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Chemosphere May 2020Brominated organic compounds (BOCs), abundant in Nature, originate from its own sources or anthropogenic activity. Many of these compounds are harmful and constitute a... (Review)
Review
Brominated organic compounds (BOCs), abundant in Nature, originate from its own sources or anthropogenic activity. Many of these compounds are harmful and constitute a serious threat, therefore it is important to study and understand their behavior and fate. In situ, BOCs undergo various chemical and biochemical reactions through distinctive mechanistic pathways. However, breaking C-Br specific bond is a crucial step in the transformation of brominated organic compounds. Understanding the mechanisms of debromination can be substantially enhanced by studying Br isotope effects. In this Mini-review we provide overlook of existing experimental techniques for Br isotope analysis, discuss Br kinetic isotope effects measured for selected chemical and biochemical reactions in the light of underlying reaction mechanisms, and review the outcome from computational study of performed to provide more insightful interpretation of observed findings.
Topics: Bromine; Halogenation; Isotopes; Kinetics
PubMed: 31918087
DOI: 10.1016/j.chemosphere.2019.125746 -
Chemical Reviews Jun 2016Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular... (Review)
Review
Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular bromine in organic synthesis is well-known. However, due to the hazardous nature of bromine, enormous growth has been witnessed in the past several decades for the development of solid bromine carriers. This review outlines the use of bromine and different bromo-organic compounds in organic synthesis. The applications of bromine, a total of 107 bromo-organic compounds, 11 other brominating agents, and a few natural bromine sources were incorporated. The scope of these reagents for various organic transformations such as bromination, cohalogenation, oxidation, cyclization, ring-opening reactions, substitution, rearrangement, hydrolysis, catalysis, etc. has been described briefly to highlight important aspects of the bromo-organic compounds in organic synthesis.
Topics: Bromine; Organic Chemicals
PubMed: 27199233
DOI: 10.1021/acs.chemrev.5b00400 -
Nature Chemistry May 2012
Topics: Bromine; Humans; Odorants
PubMed: 22614389
DOI: 10.1038/nchem.1361 -
Chemical & Pharmaceutical Bulletin 2022Bromine K-edge X-ray absorption near-edge structure (XANES) spectroscopy analyses were used to evaluate the crystals of the active pharmaceutical ingredients, eletriptan...
Bromine K-edge X-ray absorption near-edge structure (XANES) spectroscopy analyses were used to evaluate the crystals of the active pharmaceutical ingredients, eletriptan hydrobromide, dextromethorphan hydrobromide and scopolamine hydrobromide salts and the solid dispersion of eletriptan hydrobromide. The crystals and the solid dispersion of the active pharmaceutical ingredient (API) salts could be discriminated based on the shape of the XANES spectra. The differences in the shape of XANES spectra was ascribable to the differences in the interatomic interactions of the bromine ions based on the crystal structures. Ratio of the eletriptan hydrobromide α-form crystal in mixed powders of α-form and monohydrate crystals could be quantified by the linear-combination fitting using their XANES spectra. These results indicated that the XANES spectroscopy are a potent method for evaluating the APIs of pharmaceutical formulations even at the higher energy region around the bromine K-edge of 13470 eV.
Topics: Bromine; Catalysis; Hydrocarbons, Brominated; Molecular Structure; Pharmaceutical Preparations; Salts; X-Ray Absorption Spectroscopy
PubMed: 35110440
DOI: 10.1248/cpb.c21-00912 -
Chemistry (Weinheim An Der Bergstrasse,... Jan 2024NIR-II fluorescence imaging-guided photothermal therapy (PTT) has been widely investigated due to its great application potential in tumor theranostics. PTT is an...
