双核铜配合物Cu2(2,2′-bpy)2(2-bba)4的合成、表征与晶体结构

在室温下,以2-溴苯甲酸和2,2'-联吡啶为配体,通过溶液法在甲醇/水的混合溶剂中反应合成了双核铜(II)配合物Cu2(2,2'-bpy)2(2-bba)4。通过元素分析、红外光谱、热重测试技术和X射线粉末衍射对其进行了结构表征,同时用X射线单晶衍射分析确定了其晶体结构。结果表明,其晶体属正交晶系,空间群为Pbca,晶胞参数:a=20.619(4),b=10.098(2),c=21.865(4),V=4552.5(15)3,Dc=1.808g·cm-3,μ=4.505mm-1,F(000)=2440.0,Z=4,最终残差因子R1=0.0583,wR2=0.1200。配合物为双核结构,每个结构单元中2个Cu(II)离子通过2个2-溴苯甲酸根配体单齿桥联。配合物中的每个Cu(II)离子为五配位的结构,分别和来自2个单齿桥联的2-溴苯甲酸根的2个氧原子、1个单齿配位的2-溴苯甲酸根的1个氧原子及来自1个2,2'-联吡啶的2个氮原子配位形成了畸变的四方锥型结构,分子间则通过弱的C—H…O氢键作用形成了一维链状的结构。CCDC:972827。     

真空离心浓缩/气相色谱-质谱联用法测定白酒中6种邻苯二甲酸酯类增塑剂

建立了测定白酒中6种邻苯二甲酸酯类增塑剂的真空离心浓缩/气相色谱-质谱联用(GC-MS)分析方法。样品经真空离心浓缩,正己烷提取,取上层正己烷,4000r/min离心5min,采用GC-MS测定,外标法定量。在0.10～5.00μg/mL范围内,相关系数r20.992,样品在0.10～2.00 mg/kg范围内加标,平均回收率在88.83%～111.67%之间,相对标准偏差(RSD)为4.85%～11.35%,检出限(LOD)在0.02～0.05 mg/kg之间。采用该方法对16个白酒样品进行测定,结果表明该法简便、快速、结果准确可靠、灵敏度高,能够满足白酒中6种邻苯二甲酸酯增塑剂检测需求。     

Catalytic epoxidation of alkenes over supported manganese oxide with hydrogen peroxide: effect of supports and manganese loading

Manganese oxides supported on γ-Al₂O₃, amorphous SiO₂, MCM-41, and TiO₂ prepared by an impregnation method were used as heterogeneous catalysts for epoxidation of alkenes with 30 % H₂O₂ in the presence of NaHCO₃ aqueous solution. The effect of support and manganese loading on their activity was studied. The 1.3-MnO _x /γ-Al₂O₃ exhibited superior epoxidazing activity of styrene, compared with other supported MnO _x . Hydrogen temperature-programmed reduction, UV–vis and ESR analyses suggested that Mn²⁺ (catalytic activity species) dominated in 1.3 % MnO _x /γ-Al₂O₃ due to a strong interaction between MnO _x and γ-Al₂O₃. Recycling studies showed the catalyst was a heterogeneous one and retained its activity after recycling four times.     

Synthesis and photoluminescence of iridium complexes with benzothiazol-2-yl carbazole derivative ligand

Two new iridium(III) complexes containing benzothiazol-2-yl carbazole derivative as a cyclometalated ligand (L) and picolinate (pic) or acetylacetonate (acac) as the ancillary ligand, Ir(III) bis(3-(benzothiazol-2-yl)-9-butyl-carbazole)(picolinate) [Ir(L)₂(pic)] and Ir(III) bis(3-(benzothiazol-2-yl)-9-butyl-carbazole)(acetylacetonate) [Ir(L)₂(acac)], were synthesized and characterized by elemental analysis, ¹H NMR, FT-IR, and UV–Vis absorption spectra. Both the iridium(III) complexes emit intense green–yellow emissions, indicating that they are useful for the fabrication of organic light-emitting diodes.     

