1,3-Dicarbonyl compounds as phosphine-free ligands for Pd-catalyzed Heck and Suzuki reactions

Some 1,3-dicarbonyl compounds (such as pentane-2,4-dione and 3-oxo-N-phenylbutanamide) were found to constitute highly efficient, yet low-priced and phosphine-free ligands for the Pd-catalyzed Heck and Suzuki reactions of aryl bromides and iodides with very high turnover numbers (ca. 103–104).

Investigation on the Coordination Mode of IL-Supported Diols Used as Phosphine-Free Ligands for Palladium Catalyzed Heck Reaction

The coordination mode of IL-supported diols used as phosphine-free ligands for palladium catalyzed Heck reaction has been investigated by tuning their compositions. The difference in coordination of these IL-supported diols with metal Pd in Heck reaction was related to the changes of the cation rings, leading to the different activities of Pd catalyst in the reaction. The experimental results indicated that the activities of Pd catalyst were affected mainly by n-electron density of the cation rings. Compared to pyridinium and piperidinium cations, imidazolium cations showed the best coordination to metal Pd. In the meantime, C-2 hydrogen and the length of alkyl side chains had impacts on the coordination as well.

C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 pathway as a therapeutic target and regulatory mechanism for spinal cord injury

Spinal cord injury involves non-reversible damage to the central nervous system that is characterized by limited regenerative capacity and secondary inflammatory damage.The expression of the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis exhibits significant differences before and after injury.Recent studies have revealed that the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis is closely associated with secondary inflammatory responses and the recruitment of immune cells following spinal cord injury,suggesting that this axis is a novel target and regulatory control point for treatment.This review comprehensively examines the therapeutic strategies targeting the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis,along with the regenerative and repair mechanisms linking the axis to spinal cord injury.Additionally,we summarize the upstream and downstream inflammatory signaling pathways associated with spinal cord injury and the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis.This review primarily elaborates on therapeutic strategies that target the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis and the latest progress of research on antagonistic drugs,along with the approaches used to exploit new therapeutic targets within the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis and the development of targeted drugs.Nevertheless,there are presently no clinical studies relating to spinal cord injury that are focusing on the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis.This review aims to provide new ideas and therapeutic strategies for the future treatment of spinal cord injury.

4-Amino-1,2,4-triazole Resin-supported Palladium Complex as Phosphine-free Catalyst for Suzuki Reaction in Aqueous Phase

1 Introduction The Suzuki cross-coupling reaction is a powerful and versatile method for the generation of unsymmetrical biaryls from arylboronic acids and aryl halides in a single step. However, the reaction is usually performed in the presence of Pd catalyst along with phosphine ligand, which sometimes creates practical problems because organophosphines tend to be expensive, poisonous, and air sensitive. Recently, phos-phine-free ligands,

D301 resin as a solid base for phosphine-free Heck reactions with heteroaryl halides

A new and practical method of the D301 resin,a weak basic anion exchange resin with secondary amine functionality（Grade Matrix Structure：Styrene-DVB D301R）,used as base to Heck reactions catalyzed by palladium reagent without phosphine compound as ligand is described.It was found that the D301 resin used as base is an efficient and reusable base and can be regenerated and recycled in the reaction.The olefmation of heteroaryl halides prepared the corresponding products in good yields using D301 resin as base.

Phosphine-free synthesis of FeTe2 nanoparticles and self-assembly into tree-like nanoarchitectures

Manipulating the self-assembly of transition metal telluride nanocrystals(NCs) creates opportunities for exploring new properties and device applications. Iron ditelluride(FeTe2) has recently emerged as a new class of magnetic semiconductor with three-dimensional(3D) magnetic ordering and narrow band gap structure, yet the self-assembly of FeTe2 NCs has not been achieved. Herein, the tree-like FeTe2 nanoarchitectures with orthorhombic crystal structure have been successfully synthesized by hot-injection solvent thermal approach using phosphine-free Te precursor. The morphology, size, and crystal structure have been investigated using transmission electron microscopy(TEM), high-resolution TEM(HRTEM),and powder x-ray diffraction(XRD). We study the formation process of tree-like FeTe2 NCs according to trace the change of the sample morphology with the reaction time. It was found that the FeTe2 nanoparticles show oriented aggregation and self-assembly behavior with the increase of reaction time, which is attributed to size-dependent magnetism properties of the samples. The magnetic interaction is thought to be the driving force of nanoparticle self-organization.

