How Many Molecules are Required to Obtain a Steady Faradaic Current from Mediated Electron Transfer at a Single Nanoparticle on a Supporting Surface?

We investigate the chronoamperometric noise characteristics of electron‐transfer reactions occurring on single nanoparticles (NPs) and assemblies of well‐separated NPs on a supporting surface. To this end, we combine a formerly described expression for the steady‐state current of a single particle with the shot‐noise model and derive an expression for the signal‐to‐noise ratio as a function of bulk concentration and particle radius. Our findings are supported by random‐walk simulations, which closely match the analytical results.     

From Molecules to Materials: Computational Design of N‐Containing Porous Aromatic Frameworks for CO2 Capture

Porous aromatic frameworks (PAFs) are novel materials with diamond topology. With the aim of enhancing their CO₂ capture and storage capacity and investigating the effect of nitrogen and/or ‐COOH decorations on CO₂ adsorption in PAFs, a series of N‐containing PAFs were designed based on ab initio results. The interaction energies (E_int) between CO₂ and each six‐membered ring were calculated at the B2PLYP‐D2/def2‐TZVPP level, then the six‐membered rings with high CO₂‐binding affinity were selected and used in the PAFs. To explore the performance of the designed PAFs, the CO₂ uptake, selectivity of CO₂ over CH₄, H₂, and N₂, and the E_int value of CO₂ in PAFs were investigated by using grand canonical Monte Carlo (GCMC) simulations and ab initio calculations. This work shows that pyridine with one nitrogen atom can provide a strong physisorption site for CO₂, whereas more nitrogen atoms in heterocycles will reduce the interaction, especially at relatively low pressure. PAFs with ?COOH groups show high CO₂ capacity. Our work provides an efficient way to understand the adsorption mechanism and a supplemental approach to experimental work.     

Time‐Resolved,In Situ DRIFTS/EDE/MS Studies on Alumina‐Supported Rhodium Catalysts: Effects of Ceriation and Zirconiation on Rhodium–CO Interactions

The effects of ceria and zirconia on the structure–function properties of supported rhodium catalysts (1.6 and 4 wt % Rh/γ‐Al₂O₃) during CO exposure are described. Ceria and zirconia are introduced through two preparation methods: 1) ceria is deposited on γ‐Al₂O₃ from [Ce(acac)₃] and rhodium metal is subsequently added, and 2) through the controlled surface modification (CSM) technique, which involves the decomposition of [M(acac)_x] (M=Ce, x=3; M=Zr, x=4) on Rh/γ‐Al₂O₃. The structure–function correlations of ceria and/or zirconia‐doped rhodium catalysts are investigated by diffuse reflectance infrared Fourier‐transform spectroscopy/energy‐dispersive extended X‐ray absorption spectroscopy/mass spectrometry (DRIFTS/EDE/MS) under time‐resolved, in situ conditions. CeO_x and ZrO₂ facilitate the protection of Rh particles against extensive oxidation in air and CO. Larger Rh core particles of ceriated and zirconiated Rh catalysts prepared by CSM are observed and compared with Rh/γ‐Al₂O₃ samples, whereas supported Rh particles are easily disrupted by CO forming mononuclear Rh geminal dicarbonyl species. DRIFTS results indicate that, through the interaction of CO with ceriated Rh particles, a significantly larger amount of linear CO species form; this suggests the predominance of a metallic Rh phase.     

多壁碳纳米管修饰玻碳电极测定铜离子

以多壁碳纳米管(MWCNTs)修饰玻碳电极为工作电极,采用阳极溶出线性扫描法研究了铜离子的电化学测定方法。探讨了MWCNTs修饰层数、富集电位、富集时间、溶液pH、支持电解质对峰电流的影响。实验表明,铜离子浓度在1.0×10-8~1.0×10-5mol·L-1范围内与峰电流呈良好的线性关系,检测限为2.0×10-9mol·L-1,且该电极具有良好的稳定性和抗干扰能力。     

胡麻籽油咪唑啉缓蚀剂的制备及其对A30钢的缓蚀效果

以胡麻籽油、羟乙基乙二胺为原料合成咪唑啉中间体,用苄基氯进行改性,得到阳离子咪唑啉衍生物。利用FT IR对合成产物进行了表征,用静态失重法、电化学极化曲线和FESEM对其缓蚀性能进行了评价,并考察了不同缓蚀剂浓度、腐蚀浸泡时间对缓蚀效果的影响,探讨了其在A30钢表面的吸附行为。结果表明,合成的缓蚀剂在盐酸体系中对A30钢有较好的缓蚀性能,在浓度为100mg/L时对低碳钢的缓蚀效率可达87%,并且其产物为阳离子型缓蚀剂,吸附满足Langmuir等温吸附方程。最后采用量子化学方法对其缓蚀剂的缓蚀机理进行了分析。     

Iron-Catalyzed Radical Relay Enabling the Modular Synthesis of Fused Pyridines from Alkyne-Tethered Oximes and Alkenes

We have rationally designed a new class of alkyne-tethered oximes and applied them in an unprecedented iron-catalyzed radical relay protocol for the rapid assembly of a wide array of structurally new and interesting fused pyridines. This method shows broad substrate scope and good functional-group tolerance and enabled the synthesis of several biologically active molecules. Furthermore, the fused pyridines could be diversely functionalized through various simple transformations, such as cyclization, C−H alkylation, and a click reaction. DFT calculation studies indicate that the reactions involve cascade 1,5-hydrogen atom transfer, 5-exo-dig radical addition, and cyclization processes. Moreover, preliminary biological investigations suggest that some of the fused pyridines exhibit good anti-inflammatory activity by restoring the imbalance of inflammatory homeostasis of macrophages in a lipopolysaccharide-induced model.     

药学专业元素化学教学方法探究

元素化学是药学专业无机化学的重要组成部分,其内容繁多,规律性不强,传统教学方式枯燥乏味,影响了学生的学习兴趣。笔者针对这些问题,结合多年的教学经验,从优化教学内容和教学方法等方面对元素化学教学进行了探究。     

纳米金杂化酶研究进展

随着纳米技术和生物技术的发展,将纳米颗粒材料与天然酶结合起来构建纳米杂化酶,可以解决酶的负载量低、活性和稳定性不好等问题.目前,新型纳米颗粒材料-纳米金被广泛应用于构建杂化酶体系.我们将从纳米金杂化酶的种类、制备方法、优势以及应用等方面对纳米金杂化酶的研究进展进行概述.     

A group additivity methodology for predicting the thermochemistry of oxygen-containing organosilanes

A combinatorial approach was applied to devise a set of reference Si–C–O–H species that is used to derive group-additivity values (GAVs) for this class of molecules. The reference species include 62 stable single-bonded, 19 cyclic, and nine double-bonded Si–C–O–H species. The thermochemistry of these reference species, that is, the standard enthalpy of formation, entropy, and heat capacities covering the temperature range from 298 to 2000 K was obtained from quantum chemical calculations using several composite methods, including G4, G4MP2, and CBSQB3, and the isodesmic reaction approach. To calculate the GAVs from the ab initio based thermochemistry of the compounds in the training set, a multivariable linear regression analysis is performed. The sensitivity of GAVs to the different composite methods is discussed, and thermodynamics properties calculated via group additivity are compared with available ab initio calculated values from the literature.