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Comprehensive Summary: Traditional reduction coupling reactions of two bromides typically rely on transition metal catalysis. Here, we introduce the development of a visible‐light catalytic direct reduction coupling reaction between α‐CF3‐alkyl bromides and alkynyl bromides to access valuable organic frameworks. Our research confirms the excellent compatibility of this reaction with various functional groups, which could be used to modify the substrate with biologically active molecular fragments. Mechanistic investigations, including control experiments, fluorescence quenching studies, and light‐switching experiments, have provided insights into the reaction mechanism. This study paves the way for the application of visible‐light catalysis in diverse synthetic transformations, offering a sustainable and efficient approach to organic synthesis. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: An efficiently catalytic method toward the synthesis of indolin‐2‐ones featuring an allylic derived C3‐quaternary stereocenter via an intramolecular Heck cyclization/Suzuki coupling of N‐substituted‐N‐(2‐bromophenyl)acrylamides and organoboron reagents was successfully developed by using a 1,3‐bis(2,6‐diisopropylphenyl)acenaphthoimidazol‐2‐ylidene (AnIPr)‐ligated oxazoline palladacycle. It enabled a very broad substrate scope tolerating different functional groups, electronic properties and steric bulkiness. Notably, it revealed a great potential to build diverse heterocycle‐fused indoline alkaloids via the same intermediate 3‐allyl‐1,3‐dimethylindolin‐2‐ one. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Traditional reduction coupling reactions of two bromides typically rely on transition metal catalysis. Here, we introduce the development of a visible‐light catalytic direct reduction coupling reaction between α‐CF3‐alkyl bromides and alkynyl bromides to access valuable organic frameworks. Our research confirms the excellent compatibility of this reaction with various functional groups, which could be used to modify the substrate with biologically active molecular fragments. Mechanistic investigations, including control experiments, fluorescence quenching studies, and light‐switching experiments, have provided insights into the reaction mechanism. This study paves the way for the application of visible‐light catalysis in diverse synthetic transformations, offering a sustainable and efficient approach to organic synthesis. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Herein, we report an efficient and practical protocol for the photoinduced dehalocyclization of ortho‐halophenylacrylamides with formate by the engagement of a CO2 radical anion to access substituted oxindoles. This method proceeds smoothly under mild conditions and exhibits a wide range of substrate as well as remarkable functional group compatibility. [ABSTRACT FROM AUTHOR]

Negishi cross-coupling reaction is a familiar reaction for the formation of carbon–carbon bonds that couples organic halides or triflates with organozinc compounds. Palladium is used as a metal catalyst, sometimes nickel can also be used, e.g. Pd2(dba)3, PdCl2(P(otol)3)2, Pd(DPEPhos)Cl2, Ni(PPh3)2Cl2, etc. This reaction has vast applications in organic synthesis as many natural products and biologically active compounds can be obtained through this reaction. The main aim of this review is to summarize the recent synthetic applications of the Negishi reaction reported since 2011 which may be helpful to the researchers working on the development of mild and sustainable strategies regarding the synthesis of pharmaceutically important scaffolds. [ABSTRACT FROM AUTHOR]

Hybrid vapor deposition is one of the most appealing processes for perovskite photovoltaics fabrication, thanks to its versatile nature. By using sequentially different vapor deposition processes tailored to the inorganic and organic perovskite precursors' peculiarities, this type of process gives access to the full potential of vapor deposition. While vapor deposition of metal halides is well understood and mastered, vapor deposition of organohalide species is much more delicate (degradation of vapors, high vapor pressure, setup‐specific constraints). Here, a novel close space sublimation system is reported and in‐depth insights on the conversion into perovskite of a metal halide template are provided. In this evolution of the process, the substrate coated with metal halide template and the organohalide source are loaded together in a dedicated holder, then transferred into a vacuum chamber on a heating element already at temperature setpoint. The system enables a simple, fast, low‐cost, and easy‐to‐reproduce organohalide vapor deposition process. The formation of the perovskite in situ and identification different conversion regimes are studied. Furthermore, the influence of the chemical environment and chamber design on the process are discussed. Compositional tuning and additive engineering in the process are processed and fabricate proof of concept photovoltaic devices reaching high fill factors of 80% and 17% power conversion efficiency for a bandgap of 1.63 eV. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Stereoselective synthesis of multi‐substituted cyclobutanes with different substituents is still a daunting challenge in organic synthesis. We report here a practical and facile approach to synthesizing all‐trans 2,3,4‐trisubstituted cyclobutanones from readily available dichlorocyclobutanones. The substitution reaction proceeds smoothly via oxyallyl cation intermediates under mild basic conditions. Further transformation to the synthesis of 1,2,3,4‐tetrasubstituted cyclobutanes was also explored. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Stereoselective synthesis of multi‐substituted cyclobutanes with different substituents is still a daunting challenge in organic synthesis. We report here a practical and facile approach to synthesizing all‐trans 2,3,4‐trisubstituted cyclobutanones from readily available dichlorocyclobutanones. The substitution reaction proceeds smoothly via oxyallyl cation intermediates under mild basic conditions. Further transformation to the synthesis of 1,2,3,4‐tetrasubstituted cyclobutanes was also explored. [ABSTRACT FROM AUTHOR]

