reactions of unfunctionalized alkanes under mild aqueous conditions in the presence of tert-butyl hydroperoxide as co-oxidant. Secondary and tertiary C-H bonds can be converted to ketones and alcohols, respectively, and ethers can be converted to esters. The cavitands retain the catalytic metal throughout the reaction, and can be recovered by filtration.

In response to the call for an increased emphasis from the American Chemical Society on including macromolecular studies in the undergraduate curriculum, a supramolecular-themed experiment was designed for undergraduatelevel organic laboratory courses that provides a convenient platform to study physical behaviors of supramolecular assemblies. Students synthesize an easily purified resorcin[4]arene and characterize the product of its self-assembly via 1 H NMR spectroscopy. These bowl-shaped molecules are noteworthy because of their propensity to self-assemble in organic solution in the presence of trace water or alcohol solvents. Upon self-assembly, the resulting hexamer adopts a well-defined molecular cage structure with a large internal cavity that can be used to explore host:guest chemistry. After completing the experiment, students are expected to gain a better understanding of electrophilic aromatic substitution, 1 H NMR spectroscopy, supramolecular chemistry and self-assembly, and molecular recognition.

Hydrocarbon Oxidation Catalyzed by Self-Folded Metal-Coordinated Cavitands. -A novel iron-coordinated cavitand is prepared and successfully applied as a reusable oxidation catalyst for a variety of substrates. -(DJERNES, K. E.; PADILLA, M.; METTRY, M.; YOUNG, M. C.; HOOLEY*, R. J.; Chem. Commun. (Cambridge) 48 (2012) 94, 11576-11578, http://dx.doi.org/10.1039/c2cc36236h ; Dep. Chem., Univ. Calif., Riverside, CA 92521, USA; Eng.) -R. Staver