Br Anions Research Articles

Deep-Ultraviolet Nonlinear Optical Crystals: Ba3P3O10X (X = Cl, Br)

Deep-ultraviolet nonlinear optical (deep-UV NLO) crystals are of worldwide interest for the generation of coherent light with wavelength below 200 nm by the direct second-harmonic generation (SHG) output from solid-state lasers. The unprecedented deep-UV NLO phosphates representing their own structure types, Ba3P3O10Cl (BPOC), Ba3P3O10Br (BPOB), have been discovered, which display moderate powder SHG intensities in type I phase matchable behaviors with a short UV cutoff edge of 180 nm (measured by a single crystal, one of the shortest values among phosphates to date). Insightfully, the geometry and polarization of the C1-P3O10(5-) building unit are affected by the crystal packing. DFT calculations and cutoff energy dependent SHG coefficient analyses reveal that the SHG origin is from the cooperation of asymmetric C1-P3O10(5-) anion, Ba(2+) cation, and Cl(-)/Br(-) anion.

Scalar Relaxation of the Second Kind — A Potential Source of Information on the Dynamics of Molecular Movements. 2. Magnetic Dipole Moments and Magnetic Shielding of Bromine Nuclei

In this paper, we continue the exploration of possibilities, limitations, and methodological problems of the studies based on measurements of the nuclear spin relaxation rates running via the scalar relaxation of the second kind (SC2) mechanism. The attention has been focused on the (13)C-(79)Br and (13)C-(81)Br systems in organic bromo compounds, which are characterized by exceptionally small differences of Larmor frequencies, ΔωCBr, of the coupled nuclei. This unique property enables experimental observation of longitudinal SC2 relaxation of (13)C nuclei, which makes investigation of the SC2 relaxation rates an attractive experimental method of determination of spin-spin coupling constants and relaxation rates of quadrupole bromine nuclei, both types of parameters being hardly accessible by direct measurements. A careful examination of the methodology used in SC2 relaxation studies of carbon-bromine systems reveals, however, some disturbing facts that could burden the results with systematic inaccuracies. Namely, the way of calculating the Larmor frequency differences between (13)C and bromine isotopes, ΔωCBr, may cause some reservations. In this work, the values of (79)Br and (81)Br magnetogyric ratios have been rechecked using bromine NMR data for the KBr·Kryptofix 222 complex in acetonitrile solution and the results of the advanced calculations of the magnetic shielding of the bromine nucleus in the Br(-) anion. Moreover, it has been pointed out that in the case of (13)C-(79)Br, the magnetic shielding of the bromine nucleus in the investigated molecule must not be neglected during the calculation of the ΔωCBr parameter. Some recommendations concerning the exploitation of available theoretical methods to calculate bromine shielding constants for bromo compounds have also been formulated, keeping in mind relativistic effects.

Aggregation of Double-Tailed Ionic Liquid 1,3-Dioctylimidazolium Bromide and the Interaction with Triblock Copolymer F127

The aggregation of ionic liquid-based double-tailed surfactant, 1,3-dioctylimidazolium bromide ([Doim]Br) and its interaction with pluronic copolymer F127 were systematically investigated by nuclear magnetic resonance (NMR), surface tension, dynamic light scattering (DLS), and isothermal titration calorimetry (ITC). It was found that the [Doim]Br aggregates are composed with the alkyl chains embedded in the micellar core and with the imidazolium rings parallel and staggered on the hydrophilic layer of micelles, which was generally different from the single-tailed IL [omim]Br. The hydrogen bonding between protons attached to the imidazolium rings and anion Br(-) was enhanced upon the aggregation of [Doim]Br. The aggregation of F127 was promoted by addition of [Doim]Br, which was more efficient than the single-tailed surfactant. At lower [Doim]Br content, [Doim]Br monomers embedded deeply into F127 micelle core. At higher [Doim]Br concentrations, the F127 micelles were disassociated, and then F127 chains penetrated into [Doim]Br micelle. In addition, the microstructure of F127/[Doim]Br complex can also be tuned by temperature.