Proton‑Prompted Ligand Exchange to Achieve High‑Efficiency CsPbI_(3) Quantum Dot Light‑Emitting Diodes

CsPbI_(3)perovskite quantum dots(QDs)are ideal materials for the next generation of red light-emitting diodes.However,the low phase stability of CsPbI_(3)QDs and long-chain insulating capping ligands hinder the improvement of device performance.Traditional in-situ ligand replacement and ligand exchange after synthesis were often difficult to control.Here,we proposed a new ligand exchange strategy using a proton-prompted insitu exchange of short 5-aminopentanoic acid ligands with long-chain oleic acid and oleylamine ligands to obtain stable small-size CsPbI_(3)QDs.This exchange strategy maintained the size and morphology of CsPbI_(3)QDs and improved the optical properties and the conductivity of CsPbI_(3)QDs films.As a result,high-efficiency red QD-based light-emitting diodes with an emission wavelength of 645 nm demonstrated a record maximum external quantum efficiency of 24.45%and an operational half-life of 10.79 h.

Efficacy of chemotherapy containing bevacizumab in patients with metastatic colorectal cancer according to programmed cell death ligand 1

BACKGROUND Bevacizumab,an anti-vascular endothelial growth factor(VEGF)monoclonal antibody,inhibits angiogenesis and reduces tumor growth.Serum VEGF-C,lactate dehydrogenase,and inflammatory markers have been reported as predictive markers related to bevacizumab treatment.Programmed cell death ligand 1(PD-L1)could act upon VEGF receptor 2 to induce cancer cell angiogenesis and metastasis.AIM To investigate the efficacy of bevacizumab-containing chemotherapy in patients with metastatic colorectal cancer(CRC)according to the expression of PD-L1.METHODS This analysis included CRC patients who received bevacizumab plus FOLFOX or FOLFIRI as first-line therapy between June 24,2014 and February 28,2022,at Samsung Medical Center(Seoul,South Korea).Analysis of patient data included evaluation of PD-L1 expression by the combined positive score(CPS).We analyzed the efficacy of bevacizumab according to PD-L1 expression status in patients with CRC.RESULTS A total of 124 patients was included in this analysis.Almost all patients were treated with bevacizumab plus FOLFIRI or FOLFOX as the first-line chemotherapy.While 77%of patients received FOLFOX,23%received FOLFIRI as backbone first-line chemotherapy.The numbers of patients with a PD-L1 CPS of 1 or more,5 or more,or 10 or more were 105(85%),64(52%),and 32(26%),respectively.The results showed no significant difference in progression-free survival(PFS)and overall survival(OS)with bevacizumab treatment between patients with PDL1 CPS less than 1 and those with PD-L1 CPS of 1 or more(PD-L1<1%vs PD-L1≥1%;PFS:P=0.93,OS:P=0.33),between patients with PD-L1 CPS less than 5 and of 5 or more(PD-L1<5%vs PD-L1≥5%;PFS:P=0.409,OS:P=0.746),and between patients with PD-L1 CPS less than 10 and of 10 or more(PD-L1<10%vs PD-L1≥10%;PFS:P=0.529,OS:P=0.568).CONCLUSION Chemotherapy containing bevacizumab can be considered as first-line therapy in metastatic CRC irrespective of PD-L1 expression.