NIR-II fluorescence imaging-guided photothermal therapy (PTT) has been widely investigated due to its great application potential in tumor theranostics. PTT is an effective and non-invasive tumor treatment method that can adapt to tumor hypoxia; nevertheless, simple and effective strategies are still desired to develop new materials with excellent PTT properties to meet clinical requirements. In this work, we developed a bromine-substitution strategy to enhance the PTT of A-D-A'-D-A π-conjugated molecules. The experimental results reveal that bromine substitution can notably enhance the absorptivity (ϵ) and photothermal conversion efficiency (PCE) of the π-conjugated molecules, resulting in the brominated molecules generating two times more heat (ϵ ×PCE) than their unsubstituted counterpart. We disclose that the enhanced photothermal properties of bromine-substituted π-conjugated molecules are a combined outcome of the heavy-atom effect, enhanced ICT effect, and more intense bromine-mediate intermolecular π-π stacking. Finally, the NIR-II tumor imaging capability and efficient PTT tumor ablation of the brominated π-conjugated materials demonstrate that bromine substitution is a promising strategy for developing future high-performance NIR-II imaging-guided PTT agents.
Topics: Humans; Phototherapy; Bromine; Neoplasms; Photothermal Therapy; Nanoparticles; Cell Line, Tumor; Theranostic Nanomedicine
PubMed: 37915302
DOI: 10.1002/chem.202303502 -
Environmental Science & Technology Nov 2023Parabens and salicylates were examined as disinfection byproduct (DBP) precursors to explore the possible influence of ipso substitution (i.e., halogen exchange) on the...
Parabens and salicylates were examined as disinfection byproduct (DBP) precursors to explore the possible influence of ipso substitution (i.e., halogen exchange) on the yield and speciation of trihalomethanes (THMs) formed during water chlorination. Substoichiometric conversion of C-Br bonds into C-Cl bonds was confirmed for several parabens and salicylates. The co-occurrence of (mono)brominated and nonhalogenated precursors in the presence of free chlorine (but in the absence of added Br) generated polybrominated THMs, implicating ipso substitution. The THM molar yield, bromine incorporation, and bromine recovery from brominated and nonhalogenated precursor mixtures were commensurate with those observed from equimolar additions of NaBr, indicating efficient displacement of aromatic bromine by free chlorine followed by reincorporation of liberated HOBr into DBP precursors. The THM molar yield from brominated precursors was enhanced by a factor of ≤20 relative to that from nonhalogenated precursors. Trends in THM molar yields and bromine incorporation differed between brominated parabens and brominated salicylates, suggesting that the influence of ipso substitution on THM formation varies with the structure of the organic precursor. Collectively, these results provide new evidence of the often-overlooked role ipso substitution can play in promoting halogen exchange and bromine enrichment among DBPs in chlorinated waters.
Topics: Bromine; Trihalomethanes; Chlorine; Parabens; Water Purification; Water Pollutants, Chemical; Halogens; Disinfection; Halogenation; Chlorides; Salicylates; Disinfectants
PubMed: 37096875
DOI: 10.1021/acs.est.3c00852 -
Water Research Sep 2021Bromine (Br) and iodine (I) in source water can form highly toxic brominated or iodinated disinfection byproducts in treatment plants. For the first time, the occurrence...
Bromine (Br) and iodine (I) in source water can form highly toxic brominated or iodinated disinfection byproducts in treatment plants. For the first time, the occurrence of Br and I speciation and their proportion, transformation in the drinking water supply system along the Changjiang River were investigated. 96 water samples were collected from eight drinking water treatment plants under conditions of low, normal, and flood water regimes. Total Br (TBr) and total I (TI) concentrations were quantified by inductively coupled plasma mass spectrometry (ICPMS) and inorganic Br/I forms (bromide, bromate, iodide, and iodate) were determined by high-performance liquid chromatography coupled with ICPMS. Concentrations of organic Br/I were calculated as the difference between total Br/I and inorganic Br/I. Water regimes had different effect on Br and I species, and there were different rules in untreated and treated water samples. Apparent increase of TBr and TI concentrations after water treatment were observed, which indicated the possibility of Br/I introduction by chlorine-containing disinfectant. The occurrence of TBr, TI, bromide, and total organic I in the river were investigated to increase with the direction of flow. In addition, TBr and TI concentrations correlated with the concentrations of artificial sweeteners (e.g., acesulfame and sucralose, a kind of wastewater indicator), suggesting the influence of domestic sewage on Br and I in the river. In untreated water, bromide was the main Br species, and after treatment more than 50% was transformed into organic Br. Iodoorganics were the majority of I species in raw water and were partly transformed into iodate after treatment. Overall, the Br/I species have accumulation potential in the Changjiang River and organic forms occupy high proportion in treated water samples, which should be paid more attention.
