Search results for "Halogen"

Spectroscopic Investigation of the System TeCl4/[NEt4]PF6 in Solution and the Crystal Structure of [NEt4]2[Te2Cl10].

2005

Solutions containing TeCl 4 and [NEt 4 ][PF 6 ] in CH 2 Cl 2 were investigated by means of UV/vis and NMR spectroscopy in order to study the complex chemistry of TeCl 4 with the [PF 6 ] - anion. The results show formation of [TeCl 5 ] - and strong interactions of [PF 6 ] - with a tellurium containing species, presumably [TeCl 3 ] + . The life time of the Te I V -PF 6 complex is long enough to give different signals in the 1 9 F NMR spectrum of a solution containing excess [PF 6 ] - . Even a fivefold excess of Cl - ions over [PF 6 ] - does hardly lead to a dissociation of [TeCl 3 ...PF 6 ]. Crystals of [NEt 4 ] 2 [Te 2 Cl 1 0 ] were obtained from a 4:1 solution of [NEt 4 ]PF 6 and TeCl 4 in …

Very close I⋯As and I⋯Sb interactions in trimethylpnictogen-pentafluoroiodobenzene cocrystals

2022

The cocrystals (CH3)3As·C6F5I (1) and (CH3)3Sb·C6F5I (2) were generated in situ from equimolar mixtures of their components. 1 and 2 show very close I⋯As and I⋯Sb directional intermolecular interactions. They are 0.5 and 0.7 Å shorter than the sums of van der Waals radii, respectively, and are the shortest C–I⋯As and C–I⋯Sb halogen bonds of this type found for experimentally characterized molecular (co)crystals. Comparisons of the packing motifs and contacts in 1 and 2 with those in (CH3)3As (3), (CH3)3Sb (4) and C6F5I (5) illustrate the occurrence and hierarchy of the specific interactions. The heteromolecular components in 1 and 2 are assembled by I⋯As, I⋯Sb and F⋯H interactions. There ar…

Olefin metathesis reactions with fluorinated substrates, catalysts, and solvents.

2014

Synthesis of quadruped-shaped polyfunctionalized o-carborane synthons

2011

[EN] o-Carborane derivatives with precisely defined patterns of substitution have been prepared from 8,9,10,12-I-4-1,2-closo-C2B10H8 by replacing the iodine atoms, bonded to four adjacent boron vertices in the cluster, with allyl, and subsequently 3-hydroxypropyl groups. The resulting structures, comprising four pendant arms and two reactive vertices located on opposite sides of a central o-carborane core, can be envisaged as versatile precursors for dendritic growth

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…

Hydrogen and Halogen Bond Mediated Coordination Polymers of Chloro-Substituted Pyrazin-2-Amine Copper(I) Bromide Complexes

2020

A new class of six mono- (1

Palladium C–N bond formation catalysed by air-stable robust polydentate ferrocenylphosphines: a comparative study for the efficient and selective cou…

2014

The arylation of aniline derivatives with dichloroarenes under a low palladium content (below the currently used 5 to 10 mol%) was studied using nine different ferrocenylphosphine ligands, including the easily accessible 1,1′-bis(diphenylphosphino)ferrocene, DPPF. The electron-enriched air-stable tridentate ferrocenylpolyphosphine 1,2-bis(diphenylphosphino)-1′-(diisopropylphosphino)-4-tert-butylferrocene, L5, employed in 2 mol% in combination with 1 mol% [PdCl(η3-C3H5)]2 allows an efficient and selective coupling, while such demanding substrates currently induce chloroarene homocoupling and/or dehalogenation processes. The scope and limitation of the optimized system are explored, with a fo…

Miniaturized matrix solid phase dispersion procedure and solid phase microextraction for the analysis of organochlorinated pesticides and polybromina…

2009

Abstract This work has developed a miniaturized method based on matrix solid phase dispersion (MSPD) using C18 as dispersant and acetonitrile–water as eluting solvent for the analysis of legislated organochlorinated pesticides (OCPs) and polybrominated diphenylethers (PBDEs) in biota samples by GC with electron capture (GC-ECD). The method has compared Florisil®-acidic Silica and C18 as dispersant for samples as well as different solvents. Recovery studies showed that the combination of C18–Florisil® was better when using low amount of samples (0.1 g) and with low volumes of acetonitrile–water (2.6 mL). The use of SPME for extracting the analytes from the solvent mixture before the injectio…

Active alkaline traps to determine acidic-gas ratios in volcanic plumes: Sampling techniques and analytical methods

2014

In situ measurements have been the basis for monitoring volcanic gas emissions for many years and—being complemented by remote sensing techniques—still play an important role to date. Con- cerning in situ techniques for sampling a dilute plume, an increase in accuracy and a reduction of detection limits are still necessary for most gases (e.g., CO2, SO2, HCl, HF, HBr, HI). In this work, the Raschig-Tube tech- nique (RT) is modified and utilized for application on volcanic plumes. The theoretical and experimental absorption properties of the RT and the Drechsel bottle (DB) setups are characterized and both are applied simultaneously to the well-established Filter packs technique (FP) in the …

Halogen and hydrogen bonds in compressed pentachloroethane

2016

In pentachloroethane, C2HCl5, high pressure initially strongly compresses the C–H⋯Cl bonds in phase I; however, in phase II which is stable above 0.62 GPa the role of hydrogen bonds is diminished and molecular aggregation is dominated by halogen bonds Cl⋯Cl. Both phases have been determined by X-ray diffraction and the phase diagram of C2HCl5 has been outlined. The transition between phases I and II retains some relation between their structures and reduces the symmetry from class mmm (space group Pnma) to 2/m (space group P21/n11). The discontinuous transition, with the shear strain exceeding 21°, is so strong that its progress can be visually observed even for powdered samples. The single…