Search results for "Halide"

Cavitands incorporating a Lewis acid dinickel chelate function as receptors for halide anions.

2015

The halide binding properties of the cavitand [Ni2(L(Me2H4))](2+) (4) are reported. Cavitand 4 exhibits a chelating N3Ni(μ-S)2NiN3 moiety with two square-pyramidal Ni(II)N3S2 units situated in an anion binding pocket of ∼4 Å diameter formed by the organic backbone of the (L(Me2H4))(2-) macrocycle. The receptor reacts with fluoride, chloride (in MeCN/MeOH), and bromide (in MeCN) ions to afford an isostructural series of halogenido-bridged complexes [Ni2(L(Me2H4))(μ-Hal)](+) (Hal = F(-) (5), Cl(-) (6), and Br(-) (7)) featuring a N3Ni(μ-S)2(μ-Hal)NiN3 core structure. No reaction occurs with iodide or other polyatomic anions (ClO4(-), NO3(-), HCO3(-), H2PO4(-), HSO4(-), SO4(2-)). The binding ev…

Ziegler–Natta catalysts based on vanadium halides: a DFT study

2003

Abstract Ziegler–Natta ethylene insertion into the carbon–metal bond for a number of fragments containing vanadium on different oxidation states as well as the halogen ligands has been studied by means of DFT. It is shown that the complexation and insertion energies are strongly influenced by the charge on the transition metal atom and, to some extent, by the electronegativity of the halogen atom. Complexation energy varies in the range −129 to −159 kJ/mol for charged species and −64 to −77 kJ/mol for neutral ones. Insertion energy follows a similar pattern and ranges from −28 to −62 and −82 to −100 kJ/mol, respectively. The calculated values are compared with the experimental results and d…

Bismuth trihalide complexes with nitrogen and phosphorus chelating ligands

1985

Abstract Bismuth(III) halides react with 1,10-phenanthroline, 2-pyridinecarboxaldehyde-2-pyridylhydrazone and diphenylphosphynoethane in methanol. A stoichiometry differing from 1:1 is found only for BiCl 3 (Phen) 1.33 and BiCl 3 (Dpe) 1.5 . Characterization of these compounds, which are not very soluble in common solvents, follows from analytical, mass and IR spectral data. In the low frequency region, the IR spectra proved to be useful to ascertain the presence of bridging halogens.

Selective encapsulation of a chloride anion in a 1H-pyrazole Cu2+ metallocage

2021

A self-assembled metallobox from copper(ii) and two macrocycles containing 1H-pyrazole ligands has been prepared. The internal cavity of the box is able to selectively encapsulate a single chloride anion over any other halide anion.

Molecular “Pincer” from a Diimidazolium Salt: A Study of Binding Ability

2013

The anion recognition ability of the dicationic imidazolium salt 3,3′-di-n-octyl-1,1′- (1,3-phenylenedimethylene)diimidazolium 1,5-naphthalenedisulfonate ([m-Xyl-(oim)2][1,5-NDS]) was investigated in acetonitrile solution by means of proton NMR titrations. A wide range of anions, comprising simple inorganic ions, halides, and mono- and dicarboxylates was taken into account. The study showed that this receptor binds carboxylate anions more strongly than halides. Moreover [m- Xyl-(oim)2][1,5-NDS] displays selectivity for di- over monocarboxylate anions. The complex stability was mainly affected by the anion basicity in the presence of monocarboxylates, whereas the flexibility of the alkyl cha…

Applications in nanophotonics of lead halide perovskite nanocrystals

2021

Layer-dependent mechanical properties and enhanced plasticity in the van der Waals chromium trihalide magnets

2020

The mechanical properties of magnetic materials are instrumental for the development of the magnetoelastic theory and the optimization of strain-modulated magnetic devices. In particular, two-dimensional (2D) magnets hold promise to enlarge these concepts into the realm of low-dimensional physics and ultrathin devices. However, no experimental study on the intrinsic mechanical properties of the archetypal 2D magnet family of the chromium trihalides has thus far been performed. Here, we report the room temperature layer-dependent mechanical properties of atomically thin CrI3 and CrCl3, finding that bilayers of CrI3 and CrCl3 have Young's moduli of 62.1 GPa and 43.4 GPa, with the highest sust…

Fluoride-induced modulation of ionic transport in asymmetric nanopores functionalized with “caged” fluorescein moieties

2016

[EN] We demonstrate experimentally and theoretically a nanofluidic fluoride sensing device based on a single conical pore functionalized with "caged" fluorescein moieties. The nanopore functionalization is based on an amine-terminated fluorescein whose phenolic hydroxyl groups are protected with tert-butyldiphenylsilyl (TBDPS) moieties. The protected fluorescein (Fcn-TBDPS-NH2) molecules are then immobilized on the nanopore surface via carbodiimide coupling chemistry. Exposure to fluoride ions removes the uncharged TBDPS moieties due to the fluoride-promoted cleavage of the silicon-oxygen bond, leading to the generation of negatively charged groups on the fluorescein moieties immobilized on…

Studies on adducts of organotin(IV) halides with bis(acetylacetone)ethylenediimine

1971

The solid state configuration of 1/1 adducts, formed by mono-, di- and tri-organotin(IV) halides with the potentially tetradentate ligand bis(acetylacetone)ethylenediimine, has been investigated. The infrared spectra suggest that the neutral ligand coordinates SnIV through N (or O) atoms of the H-bonded acetylacetoneimine moieties. The skeletal vibrations associated to Sn-C and Sn-Cl bonds are consistent with square planar configurations of the organotin(IV) halide moieties, where SnCl3 and C3Sn groups would be T-shaped, and Alk2SnCl2 would have trans-dialkyl, trans-dichloro arrangements. The latter configuration is supported by the magnitude of the quadrupole splittings. Measurements of th…

A Simple Phosphine–Diolefin‐Promoted Copper‐Catalysed N‐Arylation of Pyrazoles with (Hetero)aromatic Bromides: The Case of Chloroarenes Revisited

2012

A molecularly defined new phosphine–diolefin cubane copper pre-catalyst used at 1.25 mol % under mild conditions promotes the coupling of pyrazoles to functionalised aryl and heteroaryl bromides, which hold a variety of functional groups. This versatile phosphorus-based system was thus successfully used, under identical conditions, for the coupling of a large scope of heteroaromatics to selectively produce pyridinyl- and pyrimidinyl-pyrazoles, as well as several novel furyl-, thienyl- and thiazolyl-substituted pyrazoles. The careful investigation of coupling with the analogous aryl and heteroaryl chlorides clearly indicated that for specifically activated chloroarenes a direct nucleophilic …