Organic chemistry is a mandatory component of chemistry II and chemistry III within the curriculum for pre-service chemistry teachers (PSCTs) pursuing a degree in chemistry teaching. The organic chemistry course sequence is well recognized as challenging and unapproachable for students, despite its significant relevance and impact across several sectors. While efforts have been made to recognize and deal with challenges faced by students in the cognitive and psychomotor aspects, there has been less attention given to identifying PSCTs' conceptual difficulties and misconceptions of organic chemistry. This includes the subsequent strategies to design instructions to enhance students' learning experiences, which are crucial elements in addressing their achievements in organic chemistry. The study aimed to identify the conceptual difficulties and misconceptions encountered by PSCTs in organohalides and stereochemistry. Furthermore, the study aimed to suggest strategies to enhance PSCTs' understanding of the course. The study was situated within the theoretical framework of constructivism and employed an interpretivist qualitative case study design. The population under study consisted of all individuals who were enrolled in the Bachelor of Education program within the faculty of educational sciences. A cohort of 33 whole-class PSCTs who had registered for the chemistry III course, where organohalides and stereochemistry were taught as units, were purposefully selected to participate in the study. The main instruments were document analysis, formal written tests, and interviews. Data were analyzed using thematic analysis. The study revealed that PSCTs encountered difficulties when attempting to solve problems related to organohalides and stereochemistry. In addition, PSCTs had misconceptions about these concepts. The study, therefore, recommends the implementation of suitable and appropriate instructional strategies to enhance PSCTs' conceptual understanding and reduce misconceptions. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A deuterated methylthiolating reagent with a broad spectrum, designated as DMTP, has been ingeniously formulated. This new reagent can be produced with high efficiency through the simple combination of commercially available methyl 3‐thiopropanoate and CD3I. This novel SCD3 reagent exhibits excellent reactivity with electrophiles such as alkyl iodides, benzyl chlorides, aryl halides (I, Br) and aryl triflates, resulting in high levels of deuterium content (99% D). Representative deuterated methylthiolated biomolecules, such as Sulfoxaflor, have been synthesized for use in pharmaceutical discovery and development. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A deuterated methylthiolating reagent with a broad spectrum, designated as DMTP, has been ingeniously formulated. This new reagent can be produced with high efficiency through the simple combination of commercially available methyl 3‐thiopropanoate and CD3I. This novel SCD3 reagent exhibits excellent reactivity with electrophiles such as alkyl iodides, benzyl chlorides, aryl halides (I, Br) and aryl triflates, resulting in high levels of deuterium content (99% D). Representative deuterated methylthiolated biomolecules, such as Sulfoxaflor, have been synthesized for use in pharmaceutical discovery and development. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The radical‐mediated reductive functionalization of aryl halides has been extensively studied. However, the related radical‐mediated intermolecular reductive 1,2‐diarylation of alkenes, using aryl halides as aryl radical sources, remains unexplored. Herein, a new electrophotocatalytic intermolecular reductive 1,2‐diarylation of alkenes is reported using aryl halides and cyanoaromatics to produce polyarylated alkanes. Using synergistic cathodic reduction and visible‐light photoredox catalysis, various electron‐rich and electron‐deficient aryl halides are combined with various alkenes and cyanoaromatics to characterize the broad substrate scope, excellent functional group compatibility, and excellent selectivity of this reaction. Mechanistic investigations reveal that this reaction may proceed via a radical process initiated by the reductive generation of aryl radicals from aryl halides and terminated by radical‐radical coupling with cyanoaromatic radical anions. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A new electrochemical strategy for the atom transfer radical addition (ATRA) of polychloroalkanes across olefins has been realized by the synergism of paired electrolysis and halogen bonding activation. Notably, readily accessible 4,4‐di‐tert‐butyl bipyridine (dtbpy), acting as a halogen bonding acceptor, shifted the reduction potential of C—Cl bonds positively by 110 mV. The decreased operating potential leads to a wide substrate scope and excellent functional group compatibility. A diverse array of terminal and internal alkenes such as (hetero)aryl olefins, unactive aliphatic olefins, and natural products and drugs‐derived olefins were well compatible. [ABSTRACT FROM AUTHOR]