Structure–performance relationship of Au nanoclusters in electrocatalysis:Metal core and ligand structure

Remarkable progress has characterized the field of electrocatalysis in recent decades,driven in part by an enhanced comprehension of catalyst structures and mechanisms at the nanoscale.Atomically precise metal nanoclusters,serving as exemplary models,significantly expand the range of accessible structures through diverse cores and ligands,creating an exceptional platform for the investigation of catalytic reactions.Notably,ligand‐protected Au nanoclusters(NCs)with precisely defined core numbers offer a distinct advantage in elucidating the correlation between their specific structures and the reaction mechanisms in electrocatalysis.The strategic modulation of the fine microstructures of Au NCs presents crucial opportunities for tailoring their electrocatalytic performance across various reactions.This review delves into the profound structural effects of Au NC cores and ligands in electrocatalysis,elucidating their underlying mechanisms.A detailed exploration of the fundamentals of Au NCs,considering core and ligand structures,follows.Subsequently,the interaction between the core and ligand structures of Au NCs and their impact on electrocatalytic performance in diverse reactions are examined.Concluding the discourse,challenges and personal prospects are presented to guide the rational design of efficient electrocatalysts and advance electrocatalytic reactions.

Transition metal coordination polymers with flexible dicarboxylate ligand:Synthesis,characterization,and photoluminescence property

Under solvothermal conditions,six new coordination polymers(CPs)[Mn(L)(phen)(H_(2)O)]_(n)(1),[Co(L)(phen)(H_(2)O)]_(n)(2),[Cu(L)(phen)(H_(2)O)]_(n)(3),[Zn_(2)(L)_(2)(phen)2(H_(2)O)]_(n)(4),[Zn(L)(phen)]_(n)(5),and[Cd(L)(phen)2]_(n)(6)were synthesized by reactions of dicarboxylate ligand 2,2'-(1,2-phenylenebis(methylene))bis(sulfanediyl)dinobutyric acid(H_(2)L)and 1,10-phenanthroline(phen)with the corresponding metal salts.Complexes 1-6 have been structurally characterized by single-crystal X-ray diffraction analyses,elemental analysis,IR,thermogravimetric analysis,and powder X-ray diffraction.The structures of 1-6 are 1D chains,which are further connected by hydrogen bonding interac-tions to form 3D supramolecular structures.Among them,1 and 2 are isomorphic with L2-of syn-conformation,while L2-shows anti-conformation in 3-6.In addition,the solid-state photoluminescence property of 4-6 was investigated.

Ligand modulation of active center to promote lead-free Cs_(2)AgInCl_(6)photocatalytic CO_(2)reduction

Metal halide perovskites(MHP)are potential candidates for the photocatalytic reduction of CO_(2)due to their long photogenerated carrier lifetime and charge diffusion length.However,the conventional long-chain ligand impedes the adsorption and activation of CO_(2)molecules in practical applications.Here,a ligand modulation technology is employed to enhance the photocatalytic CO_(2)reduction activity of lead-free Cs_(2)AgInCl_(6)microcrystals(MCs).The Cs_(2)AgInCl_(6)MCs passivated by Oleic acid(OLA)and Octanoic acid(OCA)are used for photocatalytic CO_(2)reduction.The results show that the surface defects and electronic properties of Cs_(2)AgInCl_(6)MCs can be adjusted through ligand modulation.Compared with the OLA-Cs_(2)AgInCl_(6),the OCA-Cs_(2)AgInCl_(6)catalyst demonstrated a significant improvement in the catalytic yield of CO and CH_(4).The CO and CH_(4)catalytic yields of OCA-Cs_(2)AgInCl_(6)reached 171.88 and34.15μmol g^(-1)h^(-1)which were 2.03 and 12.98 times higher than those of OLA-Cs_(2)AgInCl_(6),and the total electron consumption rate of OCA-Cs_(2)AgInCl_(6)was 615.2μmol g^(-1)h^(-1)which was 3.25 times higher than that of OLA-Cs_(2)AgInCl_(6).Furthermore,in situ diffuse reflectance infrared Fourier transform spectra revealed the enhancement of photocatalytic activity in Cs_(2)AgInCl_(6)MCs induced by ligand modulation.This study illustrates the potential of lead-free Cs_(2)AgInCl_(6)MCs for efficient photocatalytic CO_(2)reduction and provides a ligand modulation strategy for the active promotion of MHP photocatalysts.

