Electrochemical Benzylic C-H Amination via N-Aminopyridinium.

An electrochemical protocol for benzylic C(sp3)-H aminopyridylation via direct C-H/N-H cross-coupling of alkylarenes with N-aminopyridinium triflate has been developed. This method features excellent site-selectivity, broad substrate scope, redox reagent-free and facile scalability. The generated benzylaminopyridiniums can be readily converted to benzylamines via electroreductive N-N bond cleavage.

Electrochemical chemoselective hydrogenation of 1,4-enediones with HFIP as the hydrogen donor: scalable access to 1,4-diketones.

A straightforward electrochemical protocol for efficient hydrogenation of unsaturated CC bonds has been reported in an undivided cell. A series of versatile 1,4-diketones are smoothly generated under metal-free and external-reductant-free electrolytic conditions. Moreover, the tolerance of various functional groups and decagram-scale experiments have shown the practicability and potential applications of this methodology. Moreover, a range of heterocyclic compounds were easily prepared through follow-up procedures of 1,4-diketones.

Sex-specific metabolic dysregulation in digestive glands of green mussels following exposure to triazophos.

As a ubiquitous environmental pollutant in China, triazophos (TP) is known to have neurotoxicity, oxidative stress, and reproductive toxicity to mussels. To investigate the molecular mechanisms of TP toxicity, metabolic changes in the digestive glands of Perna viridis in different sexes were examined after treated with 35 µg/L TP. Notably, 158 significant different metabolites (SDMs) were detected in TP-treated mussels and more than half of the SDMs were lipids and lipid-like molecules, which suggested that TP disturbed the lipid metabolism of P. viridis. In addition, metabolites associated with neurotoxicity and reproductive disturbance were also detected in female and male mussels. Moreover, a larger number of SDMs were found in male mussels (120 SDMs) than females (99 SDMs), and 60 common metabolites exhibited consistent variation tendency and similar magnitude in both sexes. The metabolic alternations in female and male mussels displayed similar protective mechanisms and also sex-specific responses, male mussels were more sensitive to TP exposure. This research provided new data about the molecular mechanisms of TP toxicity and the gender specific changes in mussels after treated by chemicals.

Nickel-promoted oxidative domino Csp3-H/N-H bond double-isocyanide insertion reaction to construct pyrrolin-2-ones.

The first nickel-catalyzed oxidative domino Csp3-H/N-H double isocyanide insertion reaction of acetamides with isocyanides has been developed for the synthesis of pyrrolin-2-one derivatives. A wide range of acetamides bearing various functional groups are compatible with this reaction system by utilizing Ni(acac)2 as a catalyst. In this transformation, isocyanide could serve as a C1 connector and insert into the inactive Csp3-H bond, representing an effective way to construct heterocycles.

Reducing Defects Density and Enhancing Hole Extraction for Efficient Perovskite Solar Cells Enabled by π-Pb2+ Interactions.

Molecular doping is an of significance approach to reduce defects density of perovskite and to improve interfacial charge extraction in perovskite solar cells. Here, we show a new strategy for chemical doping of perovskite via an organic small molecule, which features a fused tricyclic core, showing strong intermolecular π-Pb2+ interactions with under-coordinated Pb2+ in perovskite. This π-Pb2+ interactions could reduce defects density of the perovskite and suppress the nonradiative recombination, which was also confirmed by the density functional theory calculations. In addition, this doping via π-Pb2+ interactions could deepen the surface potential and downshift the work function of the doped perovskite film, facilitating the hole extraction to hole transport layer. As a result, the doped device showed high efficiency of 21.41 % with ignorable hysteresis. This strategy of fused tricyclic core-based doping provides a new perspective for the design of new organic materials to improve the device performance.

Fast construction of isoquinolin-1(2H)-ones by direct intramolecular C-H/N-H functionalization under metal-free conditions.

The general protocol for the synthesis of isoxazolidine-fused isoquinolin-1(2H)-ones was established with the help of bench stable hypervalent iodine reagent PIDA. Polycyclic six-, seven- and eight-membered N-heterocycles can be rapidly synthesized from available amides under metal-free conditions within 1 min at room temperature through C-H/N-H functionalization. Moreover, the protocol has the merits of broad substrate scope, atom economy and operational simplicity.

The ruthenium(ii)-catalyzed C-H olefination of indoles with alkynes: the facile construction of tetrasubstituted alkenes under aqueous conditions.