The first C−SCF3/SeCF3 cross‐coupling reactions using gold redox catalysis [(MeDalphos)AuCl], AgSCF3 or Me4NSeCF3, and organohalides as substrates are reported. The new methodology enables a one‐stop shop synthesis of aryl/alkenyl/alkynyl trifluoromethylthio‐ and selenoethers with a broad substrate scope (>60 examples with up to 97 % isolated yield). The method is scalable, and its robustness is evidenced by the late‐stage functionalization of various bioactive molecules, which makes this reaction an attractive alternative in the synthesis of trifluoromethylthio‐ and selenoethers for pharmaceutical and agrochemical research and development. [ABSTRACT FROM AUTHOR]

Recently developed for the Fukuyama reaction, post-oxidative addition precatalysts (POxAPs) are also very efficient in catalyzing Negishi cross-coupling reactions between organohalides and organozinc reagents. Using very low catalyst loadings, POxAPs show similar catalytic activities to those of classical precatalysts such as XPhos Pd G4 or PEPPSI-IPr, with turnover numbers of up to 93,000. POxAPs are easily prepared, are stable to air and moisture, tolerate a wide range of functional groups in the Negishi cross-coupling reaction and contribute advantageously to the arsenal of organic chemists in terms of Pd precatalysts. [ABSTRACT FROM AUTHOR]

We present data collected from a number of snow-covered environments including two polar locations (Summit, Greenland and the South Pole) and two mid-latitude regions (a remote site in northern Michigan, and Niwot Ridge, Colorado). At each site, concentrations of CH3 I and C2 H5 I were enhanced within the interstitial air near the snow surface, compared to levels in boundary layer air. Fluxes of CH3 Br from surface snow to the atmosphere were observed at each site except Niwot Ridge, where CH3 Br appeared to have a sink. The mid-latitude sites showed significant emissions of CH3 Cl, mostly originating at the ground surface and traveling up through the snow, while at the polar locations CH3 Cl emissions from firn air were relatively small. In general, methyl halide mixing ratios in firn air were significantly greater at Summit than at the South Pole, with Summit showing a strong diurnal cycle in the production of alkyl halides that was well correlated with actinic radiation and firn temperature. We suggest that the most likely route to alkyl halide formation is through an acid catalyzed nucleophilic substitution of an alcohol type function by a halide, both of which should be preferentially segregated to the quasi-liquid layer at the surface of the snow grains. A series of experiments using a snow-filled quartz chamber irradiated by natural sunlight allowed estimation of emission trends that were hard to measure in the natural snowpack. These static chamber experiments confirmed significant production of the primary alkyl halides, following the order CH3 Cl > CH3 Br > C2 H5 Cl > CH3 I > C2 H5 Br > C2 H5 I > 1 - C3 H7 Br > 1 - C3 H7 I. Our observations at all four locations, including polar and mid-latitude sites, imply that alkyl halide production may be associated with all surface snows. © 2007 Elsevier Ltd. All rights reserved.