Assessment of programmed death-ligand 1 expression in primary tumors and paired lymph node metastases of gastric adenocarcinoma

BACKGROUND Anti-programmed death-1/programmed death-ligand 1(PD-1/PD-L1)immuno-therapy has demonstrated promising results on gastric cancer(GC).However,PD-L1 can express differently between metastatic sites and primary tumors(PT).AIM To compare PD-L1 status in PT and matched lymph node metastases(LNM)of GC patients and to determine the correlation between the PD-L1 status and clinicopathological characteristics.METHODS We retrospectively reviewed 284 GC patients who underwent D2-gastrectomy.PD-L1 was evaluated by immunohistochemistry(clone SP142)using the com-bined positive score.All PD-L1+PT staged as pN+were also tested for PD-L1 expression in their LNM.PD-L1(-)GC with pN+served as the comparison group.RESULTS Among 284 GC patients included,45 had PD-L1+PT and 24 of them had pN+.For comparison,44 PD-L1(-)cases with pN+were included(sample loss of 4 cases).Of the PD-L1+PT,54.2%(13/24 cases)were also PD-L1+in the LNM.Regarding PD-L1(-)PT,9.1%(4/44)had PD-L1+in the LNM.The agreement between PT and LNM had a kappa value of 0.483.Larger tumor size and moderate/severe peritumoral inflammatory response were associated with PD-L1 positivity in both sites.There was no statistical difference in overall survival for PT and LNM according to the PD-L1 status(P=0.166 and P=0.837,respectively).CONCLUSION Intra-patient heterogeneity in PD-L1 expression was observed between the PT and matched LNM.This disagreement in PD-L1 status may emphasize the importance of considering different tumor sites for analyses to select patients for immunotherapy.

Syntheses,structures,and properties of three coordination polymers based on 5⁃ethylpyridine⁃2,3⁃dicarboxylic acid and N⁃containing ligands

Three coordination polymers[Mn(epda)(2,2'⁃bipy)(H_(2)O)](1),[Mn(epda)(phen)](2),and[Co_(2)(epda)2(bpe)2(H_(2)O)_(4)]·5H_(2)O(3)(H2epda=5⁃ethyl⁃pyridine⁃2,3⁃dicarboxylic acid,2,2'⁃bipy=2,2'⁃bipyridine,phen=phenanthroline,bpe=1,2⁃bis(4⁃pyridyl)ethylene)were synthesized by solvothermal reactions and characterized by single⁃crystal X⁃ray diffraction,thermogravimetric analyses,IR spectroscopy and elemental analysis.1 displays a 1D chain struc⁃ture,and these chains are joined by O-H…O hydrogen bonding andπ⁃πstacking interactions to generate a 2D layer structure.2 displays a 2D layer structure,and adjacent layers are generated 3D architecture throughπ⁃πstacking interactions.3 displays a 1D chain structure,and adjacent chains are generated double layer structure through O-H…O hydrogen bonding.The fluorescent properties of 1 and 3 indicate that they can potentially be used as a luminescent sensor.1 was highly selective and sensitive towards o⁃nitrophenol through different detection mechanisms,however,3 was highly selective and sensitive towards 2,4,6⁃trinitrophenol.In addition,the magnetic behavior of 2 has also been investigated.CCDC:2172533,1,2355773,2,2355774,3.

Comparative Study of the Efficacy of Metal Removal from Contaminated Aqueous Solutions by Solid Bidentate Ligands&Liquid Plant Materials

Heavy metal contaminated water sources pose serious health risks for humans,animals,and plants.Exposure to and ingestion of heavy metals have been associated to liver,kidney,and brain function.Objective:The aim of this research is to comparatively examine the metal removal efficacy of three solid bidentate chemicals and four plant materials.Study Design&Methods:Standard solutions of zinc(II)and lead(II)ions with concentrations of 1,000 ppm were respectively treated with OA(Oxalic Acid),dibasic bidentate ligands(sodium hydrogen phosphate and sodium carbonate).Then,the solutions were placed on a shaker for 15 h,centrifuged,and the supernatant was analyzed using ICP-AES(Inductively Coupled Plasma-Atomic Emission Spectrometry).Results:All the solid bidentate adsorbents were very effective in removing zinc and lead(>90%).However,more lead than zinc was removed across all adsorbents except for lemon where equal percent of zinc and lead(49%)were removed.OA and Na2HPO4 removed about equal amount of lead(>99%).The plant materials(SP(Spinach),bell pepper and GBP(Green Bell Pepper)),respectively and preferentially removed more lead(98.9%,98.3%,81.5%)than zinc(91.7%,46%,46%).Conclusion:Although plant materials have gained attraction for the remediation of heavy metal,however,some bidentate chemical ligands such as OA,sodium carbonate and sodium hydrogen phosphates are even more effective in removing these metals from contaminated water.Furthermore,heavier metals are preferentially removed than lighter metals.

