Progress in Analytical Methods of Halogenated Disinfection By-Products

Ensuring the health and safety of drinking water is crucial for both nations and their citizens.Since the 20th century,the disinfection of drinking water,effectively controlling pathogens in water sources,has become one of the significant advances in public health.However,the disinfectants used in the process,such as chlorine and chlorine dioxide,react with natural organic matter in the water to produce disinfection by-products(DBPs).Most of these DBPs contain chlorine,and if the source water contains bromine or iodine,brominated or iodinated DBPs,collectively referred to as Halogenated disinfection byproducts(X-DBPs),are formed.Numerous studies have found that X-DBPs pose potential risks to human health and the environment,leading to widespread concern.Mass spectrometry has become an important means of discovering new types of X-DBPs.This paper focuses on the study of methods for analyzing X-DBPs in drinking water using mass spectrometry.

A QSRR Study on the Relative Retention Time of Halogenated Methyl-phenyl Ethers

Halogenated methyl-phenyl ethers (anisoles) are ubiquitous organic compounds in the environment. In the present study, geometrical optimization and electrostatic potential calcu- lations have been performed for 42 halogenated anisoles at the HF/6-31G* level. A number of sta- tistically based parameters have been obtained. By multiple regression method, linear relationships between the gas-chromatographic relative retention time (RRT) and structural descriptors have been established for the training set of 32 halogenated anisoles. The result showed that the parameters derived from electrostatic potentials (ESPs) together with the molecular volume (Vmc) could be well used to express the quantitative structure-RRT relationships of halogenated anisoles. The best two-variable regression model gives a correlation coefficient of 0.980 and a standard deviation of 0.07, and the leave-one-out cross-validated correlation coefficient is 0.975. The goodness of the model has been further validated through exploring the predictive power for the testing set of 10 halogenated anisoles.

Quantitative structure－activity study on the reductive dehalogenation potency of the halogenated aromatics

In this paper . the reductive dehalogenation potency of haloarenes in mathanogenic sedirnent - watersystems was divided into two classes according to the length of acclimation period and degradation rate con-stants during acclimation time. Based on the rn

Halogenated thiophene substitutions on quinoxaline unit to achieve morphology optimization in efficient organic solar cells

Halogenated thiophenes are generally used units for constructing organic semiconductor materials for photovoltaic applications.Here,we introduced thiophene,2-bromothiophene,and 2-chlorothiophene units to the central core of quinoxaline-based acceptors and obtained three acceptors,Qx-H,Qx-Br,and Qx-Cl,respectively.Compared with Qx-H,Qx-Br and Qx-Cl showed enhanced absorption,down-shifted energy levels,improved crystallinity,and reduced energy disorder.The improved crystallinity significantly optimized the blend morphology,leading to efficient charge generation and transport and,therefore,less bimolecular recombination.Eventually,PM6:Qx-Br-based devices exhibited an outstanding power conversion efficiency of 17.42%with a high open-circuit voltage(VOC)of 0.915 V.Furthermore,Y6 was introduced into the PM6:Qx-Br binary system to improve the light utilization,and the resulting ternary devices delivered a high PCE of 18.36%.This study demonstrated the great potential of halogenated thiophene substitution in quinoxaline-based acceptors for building high-performance organic solar cell acceptor materials.

Electrophilic Halogen Reagents-mediated Halogenation: Synthesis of Halogenated Dihydro-1,3-oxazine Derivatives

Halogenation of N-cinnamylbenzamides and N-[(2H-chromen-3-yl)methyl]benzamides using electrophilic halogen source was reported.Various halogenated dihydro-1,3-oxazine derivatives(45 examples)were synthesized in high to excellent yields(up to 98%yields),as well as halogenated dihydrochromeno-1,3-oxazine derivatives(56 examples,up to 96%yields).The properties of mild conditions,metal-free and high efficiency of the reaction made it a promising strategy in future applications for the construction of carbon-halogen(fluorine,F;chlorine,Cl;bromine,Br;iodine,I)bond and 1,3-oxazine derivatives.