Addition of DMSO is found to greatly accelerate the aqueous hydrolysis of organohalides to alcohols, providing a neutral, more efficient, milder and more economic process. Mechanistic studies using 18O‐DMSO and 18O‐H2O showed that, contrary to the opinion that DMSO works as a dipolar solvent to enhance water's nucleophilicity, the accelerating effect comes from a complete oxygen transfer from DMSO to organohalides through generation of ROS+Me2⋅X− salts through C−O bond formation, followed by O−S bond disassociative hydrolysis of ROS+Me2⋅X− with water. This method is applicable to a wide range of organohalides and thus may have potential for practical industrial application, owing to easy recovery of DMSO from the H2O/DMSO mixture by regular vacuum rectification. [ABSTRACT FROM AUTHOR]

Despite the high potential impact of aqueous battery systems, fundamental characteristics such as cost, safety, and stability make them less feasible for large-scale energy storage systems. One of the main barriers encountered in the commercialization of aqueous batteries is the development of large-scale electrodes with high reversibility, high rate capability, and extended cycle stability at low operational and maintenance costs. To overcome some of these issues, the current research work is focused on a new class of material based on phenethylammonium bismuth iodide on fluorine doped SnO2-precoated glass substrate via aerosol-assisted chemical vapor deposition, a technology that is industrially competitive. The anode materials were electrochemically investigated in Zn2+ aqueous electrolytes as a proof of concept, which presented a specific capacity of 220 mAh g−1 at 0.4 A g−1 with excellent stability after 50 scans and capacity retention of almost 100%.

Extensive utilization of polybrominated diphenyl ethers (PBDEs) as flame retardants since the 1960s in a variety of commercial products has resulted in ubiquitous environmental distribution of commercial PBDE mixtures. Dangers posed to biological populations became apparent after the discovery of elevated levels of PBDEs in biota, most notably in human breast milk and tissues. Environmental persistence of PBDEs results in significant transboundary displacement, threatening fragile ecosystems globally. Despite efforts to curtail usage of PBDEs, public concern remains about the effects of legacy PBDEs contamination and continued discharge of PBDEs in regions lacking restrictions on usage and manufacture. Among available technologies for remediation of PBDEs such as ex-situ soil washing, electrokinetic degradation, and biodegradation, this review focuses on bioremediation by microbes under anaerobic conditions. Bioremediation is generally preferred as it is less disruptive to contaminated ecosystems, is cost-effective, and can be implemented at sites that may be inaccessible to more traditional ex-situ methods. The aims of this review are to (1) summarize current knowledge of anaerobic microbes that debrominate PBDEs and their associated synergistic partnerships with non-dehalogenating microbes; (2) explore current understandings of the metabolic reductive debromination of PBDE congeners; (3) discuss recent discoveries on dehalogenase genes involved in debromination of PBDEs.

Extensive utilization of polybrominated diphenyl ethers (PBDEs) as flame retardants since the 1960s in a variety of commercial products has resulted in ubiquitous environmental distribution of commercial PBDE mixtures. Dangers posed to biological populations became apparent after the discovery of elevated levels of PBDEs in biota, most notably in human breast milk and tissues. Environmental persistence of PBDEs results in significant transboundary displacement, threatening fragile ecosystems globally. Despite efforts to curtail usage of PBDEs, public concern remains about the effects of legacy PBDEs contamination and continued discharge of PBDEs in regions lacking restrictions on usage and manufacture. Among available technologies for remediation of PBDEs such as ex-situ soil washing, electrokinetic degradation, and biodegradation, this review focuses on bioremediation by microbes under anaerobic conditions. Bioremediation is generally preferred as it is less disruptive to contaminated ecosystems, is cost-effective, and can be implemented at sites that may be inaccessible to more traditional ex-situ methods. The aims of this review are to (1) summarize current knowledge of anaerobic microbes that debrominate PBDEs and their associated synergistic partnerships with non-dehalogenating microbes; (2) explore current understandings of the metabolic reductive debromination of PBDE congeners; (3) discuss recent discoveries on dehalogenase genes involved in debromination of PBDEs. [ABSTRACT FROM AUTHOR]