Bis(2,2′-bipyridine)[1,9-bis(diphenylphosphanyl)-1,2,3,4,6,7,8,9-octahydropyrimido[1,2-a]pyrimidin-5-ium]ruthenium(II) hexafluoridophosphate dibromide dichloromethane disolvate monohydrate

In the cation of the title complex, [Ru(C31H32N3P2)(C10H8N2)2](PF6)(Br)2·2CH2Cl2·H2O, the ruthenium ion is coordinated in a distorted octa­hedral geometry by two 2,2′-bi­pyridine (bpy) ligands and a chelating cationic N-di­phenyl­phosphino-1,3,4,6,7,8-hexa­hydro-2-pyrimido[1,2-a]pyrimidine [(PPh2)2-hpp] ligand. The tricationic charge of the complex is balanced by two bromide and one hexa­fluorido­phosphate counter-anions. The compound crystallized with two mol­ecules of di­chloro­methane (one of which is equally disordered about a Cl atom) and a water mol­ecule. In the crystal, one of the Br anions bridges two water mol­ecules via O—H⋯Br hydrogen bonds, forming a centrosymmetric diamond-shaped R 4 2(8) motif. The cation and anions and the solvent mol­ecules are linked via C—H⋯F, C—H⋯Br, C—H⋯Cl and C—H⋯O hydrogen bonds, forming a three-dimensional network.

Communication: Transfer ionization in a thermal reaction of a cation and anion: Ar+ with Br− and I−

We present experimental evidence that reactions of argon cations Ar(+) with the halogen anions Br(-) and I(-) do not occur exclusively by mutual neutralization, but also produce the cations Br(+) or I(+) ions by transfer ionization (TI). The experiments were carried out in flowing-afterglow plasmas at gas temperatures between and 300 and 500 K, and employed a variant of the Variable Electron and Neutral Density Attachment Mass Spectrometry method. The measured TI rate coefficients are 1.9 ± 0.6 × 10(-9) cm(3) s(-1) and 1.1 ± (0.3)(0.8) × 10(-9) cm(3) s(-1) for the Br(-) and I(-) reactions, respectively. We find that the TI rate coefficients decline with temperature as T(-0.5) to T(-1). No indication of TI was found in the reaction with Cl(-), where it is endoergic.

First-Principles Molecular Dynamics Simulation of Atmospherically Relevant Anion Solvation in Supercooled Water Droplet

We present a comprehensive first-principles Born-Oppenheimer molecular dynamics (BOMD) simulation study of halide anion solvation in a deeply supercooled water droplet (with diameter ∼1.8 nm). We show that larger halide anions Br(-) and I(-) show "outer-layer surface preference", whereas F(-) exhibits bulk preference. Contrary to behavior of other halide anions, Cl(-) in the water droplet appears to exhibit no strong tendency of surface or bulk preference at either the supercooled or ambient condition, a phenomenon not previously reported in the literature. BOMD simulation indicates that fully hydrated complex of F(-) is mainly five-fold coordinated (showing square pyramid structure), whereas Cl(-), Br(-) and I(-) hydrated complexes are either five- or six-fold coordinated (showing sandwich-like structure). Among Cl(-), Br(-) and I(-) anions, BOMD simulation indicates that I(-) exhibits the largest diffusion coefficient despite its largest size. However, computed resident time of the four halide ions suggests that Br(-) can approach from the interior to the surface of the water droplet at a much faster rate than I(-) and Cl(-).

