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Copper is the catalyst widely used to produce multicarbon products for the carbon dioxide reduction reaction (CO 2 RR). The surrounding microenvironment of copper plays a crucial role in determining its catalytic activity and selectivity. In this study, we compare three copper electrocatalysts with different microenvironments: pure metallic copper, a copper metal-organic framework (MOF), and a MOF-derived copper-carbon composite. Operando X-ray absorption spectroscopy, transmission electron microscopy, and Raman spectroscopy reveal that copper in the copper-carbon composite remains in a metallic state, encapsulated by a carbon matrix. The composite catalyst achieves a Faradaic efficiency of 75.6% for C 2 products, including ethylene and ethanol, at a current density of 500 mA cm -2 , with a C 2 current density of 377.9 mA cm -2 . This performance suppresses pure metallic copper, which reaches an optimal Faradaic efficiency of 64.5% for C 2 products at a current density of 300 mA cm -2 , with a C 2 current density of 193.5 mA cm -2 . The copper-carbon composite also significantly overperforms the copper-MOF catalyst, which shows an optimal Faradaic efficiency of 52.0% for C 2 products at a current density of 400 mA cm -2 , with a C 2 current density of 208.0 mA cm -2 . These findings highlight the importance of the microenvironment near active copper sites in determining CO 2 RR efficiency. We hope that our results provide valuable insights for advancing catalyst design in carbon dioxide reduction, contributing to reduced carbon emissions and improved environmental sustainability.

A chiral W-shaped fully π-extended double [7]helicene ( ED7H ) has been synthesized and fully characterized. It displays fluorescence emission (λ em = 636 nm) with a quantum yield (Φ f ) of 0.10. In comparison to its X-shaped and monomict π-extended [7]helicene analogues, enantiopure W-shaped ED7H exhibited superior chiral optical characteristics, including distinct circular dichroism signals from 400 to 650 nm, a good dissymmetric emission factor | g lum | of 4 × 10 -3 , and a circularly polarized luminescence brightness value B CPL of 42 M -1 cm -1 .

Dinitrosyl iron unit (DNIU), [Fe(NO) 2 ], is a natural metallocofactor for biological storage, delivery, and metabolism of nitric oxide (NO). In the attempt to gain a biomimetic insight into the natural DNIU under biological system, in this study, synthetic dinitrosyl iron complexes (DNICs) [(NO) 2 Fe(μ-SCH 2 CH 2 COOH) 2 Fe(NO) 2 ] ( DNIC-COOH ) and [(NO) 2 Fe(μ-SCH 2 CH 2 COOCH 3 ) 2 Fe(NO) 2 ] ( DNIC-COOMe ) were employed to investigate the structure-reactivity relationship of mechanism and kinetics for cellular uptake of DNICs, intracellular delivery of NO, and activation of cytoprotective heme oxygenase (HO)-1. After rapid cellular uptake of dinuclear DNIC-COOMe through a thiol-mediated pathway ( t max = 0.5 h), intracellular assembly of mononuclear DNIC [(NO) 2 Fe(SR)(S Cys )] n - /[(NO) 2 Fe(SR)(S Cys-protein )] n - occurred, followed by O 2 -induced release of free NO ( t max = 1-2 h) or direct transfer of NO to soluble guanylate cyclase, which triggered the downstream HO-1. In contrast, steady kinetics for cellular uptake of DNIC-COOH via endocytosis ( t max = 2-8 h) and for intracellular release of NO ( t max = 4-6 h) reflected on the elevated activation of cytoprotective HO-1 (∼50-150-fold change at t = 3-10 h) and on the improved survival of DNIC-COOH -primed mesenchymal stem cell (MSC)/human corneal endothelial cell (HCEC) under stressed conditions. Consequently, this study unravels the bridging thiolate ligands in dinuclear DNIC-COOH / DNIC-COOMe as a switch to control the mechanism, kinetics, and efficacy for cellular uptake of DNICs, intracellular delivery of NO, and activation of cytoprotective HO-1, which poses an implication on enhanced survival of postengrafted MSC for advancing the MSC-based regenerative medicine., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Separating low/high-valent ions with sub-nanometer sizes is a crucial yet challenging task in various areas ( e . g ., within environmental, healthcare, chemical, and energy engineering). Satisfying high separation precision requires membranes with exceptionally high selectivity. One way to realize this is constructing well-designed ion-selective nanochannels in pressure-driven membranes where the separation mechanism relies on combined steric, dielectric exclusion, and Donnan effects. To this aim, charged nanochannels in polyamide (PA) membranes are created by incorporating ionic polyamidoamine (PAMAM) dendrimers via interfacial polymerization. Both sub-10 nm sizes of the ionic PAMAM dendrimer molecules and their gradient distributions in the PA nanofilms contribute to the successful formation of defect-free PA nanofilms, containing both internal (intramolecular voids) and external (interfacial voids between the ionic PAMAM dendrimers and the PA matrix) nanochannels for fast transport of water molecules. The external nanochannels with tunable ionizable groups endow the PA membranes with both high low/high-valent co-ion selectivity and chemical cleaning tolerance, while the ion sieving/transport mechanism was analyzed by employing the Donnan steric pore model with dielectric exclusion.