Chemistry,Biosynthesis,and Biological Activity of Halogenated Compounds Produced by Marine Microorganisms

Natural products derived from marine microorganisms have been received great attention as a potential source of new compound entities for drug discovery.The unique marine environment brings us a large group of halogen-containing natural products with abundant biological functionality and good drugability.Meanwhile,biosynthetically halogenated reactions are known as a significant strategy used to increase the pharmacological activities and pharmacokinetic properties of compounds.Given that a tremendous increase in the number of new halogenated compounds from marine microorganisms in the last five years,it is necessary to summarize these compounds with their diverse structures and promising bioactivities.In this review,we have summarized the chemistry,biosynthesis(related halogenases),and biological activity of a total of 316 naturally halogenated compounds from marine microorganisms covering the period of 2015 to May 2021.Those reviewed chlorinated and brominated compounds with the ratio of 9:1 were predominantly originated from 36 genera of fungi(62%)and 9 bacterial strains(38%)with cytotoxic,antibacterial,and enzyme inhibitory activities,structural types of which are polyketides(38%),alkaloids(27%),phenols(11%),and others.This review would provide a plenty variety of promising lead halogenated compounds for drug discovery and inspire the development of new pharmaceutical agents.

A review of halogenated natural products in Arctic,Subarctic and Nordic ecosystems

Halogenated natural products(HNPs)are organic compounds containing bromine,chlorine,iodine,and rarely fluorine.HNPs comprise many classes of compounds,ranging in complexity from halocarbons to higher molecular weight compounds,which often contain oxygen and/or nitrogen atoms in addition to halogens.Many HNPs are biosynthesized by marine bacteria,macroalgae,phytoplankton,tunicates,corals,worms,sponges and other invertebrates.This paper reviews HNPs in Arctic,Subarctic and Nordic ecosystems and is based on sections of Chapter 2.16 in the Arctic Monitoring and Assessment Program(AMAP)assessment Chemicals of Emerging Arctic Concern(AMAP,2017)which deal with the higher molecular weight HNPs.Material is updated and expanded to include more Nordic examples.Much of the chapter is devoted to“bromophenolic”HNPs,viz bromophenols(BPs)and transformation products bromoanisoles(BAs),hydroxylated and methoxylated bromodiphenyl ethers(OH-BDEs,MeO-BDEs)and polybrominated dibenzo-p-dioxins(PBDDs),since these HNPs are most frequently reported.Others discussed are 2,20-dimethoxy-3,30,5,50-tetrabromobiphenyl(2,20-dimethoxy-BB80),polyhalogenated 10-methyl-1,20-bipyrroles(PMBPs),polyhalogenated 1,10-dimethyl-2,20-bipyrroles(PDBPs),polyhalogenated N-methylpyrroles(PMPs),polyhalogenated N-methylindoles(PMIs),bromoheptyl-and bromooctyl pyrroles,(1R,2S,4R,5R,10E)-2-bromo-1-bromomethyl-1,4-dichloro-5-(20-chloroethenyl)-5-methylcyclohexane(mixed halogenated compound MHC-1),polybrominated hexahydroxanthene derivatives(PBHDs)and polyhalogenated carbazoles(PHCs).Aspects of HNPs covered are physicochemical properties,sources and production,transformation processes,concentrations and trends in the physical environment and biota(marine and freshwater).Toxic properties of some HNPs and a discussion of how climate change might affect HNPs production and distribution are also included.The review concludes with a summary of research needs to better understand the role of HNPs as“chemicals of emerging Arctic concern”.

Room-temperature hydrogenation of halogenated nitrobenzenes over metal-organic-framework-derived ultra-dispersed Ni stabilized by N-doped carbon nanoneedles

Ultra-dispersed Ni nanoparticles(7.5 nm)on nitrogen-doped carbon nanoneedles(Ni@NCNs)were prepared by simple pyrolysis of Ni-based metal–organic-framework for selective hydrogenation of halogenated nitrobenzenes to corresponding anilines.Two different crystallization methods(stirring and static)were compared and the optimal pyrolysis temperature was explored.Ni@NCNs were systematically characterized by wide analytical techniques.In the hydrogenation of p-chloronitrobenzene,Ni@NCNs-600(pyrolyzed at 600°C)exhibited extraordinarily high performance with 77.9 h^(–1)catalytic productivity and>99%p-chloroaniline selectivity at full p-chloronitrobenzene conversion under mild conditions(90°C,1.5 MPa H2),showing obvious superiority compared with reported Ni-based catalysts.Notably,the reaction smoothly proceeded at room temperature with full conversion and>99%selectivity.Moreover,Ni@NCNs-600 afforded good tolerance to various nitroarenes substituted by sensitive groups(halogen,nitrile,keto,carboxylic,etc.),and could be easily recycled by magnetic separation and reused for 5 times without deactivation.The adsorption tests showed that the preferential adsorption of–NO2 on the catalyst can restrain the dehalogenation of p-chloronitrobenzene,thus achieving high p-chloroaniline selectivity.While the high activity can be attributed to high Ni dispersion,special morphology,and rich pore structure of the catalyst.

