Browsing by Subject "Hydrogen bond"

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    Enhancement of anion recognition exhibited by a zinc-imidazole-based ion-pair receptor composed of C–H hydrogen- and halogen-bond donor groups
    (Royal Society of Chemistry, ) Zapata Fernández, Fabiola; Sabater, Paula; López, Bernardo; Fernández, Israel; Caballero, Antonio; Molina, Pedro; Química Orgánica
    A 2-haloimidazole-tetraphenylethylene ion-pair receptor 1 is shown to recognise only HSO4− anions in the presence of a cobound Zn2+ cation guest species, which induced a remarkable increase with conco- mitant blue shift of the emission band of the complex [1·2Zn]4+ whereas no affinity of the free receptor 1 by the anions is observed. In addition, the downfield shifts observed by 1H NMR of the Ha, Hb and Hc protons of the complex [1·2Zn]4+ upon the addition of HSO4− anions indicate their participation in the recognition event. According to DFT studies, upon chelating a Zn2+ cation with two imidazole nitrogen atoms, receptor 1 adopts a conformation ideally fitted to recognise HSO4− through a combination of C(sp2)–H⋯O and C(sp3)–H⋯O hydrogen bondings, C+(sp2)–Br⋯O halogen bonding and C(sp2)⋯O tetrel bonding."
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    Versatile control of the submolecular motion of di(acylamino)pyridine-based [2]rotaxanes
    (2015-03-18) Martínez Cuezva, Alberto; Pastor Vivero, Aurelia; Cioncoloni, Giacomo; Orenes Martínez, Raúl Angel; Alajarín, Mateo; Symes, Mark D.; Berná Cánovas, José; Química Orgánica; WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
    A cyclic network of chemical reactions has been conceived for exchanging the dynamic behaviour of di(acylamino)pyridine-based rotaxanes and surrogates. X-ray diffraction studies revealed the intercomponent interactions in these interlocked compounds and were consistent with those found in solution by dynamic NMR experiments. This particular binding site was incorporated into a molecular shuttle enabled for accessing two states with an outstanding positional discrimination through chemical manipulation. Furthermore, the ability of the di(acylamino)pyridine domain to associate with external binders with a complementary array of HB donor and acceptor sites was exploited for the advance of an unprecedented electrochemical switch operating through a reversible anion radical recognition process.