Browsing by Subject "Supramolecular polymers"

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    Host–guest complexes vs. supramolecular polymers in chalcogen bonding receptors: an experimental and theoretical study
    (Royal Society of Chemistry, 2022-01-25) Navarro García, Encarnación; Galmés, Bartomeu; Esquivel, José Luis; Velasco, María D.; Bastida, Adolfo; Zapata Fernández, Fabiola; Caballero, Antonio; Frontera, Antonio; Química Orgánica
    We describe here a comparative study between two tripodal anion receptors based on selenophene as the binding motif. The receptors use benzene or perfluorobenzene as a spacer. The presence of the electron- withdrawing ring activates the selenium atom for anion recognition inducing the formation of selfassembled supramolecular structures in the presence of chloride or bromide anions, which are bonded by the cooperative action of hydrogen and chalcogen bonding interactions. DOSY NMR and DLS experiments provided evidence for the formation of the supramolecular structures only in the presence of a perfluorobenzene based anion receptor while the analogous benzene one shows the classical anion/ receptor complex without the participation of the selenium atom. The energetic and geometric features of the complexes of both receptors with the Cl and Br anions have been studied in solution. These results combined with the molecular electrostatic potential (MEP) surface plots allow us to rationalize the quite different behaviors of both receptors observed experimentally.
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    Interlocked Supramolecular Polymers Created by Combination of Halogen- and Hydrogen-Bonding Interactions through AnionTemplate Self-Assembly
    (American Chemical Society, ) Zapata, Fabiola; González, Lidia; Caballero, Antonio; Bastida, Adolfo; Bautista, Delia; Molina, Pedro; Química Orgánica
    We present the synthesis and oxoanion assembling properties of a monomer with a naphthalene ring as a central core decorated with two arms containing iodotriazolium rings as anion binding sites. Interactions with SO42−, H2PO4−, and HP2O73− anions, via a cooperative mechanism, afforded new supramolecular materials stabilized by a combination of halogen- and hydrogen-bonding interactions. 1 H NMR experiments and solid-state structure provided evidence for the initial formation of a supramolecular linear chain, nucleation step, and then two different supramolecular chains are interpenetrated with each other, elongation steps, involving the formation of hydrogen bonds between two oxygens of the anion from one of the chains and the naphthalene inner protons from the other chain. Scanning electron microscopy studies revealed that the morphology of the crystals changed dramatically with the nature of the anion added.