Search

NHC boryl radical mediated halogen atom transfer (XAT) is useful in organic synthesis. Yet, most of the reaction ends only with reducing the halogen to hydrogen, that is, the C-X to C-H. This is especially dominant for electron-deficient alkyl halides, where the formed electrophilic radical reacts rapidly with NHC boranes. Herein, by employing a sterically hindered NHC borane as the boryl radical precursor (IPr·BH 3 ), we were able to use the electrophilic-deficient alkyl halide (α-Iodide gem -di(B(pin))methane) in the C-C bond formation reaction. Mono-, disubstituted styrene, aliphatic alkenes, and heteroatom-substituted alkenes were used as reaction partners. Forty hydro( gem -diboryl)methylation products were obtained at room temperature in moderate to good yields. Detailed mechanistic studies revealed that the reaction mainly involved the radical process.

Microplastics (MPs) pollution and seawater acidification have increasingly become huge threats to the ocean ecosystem. Their impacts on microalgae are of great importance, since microalgae are the main primary producers and play a critical role in marine ecosystems. However, the impact of microplastics and acidification on unicellular red algae, which have a unique phycobiliprotein antenna system, remains unclear. Therefore, the impacts of polystyrene-MPs alone and the combined effects of MPs and seawater acidification on the typical unicellular marine red algae Porphyridium purpureum were investigated in the current study. The result showed that, under normal seawater condition, microalgae densities were increased by 17.75-41.67 % compared to the control when microalgae were exposed to small-sized MPs (0.1 μm) at concentrations of 5-100 mg L -1 . In addition, the photosystem II and antioxidant enzyme system were not subjected to negative effects. The large-sized MPs (1 μm) boosted microalgae growth at a low concentration of MPs (5 mg L -1 ). However, it was observed that microalgae growth was significantly inhibited when MPs concentration increased up to 50 and 100 mg L -1 , accompanied by the remarkably reduced F v /F m value and the elevated levels of SOD, CAT enzymes, phycoerythrin (PE), and extracellular polysaccharide (EPS). Compared to the normal seawater condition, microalgae densities were enhanced by 52.11-332.56 % under seawater acidification, depending on MPs sizes and concentrations, due to the formed CO 2 -enrichment condition and appropriate pH range. PE content in microalgal cells was significantly enhanced, but SOD and CAT activities as well as EPS content markedly decreased under acidification conditions. Overall, the impacts of seawater acidification were more pronounced than MPs impacts on microalgae growth and physiological responses. These findings will contribute to a substantial understanding of the effects of MPs on marine unicellular red microalgae, especially in future seawater acidification scenarios., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Markovnikov hydrobromination and hydrochlorination of alkynes were achieved using TMSX (X = Br, Cl) instead of corrosive HX (X = Br, Cl) as the bromination and chlorination reagents. Mn(OAc) 2 ·4H 2 O was used as the hydrobromination catalyst for electron-neutral/rich alkynes. For the hydrobromination of electron-deficient alkynes and hydrochlorination of alkynes, Zn(OAc) 2 ·2H 2 O was employed as the catalyst. Mechanistic studies suggested that the in situ formed TMS-substituted alkyne might be a reactive intermediate and the proton of the terminal alkyne should be a hydrogen source for the hydrohalogenation reaction.

Recently, using microalgae to remediate heavy metal polluted water has been attained a huge attention. However, heavy metals are generally toxic to microalgae and consequently decrease biomass accumulation. To address this issue, the feasibility of adding exogenous glucose, employing algae-bacteria system and algae-bacteria-activated carbon consortium to enhance microalgae growth were evaluated. The result showed that Cd 2+ removal efficiency was negatively correlated with microalgal specific growth rate. The exogenous glucose alleviated the heavy metal toxicity to algal cells and thus increased the microalgae growth rate. Among the different treatments, the algae-bacteria-activated carbon combination had the highest biomass concentration (1.15 g L -1 ) and lipid yield (334.97 mg L -1 ), which were respectively 3.03 times of biomass (0.38 g L -1 ) and 4.92 times of lipid yield (68.08 mg L -1 ) in the single microalgae treatment system. Additionally, this algae-bacteria-activated carbon consortium remained a high Cd 2+ removal efficiency (91.61%). In all, the present study developed an approach that had a great potential in simultaneous heavy metal wastewater treatment and microalgal lipid production., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)