Aliphatic Halogenated Hydrocarbons: Report and Analysis of Liver Injury in 60 Patients

Background and Aims:Intoxications by aliphatic halogenated hydrocarbons(AHH),used as effective solvents,are rare and may cause life-threatening liver injury.Patients with acute intoxications by AHH received an innovative treatment.Methods:Analyzed were data of 60 patients intoxicated by AHH,such as dichloromethane(n=3),chloroform(n=2),carbon tetrachloride(n=12),1,2-dichloroethane(n=18),1,1,2-trichloroethane(n=2),trichloroethylene(n=2),tetrachloroethylene(n=13)or mixed AHH chemicals(n=8),who received a new treatment consisting of CO2-induced hyperventilation to accelerate toxin removal via the lungs.Results:Added to the inspiration air at a flow rate of 2-3 Liter min-1,CO2 increased the respiratory volume up to 25-30 Liter min-1,ensuring forced AHH exhalation.This CO2-induced hyperventilation therapy was commonly well tolerated by the 60 patients and lasted for 106.0±10.5 hours.In most cases,initially increased liver test results of aminotransferases normalized quickly under the therapy,and liver histology obtained at completion of the therapy revealed,in the majority of patients,normal findings or fatty changes,and rarely severe single cell necrosis but no confluent liver cell necrosis.Despite therapy,clinical outcome was unfavorable for 4/60 patients(6.7%)of the study cohort,due to single or combined risk factors.These included late initiation of the CO2-induced hyperventilation therapy,intentional intoxication,uptake of high amounts of AHH,concomitant ingestion of overdosed drugs,consumption of high amounts of alcohol,and history of alcohol abuse.Conclusions:For intoxications by AHH,effective therapy approaches including forced hyperventilation to increase toxin removal via the lungs are available and require prompt initiation.

Environmental levels and toxicological potencies of a novel mixed halogenated carbazole

The present work involves an extensive analytical and toxicological description of a recently identified mixed halogenated carbazole found in sediment samples,1,8-dibromo-3,6-dichloro-9H-carbazole(BCCZ).Concentrations and the relative effect potency(REP)were calculated for the target BCCZ in a set of stream sediments collected in 2008 in Ontario,Canada.The levels calculated for BCCZ as compared to those previously assessed for legacy persistent organic pollutants(POPs)in the same samples revealed a significant contribution of BCCZ to the total organic chemical contamination(<1%e95%;average 37%).The corresponding dioxin toxic equivalencies(TEQs)of BCCZ in the sediment extracts were estimated from experimental REP data.The experimental data presented supports the classification of this emerging halogenated chemical as a contaminant of emerging environmental concern.Although potential emission sources could not be identified,this study highlights the importance of on-going research for complete characterization of halogenated carbazoles and related compounds.

Detection and Identification of a Novel Quinone Ketoxy Radical Produced by Metal-independent Decomposition of Hydroperoxides by Halogenated Quinones

We have shown recently that halogenated quinones could enhance the decomposition of hydroperoxides and formation of alkoxyl/hydroxyl radicals independent of transition

Evaluation of N-acetylcysteine and glutathione as quenching agents for the analysis of halogenated disinfection by-products

Disinfection by-products(DBPs), formed from the reactions of disinfectants with natural organic matter and halides in drinking water, were considered to be cytotoxic and genotoxic, and might trigger various cancers. The relatively low concentration of DBPs in finished water(low μg/L or even ng/L levels) and the interference from water matrix inhibited in situ determination of DBPs. Moreover, the further formation and degradation of DBPs by disinfectants during the holding time(several hours to several days) from sample collection to analysis could adversely affect the determination of DBPs. To obtain accurate, precise and reliable data of DBP occurrence and formation, robust and reliable sample preservation is indispensable. However, the commonly used quenching agents(e.g., sodium sulfite, sodium thiosulfate, and ascorbic acid) for sample preservation can decompose reactive DBPs by reductive dehalogenation. This study evaluated the performance of N-acetylcysteine(NAC) and glutathione(GSH) as quenching agents for the analysis of halogenated DBPs by investigating the stoichiometry of the disinfectant-quenching agent reaction, the formation of DBPs during chlor(am)ination of NAC or GSH, and the effects of NAC or GSH on the stability of 18 individual DBPs and total organic halogen(TOX). Based on the results of this study, NAC and GSH were considered to be ideal quenching agents for the analysis of most DBPs and TOX, except halonitromethanes.