The utilization of halogenated organic compounds as terminal electron acceptors separates the phylogenetically diverse organohalide-respiring bacteria from other respiratory anaerobes that predominantly use nitrate, fumarate, sulfate or oxidized metals. Organohalide respiration is unique in recruiting a cobamide-containing iron--sulfur protein, the extracellular membrane-bound reductive dehalogenase, as terminal reductase in the electron transfer chain. In recent years substantial contributions have been made to the understanding of how electron transfer paths couple mechanistically to chemiosmosis in the organohalide-respiring bacteria. The structural analysis of a respiratory and a non-respiratory reductive dehalogenase revealed the intramolecular electron transfer via two cubane iron--sulfur clusters to the cobamide at the active site. Based on whether quinones are involved, two types of intermolecular electron transfer chains have been identified, which differ in their composition and mode of proton translocation. Indeed, various respiratory chain architectures have been unraveled and evidence for different putative coupling mechanisms presented. The identification of a multienzyme respiratory complex that combines uptake hydrogenase, a complex iron--sulfur molybdoenzyme and a reductive dehalogenase in Dehalococcoides mccartyi strain CBDB1 has raised new questions regarding the mode of energy conservation in these enigmatic microbes. In this mini-review, we highlight these findings and provide an outlook on potential future developments. [ABSTRACT FROM AUTHOR]

The degradation of hexachloroethane using chloridobis(dimethylglyoximato)pyridinecobalt(III), chloridobis(methylphenylglyoximato)pyridinecobalt(III) and chloridobis(diphenylglyoximato)pyridinecobalt(III) is described. To achieve the degradation, the cobalt complexes were reduced to the Co(I) oxidation state by electrochemical means. The chemical catalysis was studied using cyclic voltammetry by monitoring the current increase near the Co(II)/Co(I) reduction potential as the concentration of organohalogen was increased in solution. Tetrachloroethene was found as the degradation product. The apparent rate constant for the dehalogenation of hexachloroethane was estimated for all cobaloximes, obtaining 2.54 ± 0.08 × 10 5 for [Co(dmgH) 2 Cl(py)]; 2.38 ± 0.06 × 10 5 for [Co(mpgH) 2 Cl(py)] and 2.79 ± 0.15 × 10 5 for [Co(dpgH) 2 Cl(py)]. [ABSTRACT FROM AUTHOR]

A new reaction has been developed for the formal nucleophilic silyl substitution of aryl halides with silyllithium or silylpotassium reagents. Dimethylphenylsilyllithium reacted with various aryl halides to form the corresponding arylsilanes in moderate to good yields with concomitant formation of the disilanes under the optimized reaction conditions. Mechanistic studies indicated that this silyl substitution reaction progresses through polar halogenophilic attack of silyl nucleophiles. [ABSTRACT FROM AUTHOR]

We have calculated the 13C NMR chemical shifts of a large ensemble of halogenated organic molecules (81 molecules for a total of 250 experimental 13C NMR data at four different levels of theory), ranging from small rigid organic compounds, used to benchmark the performance of various levels of theory, to natural substances of marine origin with conformational degrees of freedom. Carbon atoms bonded to heavy halogen atoms, particularly bromine and iodine, are known to be rather challenging when it comes to the prediction of their chemical shifts by quantum methods, due to relativistic effects. In this paper, we have applied the state-of-the-art four-component relativistic density functional theory for the prediction of such NMR properties and compared the performance with two-component and nonrelativistic methods. Our results highlight the necessity to include relativistic corrections within a four-component description for the most accurate prediction of the NMR properties of halogenated organic substances. [ABSTRACT FROM AUTHOR]

Abstract: A quantitative structure–retention relationship (QSRR) study, has been carried out on the gas chromatograph/electron capture detector (GC/ECD) system retention times (t Rs) of 38 diverse chlorinated pesticides, herbicides, and organohalides by using molecular structural descriptors. Modeling of retention times of these compounds as a function of the theoretically derived descriptors was established by multiple linear regression (MLR) and partial least squares (PLS) regression. The stepwise regression using SPSS was used for the selection of the variables that resulted in the best-fitted models. Appropriate models with low standard errors and high correlation coefficients were obtained. Three types of molecular descriptors including electronic, steric and thermodynamic were used to develop a quantitative relationship between the retention times and structural properties. MLR and PLS analysis has been carried out to derive the best QSRR models. After variables selection, MLR and PLS methods used with leave-one-out cross validation for building the regression models. The predictive quality of the QSRR models were tested for an external prediction set of 12 compounds randomly chosen from 38 compounds. The PLS regression method was used to model the structure-retention relationships, more accurately. However, the results surprisingly showed more or less the same quality for MLR and PLS modeling according to squared regression coefficients R 2 which were 0.951 and 0.948 for MLR and PLS, respectively. [Copyright &y& Elsevier]