硫脲络合–火焰原子吸收光谱法测定低硅铝合金中的银含量

采用硫脲络合–火焰原子吸收光谱法测定低硅铝合金中的银元素含量。实验探讨了酸度及硫脲用量对银测定的影响及铝合金中基体元素与共存元素对银元素分析线的干扰情况。结果表明:选用9%的盐酸和3%的硝酸溶解试样最好,加入5 mL 50 g/L硫脲溶液可消除氯离子对试验结果的影响,基体铝元素和其它共存元素不干扰银的测定。根据低硅铝合金中银元素的含量范围,合成系列标准溶液,建立工作曲线,工作曲线的线性范围为0.05%~0.50%。银元素含量为0.30%的样品测定结果的相对标准偏差为0.15%(n=8),标准加入回收率为96.8%~98.5%。该方法操作简便、重现性好、测量结果准确可靠。     

π-Interactions between Cyclic Carbocations and Aromatics Cause Zeolite Deactivation in Methanol-to-Hydrocarbon Conversion

The understanding of catalyst deactivation represents one of the major challenges for the methanol-to-hydrocarbon (MTH) reaction over acidic zeolites. Here we report the critical role of intermolecular π-interactions in catalyst deactivation in the MTH reaction on zeolites H-SSZ-13 and H-ZSM-5. π-interaction-induced spatial proximities between cyclopentenyl cations and aromatics in the confined channels and/or cages of zeolites are revealed by two-dimensional solid-state NMR spectroscopy. The formation of naphtalene as a precursor to coke species is favored due to the reaction of aromatics with the nearby cyclopentenyl cations and correlates with both acid density and zeolite topology.     

Deep-Eutectic-Solvent-Based Self-Healing Polymer Electrolyte for Safe and Long-Life Lithium-Metal Batteries

The deployment of high-energy-density lithium-metal batteries has been greatly impeded by Li dendrite growth and safety concerns originating from flammable liquid electrolytes. Herein, we report a stable quasi-solid-state Li metal battery with a deep eutectic solvent (DES)-based self-healing polymer (DSP) electrolyte. This electrolyte was fabricated in a facile manner by in situ copolymerization of 2-(3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)ureido)ethyl methacrylate (UPyMA) and pentaerythritol tetraacrylate (PETEA) monomers in a DES-based electrolyte containing fluoroethylene carbonate (FEC) as an additive. The well-designed DSP electrolyte simultaneously possesses non-flammability, high ionic conductivity and electrochemical stability, and dendrite-free Li plating. When applied in Li metal batteries with a LiMn₂O₄ cathode, the DSP electrolyte effectively suppressed manganese dissolution from the cathode and enabled high-capacity and a long lifespan at room and elevated temperatures.     

Electrochemical Phase Evolution of Metal-Based Pre-Catalysts for High-Rate Polysulfide Conversion

In situ evolution of electrocatalysts is of paramount importance in defining catalytic reactions. Catalysts for aprotic electrochemistry such as lithium–sulfur (Li-S) batteries are the cornerstone to enhance intrinsically sluggish reaction kinetics but the true active phases are often controversial. Herein, we reveal the electrochemical phase evolution of metal-based pre-catalysts (Co₄N) in working Li-S batteries that renders highly active electrocatalysts (CoS_x). Electrochemical cycling induces the transformation from single-crystalline Co₄N to polycrystalline CoS_x that are rich in active sites. This transformation propels all-phase polysulfide-involving reactions. Consequently, Co₄N enables stable operation of high-rate (10 C, 16.7 mA cm⁻²) and electrolyte-starved (4.7 μL mg_S⁻¹) Li-S batteries. The general concept of electrochemically induced sulfurization is verified by thermodynamic energetics for most of low-valence metal compounds.     

Chemically Programmable and Switchable CAR-T Therapy

Although macromolecules on cell surfaces are predominantly targeted and drugged with antibodies, they harbor pockets that are only accessible to small molecules and constitutes a rich subset of binding sites with immense potential diagnostic and therapeutic utility. Compared to antibodies, however, small molecules are disadvantaged by a less confined biodistribution, shorter circulatory half-life, and inability to communicate with the immune system. Presented herein is a method that endows small molecules with the ability to recruit and activate chimeric antigen receptor T cells (CAR-Ts). It is based on a CAR-T platform that uses a chemically programmed antibody fragment (cp-Fab) as on/off switch. In proof-of-concept studies, this cp-Fab/CAR-T system targeting folate binding proteins on the cell surface mediated potent and specific eradication of folate-receptor-expressing cancer cells in vitro and in vivo.