Synthesis and Evaluation of Photophysical Properties of C-3 Halogenated Derivatives of 2-Phenylimidazo[1,2-a]pyridine

A CuX-mediated regioselective halogenation reaction of 2-phenylimidazo[1,2-a]pyridine in the presence of oxygen is introduced in this paper.This reaction provides an effective method for the production of C-3 halogenated 2-phenylimidazo[1,2-a]pyridines with a yield of up to 96%.A plausible mechanism for the formation of title compounds via 2-phenylimidazo[1,2-a]pyridine–CuX complex intermediate is proposed.The structure of representative compounds is established by the single crystal XRD method.The electronic structure,corroborated by Hirshfeld surface analysis and DFT calculations,rationalizes characters of relevant absorptions and emission as well as large Stokes shifts.

Textural and compositional variation of mica from the Dexing porphyry Cu deposit:constraints on the behavior of halogens in porphyry systems

The Dexing porphyry deposit is the largest porphyry Cu–Mo–Au deposit in South China.Biotite composition can record the physicochemical conditions and evolution history of magmatic-hydrothermal system.Biotite from the Dexing porphyry deposit could be divided to three types:primary magmatic biotite(Bi-M),hydrothermal altered magmatic biotite(Bi-A)and hydrothermal biotite(Bi-H).The temperature of Bi-M and Bi-H range from 719 to 767℃ and 690 to 727℃,respectively.Both magmatic and hydrothermal biotite have high Fe^(3+)/Fe^(2+)ratios(from 0.18 to 0.24)and XMgvalues(from 0.57 to 0.66),indicating a high oxygen fugacity.BiM has F lower than Bi-A and Bi-H(up to 0.26 wt%),but has Cl(Cl=0.18–0.30 wt%)similar to Bi-A and Bi-H(Cl=0.21–0.35 wt%),suggesting that high Cl/F ratios of early hydrothermal fluid may result from the exsolution from high Cl magma.From potassic alteration zone to phyllic and propylitic alteration zones,Cl decreases with increasing Cu,whereas F increases roughly.Therefore,Cl mostly originate from magma,but enrichment of F possibly results from reaction of fluids and Neoproterozoic strata.Negative correlation between Cl and Cu indicates that Cl might act as an important catalyst during Cu mineralization process.Biotite from Dexing has similar halogen compositions to other porphyry Cu-/Mo deposits in the world.Chlorine contents of hydrothermal fluid may be critical for Cu transportation and enrichment,while consumption of Cl would promote Cu deposition.

A Rational Design of Metal–Organic Framework Nanozyme with High‑Performance Copper Active Centers for Alleviating Chemical Corneal Burns

Metal–organic frameworks(MOFs)have attracted significant research interest in biomimetic catalysis.However,the modulation of the activity of MOFs by precisely tuning the coordination of metal nodes is still a significant challenge.Inspired by metalloenzymes with well-defined coordination structures,a series of MOFs containing halogen-coordinated copper nodes(Cu-X MOFs,X=Cl,Br,I)are employed to elucidate their structure–activity relationship.Intriguingly,experimental and theoretical results strongly support that precisely tuning the coordination of halogen atoms directly regulates the enzyme-like activities of Cu-X MOFs by influencing the spatial configuration and electronic structure of the Cu active center.The optimal Cu–Cl MOF exhibits excellent superoxide dismutase-like activity with a specific activity one order of magnitude higher than the reported Cu-based nanozymes.More importantly,by performing enzyme-mimicking catalysis,the Cu–Cl MOF nanozyme can significantly scavenge reactive oxygen species and alleviate oxidative stress,thus effectively relieving ocular chemical burns.Mechanistically,the antioxidant and antiapoptotic properties of Cu–Cl MOF are achieved by regulating the NRF2 and JNK or P38 MAPK pathways.Our work provides a novel way to refine MOF nanozymes by directly engineering the coordination microenvironment and,more significantly,demonstrating their potential therapeutic effect in ophthalmic disease.

An In-Situ Formed Tunneling Layer Enriches the Options of Anode for Efficient and Stable Regular Perovskite Solar Cells

Perovskite solar cells(PSCs)are taking steps to commercialization.However,the halogen-reactive anode with high cost becomes a stumbling block.Here,the halogen migration in PSCs is utilized to in situ generate a uniform tunneling layer between the hole transport materials and anodes,which enriches the options of anodes by breaking the Schottky barrier,enabling the regular PSCs with both high efficiency and stability.Specifically,the regular PSC that uses silver iodide as the tunneling layer and copper as the anode obtains a champion power conversion efficiency of 23.24%(certified 22.74%)with an aperture area of 1.04 cm^(2).The devices are stable,maintaining 98.6%of the initial effi-ciency after 500 h of operation at the maximum power point with continuous 1 sun illumination.PSCs with different tunneling layers and anodes are fabricated,which confirm the generality of the strategy.

