Search results for "Anion binding"

Anion-driven encapsulation of cationic guests inside pyridine[4]arene dimers

2019

Pyridine[4]arenes have previously been considered as anion binding hosts due to the electron-poor nature of the pyridine ring. Herein, we demonstrate the encapsulation of Me4N+ cations inside a dimeric hydrogen-bonded pyridine[4]arene capsule, which contradicts with earlier assumptions. The complexation of a cationic guest inside the pyridine[4]arene dimer has been detected and studied by multiple gas-phase techniques, ESI-QTOF-MS, IRMPD, and DT-IMMS experiments, as well as DFT calculations. The comparison of classical resorcinarenes with pyridinearenes by MS and NMR experiments reveals clear differences in their host–guest chemistry and implies that cation encapsulation in pyridine[4]arene…

Electrochemical chiral recognition by microparticle coatings of Pd complexes with bridging cyclometalated phosphines

2008

Abstract The palladium(II) dinuclear complex with bridging cyclometalated phosphines, {Pd2[μ-(C6H4)PPh2]2(μ-O2CCH3)2} (Pd2L2), having a paddlewheel structure, is reversibly oxidized in CH2Cl2 to a dinuclear palladium(III) analogue via two successive one-electron steps. Solid state voltammetry of Pd2L2 in contact with aqueous electrolytes produce as one-electron oxidation with two competing mechanisms involving anion intercalation/anion binding between/to metal centres, chloride ions acting as inhibitors for the first pathway. R- and S-Pd2L2 produces a significant stereoselective electrocatalytic activity with respect to the oxidation of l - and d -glutamic acid in alkaline media.

Anion binding to resorcinarene-based cavitands: the importance of C-H...anion interactions.

2008

Exploiting 1,4-naphthoquinone and 3-iodo-1,4-naphthoquinone motifs as anion binding sites by hydrogen or halogen-bonding interactions

2019

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 HP2O73−, H2PO4−, F−, AcO− and C6H5CO2− and in the haloge…

Counter anion binding in the phenoxyimine, salan and metallocene olefin polymerization catalysts activated with perfluorophenylborate

2012

Abstract Ion pair separation is a process that may influence the activity of homogeneous catalysts of olefin polymerization. We have studied the energy of separation for selected titanium and zirconium metallocene and post-metallocene catalytic ion pairs by means of DFT, dispersion-corrected DFT and Paired Interacting Orbitals method (PIO). Unusually weak cation–anion interactions in the bis(phenoxyimine) systems were attributed to strong electron-donating properties of the phenoxyimine ligands. Energy decomposition analysis (EDA) revealed that almost 70% of the counter ion binding energy results from electrostatic interactions. The PIO method made it possible to analyze the nature of the c…

In the Pursuit of Efficient Anion-Binding Organic Ligands Based on Halogen Bonding

2013

The syntheses and the crystal structures of new multitopic anion-binding organic ligands based on a benzenoid scaffold and bearing two or three 2-iodo-imidazolium arms are reported. The quite short...

Hydrogen Bonding and Anion Binding in Structures of Tris(pyrazolyl)boratenickel(II) and Phosphate Esters

2008

This paper presents the syntheses, crystal structures and spectroscopic properties of a series of nickel(II) complexes containing hydrotris(3,5-dimethylpyrazolyl)borate and phosphate esters: [Tp*Ni(Hpz*)2(L)][(RO)2PO2] [R = Et, Bu; L = H2O (1), (BuO)2P(O)OH (2)] and [Tp*Ni(Hpz*)(H2O)2][(EtO)2PO2] (5) {Tp* = hydrotris(3,5-dimethylpyrazolyl)borate, Hpz* = 3,5-dimethylpyrazole}. The complexes [Ni(Tp*)2] (3) and [(Tp*Ni)2(μ-pz*)(μ-OH)](4) were also prepared and fully characterized. X-ray crystallographic studies of 1 and 2 reveal that the pyrazole moieties are hydrogen bonded to the guest phosphate ester anion. In complex 5, the phosphate anion is hydrogen-bonded by two O–H groups of the water …

"Comment on ""Non-symmetric substituted ureas locked in an (E,Z) conformation: an unusual anion binding via supramolecular assembly"" by M. Olivari, …

2014

We propose another point of view on the type of hydrogen bonded complexes that were described in this journal (M. Olivari et al., New J. Chem., 2013, 37, 663). The main difference is the molecular geometry and breakage of the intramolecular hydrogen bond during association. The current comment is to highlight mentioned aspects and to point out that in some cases the interpretation may not be straightforward due to the simultaneous effects associated with complexation.

Synthesis of 7-Pentafluorophenyl-1H-indole: An Anion Receptor for Anion–π Interactions

2014

7-Pentafluorophenyl-1H-indole has the potential to be a key compound for the investigation of anion–π interactions in solution. Unfortunately, it was not possible to obtain it by aryl–aryl coupling reaction. Finally, it has been prepared by Bartoli indole synthesis. The key compound as well as analogues were submitted to preliminary studies of anion binding. Single crystals of two key receptors were obtained.

Solid lipid nanoparticles from amphiphilic calixpyrroles

2016

Abstract Hypothesis Macrocyclic amphiphiles form interesting self-assembling structures, including solid lipid nanoparticles, which have potential applications in drug encapsulation. Aryl-extended calixpyrroles, which act as anion binding hosts, are expected to form solid lipid nanoparticles, even though the alkyl chains have unusual perpendicular geometry with respect to the hydrophilic head group. The preparation conditions and the alkyl chain length should affect the size and stability of the particles. Experiments Solid lipid nanoparticles of two aryl-extended calixpyrroles with resorcinol walls and either meso-dodecyl or meso-methyl alkyl chains were compared. Ethanolic solutions of th…