An environmentally-friendly and facile protocol for the construction of tetrasubstituted alkenes has been established with Ru(ii)-catalyzed C-H bond functionalizations under mild conditions. The method features the usage of readily available substrates, without external oxidants and additives, 100% atom economy, and excellent regioselectivity, thus enhancing the practicability of this protocol. Moreover, this transformation proceeded smoothly under aqueous conditions and could be extended to the gram scale. N-Methoxyamide, as a directing group (DG), played a vital role in the transformation.

N-Phenoxyamides as Multitasking Reagents: Base-Controlled Selective Construction of Benzofurans or Dihydrobenzofuro[2,3- d]oxazoles.

An efficient method to selectively construct benzofuran and dihydrobenzofuro[2,3- d]oxazole derivatives has been successfully established by means of base-controlled cyclization of N-phenoxyamides with 1-[(triisopropylsilyl)ethynyl]-1,2-benziodoxol-3(1 H)-one (TIPS-EBX). N-phenoxyamides as multitasking reagents have triggered two different cascade reaction sequences. This is the first example of using TIPS-EBX for the transformation of C(sp) to either C(sp2) or C(sp3) under metal-free conditions.

A sialic acid-binding lectin with bactericidal and opsonic activities from Ruditapes philippinarum.

In the present study, a sialic acid-binding lectin was cloned and characterized from Manila clam Ruditapes philippinarum (designed as RpSabl). The open reading frame of RpSabl encoded a polypeptide of 162 amino acids with a calculated molecular mass of 17.7 kDa. Analysis of the conserved domain suggested that RpSabl was a new member of the sialic acid-binding lectins family. In non-stimulated clams, RpSabl transcripts were constitutively expressed in all five tested tissues, especially in hepatopancreas. After Vibrio anguillarum challenge, the expression of RpSabl mRNA in hepatopancreas was significantly up-regulated at 3 h (3.8-fold, P < 0.05), 6 h (4.9-fold, P < 0.05), 12 h (12.3-fold, P < 0.01) and 24 h (9.7-fold, P < 0.01), while RpSabl transcripts in hemocytes was only significantly up-regulated at 6 h (8.5-Fold, P < 0.01). RNAi-mediated knockdown of RpSabl transcripts affected the survival rates of Manila clam against V. anguillarum, perhaps mainly due to the inhibited expression of antibacterial effectors (e.g. lysozyme and defensin). Moreover, recombinant protein of RpSabl (rRpSabl) possessed binding activities towards lipopolysaccharides (LPS), peptidoglycan (PGN) and glucan in vitro. Coinciding with the Pathogen-associated molecular patterns (PAMPs) binding assay, rRpSabl displayed broad bacterial-agglutination properties towards Vibrio harveyi, Vibrio splendidus, V. anguillarum, Enterobacter cloacae and Aeromonas hydrophila. Meanwhile, the phagocytosis and encapsulation ability of hemocytes could be significantly enhanced by rRpSabl incubation. All these results showed that RpSabl could function as a versatile molecule involved in the innate immune responses of R. philippinarum.

Transcriptomic responses of Nile tilapia (Oreochromis niloticus) liver to environmental concentration of di(2-ethylhexyl)phthalate.

Di-(2-ethylhexyl) phthalate (DEHP) is currently the most frequently detected phthalic acid esters (PAEs) compounds and can induce diverse toxicities on aquatic organisms. To understand the molecular responses of fish to DEHP, we performed transcriptomic profiles in liver of tilapia (Oreochromis niloticus) which were exposed to environmental concentration of DEHP. A total of 30.10 Mb and 30.16 Mb clean reads were retrieved from the control and DEHP treated libraries, respectively. De-novo assembly of all the clean reads obtained 58,585 unigenes. After comparing the two libraries, 2814 and 1790 genes were identified as significantly increased and depressed, respectively. Gene ontology (GO) classification system and Kyoto Encyclopedia of Genes and Genomes (KEGG) database analysis demonstrated that DEHP significantly disturbed the expression level of genes associated with immunity, endocrine and reproductive system, lipid metabolism and so on. Quantitative real-time PCR was performed to validate the results of RNA-sequencing (RNA-seq) analysis. The resulting data provide new insights for exploring the molecular basis of tilapia response to DEHP exposure.

Transcriptional response of four C1q domain containing protein (C1qDC) genes from Venerupis philippinarum exposed to the water soluble fraction of No.0 diesel oil.