Hemin, iron(III) protoporphyrin IX chloride, was found to bind to mesoporous nanocrystalline (anatase) TiO2 thin films from DMSO solution, K = 105 M−1 at 298 K. The reactions of iron(II) protoporphyrin IX (heme) anchored to the TiO2 thin films, heme/TiO2, with CCl4, CHCl3, propachlor, and trichloroethylene were investigated in methanol, and pH 4 and 8 aqueous solution. The reactions were found to be first-order in heme/TiO2 and in organohalide. Second-order rate constants measured in aqueous solution increased in the order of CCl4 > propachlor > trichloroethylene > CHCl3. The FeIII/II formal reduction potentials of heme/TiO2 were estimated by cyclic voltammetry and found to be −340 mV at pH 4 and −600 mV at pH 8 vs. Ag/AgCl. Reactions with CCl4 and CHCl3 were faster at pH 8 than pH 4 ( k = 14.1 ± 0.7 and 0.63 ± 0.03 M−1 s−1 at pH 4 vs. k = 69 ± 3 and 1.33 ± 0.07 M−1 s−1 at pH 8, respectively), which was attributed to the more negative formal FeIII/II reduction potential at higher pH. The rate constants for propachlor reduction were similar at both pHs. Experiments were also performed with excess electrons trapped in TiO2, TiO2(e−), and heme/TiO2(e−). The reaction of CCl4 was 20 times faster with heme/TiO2(e−) compared to TiO2(e−) alone. In the case of trichloroethylene, no reaction was observed for TiO2(e−), but rapid reactivity was observed for heme/TiO2(e−), kobs = 1.0 × 10−3 s −1 suggestive of a multielectron transfer reaction mechanism. Dechlorinated products of propachlor and CCl4 were identified by GC/MS analysis. [ABSTRACT FROM AUTHOR]

Abstract: The reactions of NdI2 (1) with aryl halides, PhX (X=Cl, Br, I), in THF afford benzene and a minor amount of biphenyl. Benzyl chloride under the same conditions yields 1,2-diphenylethane, toluene and PhCH2I due to Cl/I exchange. Alkyl halides C7H15Br and cyclo-C6H11Cl are reduced to the corresponding hydrocarbons. t-BuCl affords a mixture of isobutane/isobutylene. Chlorotrimethylsilane is converted into Me3SiH, hexamethyldisilane and Me3SiO(CH2)4CH3 in 10%, 8% and 31% yields respectively at room temperature but 1%, 2% and 88% yields at −60°C. In benzene, the interaction of 1 with benzyl chloride proceeds at 80°C to give diphenylmethane in 66% yield. Without solvent the same reaction leads to formation of the oligomers PhCH2(p-C6H4CH2) n C6H4CH2Cl. Heating 1 in benzene with n-BuCl or cyclo-C6H11Cl affords mono- and disubstituted products, RC6H5 and 1,4-R2C6H4. The n-Bu groups in the reaction transform into sec-Bu isomers. Iodobenzene, bromobenzene, Me3SiCH2Cl and Me3SiCl are inert towards 1 in benzene. [Copyright &y& Elsevier]

Marine sediments are a major sink of organohalide pollutants, but the potential for offshore marine microbiota to transform these pollutants remains underexplored. Here, we report dehalogenation of diverse organohalide pollutants by offshore marine microbiota. Dechlorination of polychlorinated biphenyls (PCBs) was observed in four marine sediment microcosms, which was positively correlated with in situ PCB contamination. Three distinct enrichment cultures were enriched from these PCB-dechlorinating microcosms using tetrachloroethene (PCE) as the sole organohalide. All enrichment cultures also dehalogenated polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA), and 2,4,6-trichlorophenol (2,4,6-TCP). Particularly, two enrichments completely debrominated penta-BDEs, the first observation of complete debromination of penta-BDEs in marine cultures. Multiple Dehalococcoides and uncultivated Dehalococcoidia were identified in the initial sediment microcosms, but only Dehalococcoides was dominant in all enrichments. Transcription of a gene encoding a PcbA5-like reductive dehalogenase (RDase) was observed during dehalogenation of different organohalides in each enrichment culture. When induced by a single organohalide substrate, the PcbA5-like RDase dehalogenated all tested organohalides (PCE, PCBs, PBDEs, TBBPA, and 2,4,6-TCP) in in vitro tests, suggesting its involvement in dehalogenation of structurally distinct organohalides. Our results demonstrate the versatile dehalogenation capacity of marine Dehalococcoidia and contribute to a better understanding of the fate of these pollutants in marine systems.