Identification of mixed bromidochloridotellurate anions in disordered crystal structures of (bdmim)2[TeX2Y4] (X, Y = Br, Cl; bdmim = 1-butyl-2,3-dimethylimidazolium) by combined application of Raman spectroscopy and solid-state DFT calculations

The discrete mixed [TeBrxCl6−x]2− anions in their disordered crystal structures have been identified by using the phases prepared by the reaction of 1-butyl-2,3-dimethylimidazolium halogenides (bdmim)X with tellurium tetrahalogenides TeX4 (X=Cl, Br) as examples. Homoleptic (bdmim)2[TeX6] [X=Cl (1), Br (2)] and mixed (bdmim)2[TeBr2Cl4] (3), and (bdmim)2[TeBr4Cl2] (4) are formed depending on the choice of the reagents, and their crystal structures have been determined by single-crystal X-ray diffraction. The coordination environments of tellurium in all hexahalogenidotellurates are almost octahedral. Because of the crystallographic disorder, the mixed [TeBr2Cl4]2− and [TeBr4Cl2]2− anions in 3 and 4 cannot be identified in their crystal structures. Pawley refinement of the X-ray powder diffraction patterns of 1–4 indicates the presence of single phases in all four products. The solid state Raman spectra of 1–4 were assigned with help of DFT calculations that were performed both for the discrete anions in vacuum and for the complete crystal structures employing periodic boundary conditions. The fundamental vibrations of the homoleptic [TeX6]2− (X=Cl, Br) anions could be well reproduced by the solid-state DFT computations and enabled a complete assignment of the Raman spectra. While the presence of cis-isomers in both [TeBr2Cl4]2− and [TeBr4Cl2]2− could be inferred by the computed fundamental vibrations, that of trans-isomers among the reaction products is, however, also possible. The pathway of the formation of [TeX4Y2]2− isomers from TeX4 and Y− (X, Y=Cl, Br) was also explored by DFT calculations both in vacuum and in solution and indicated that both reactions afforded 80mol% of cis-isomers and 20mol% of trans-isomers.

Catena-Poly[di-μ3-bromido-bis[(1-ethyl-1H-imidazole-κN3)disilver(I)

The asymmetric unit of the title coordination complex, [Ag2Br2(C5H8N2)2]n, comprises a monodentate 1-ethyl­imida­zole ligand, an Ag+ cation and a μ3-bridging Br− anion, giving a distorted tetra­hedral AgNBr3 stereochemistry about the Ag+ cation [Ag—N = 2.247 (2) Å and Ag—Br = 2.7372 (4)–2.7523 (4) Å]. Two bridging bromide anions generate the dimeric [Ag2Br2(C5H8N)2] repeat unit [Ag⋯Ag = 3.0028 (5) Å], while a third Br− anion links the units through corner sharing in an inversion-related Ag2Br2 association [Ag⋯Ag = 3.0407 (4) Å], generating a one-dimensional ribbon step-polymer structure, extending along the c axis.

Optical Recognition of Anions by Ruthenium(II)-Bipyridine-Calix[4]Arene System

The two t-butylcalix[4]arene attached ruthenium(II)-bipyridine complexes (Rubc2 and Rubc3) has been synthesized and the anion recognition studies have been carried out using emission techniques. The binding of anions, which are sensed by the complexes, are studied by UV-visible and emission techniques. The complex Rubc2 recognizes the Cl(-), H2PO4 (-) and AcO(-) anions. The complex Rubc3 recognizes the Br(-) and AcO(-) anions. The AcO(-) quenches the emission intensity of both two complexes but the other anion increases the emission intensity of the complexes. The excited state lifetime and transient absorption studies were carried out the AcO(-) facilitates non radiative pathway. The other anions stabilize the excited state and facilitate the radiative pathway.