As pattern recognitionreceptors, the C1q-domain-containing (C1qDC) proteins play an important role in the pathogen recognition and complement pathway activation. In the present study, four novel C1q domain containing proteins (designated as VpC1qDC1, VpC1qDC2, VpC1qDC3 and VpC1qDC4) were cloned and characterized from clam Venerupis philippinarum. The four VpC1qDCs all possessed the conserved features critical for the fundamental structure and function of the C1q family. The four VpC1qDCs genes showed differential response profiles after exposure to the water soluble fraction of No.0 diesel oil (WSFD). More notably, VpC1qDC1 and VpC1qDC3 were more sensitive to low concentration of WSFD, as their mRNA level changed by higher magnitudes. In addition, VpC1qDC2 and VpC1qDC4 displayed notable increases with larger amplitude to high concentration of WSFD. All these results suggested that the transcriptional response of VpC1qDCs genes were probably a protective mechanism of the cell to oils pollution. The diverse expression patterns of VpC1qDCs demonstrated that VpC1qDC1 and VpC1qDC3 were sensitive responders to environmental stress in V. philippinarum.

Molecular diversity and evolution of defensins in the manila clam Ruditapes philippinarum.

Four types of defensins were identified in Manila clam and designated as Rpdef1, Rpdef2, Rpdef3 and Rpdef4, which encoded a polypeptide of 49, 46, 45 and 42 amino acids, respectively. Sequence alignments indicated that Rpdef1 shared 46.9% identity with Rpdef2, 40.8% with Rpdef3, and 34.7% with Rpdef4. Analysis of transcript polymorphism showed that Rpdef3 accounted for about 60% frequency of Rpdefs occurrence in clams from three geographic origins (Dalian, Qingdao and Hangzhou). By quantitative real-time RT-PCR (qRT-PCR) analysis, the transcripts of Rpdefs were mainly detected in hemocytes and they responded sensitively to bacterial challenge in hemocytes. Evolutionary analysis indicated that all Rpdefs were under positive selection with positively selected basic amino acid residues detected in the C-terminal regions, which perhaps have a functional relevance by modifying the charge distribution of Rpdefs. The results also showed some lineages with dN/dS > 1, suggesting positive selection pressures existed in some lineages of phylogeny tree constructed by mollusk defensins. Overall, our results suggest that Rpdefs perhaps played important roles in host defense and positive selection is the major driving force in generating high diversity of defensins in the Manila clam.

Cobalt-catalyzed C(sp(2))-H alkoxylation of aromatic and olefinic carboxamides.

The cobalt-catalyzed alkoxylation of C(sp(2) )H bonds in aromatic and olefinic carboxamides has been developed. The reaction proceeded under mild conditions in the presence of Co(OAc)2 ⋅4H2 O as the catalyst and tolerates a wide range of both alcohols and benzamide substrates, including even olefinic carboxamides. In addition, this reaction is the first example of the direct alkoxylation of alkenes through CH bond activation.

Cobalt(II)-Catalyzed C(sp2)-H Alkynylation/Annulation with Terminal Alkynes: Selective Access to 3-Methyleneisoindolin-1-one.

A highly efficient cobalt(II)-catalyzed alkynylation/annulation of terminal alkynes assisted by an N,O-bidentate directing group is described. This protocol is characterized by wide substrate scope utilizing cheap cobalt catalysts, and offers a new approach to 3-methyleneisoindolin-1-one, which can be converted into an oxadiazine salt in one step. Moreover, the directing group could be removed in three steps.

Copper-mediated direct alkoxylation of arenes using an N,O-bidentate directing system.

Highly effective CuCl-mediated C-H alkoxylation of arenes and heteroarenes has been developed by using a 2-aminopyridine 1-oxide moiety as an N,O-bidentate directing group. The reaction proceeds smoothly using a broad range of substrates to afford o-alkoxylated benzoic and heteroaromatic amide products. Moreover, the reaction system shows remarkable compatibility when hexafluoroisopropanol is used as a coupling parter; halogen, nitro, ether, alkoxy, ester, and sulfonyl functional groups are all tolerated. The directing group can be easily removed by base hydrolysis, affording o-alkoxylated benzoic acids.

Distribution and typologies of anthropogenic seafloor litter in the Pearl River Estuary and adjacent coastal waters, China.