An assessment study of absorption effect:LED vs tungsten halogen lamp for noninvasive glucose detection

Noninvasive gluoose monitoring development is critical for diabetic patient continuous moni-toring.However,almost all the available devices are invasive and painful.Noninvasive methods such as using spectroscopy have shown some good results.Unfortunately,the drawback was that the tungsten halogen lamps 1usage that is impractical if applied on human skin.This paper compared the light emitting diode(LED)to traditional tungsten halogen lamps as light source for glucose detection where the type of light source plays an important role in achieving a good spectrum quality.Glucose concentration measurement has been developed as part of noninvasive technique using optical spectroscopy.Small change and overlapping in tungsten halogen results need to replace it with a more convenient light source such as LED.Based on the result obtained,the performance of LED for absorbance spectrum gives a signifcantly different and is directly proportional to the glucose concentration.The result shows a linear trend and scucssully detects lowest at 60 to 160 mg/dL glucose concentration.

Chlorine-anion doping induced multi-factor optimization in perovskites for boosting intrinsic oxygen evolution

The oxygen evolution reaction(OER) plays a crucial role in many electrochemical energy technologies,and creating multiple beneficial factors for OER catalysis is desirable for achieving high catalytic efficiency.Here,we highlight a new halogen-chlorine(Cl)-anion doping strategy to boost the OER activity of perovskite oxides.As a proof-of-concept,proper Cl doping at the oxygen site of LaFeO3(LFO) perovskite can induce multiple favorable characteristics for catalyzing the OER,including rich oxygen vacancies,increased electrical conductivity and enhanced Fe-O covalency.Benefiting from these factors,the LaFeO2.9-δCl0.1(LFOCl) perovskite displays significant intrinsic activity enhancement by a factor of around three relative to its parent LFO.This work uncovers the effect of Cl-anion doping in perovskites on promoting OER performance and paves a new way to design highly efficient electrocatalysts.

The Principle of Introducing Halogen Ions Into β-FeOOH: Controlling Electronic Structure and Electrochemical Performance

Coordination tuning electronic structure of host materials is a quite effective strategy for activating and improving the intrinsic properties.Herein,halogen anion(X-)-incorporated β-FeOOH(β-FeOOH(X),X=F-,Cl-,and Br-) was investigated with a spontaneous adsorption process,which realized a great improvement of supercapacitor performances by adjusting the coordination geometry.Experiments coupled with theoretical calculations demonstrated that the change of Fe-O bond length and structural distortion of β-FeOOH,which is rooted in halogen ions embedment,led to the relatively narrow band gap.Because of the strong electronegativity of X-,the Fe element in β-FeOOH(X)s presented the unexpected high valence state(3+δ),which is facilitating to adsorb S032-species.Consequently,the designed β-FeOOH(X)s exhibited the good electric conductivity and enhanced the contact between electrode and electrolyte.When used as a negative electrode,the β-FeOOH(F) showed the excellent specific capacity of 391.9 F g-1 at 1 A g-1 current density,almost tenfold improvement compared with initial β-FeOOH,with the superior rate capacity and cyclic stability.This combinational design principle of electronic structure and electrochemical performances provides a promising way to develop advanced electrode materials for supercapacitor.

Halogen Storage Electrode Materials for Rechargeable Batteries

The ever-increasing demand for rechargeable batteries with high energy density,abundant resources,and high safety has pushed the development of various battery technologies based on cation,anion,or dual-ion transfer.The use of halogen storage electrode materials has led to new concept battery systems such as halide-ion batteries(HIB)and dual-ion batteries(DIB).This review highlights the recent progress on these electrode materials,including metal(oxy)halides,layered double hydroxides,MXenes,graphite-based materials,and organic materials with carbon or nitrogen redox centers.The reversible electrochemical halogen storage of halide ions(e.g.,F^(−),Cl^(−),and Br^(−)),dual halogen(e.g.,Br_(m)Cl_(n) and [ICl_(2)]^(−)),or binary halide anions(e.g.,PF_(6)^(−),AlCl_(4)^(−),[ZnCl_(x)]^(2−x),and [MgCl_(x)]^(2−x)) in the electrodes is covered.The challenges and mechanisms of halogen storage in various electrode materials in HIBs and DIBs are summarized and analyzed,providing insights into the development of high-performance halogen storage electrode materials for rechargeable batteries.