A portable lab‐on‐a‐chip instrument based onMCEwith dual top–bottom capacitive coupled contactless conductivity detector in replaceable cell cartridge

A new design for a compact portable lab-on-a-chip instrument based on MCE and dual capacitively coupled contactless conductivity detection (dC(4) D) is described. The instrument is battery powered with total dimension of 14 × 25 × 8 cm(3) (w × l × h), and weighs 1.2 kg. The device consists of a front electrophoresis compartment which has the chip holder and the chip, the associated high-voltage electrodes for electrophoresis injection and separation and the detector. The detection cell is integrated into the device housing with an exchangeable plug-and-play cartridge format. The design of the dC(4) D cell has been optimized for maximum performance. The cartridge includes the top-bottom excitation and pick up electrodes incorporated into the cell and connected to push-pull self-latching pins that are insulated with plastic. The metal frame of the cartridge is grounded completely to eliminate electronic interferences. The cartridge is designed to clamp a thin fluidic chip at the detection point. The cartridges are replaceable whereby different cartridges have different detection electrode configurations to employ according to the sensitivity or resolution needed in the specific analytical application. The second compartment consists of all the electronics, data acquisition card, high-voltage modules of up to ±5kV both polarity, and batteries for 10 h of operation. The improved detector performance is illustrated by the electrophoresis analysis of six cations (NH4 (+) , K(+) , Ca(2+) , Na(+) , Mg(2+) , Li(+) ) with a detection limit of approximately 5 μM and the analysis of the anions (Br(-) , Cl(-) , NO2 (-) , NO3 (-) , SO4 (2-) , F(-) ) with a detection limit of about 3 μM. Analytical capabilities of the instrument for food and medical applications were evaluated by simultaneous detection of organic and inorganic acids in fruit juice and inorganic cations and anions in rabbit blood samples and human urine samples are also demonstrated.

Specific solubility behavior of quaternary ammonium-based poly(ionic liquid) particles by changing counter anion

The solubility behavior of poly(ionic liquid) (PIL) particles, which were prepared by dispersion polymerization of ([2-(methacryloyloxy)ethyl]trimethylammonium bis(trifluoromethanesulfonyl)amide), [MTMA][TFSA], was observed in detail. The solubility of PILs was varied by changing the counter anion. A PIL with [TFSA] anion does not dissolve in polar solvents such as ethanol; however, a PIL with Br anions does dissolve in ethanol. Upon the addition of LiBr to ethanol solution at high concentrations (>2.5wt.%), the PIL particles dissolved from their outer surface and the counter anions [TFSA] were replaced with Br anions on the particle surfaces. On the other hand, in the case of the ethanol solutions at low LiBr concentrations (<2.5wt.%), a specific solubility behavior was observed: domains inside the PIL particles were generated before their dissolution, most likely due to osmotic pressure. Moreover, PIL particles having hollow structures were prepared using this specific solubility behavior.

Removal of Molecular Adsorbates on Gold Nanoparticles Using Sodium Borohydride in Water

The mechanism of sodium borohydride removal of organothiols from gold nanoparticles (AuNPs) was studied using an experimental investigation and computational modeling. Organothiols and other AuNP surface adsorbates such as thiophene, adenine, rhodamine, small anions (Br(-) and I(-)), and a polymer (PVP, poly(N-vinylpyrrolidone)) can all be rapidly and completely removed from the AuNP surfaces. A computational study showed that hydride derived from sodium borohydride has a higher binding affinity to AuNPs than organothiols. Thus, it can displace organothiols and all the other adsorbates tested from AuNPs. Sodium borohydride may be used as a hazard-free, general-purpose detergent that should find utility in a variety of AuNP applications including catalysis, biosensing, surface enhanced Raman spectroscopy, and AuNP recycle and reuse.