银杏内酯B抑制血小板CD40Ligand表达的分子机制研究

目的探讨银杏内酯B(ginkgolide B)对活化血小板CD40 Ligand(CD40L)的影响以及相关的分子机制。方法取正常人血分离血小板,用不同浓度银杏内酯B孵育血小板5 min,然后用胶原(collagen)刺激血小板活化。用Westernblot分析PI3K表达,Akt磷酸化,CD40L的变化。结果①用collagen刺激血小板聚集,银杏内酯B(0.2、0.4、0.6 g.L-1)预处理血小板5 min,血小板聚集率明显降低,聚集率分别为77%,60%和48%。②Western blot结果显示胶原刺激血小板活化后CD40L表达明显增加,银杏内酯B以剂量依赖方式抑制了CD40L表达。③银杏内酯B对胶原刺激的血小板PI3K表达无明显影响。④collagen刺激血小板活化后Akt的磷酸化增加,银杏内酯B抑制了Akt磷酸化。结论银杏内酯B能够有效抑制collagen诱导的血小板聚集以及CD40L的表达,并明显抑制了Akt磷酸化,表明银杏内酯B能够通过PI3K/Akt信号传导通路抑制血小板活化。

Cloning and Prokaryotic Expression of FnBP Ligand Binding Gene of Staphylococcus aureus

[Objective] The study aimed to clone the FnBP ligand binding gene of Staphylococcus aureus and run prokaryotic expression by constructing a prokaryotic expression vector. [Method] The gene encoding FnBP ligand binding gene was amplified from S.aureus chromosomal DNA by PCR technique. After T-A cloning, plasmid pMD18- FnBP was constructed. pMD18- FnBP and pET28a(+)were digested by BamH Ⅰ and EcoR Ⅰ double enzymes, then the purified FnBP ligand binding gene was subcloned into the expression vector pET28a(+), and the prokaryotic expression vector pET28a-FnBP was thus constructed. The constructed plasmid pET28a-FnBP was transformed into Escherichia coli BL21(DE3) competent cells. The bacterium was induced by IPTG and the expressed products were analyzed by SDS-PAGE and Western blot. [Result] The gene fragment with the length of 370 bp was amplified by PCR approach. One approximately 30 kD exogenous protein was observed in SDS-PAGE analysis. Western blot analysis indicates the protein has antigenicity of S.aureus. [Conclusion] The FnBP ligand binding gene of S.aureus was successfully cloned and expressed in prokaryotic cells.

Effect of novel ternary ligand system on acidic electroless Ni-P plating on AZ91D magnesium alloy

The electroless Ni-P coatings on AZ91 D magnesium alloy substrate were prepared using the acidic hypophosphite-reduced electroless nickel bath containing the novel ternary ligand system. The results indicate that the deposition rate varies with the ternary ligand concentration in plating solution. The structural and morphological characteristics of the coatings were analyzed by XRD and SEM. The anticorrosion properties of the Ni-P coatings were evaluated in 3.5% NaCl solution by electrochemical impedance and potentiodynamic polarization methods. The amount of ternary ligands in electroless plating bath has an significant effect on the surface morphology and structure of Ni-P coatings. The decrease of crystallization temperature and increase of crystallization heat of all the deposits with an increase in ternary ligand concentration are found by DSC measurements. The coating obtained with 0.035 mol/L ternary ligand additive in plating bath can offer a better surface homogeneity and improve corrosion resistance.

