Tight Xenon Confinement in a Crystalline Sandwich-like Hydrogen-Bonded Dimeric Capsule of a Cyclic Peptide

Pizzi, A.^a, Ozores, H.L.^b, Calvelo, M.^b, García-Fandiño, R.^b, Amorín, M.^b, Demitri, N.^c, Terraneo, G.^a, Bracco, S.^d, Comotti, A.^d, Sozzani, P.^d, Bezuidenhout, C.X.^d, Metrangolo, P.^a, Granja, J.R.^b

^a Laboratory of Supramolecular and Bio-Nanomaterials, (SupraBioNanoLab), Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Milano, 20131, Italy
^b Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica, Universidad de Santiago de Compostela, Santiago de Compostela, 15782, Spain
^c Elettra—Sincrotrone Trieste, S.S. 14 Km 163.5 in Area Science Park, Basovizza—Trieste, 34149, Italy
^d Department of Materials Science, University of Milano Bicocca, Via R. Cozzi 55, Milan, 20125, Italy

Angewandte Chemie - International Edition 2019, 58(41), 14472-14476

A cyclic hexapeptide with three pyridyl moieties connected to its backbone forms a hydrogen-bonded dimer, which tightly encapsulates a single xenon atom, like a pearl in its shell. The dimer imprints its shape and symmetry to the captured xenon atom, as demonstrated by 129Xe NMR spectroscopy, single-crystal X-ray diffraction, and computational studies. The dimers self-assemble hierarchically into tubular structures to form a porous supramolecular architecture, whose cavities are filled by small molecules and gases.