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A new capsule based on a β-sheet self-assembling cyclic peptide with the ability to recognize and release several guests is described. The host structure is composed of two self-complementary α,γ-cyclic peptides bearing a Zn porphyrin cap that is used for the selective recognition of the guest. The two components are linked through two dynamic covalent bonds. The combination of binding forces, including hydrogen bonding, metal coordination, and dynamic hydrazone bonds, allows the reversible recognition of long bipyridine guests. The affinity for these ligands showed a strong dependence on the guest length. Delivery of the encapsulated ligand can be achieved by hydrolysis of hydrazones to disrupt the sandwich complex structure.

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 129 Xe 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.

We describe the design and synthesis of self-assembling peptide nanotubes that have an internal filter area and whose length and internal diameters, at the entrance and in the constricted area, are precisely controlled This work was supported by the Spanish Ministry of Economy and Competitivity (Mineco) and the ERDF (CTQ2013‐43264‐R), and by the Xunta de Galicia and the ERDF (EM2014/011). A. F. and H. L. O. thank Mineco for their FPU contracts. We also thank the ORFEO‐CINCA network and Mineco (CTQ2014‐ 51912‐REDC). We very much appreciate Dr. Ignacio Alfonso (IQAC‐CSIC) for his help in designing DOSY experiments NON

et al., Self-assembling cyclic peptides decorated with mesogens form porous columnar mesophases in which, depending on the number of hydrocarbon chains, double or single channels are formed along each column. © 2014 The Royal Society of Chemistry., This work was supported by the MINECO and the ERDF [CTQ2010-15725,MAT2009-14636-C03-01,MAT2012-38538-C03-01, CTQ2012-35692] and Consolider Ingenio 2010 (CSD2006-00012, CSD2007-00006), Xunta de Galicia (GPC2013-039) and Aragon Government and FEDER foundation. M.A. thanks the Spanish MEC for his Ramón y Cajal contract.