Potential of silver against human colon cancer: (synthesis, characterization and crystal structures of xylyl (Ortho, meta, &amp; Para) linked bis-benzimidazolium salts and Ag(I)-NHC complexes: In vitroanticancer studies)

BackgroundSince the first successful synthesis of Ag(I)-N-heterocyclic carbene complex in 1993, this class of compounds has been extensively used for transmetallation reactions where the direct synthesis using other metal ions was either difficult or impossible. Initially, silver(I)-NHC complexes were tested for their catalytic potential but could not get fame because of lower potential compare to other competent compounds in this field; however, these compounds proved to have vital antimicrobial activities. These encouraging biomedical applications further convinced researchers to test these compounds against cancer. The current work has been carried out with this aim.ResultsN-ipropylbenzimidazole was synthesized by reaction of benzimidazole with ipropyl bromide. The subsequent treatment of the resulting N-alkylbenzimidazole with ortho/meta/para-(bromomethylene) benzene afforded corresponding bis-benzimidazolium bromides (5-7). The counter anion (Br-) of each salt was replaced by hexaflourophosphate (PF6-) for the ease of handling and further purification (8-10). Each salt (Ligand), in halide form, was further allowed to react with Ag2O with stirring at room temperature for a period of two days to synthesize dinuclear Ag(I)-NHC complexes (11-13). All synthesized compounds were characterized by spectroscopic techniques and microanalysis. Molecular structures of compounds 5, 9 &10 were established through single crystal x-ray diffraction technique. All the compounds were assessed for their anti-proliferation test on human colorectal cancer cell line (HCT 116). Results showed that the ligands (5-10) showed mild to negligible cytotoxicity on HCT 116 cells whereas respective silver complexes (11-13) exhibited dose dependent cytotoxicity towards the colon cancer cells with IC50 ranges between 9.7 to 44.5 μM. Interestingly, the complex 13 having para-xylyl spacer was found the most active (IC50 9.7 μM) that verifies our previously reported results.ConclusionsAll the bis-benzimidazolium salts (8-10) were found inactive whereas after bonding with silver cations, the Ag(I)-NHC complexes (11-13) showed a dose dependent cytotoxic activity. This proved that silver practice an important role in death of cancer cells. Also, the N-alkyl/aryl substitutions and ortho/metal/para xylyl units regulate the cytotoxicity.

Alkyl-bis(imidazolium) salts: a new amphiphile platform that forms thermotropic and non-aqueous lyotropic bicontinuous cubic phases

New ionic amphiphiles with a hexyl-bridged bis(imidazolium) headgroup; Br(-), BF4(-), or Tf2N(-) anions; and a long n-alkyl tail can form thermotropic bicontinuous cubic liquid crystal phases in neat form and/or lyotropic bicontinuous cubic phases with several non-aqueous solvents or water.

Pd@Au core–shell nanocrystals with concave cubic shapes: kinetically controlled synthesis and electrocatalytic properties

A new type of concave cubic Pd@Au core-shell nanocrystals is synthesized through a kinetically controlled growth process. Pd nanocubes of 56 nm are used as the inner core, and CTAC and Br(-) are used as the capping agent and selective adsorbent, respectively. A suitable ratio of HAuCl4 and cubic Pd seeds and the presence of Br(-) anions are critical to the growth of the concave cubic Pd@Au core-shell nanocrystals. The fast deposition rate on the corners of the cubic Pd seeds promotes the overgrowth of the Au outer shell along the <111> direction, leading to the formation of concave cubic nanostructures. The reduction process is monitored by the surface plasmon resonance spectra of the nanocrystals, and the extinction band became broader and red shifted as the nanocrystals became larger. The electrocatalytic properties of the concave cubic Pd@Au core-shell nanocrystals were investigated with the cathodic electrochemiluminescence reaction of luminol and H2O2. A possible electrocatalytic mechanism was proposed and analyzed.

Study of receptor mediated selective anion transmembrane transport using parallel artificial membrane permeability assay

The separation performance of inorganic anions ReO4(-), Br(-), SO4(2-), and NO3(-) using porphyrin-alkaloid quaternary salt transporters is examined using parallel artificial membrane permeability assay. Active and selective transport of perrhenate is achieved by porphyrin-brucine conjugates. Herein, chlorides are used as antiporters and complete removal of perrhenates from a source solution is stimulated due to electrostatic effects.