Due to its enriched organic matter, nutrients and growth cofactors, as well as a diverse range of microorganisms, waste activated sludge (WAS) might be an ideal additive to stimulate organohalide respiration for in situ bioremediation of organohalide-contaminated sites. In this study, we investigated the biostimulation and bioaugmentation impacts of WAS-amendment on the performance and microbiome in tetrachloroethene (PCE) and polychlorinated biphenyls (PCBs) dechlorinating microcosms. Results demonstrated that WAS-amendment increased PCE- and PCBs-dechlorination rate as much as 6.06 and 10.67 folds, respectively. The presence of WAS provided a favorable growth niche for organohalide-respiring bacteria (OHRB), including redox mediation and generation of electron donors and carbon sources. Particularly for the PCE dechlorination, indigenous Geobacter and WAS-derived Dehalococcoides were identified to play key roles in PCE-to-dichloroethene (DCE) and DCE-to-ethene dechlorination, respectively. Similar biostimulation and bioaugmentation effects of WAS-amendment were observed on both PCE- and PCBs-dechlorination in three different soils, i.e., laterite, brown loam and paddy soil. Risk assessment suggested low potential ecological risk of WAS amendment in remediation of organohalide-contaminated soil. Overall, this study provided an economic and efficient strategy to stimulate the organohalide respiration-based bioremediation in field applications. [Display omitted] • Waste activated sludge (WAS) is an effective and applicable additive to enhance organohalide dehalogenation. • PCE and PCBs dechlorination rates were increased by 6.06 and 10.67 folds upon WAS amendment. • Biostimulation effects of WAS were observed on PCE and PCB dechlorination. • WAS bioaugmentation introduced both OHRB and OHRB's partners into bioremediation sites. [ABSTRACT FROM AUTHOR]

Despite the high potential impact of aqueous battery systems, fundamental characteristics such as cost, safety, and stability make them less feasible for large-scale energy storage systems. One of the main barriers encountered in the commercialization of aqueous batteries is the development of large-scale electrodes with high reversibility, high rate capability, and extended cycle stability at low operational and maintenance costs. To overcome some of these issues, the current research work is focused on a new class of material based on phenethylammonium bismuth iodide on fluorine doped SnO2-precoated glass substrate via aerosol-assisted chemical vapor deposition, a technology that is industrially competitive. The anode materials were electrochemically investigated in Zn2+ aqueous electrolytes as a proof of concept, which presented a specific capacity of 220 mAh g−1 at 0.4 A g−1 with excellent stability after 50 scans and capacity retention of almost 100%. [ABSTRACT FROM AUTHOR]

This review article highlights selected advances in triphosgene-enabled organic synthetic reactions that were reported in the decade of 2010–2019. Triphosgene is a versatile reagent in organic synthesis. It serves as a convenient substitute for the toxic phosgene gas. Despite its first known preparation in the late 19th century, the upward surge in the development of organic reactions using triphosgene interestingly began only three decades ago. Despite the relatively short history, triphosgene has been proven to be very useful in facilitating the preparation of a vast scope of value-added compounds, such as organohalides, acid chlorides, isocyanates, carbonyl addition adducts, heterocycles, among others. Furthermore, applications of triphosgene in complex molecules synthesis, polymer synthesis, and other techniques, such as flow chemistry and solid phase synthesis, have also emerged in the literature. Image 1 • A versatile reagent in organic synthesis and convenient substitute for phosgene gas. • Enabling the preparation of a vast scope of value-added compounds. • Applicable in solution- and solid-phase syntheses, as well as flow chemistry. [ABSTRACT FROM AUTHOR]

