Browsing by Subject "Halogen bonding"

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    Exploiting 1,4-naphthoquinone and 3-iodo-1,4- naphthoquinone motifs as anion binding sites by hydrogen or halogen-bonding interactions
    (Royal Society of Chemistry, 2019-08-21) Navarro García, Encarnación; Velasco, María D.; Zapata Fernández, Fabiola; Bauzá, Antonio; Frontera, Antonio; Ramírez de Arellano, Carmen; Caballero, Antonio; Química Orgánica
    We describe here the utilization of 1,4-naphthoquinone and 3-iodo-1,4-naphthoquinone motifs as new anion binding sites by hydrogen- or halogen-bonding interactions, respectively. These binding sites have been integrated in bidentate ester based receptors. Emission experiments reveal that both receptors selectively recognize sulfate anions, which induced a remarkable increase of a new emission band attributed to the formation of π-stacking interactions between two 1,4-naphthoquinone units. Absorption spectroscopy and mass spectrometry indicate the disruption of the ester group of the 1,4- naphthoquinone based receptor in the presence of HP2O7 3−, H2PO4−, F−, AcO− and C6H5CO2− and in the halogenated receptor with HP2O7 3−, F− and AcO− anions, while the presence of sulfate anions showed the clasical complexation behaviour. The 1H-NMR experiment showed a slow exchange process of the receptors with their sulfate complexes. The binding mode of the receptors with sulfate has been studied by DFT calculations along with the Molecular Electrostatic Potential (MEP) surface computational tool that reveals those parts of the receptors which are more suitable for interacting with anions.
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    Formation of self-assembled supramolecular polymers by anti-electrostatic anion–anion and halogen bonding interactions
    (Royal Society of Chemistry, 2020-07-04) Zapata Fernández, Fabiola; González, Lidia; Bastida, Adolfo; Bautista, Delia; Caballero, Antonio; Química Orgánica
    We report here the formation of self-assembled supramolecular polymers in which the cooperative action of anti-electrostatic anion–anion and halogen-bonding interactions serve as a powerful driving force for the formation of large supramolecular polymers. DOSY-NMR, DLS, TEM, SEM and X-ray experiments provide evidence of the formation of supramolecular structures in solution and solid state.
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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.