Non-heme iron, vanadium, and copper complexes bearing hemicryptophane cavities were evaluated in the oxidation of methane in water by hydrogen peroxide. According to 1 H nuclear magnetic resonance studies, a hydrophobic hemicryptophane cage accommodates a methane molecule in the proximity of the oxidizing site, leading to an improvement in the efficiency and selectivity for CH 3 OH and CH 3 OOH compared to those of the analogous complexes devoid of a hemicryptophane cage. While copper complexes showed low catalytic efficiency, their vanadium and iron counterparts exhibited higher turnover numbers, ≤13.2 and ≤9.2, respectively, providing target primary oxidation products (CH 3 OH and CH 3 OOH) as well as over-oxidation products (HCHO and HCOOH). In the case of caged vanadium complexes, the confinement effect was found to improve either the selectivity for CH 3 OH and CH 3 OOH (≤15%) or the catalytic efficiency. The confined space of the hydrophobic pocket of iron-based supramolecular complexes plays a significant role in the improvement of both the selectivity (≤27% for CH 3 OH and CH 3 OOH) and the turnover number of methane oxidation. These results indicate that the supramolecular approach is a promising strategy for the development of efficient and selective bioinspired catalysts for the mild oxidation of methane to methanol.

A highly selective recognition of fluoride was achieved through the design of a small hemicryptophane cage (3) presenting a southern tris-urea hosting moiety. The resulting host−guest complex has been characterized by electrospray ionization-highresolution mass spectrometry, 1 H and 19 F NMR, and X-ray diffraction techniques. In particular, X-ray diffraction analysis of [3•F − ] reveals that the encapsulation of one fluoride, within 3, occurs through NH•••F − H-bonding with the six NH residues of the tris-urea ligand. An association constant of 1200 M −1 was extracted from 1 H NMR titration experiments, indicating that efficient fluoride binding also occurs in solution. Finally, in sharp contrast with previously reported urea-based hemicryptophane hosts, the small preorganized cavity found in 3 allows for an exclusive selectivity for fluoride over other competing halides.