Catena-Poly[[(4,4′-dimethyl-2,2′-bipyridine-κ2N,N′)cadmium]-di-μ-bromido

In the crystal of the title polymeric compound, [CdBr2(C12H12N2)]n, the CdII cation is located on a twofold rotation axis and is six-coordinated in a distorted octa­hedral geometry formed by two N atoms from the 4,4′-dimethyl-2,2′-bipyridine ligand and by four bridging Br− anions. The bridging function of the Br− anions leads to a polymeric chain running along the c axis. Weak C—H⋯π inter­actions observed between adjacent chains are effective in the stabilization of the three-dimensional packing.

3-(Ammoniomethyl)pyridinium dibromide

In the title salt, C6H10N2 2+·2Br−, the non-H atoms of the 3-methyl­pyridinium unit of the cation are almost coplanar (r.m.s. deviation = 0.0052 Å). In the crystal, the dications and Br anions are linked by a combination of six hydrogen bonds, viz. one Npy—H⋯Br, two C—H⋯Br and three H2N–H⋯Br, into supra­molecular layers, parallel to the bc plane, composed of alternating R24(10) and R24(8) loops. Weak π–π inter­actions between cationic rings with centroid–centroid distances of 3.891 (2) Å are also observed.

Synthesis and structural studies of mono- and dinuclear Cu(II) complexes with an ONO donor Schiff base ligand: Self-assembly and sulfato-bridged

Five Cu(II) complexes, [CuL(NO3)] (1), [CuLBr][CuLCH3OH]2Br2 (2), [CuLN3] (3), [CuL(ClO4)]2 (4) and [H2OLCu(μ-SO4)CuLH2O] (5), where L is the salicylaldehyde semicarbazone tridentate Schiff base ligand, have been synthesized and characterized by elemental analysis, FT-IR, UV–Vis and mass spectroscopy. The structures of compounds 2, 4 and 5 have been determined by single-crystal X-ray diffraction analyses. The structure of 2 contains both a mononuclear and a dinuclear species as distinct entities. The coordination geometry around the copper(II) ion in the mononuclear species is four coordinated square planar, whereas the dinuclear complex cation is five coordinated square pyramidal in which each copper(II) ion has a distorted square pyramidal geometry. In the mononuclear species, L acts as a tridentate ligand and the fourth position at the Cu ion is occupied by the Br anion, while in the dinuclear species, L acts as a bridging tridentate ligand connecting two Cu(II) ions, so there is an intramolecular copper–copper separation of 3.034Å and the apical position of each Cu ion is occupied by the oxygen of a methanol molecule. Complex 4 is a dinuclear species, in which each copper(II) ion exhibits a distorted square pyramidal geometry, which is similar to complex 2. The L ligand adopts a tridentate bridging mode with a copper–copper distance of 3.011Å. The apical position is occupied by a perchlorate anion. The molecular structure of 5 shows that it is a sulfato bridged dimeric Cu(II) complex with an intramolecular copper–copper separation of 4.733Å. The coordination geometry around each copper is five coordinated square pyramidal with two oxygen and one nitrogen atom from the tridentate ligand, L, and an oxygen from a coordinated water in equatorial positions and an oxygen from the bridging sulfato group in the axial position.

Cis-Dibromidobis(2-phenylpyridine-κN)platinum(II)

In the title complex, [PtBr2(C11H9N)2], the PtII ion has a distorted cis-Br2N2 square-planar coordination geometry defined by two N atoms from two 2-phenyl­pyridine (ppy) ligands and two Br− anions. The ppy ligands are not planar, the dihedral angles between the pyridine and benzene rings being 49.0 (3) and 47.3 (3)°. In the crystal, the complex mol­ecules are stacked in columns along the a axis. In the columns, there are numerous intra- and inter­molecular π–π inter­actions between the six-membered rings, the shortest ring centroid–centroid distance being 3.774 (6) Å.