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Helical aromatic oligoamide foldamers (1a–c) with tunable lengths were computationally examined for their ability to bind selected sugars and sugar alcohols. These helices feature cylindrically shaped inner cavities lined with multiple inward-facing amide carbonyl oxygens acting as hydrogen-bond acceptors, enabling sugar binding via hydrogen bonding. Each of the helical foldamers has an overall dipole moment that increases with the length of the helix. The binding of a guest typically results in a reduction of the overall helix dipole moment within the complex, although there are several exceptions. The strength of host–guest interactions correlated positively with the number of hydrogen bonds formed. Longer helix 1c showed stronger interaction energies (up to −84.45 kcal mol−1), particularly with disaccharides, while shorter helix 1a bound sugars more weakly due to fewer established hydrogen bonds. The helical hosts exhibit structural adaptibility upon binding guests, with host distortion upon binding decreased with increasing helix length. Despite reduced binding energies, the complexes retained binding capability in aqueous environments, demonstrating their viability for aqueous-phase applications. This study underscores the critical roles of helical length and dipole alignment in optimizing sugar binding, providing a theoretical foundation for designing synthetic receptors for sugars and sugar alcohols based on aromatic oligoamide foldamers. 

Catalytic hydrogenation of aromatic compounds is an important industrial process, particularly for the production of many petrochemical and pharmaceutical derivatives. This reaction is mainly catalyzed by noble metals, but rarely by metal oxides. Here, we report the development of monoclinic hydrogen-bearing ruthenium dioxide with a nominal composition of H x RuO 2 that can serve as a standalone catalyst for various hydrogenation reactions. The hydrogen-bearing oxide was synthesized through the water gas shift reaction of CO and H 2 O in the presence of rutile RuO 2 . The structure of H x RuO 2 was determined by synchrotron X-ray diffraction and density functional theory (DFT) studies. Solid-state 1 H NMR and Raman studies suggest that this compound possesses two types of isolated interstitial protons. H x RuO 2 is very active in hydrogenation of various arenes, including liquid organic hydrogen carriers, which are completely converted to the corresponding fully hydrogenated products under relatively mild conditions. In addition, high selectivities (>99%) were observed for the catalytic hydrogenation of functionalized nitroarenes to corresponding anilines. DFT simulations yield a small barrier for concerted proton transfer. The facile proton dynamics may be key in enabling selective hydrogenation reactions at relatively low temperature. Our findings inspire the search for hydrogen-containing metal oxides that could be employed as high-performance materials for catalysts, electrocatalysts, and fuel cells. 

New aromatic oligoamide macrocycles with C 3 -symmetry bind a bipyridinium guest (G) to form compact pseudo[3]rotaxanes involving interesting enthalpic and entropic contributions. The observed high stabilities and strong positive binding cooperativity are found in few other host–guest systems.