The total synthesis of the oligosaccharide moiety of disialosyl globopentaosylceramide (DSGb5 Cer), a dominant ganglioside isolated from malignant renal cell carcinoma tissues, is reported. The synthetic strategy relies on a chemical α(2,6)-sialylation at the internal GalNAc unit of a Gb5 pentasaccharide backbone that furnishes a Neu5Acα(2,6)GalNAc-linked hexasaccharide, suitable for an enzymatic α(2,3)-sialylation of the terminal Gal residue to construct a heptasaccharide glycan. Convergent access to this key α(2,6)-sialylated hexasaccharide was also achieved through a [3+3] glycosylation building upon a Galβ(1,3)[Neu5Acα(2,6)]GalNAc-based trisaccharide donor and a Gb3 acceptor. The synthetic DSGb5 glycan bearing a 6-azidohexyl aglycon at the reducing end could undergo further regioselective functionalization. This approach represents a viable chemoenzymatic method for accessing complex ganglioside glycans and should be useful for the synthesis and biological investigation of DSGb5 derivatives.

The multidrug resistance protein MRP1 is an ATP binding cassette (ABC) transporter that confers resistance to many anticancer drugs and regulates redox homeostasis, inflammation, and hormone secretion. MRP1 actively transports compounds across cell membranes, and the presence of glutathione (GSH) is required in many cases. However, the process of MRP1-mediated substrate transportation has been poorly understood. With extensive molecular dynamics simulations, we have found a sandwich-like structure which is generated by GSH, a transmembrane α-helices 11 (TM11)-TM17 axis, and anticancer drugs. This structure is crucial in MRP1 transportation. It triggers the motion of TM11 and TM17, followed by the movement of nucleotide-binding domains 1 (NBD1) and 2 (NBD2), and finally an occluded structure is formed. Trp1246, Lys332, and Phe594 were identified as the main contributors in the formation of the sandwich-like structure. Our findings clearly explain the synergy of GSH with an anticancer drug in MRP1 transportation and have significant meanings for the rational design of novel inhibitors against MRP1.

Substituent effects play critical roles in both modulating reaction chemistry and supramolecular self-assembly processes. Using substituted terephthalate dianions ( p -phthalic acid dianions; PTADA s), the effect of varying the type, number, and position of the substituents was explored in terms of their ability to regulate the inherent anion complexation features of a tetracationic macrocycle, cyclo[2](2,6-di(1 H -imidazol-1-yl)pyridine)[2](1,4-dimethylenebenzene) (referred to as the Texas-sized molecular box; 1 4+ ), in the form of its tetrakis-PF 6 - salt in DMSO. Several of the tested substituents, including 2-OH, 2,5-di(OH), 2,5-di(NH 2 ), 2,5-di(Me), 2,5-di(Cl), 2,5-di(Br), and 2,5-di(I), were found to promote pseudorotaxane formation in contrast to what was seen for the parent PTADA system. Other derivatives of PTADA , including those with 2,3-di(OH), 2,6-di(OH), 2,5-di(OMe), 2,3,5,6-tetra(Cl), and 2,3,5,6-tetra(F) substituents, led only to so-called outside binding, where the anion interacts with 1 4+ on the outside of the macrocyclic cavity. The differing binding modes produced by the choice of PTADA derivative were found to regulate further supramolecular self-assembly when the reaction components included additional metal cations (M). Depending on the specific choice of PTADA derivatives and metal cations (M = Co 2+ , Ni 2+ , Zn 2+ , Cd 2+ , Gd 3+ , Nd 3+ , Eu 3+ , Sm 3+ , Tb 3+ ), constructs involving one-dimensional polyrotaxanes, outside-type rotaxanated supramolecular organic frameworks (RSOFs), or two-dimensional metal-organic rotaxane frameworks (MORFs) could be stabilized. The presence and nature of the substituent were found to dictate which specific higher order self-assembled structure was obtained using a given cation. In the specific case of the 2,5-di(OH), 2,5-di(Cl), and 2,5-di(Br) PTADA derivatives and Eu 3+ , so-called MORFs with distinct fluorescence emission properties could be produced. The present work serves to illustrate how small changes in guest substitution patterns may be used to control structure well beyond the first interaction sphere.

