Synthesis, structure, spectroscopic properties, and electrochemistry of (1,8,15,22-tetrasubstituted phthalocyaninato)lead complexes

Three (1,8,15,22-tetrasubstituted phthalocyaninato)lead complexes Pb[Pc(alpha-OR)(4)] [H(2)Pc(alpha-OC(5)H(11))(4) = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine; H(2)Pc(alpha-OC(7)H(15))(4) = 1,8,15,22-tetrakis(2,4-dimethyl-3-pentyloxy)phthalocyanine; H(2)Pc(alpha-OC(10)H(7))(4) = 1,8,15,22-tetrakis(2-naphthyloxy)phthalocyanine] (1-3) have been prepared as racemic mixtures by treating the corresponding metal-free phthalocyanines H(2)Pc(alpha-OR)(4) (4-6) with Pb(OAc)(2).3H(2)O in refluxing n-pentanol. The molecular structure of Pb[Pc(alpha-OC(5)H(11))(4)] (1) in the solid state has been determined by single-crystal X-ray diffraction analysis. This compound, having a nonplanar structure, crystallizes in the monoclinic system with a P2(1)/c space group. Each unit cell contains two pairs of enantiomeric molecules, which are linked by weak coordination of the Pb atom of one molecule with an aza nitrogen atom and its neighboring oxygen atom from the alkoxy substituent of another molecule, forming a pseudo-double-decker supramolecular structure in the crystals with a short ring-to-ring separation, 2.726 A, and thus a strong ring-ring pi-pi interaction. The decreased molecular symmetry for these complexes has also been revealed by the NMR spectra of 1 and 2. The methyl protons of the 3-pentyloxy and 2,4-dimethyl-3-pentyloxy side chains of 1 and 2, respectively, are chemically inequivalent. In addition to the elemental analysis and various spectroscopic characterizations, these compounds have also been electrochemically studied. Two one-electron oxidations and up to five one-electron reductions have been revealed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods.     

镧浸种对辣椒种子抗酸雨胁迫能力的强化作用

为了检测镧浸种对辣椒种子抗酸雨胁迫能力的影响,对来自辣椒种子经镧处理和酸雨胁迫1,3和7 d的幼苗生长状况和活性氧代谢进行了测定。结果显示:经镧溶液浸种后,辣椒种子的抗酸雨能力增强,可抵御中强酸雨(pH 3.5)持续胁迫7 d,表现为胚根长和幼苗鲜重均达到对照水平;相对于酸雨组,镧处理组辣椒幼苗中POD活性提高了5.4%,MDA含量降低了6.9%;酸雨组的POD活性和MDA含量均高于对照,分别提高3.9%和25.5%,说明酸雨引发的POD合成是应急,不能有效地限制MDA的积累;基于镧对照的POD活性比对照高,而MDA含量没有相应的提高,说明镧浸种提高了幼苗中POD活性的本底水平。因此,稀土元素是作物的免疫刺激物,镧浸种属于抗胁迫锻炼。     

金属Cu熔化结晶过程的分子动力学模拟

采用常温、常压分子动力学模拟技术,研究了在周期性边界条件下,由864个Cu原子构成的模型系统的熔化、结晶过程。原子间相互作用势采用EAM势。模拟结果表明：在连续升温过程中,金属Cu在1520 K熔化;以不同的冷速进行冷却,在较慢冷却条件下,液态Cu在1010 K结晶;当冷速较快时,液态Cu形成非晶态。分析了升降温过程中熔体偶分布函数、原子体积、能量、MSD随温度的变化特征。     

Electrochemical Behavior of Herbal Antitumor Drug Aloe‐Emodin at Carbon‐Coated Nickel Magnetic Nanoparticles Modified Glassy Carbon Electrode

The electrochemical behavior of aloe‐emodin (AE), an important herbal antitumor drug, was investigated at a carbon‐coated nickel magnetic nanoparticles modified glassy carbon electrode (CNN/GCE). A couple of well‐defined redox peaks was obtained. Some electrochemical parameters of AE at a CNN/GCE, such as the charge number, exchange current density, standard heterogeneous rate constant, were measured. The square wave voltammetry (SWV) response of AE was linear with the concentration over two concentration intervals viz. 6.24×10^?9?1.13×10^?6 M and 1.13×10^?6?1.23×10^?5 M, with a detection limit of 2.08 nM. A fast, simple and sensitive detection and analysis of AE was developed.     

Theoretical study of the inhibitive properties of a group of benzimidazoles

In this work, a group of benzimidazoles, namely benzimidazole (BIM), 2‐hexyl benzimidazole (2‐HBIM), and 2‐benzyl chloride benzimidazole (2‐ClBBIM), have been studied using density functional theory (DFT) at the level of B3LYP with the 6‐31G (d) and 6‐311G (d, p) base sets in order to elucidate the different inhibition efficiencies and reactive sites of these compounds as corrosion inhibitors. Based on the calculated results, the studied molecules interact with Fe‐atoms mainly in their stable pyridine‐N protonated forms. It is found that the inhibition efficiencies of the stable protonated molecules involved in this study have a certain relation with some parameters, such as the highest occupied molecular orbital energy (E_HOMO) and the global hardness (η). The results indicate that the C (7) atoms, as the reactive sites, receive electrons from Fe‐atoms, benzene ring denote electrons to vacant orbital of Fe‐atoms. Additionally, Fukui indices and the orbital analyses suggest that 2‐ClBBIM has the highest reaction activity among the three molecules, the efficiency order of three inhibitors is found to be 2‐ClBBIM > 2‐HBIM > BIM, which accords with experimental results. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010     

Solvothermal synthesis of well-defined TiO(2) mesoporous nanotubes with enhanced photocatalytic activity

High efficiency TiO(2) photocatalyst in porous nanotubes were prepared by solvothermal alcoholysis of TiOSO(4) in the presence of carbon nanotube template.     

para-Sulfonatocalix[6]arene-modified silver nanoparticles electrodeposited on glassy carbon electrode: Preparation and electrochemical sensing of methyl parathion

In this paper, a new electrochemical sensor, based on modified silver nanoparticles, was fabricated using one-step electrodeposition approach. The para-sulfonatocalix[6]arene-modified silver nanoparticles coated on glassy carbon electrode (pSC₆-Ag NPs/GCE) was characterized by attenuated total reflection IR spectroscopy (ATR-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), etc. The pSC₆ as the host are highly efficient to capture organophosphates (OPs), which dramatically facilitates the enrichment of nitroaromatic OPs onto the electrochemical sensor surface. The combination of the host-guest supramolecular structure and the excellent electrochemical catalytic activities of the pSC₆-Ag NPs/GCE provides a fast, simple, and sensitive electrochemical method for detecting nitroaromatic OPs. In this work, methyl parathion (MP) was used as a nitroaromatic OP model for testing the proposed sensor. In comparison with Ag NPs-modified electrode, the cathodic peak current of MP was amplified significantly. Differential pulse voltammetry was used for the simultaneous determination of MP. Under optimum conditions, the current increased linearly with the increasing concentration of MP in the range of 0.01-80 μM, with a detection limit of 4.0 nM (S/N = 3). The fabrication reproducibility and stability of the sensor is better than that of enzyme-based electrodes. The possible underlying mechanism is discussed.     

Transition metal complexes as linkages for assembly of supertetrahedral T4 clusters

Tn clusters are usually connected into frameworks by sulfur bridges. A new type of T4 compounds in which the clusters are linked by both sulfur bridges and transition metal complexes are described.