Topics: Bromine; Disinfection; Drinking Water; Halogenation; Iodides; Iodine; Rivers; Water Pollutants, Chemical; Water Purification; Water Supply
PubMed: 34252864
DOI: 10.1016/j.watres.2021.117401 -
Forensic Science 1978The normal levels of bromine in human tissue are given and their use in the interpretation of levels found when over-exposure is a possibility is described. Bromine is...
The normal levels of bromine in human tissue are given and their use in the interpretation of levels found when over-exposure is a possibility is described. Bromine is "normally" distributed in human tissue as are essential trace elements. This allows a bromine (microgram) to chlorine (mg) ratio to be established (3.2) above which bromine exposure must be considered. The bromine concentrations in sections of hair can be used to establish the time of administration even when small amounts are ingested, but owing to the long half-life (about 15 days) found in human tissue interpretation after multiple doses may be difficult.
Topics: Bromine; Hair; Humans; Neutron Activation Analysis; Substance-Related Disorders; Tissue Distribution
PubMed: 658861
DOI: 10.1016/s0379-0738(78)80009-7 -
Talanta Jan 2019In this work, an analytical method for bromine and iodine determination in human saliva was proposed. A simple protocol based on centrifugation and direct analysis of...
In this work, an analytical method for bromine and iodine determination in human saliva was proposed. A simple protocol based on centrifugation and direct analysis of supernatant by inductively coupled plasma mass spectrometry (ICP-MS) was investigated. Although this method was feasible for bromine determination, iodine was partially present in the supernatant and an agreement about 54% with reference value was obtained. In addition, microwave-induced combustion (MIC) and microwave-assisted dissolution were also evaluated. Using MIC, 0.2 mL of saliva added on 300 mg of microcrystalline cellulose were efficiently digested. A diluted solution (50 mmol L NHOH) was used for analytes absorption, and a reflux step of 5 min was applied to ensure quantitative recoveries of Br and I. Accuracy was evaluated by analyte recovery experiments, and recoveries between 94% and 98% were obtained. Microwave-assisted dissolution was evaluated for 2.0 mL of saliva using also a diluted alkaline solution (25 mmol L NHOH) and a microwave irradiation program of 35 min (including the cooling step). Results for this method agreed with those obtained using MIC. Although MIC has also been appropriated for further determination of Br and I in saliva, microwave-assisted dissolution can be considered a simpler sample preparation method and it was effective for high amount of sample (up to 2.0 mL). Moreover, final solutions were compatible with ICP-MS analysis, allowing the quantification of Br and I in human saliva at ultra-trace concentrations (limits of quantification were 0.052 μg mL for Br and 0.022 μg mL for I).
Topics: Bromine; Clinical Chemistry Tests; Humans; Iodine; Mass Spectrometry; Microwaves; Saliva
PubMed: 30262078
DOI: 10.1016/j.talanta.2018.08.081 -
Physical Chemistry Chemical Physics :... May 2023To understand the mechanism underlying the high radio-sensitisation of living cells possessing brominated genomic DNA, X-ray photoelectron spectroscopy (XPS) using...
To understand the mechanism underlying the high radio-sensitisation of living cells possessing brominated genomic DNA, X-ray photoelectron spectroscopy (XPS) using synchrotron X-rays with energies of 2000 or 2500 eV was used to study brominated and nonbrominated nucleobases, nucleosides and nucleotides. The bromine atom significantly reduced the energy gap between the valence and conduction states, although the core level states were not greatly affected. This finding was supported by quantum chemical calculation for the nucleobases and nucleosides. Our findings strongly indicate that the energy gaps between the valence and conduction levels of the molecules are significantly reduced by bromination. Furthermore, the brominated molecules are more likely to produce inelastic scattering low energy electrons upon exposure to 2000 or 3000 eV X-rays. This modification of electronic properties around the brominated group may both facilitate electron transfer to the brominated site in DNA and increase the probability of reaction with low energy electrons. These processes can induce DNA damage, presumably resulting in debromination of the uracil moiety and a subsequent cytotoxic effect.
Topics: Bromine; DNA; Uracil; DNA Damage
PubMed: 37198941
DOI: 10.1039/d3cp01597a