Here, we report our trials to regulate the luminescence performance of the macrocyclic samarium(III) complex and prepare four excellent luminescent Sm(III) complex-doped poly(methylmethacrylate) (PMMA) composites. Four 23-membered [1 + 1] Schiff-base macrocyclic mononuclear Sm(III) complexes, Sm-2 a - Sm-2 d , originating from dialdehydes with different pendant arms and 1,2-bis(2-aminoethoxy)ethane, have been constructed by the template method. Crystal structures reveal that every Sm(III) ion with the coordination geometry of a distorted bicapped square antiprism is capsulated by the macrocyclic cavity environment forming the "lasso-type" protection. Relative photophysical properties of macrocyclic Sm(III) complexes are carefully investigated in solid-state, methanol solution, and doped PMMA film, and all these show characteristic emissions of the Sm(III) ion associated with satisfactory lifetimes and quantum yields in all media, which could be comparable to reported outstanding examples. Especially, the luminescence performance for this type of Sm(III) complex could be regulated in the solid state by the use of different functional groups in the pendant arm while it is not achieved in solution and the doped PMMA composite. High emitting and air-stable plastic materials could be obtained when these Sm(III) complexes are doped in PMMA with 0.1 wt % mixing ratio, and the corresponding maximum lifetime and quantum yield are 61.2 μs and 0.63% in the case of complex Sm-2 a , respectively. We believe that these highly luminescent "lasso-type" Sm(III) complexes and doped PMMA composites are valuable references in the design of luminescent lanthanide(III) hybrid materials., Competing Interests: The authors declare no competing financial interest., (Copyright © 2019 American Chemical Society.)

Sulfur dioxide (SO 2 ) plays significant roles in regulating cell apotosis and inflammation. However, there are complex interactions between small biomolecules in cells, and the identification of these coexisting biomarkers remains a challenge. Herein, we report an AND logic gate based fluorescent probe ( NY-Lyso ), operating by responding to pH differences between organelles in cell and selectively reacting with bisulfite (HSO 3 - ). This approach allows the fluorescence of the probe to remain silent under neutral or alkaline conditions, notably, is activated by costimulation of lower pH and bisulfite. Furthermore, it was confirmed to be biocompatible and could be employed to monitor HSO 3 - in lysosomes of living cells. The proposed method demonstrated more practical and outstanding capabilities in targeted and real-time monitoring, providing an effective optical tool for biomarker sensing.

Three different solvent extracts (methanol, ethyl acetate, and n-hexane) of longan ( Dimocarpus longan Lour.) flowers were assayed with three different antioxidant capacity methods, namely, the DPPH free radical scavenging effect, the oxygen radical absorbance capacity (ORAC) assay, and the inhibition of Cu(2+)-induced oxidation of human low-density lipoprotein (LDL). It was revealed that the methanol extract has the best antioxidative activity, followed by ethyl acetate and n-hexane extracts. The methanol extract was separated by liquid-liquid partition into n-hexane, ethyl acetate, n-butanol, and water fractions. The ethyl acetate fraction was found to have the highest activity of delaying LDL oxidation. After silica gel column chromatography, the fraction having a superior activity was identified as containing two major compounds, (-)-epicatechin and proanthocyanidin A2.

