cooperativity between hydrogen bonding and anion-π interaction in anion recognition and catalysis

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Synergistic hydrogen bonding and Anion-π interaction for anion recognition

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Multi-approach strategy to probe the interactions between anions and new classes of molecular receptors

The anion distribution across cell membranes is a major element governing biological processes in the human body. This is ensured by ion channels, membrane proteins with the capacity to selectively regulate ion flows. Disruption of these electrophysiological ion transport phenomena can lead to serious pathologies (channelopathies). One example is the deregulation of chloride ion concentration, leading in particular to cystic fibrosis.[1]A new therapeutic strategy for treating channelopathies involves designing molecules that allow ions to be transported across lipid membranes, thereby restoring ionic currents and their physiological functions. [2] In this context, new families of receptors are being developed that combine several low-energy interactions (hydrogen, halogen and pi-anion bonds). A combination of several weak interactions is likely to generate stronger and more selective bonds, thereby modulating existing properties or generating new ones.The aim of the work presented here is to characterize in detail, using a multi-approach experimental strategy, the interaction processes at play between these receptors and a series of target anions. Gas-phase studies can provide valuable information about the interactions established at the molecular level between the anions and the receptors. These will be carried out using mass spectrometry to determine the stoichiometry of the anion/receptor complexes and to obtain structural characterization using tandem mass spectrometry (MSn) to determine the position of the anion on these new structures. This work is complemented by theoretical calculations using DFT (Density Functional Theory). The results obtained in the gas phase are complemented by the characterization of ligand-host complexes in solution [3], by NMR titrations and by UV/vis and fluorescence spectroscopy experiments.References[1] S.M. Rowe et al. N. Engl. J. Med. 2005, 352, 1992-2001.[2] T. Sato et al. J. Biol. Chem. 1998, 273, 21455-21462.[3] R. Plais et al. ChemPhysChem, 2022, e20220052

Multi-approach strategy to probe the interactions between anions and new classes of molecular receptors

The anion distribution across cell membranes is a major element governing biological processes in the human body. This is ensured by ion channels, membrane proteins with the capacity to selectively regulate ion flows. Disruption of these electrophysiological ion transport phenomena can lead to serious pathologies (channelopathies). One example is the deregulation of chloride ion concentration, leading in particular to cystic fibrosis.[1]A new therapeutic strategy for treating channelopathies involves designing molecules that allow ions to be transported across lipid membranes, thereby restoring ionic currents and their physiological functions. [2] In this context, new families of receptors are being developed that combine several low-energy interactions (hydrogen, halogen and pi-anion bonds). A combination of several weak interactions is likely to generate stronger and more selective bonds, thereby modulating existing properties or generating new ones.The aim of the work presented here is to characterize in detail, using a multi-approach experimental strategy, the interaction processes at play between these receptors and a series of target anions. Gas-phase studies can provide valuable information about the interactions established at the molecular level between the anions and the receptors. These will be carried out using mass spectrometry to determine the stoichiometry of the anion/receptor complexes and to obtain structural characterization using tandem mass spectrometry (MSn) to determine the position of the anion on these new structures. This work is complemented by theoretical calculations using DFT (Density Functional Theory). The results obtained in the gas phase are complemented by the characterization of ligand-host complexes in solution [3], by NMR titrations and by UV/vis and fluorescence spectroscopy experiments.References[1] S.M. Rowe et al. N. Engl. J. Med. 2005, 352, 1992-2001.[2] T. Sato et al. J. Biol. Chem. 1998, 273, 21455-21462.[3] R. Plais et al. ChemPhysChem, 2022, e20220052

Tetrafluoroterephthalonitrile as an anion‐π donor: theoretical evaluation and application to anion recognition

International audienceThe ability of perfluorinated terephthalonitrile to act as an anion‐π donor fragment in anion receptors is evaluated. New receptors combining an urea and a perfluorinated terephthalonitrile motif into a single architecture have been designed and synthesized. Their molecular recognition properties towards Cl$^−$ , Br$^−$ and I$^−$ , have been studied in solution by means of 1 H and 19 F NMR as well as photophysical experiments. A complementary electrospray ionization‐tandem mass spectrometry study confirmed the ranking of recognition properties between the receptors. A further theoretical evaluation of binding properties confirmed the association constant trend and suggests a main contribution of the urea motif weakly complemented by a η$^2$‐type anion‐π interaction

Application of Raw and Chemically Modified Biomasses for Heterogeneous Cu-Catalysed Conversion of Aryl boronic Acids to Phenols Derivatives

International audienceThis work describes the application of raw and chemically modified cellulose and sugarcane bagasse for ipso-hydroxylation of aryl boronic acids in environmentally friendly reaction conditions. The catalytic efficiency of five support-[Cu] materials was compared in forming phenols from aryl boronic acids. Our investigation highlights that the CEDA-[Cu] material (6-deoxy-6aminoethyleneamino cellulose loaded with Cu) leads to the best results under very mild reaction conditions. The optimized catalytic sequence, allowing a facile transformation of boronic acids to phenols, required the mandatory and joint presence of the support, Cu2O, and KOH at room temperature. CEDA-[Cu] was characterized using13C solid-state NMR, ICP, and FTIR. The use of CEDA-[Cu] accounts for the efficacious synthesis of variously substituted phenol derivatives and presents very good recyclability after five catalytic cycles

Chloride Binding Modulated by Anion Receptors Bearing Tetrazine and Urea

International audienceModulation and fine-tuning of the strength of weak interactions to bind anions are described in a series of synthetic receptors. The general design of the receptors includes both a urea motif and a tetrazine motif. The synthetic sequence towards three receptors is detailed. Impacts of H-bond strength and linker length between urea and tetrazine on chloride complexation are studied. Binding properties of the chloride anion are examined in both the ground and excited states using a panel of analytical methods (NMR spectroscopy, mass spectrometry, UV/Visible spectroscopies, and fluorescence). A ranking of the receptors by complexation strength has been determined, allowing a better understanding of the structure-properties relationship on these compounds