Marine litter pollution poses a significant threat to offshore ecosystems, eliciting widespread concern. We investigated seafloor litter patterns in the Pearl River Estuary and adjacent coastal waters of China in 2023 via bottom trawl survey. Average number and weight densities were found to be 154.34 ± 30.95 n/km2 and 2384.63 ± 923.98 g/km2, respectively. Plastic was the most abundant material by number density (79.07 %), and rubber the highest by weight density (22.93 %). Overall number density varied from 40.50 ± 22.50 to 221.13 ± 52.44 n/km2, with the highest in Daya Bay and the lowest in Guanghai Bay. Weight density varied from 189.93 ± 71.94 to 5386.70 ± 3050.30 g/km2, with the highest in Qiao Island and the lowest in Honghai Bay. The main source was plastic bags and wrappers. The Pearl River Delta and Daya Bay were identified as seafloor litter distribution hotspots. Controlling plastic waste input is crucial for reducing seafloor litter in the Pearl River Estuary.

Electrochemical Allylic C(sp3)-H Isothiocyanation via [3,3]-Sigmatropic Rearrangement.

The direct allylic C(sp3)-H functionalization provides a straightforward protocol for the synthesis of valuable molecules. We report herein the first chemo- and site-selective method for allylic C(sp3)-H isothiocyanation of various internal alkenes under mild electrochemical conditions. This method exhibits broad functional group tolerance and excellent selectivity and can be applied for late-stage isothiocyanation of bioactive molecules. Combined experimental and computational studies indicate that the reaction proceeds via an unexpected [3,3]-sigmatropic rearrangement.

Dynamic impacts of short-term bath administration of enrofloxacin on juvenile black seabream Acanthopagrus schlegelii.

Dynamic impacts of short-term enrofloxacin (ENR) exposure on juvenile marine fish are not well understood, and the underlying mechanisms remain unclear. We therefore investigated the accumulation and elimination of ENR in the liver of juvenile black seabream Acanthopagrus schlegelii. Meanwhile, the dynamic alterations of biochemical parameters and liver transcriptomes after short-term bath immersion and withdrawal treatment were explored. The results indicated that the contents of ENR in the liver were significantly increased after bath administration for 24 h, and then quickly declined to very low concentrations along with the decontamination time increasing. Judging from the changes in biochemical indicators and liver transcriptomic alterations, 0.5 and 1 mg/L ENR exposure for 24 h triggered oxidative stress, impairment of immune system, as well as aberrant lipid metabolism via differential molecular pathways. Interestingly, biochemical and transcriptome analysis as well as integrated biomarker response (IBR) values showed that more significant changes appeared in 1 mg/L ENR group at decontamination periods, which indicated that the impact of high dose ENR on juvenile A. schlegelii may persist even after depuration for 7 days. These results revealed that the risk of short-term bath of 1 mg/L ENR should not be overlooked even after depuration period. Therefore, attention should be paid to the dosage control when administering the drug to juvenile A. schlegelii, and the restoration of physiological disturbance may be an important factor in formulating a reasonable treatment plan.

Sustainable thermal regulation improves stability and efficiency in all-perovskite tandem solar cells.

Mixed Sn-Pb perovskites have emerged as promising photovoltaic materials for both single- and multi-junction solar cells. However, achieving their scale-up and practical application requires further enhancement in stability. We identify that their poor thermal conductivity results in insufficient thermal transfer, leading to heat accumulation within the absorber layer that accelerates thermal degradation. A thermal regulation strategy by incorporating carboranes into perovskites is developed; these are electron-delocalized carbon-boron molecules known for their efficient heat transfer capability. We specifically select ortho-carborane due to its low thermal hysteresis. We observe its existence through the perovskite layer showing a decreasing trend from the buried interface to the top surface, effectively transferring heat and lowering the surface temperature by around 5 °C under illumination. o-CB also facilitates hole extraction at the perovskite/PEDOT:PSS interface and reduces charge recombination. These enable mixed Sn-Pb cells to exhibit improved thermal stability, retaining 80% of their initial efficiencies after aging at 85 °C for 1080 hours. When integrated into monolithic all-perovskite tandems, we achieve efficiencies of over 27%. A tandem cell maintains 87% of its initial PCE after 704 h of continuous operation under illumination.

Electrochemical stereoselective synthesis of polysubstituted 1,4-dicarbonyl Z-alkenes via three-component coupling of sulfoxonium ylides and alkynes with water.

The first straightforward strategy for the synthesis of 1,4-dicarbonyl Z-alkenes has been developed via an electrochemical cross-coupling reaction of sulfoxonium ylides and alkynes with water. The metal-free protocol showed an easy-to-handle nature, good functional group tolerance, and high Z-stereoselectivity, which is rare in previous cases. The proposed reaction mechanism was convincingly established by carrying out a series of control experiments, cyclic voltammetry experiments, and density functional theory (DFT) studies.