人脑胶质瘤Fas和Fas Ligand的表达

目的 探讨 Fas受体配体系统在胶质瘤凋亡调变中的作用和意义 .方法 应用免疫组织化学技术对 34例胶质瘤中 Fas和 Fas L igand的表达及其意义进行了研究 .其中低恶性胶质瘤 1 8例 ,高恶性 1 6例 .结果 Fas在部分胶质瘤中有表达 ,其在高分化的 ～ 级胶质瘤的免疫反应阳性率明显低于 ～ 级胶质瘤 (P<0 .0 1 ) .Fas L 在各型胶质瘤中均有表达 ,其表达强度与胶质瘤的良、恶性程度无明显相关 (P>0 .0 5 ) .结论 Fas- Fas L 系统在胶质瘤凋亡调变的过程中可能起较重要的作用 ,Fas可辅助临床判断胶质瘤的良、恶性程度 .

Visualization of Metal-to-Ligand and Ligand-to-Ligand Charge Transfer in MetaloLigand Complexes

Three methods including the atomic resolved density of state, charge difference density, and the transition density matrix are used to visualize metal to ligand charge transfer （MLCT） in ruthenium（II） ammine complex. The atomic resolved density of state shows that there is density of Ru on the HOMOs. All the density is localized on the ammine, which reveals that the excited electrons in the Ru complex are delocalized over the ammine ligand. The charge difference density shows that all the holes are localized on the Ru and the electrons on the ammine. The localization explains the MLCT on excitation. The transition density matrix shows that there is electron-hole coherence between Ru and ammine. These methods are also used to examine the MLCT in Os（bpy）2（p0p）Cl （＂Osp0p＂： bpy=2,2-bipyrldyl; p0p=4,4＇- bipyridyl） and the ligand-to-ligand charge transfer （LLCT） in Alq3. The calculated results show that these methods are powerful to examine MLCT and LLCT in the metal-ligand system.

白藜芦醇激活细胞外信号调节激酶5信号蛋白促进小鼠MC3T3-E1细胞增殖

背景:细胞外信号调节激酶5信号蛋白对生物体的存活不可或缺,白藜芦醇能通过多种途径促进成骨细胞增殖,但其是否能通过细胞外信号调节激酶5信号蛋白调控成骨细胞功能还需进一步验证。目的:探究细胞外信号调节激酶5对MC3T3-E1细胞增殖以及相关分泌蛋白的调控作用,进一步验证白藜芦醇通过激活细胞外信号调节激酶5完成上述过程。方法:小鼠MC3T3-E1前成骨细胞分别用完全培养基、XMD8-92(细胞外信号调节激酶5抑制剂)、表皮生长因子(细胞外信号调节激酶5激活剂)和白藜芦醇单独干预及XMD8-92+表皮生长因子、白藜芦醇+XMD8-92干预后,通过Western blot检测各组细胞内细胞外信号调节激酶5、磷酸化细胞外信号调节激酶5蛋白,增殖相关蛋白Cyclin D1、CDK4、PCNA,以及成骨细胞分泌蛋白骨保护素、核因子κB受体活化因子配体的表达情况,使用细胞免疫荧光染色检测各组细胞外信号调节激酶5、骨保护素和核因子κB受体活化因子配体荧光强度,使用EdU染色检测各组细胞增殖情况。白藜芦醇干预MC3T3-E1细胞的适宜浓度及时间由细胞形态学观察和CCK-8实验确定。结果与结论:①细胞外信号调节激酶5信号蛋白的激活能有效促进MC3T3-E1细胞增殖、上调骨保护素/核因子κB受体活化因子配体比值;②白藜芦醇干预MC3T3-E1细胞的适宜浓度及时间为5μmol/L,24 h;③白藜芦醇可以激活细胞外信号调节激酶5信号蛋白,进而促进成骨细胞增殖,并上调骨保护素/核因子κB受体活化因子配体比值;④研究结果表明,白藜芦醇可以通过激活细胞外信号调节激酶5信号蛋白促进MC3T3-E1细胞增殖,并通过激活细胞外信号调节激酶5信号蛋白上调骨保护素/核因子κB受体活化因子配体比值。