Anthocyanidins found in certain flowers have been shown to act as strong antioxidants in various systems, exhibiting multiple biological actions. The antioxidative effects of water extract and ethanolic extract of longan (Dimocarpus longan Lour.) flowers were evaluated by radical scavenging activity and compared to those of gallic acid, myricetin, and epigallocatechin gallate. In this study, the suppressive effects of longan flower extracts on nitric oxide and prostaglandin E2 production were investigated using a lipopolysaccharide-stimulated RAW 264.7 cell model. Abundant levels of phenolic compounds including flavonoids, condensed tannins, and proanthocyanidins were found in water or ethanolic extracts prepared from dried longan flowers. The antioxidative effect of longan flower extract was similar to the effect exhibited by pure antioxidants. Moreover, longan flower extract showed prominent inhibitory effects on prostaglandin E2 production. Significant concentration-dependent inhibition of nitric oxide production was detected when cells were cotreated with lipopolysaccharide and various concentrations of longan flower extracts. These inhibitory effects were further attributed to suppression of inducible nitric oxide synthase protein expression and not to reduced enzymatic activity. These results suggest that longan flower crude extracts, especially ethanolic extract, have antioxidant and anti-inflammatory effects, and the probable mechanism involves inhibition of inflammation by proanthocyanidins. Preliminary observations suggest that longan flower extract, especially alcoholic extract, could be another potential source of natural dietary antioxidant and anti-inflammatory agent.

Cadmium sulfide (CdS) quantum dots (QDs) were prepared and surface modified by dodecanthiol or mercaptosuccinic acid (MSA) to render a surface with alkyl chains (C(12)-CdS) or carboxylic acid groups (MSA-CdS), respectively. Due to the hydrophobic property of C(12)-CdS, the nanoparticles disperse well in chloroform and stay stable at the air/water interface. However, 3-dimensional (3D) aggregative domains and particle-free pores were formed in the monolayer due to poor particle-water interaction. For the MSA-CdS nanoparticles, the surface was hydrophobized through physical adsorption of a cationic surfactant, cetyltrimethylammonium bromide (CTAB). The capped MSA on the CdS plays an important role in enhancing the adsorption of CTAB and improving the stability of the QDs at the air/water interface. Due to the reversible adsorption of CTAB on MSA-CdS, a hydrophilic area can be exposed in the water-contacting region of a nanoparticle when it stays at the air/water interface. Thus, the CTAB-MSA-CdS QD behaves as an amphiphilic compound at the air/water interface and has properties superior to those of C(12)-CdS QDs in fabrication of layer-by-layer 2D structure of particulate films. The distinct behaviors of the two QDs at the air/water interface and the related effect on the properties of LB films were studied using a number of methods, including pressure-area (pi-A) isotherm, relaxation and hysteresis experiments, in-situ observation of Brewster angle microscopy (BAM), the postdeposition analysis of atomic force microscopy (AFM), and UV-vis spectroscopy.

Mixed monolayers of stearic acid (SA) and octadecylamine (ODA) at the air/water interface were investigated in this article. The miscibility of the two compounds was evaluated by the measurement of surface pressure-area per molecule (pi-A) isothems and the direct observation of Brewster angle microscopy (BAM) on the water surface. The two compounds were spread individually on the subphase (method 1) or premixed first in the spreading solvent and then cospread (method 2). The effect of spreading method on the miscibility of the two compounds was also studied. The results show that the mixed monolayers prepared by method 1 cannot get a well-mixed state. The isotherms of mixed monolayers preserve both characteristics of SA and ODA and exhibit two collapse points. The calculated excess surface area is very small. Besides, distinguished domains corresponding to those of pure SA and ODA can be inspected from the BAM images. Such results indicate that SA and ODA cannot get a well-mixed phase via 2-dimensional mixing. On the contrary, in the mixed monolayer prepared by cospreading, the two compounds exhibit high miscibility. In the pi-A isotherms, the individual characteristics of SA and ODA disappear. The calculated excess area exhibits a highly positive deviation which indicates the existence of special interaction between the two compounds. The low compressibility of isotherm implies the highly rigid characteristic of the mixed monolayer. which was also sustained by the striplike collapse morphology observed from the BAM. The rigid characteristic of SA/ODA mixed monolayer was attributed to the formation of "catanionic surfactant" by electrostatic adsorption of headgroups of SA and ODA or to the formation of salt by acid-base reaction.