• Organohalide respiration has relatively high tolerance to metal ions, among which Cd2+ is the most inhibitive heavy metal. • No synergistic inhibition of metal ion mixtures on reductive dechlorination of PCE and PCB. • Metal ions may have indirect inhibition on organohalide respiration through affecting non-dechlorinating populations. Bioremediation of sites co-contaminated with organohalides and metal pollutants may have unsatisfactory performance, since metal ions can potentially inhibit organohalide respiration. To understand the detailed impact of metals on organohalide respiration, we tested the effects of four metal ions (i.e., Cu2+, Cd2+, Cr3+ and Pb2+), as well as their mixtures, on reductive dechlorination of perchloroethene (PCE) and polychlorinated biphenyls (PCBs) in three different cultures, including a pure culture of Dehalococcoides mccartyi CG1, a Dehalococcoides -containing microcosm and a Dehalococcoides-Geobacter coculture. Results showed that the inhibitive impact on organohalide respiration depended on both the type and concentration of metal ions. Interestingly, the metal ions might indirectly inhibit organohalide respiration through affecting non-dechlorinating populations in the Dehalococcoides -containing microcosm. Nonetheless, compared to the CG1 pure culture, the Dehalococcoides -containing microcosm had higher tolerance to the individual metal ions. In addition, no synergistic inhibition was observed for reductive dechlorination of PCE and PCBs in cultures amended with metal ion mixtures. These results provide insights into the impact of metal ions on organohalide respiration, which may be helpful for future in situ bioremediation of organohalide-metal co-contaminated sites. [ABSTRACT FROM AUTHOR]

Highlights from the article: Cover Feature: DMSO-Triggered Complete Oxygen Transfer Leading to Accelerated Aqueous Hydrolysis of Organohalides under Mild Conditions (ChemSusChem 13/2019) B The Front Cover b shows that addition of DMSO can greatly accelerate the aqueous hydrolysis of organohalides, thus providing a neutral, more efficient, milder, and more economic new process for alcohol preparation. This method is applicable to a wide range of organohalides and thus may have potential for practical industrial applications owing to the easy recovery of DMSO from the H SB 2 sb O/DMSO mixture by regular vacuum rectification.

Theoretical calculations focusing on the cleavage of the C-X bond in methyl halides (CH3X; X = Cl, Br, I) as mediated by CoI-based systems have been carried out using the hybrid functional ωB97-XD together with the basis set 6-311++G(2d,2p). A total of seven CoI-based compounds were evaluated: cob[I]alamin (CoICbl) in its base-on form and cobaloxime (CoICbx) with either no ligand or different ligands (either pyridine (PYR), tributylphosphine (TBP), dimethyl sulfide (DMS), cyclohexylisocyanide (CI), or 5,6-dimethylbenzimidazole (DMB)) at the lower axial position. For the large CoICbl system, an ONIOM scheme was employed, where the high layer was described at the DFT level and the low layer was computed using the semi-empirical method PM6. A full DFT model was employed for the CoICbx cases. An SN2-like mechanism was evaluated in all cases. The intrinsic reaction coordinate profiles suggested early transition states with activation energies of ≈ 12 kcal/mol, ≈ 10 kcal/mol, and ≈ 5 kcal/mol for C-Cl, C-Br, and C-I cleavage, respectively, which is consistent with the leaving group abilities of these halides. The evolutions of the atomic charges in and the bond orders of Co-C and C-X were computed, and the results confirmed the existence of early transition states (δBav≈ 40%), where the polarization Cδ+-Xδ− (%Ev ≈ 43%) is the determining factor in the reaction process. Finally, a comparison of all the determined parameters showed that the reaction in the DMB-CoICbx system resembles the process that occurs in the larger CoICbl, suggesting that the former system could be a reliable model for the study of reductive dehalogenation mediated by vitamin B12, which is key to the anaerobic microbiological treatment of halocarbon contaminants. [ABSTRACT FROM AUTHOR]

We have calculated the (13)C NMR chemical shifts of a large ensemble of halogenated organic molecules (81 molecules for a total of 250 experimental (13)C NMR data at four different levels of theory), ranging from small rigid organic compounds, used to benchmark the performance of various levels of theory, to natural substances of marine origin with conformational degrees of freedom. Carbon atoms bonded to heavy halogen atoms, particularly bromine and iodine, are known to be rather challenging when it comes to the prediction of their chemical shifts by quantum methods, due to relativistic effects. In this paper, we have applied the state-of-the-art four-component relativistic density functional theory for the prediction of such NMR properties and compared the performance with two-component and nonrelativistic methods. Our results highlight the necessity to include relativistic corrections within a four-component description for the most accurate prediction of the NMR properties of halogenated organic substances., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)