2-甲基-4,5-二硝基三唑-1-氧化物的合成及其结构表征

以乙二醛、甲基肼和盐酸羟胺为起始原料,经缩合、肟化得到中间体肟基甲腙;该中间体不经分离直接加入到硫酸铜-吡啶-水体系中,经缩合环化得到2-甲基三唑-1-氧化物(MTO);随后用混酸(硝酸+硫酸)硝化得到目标产物2-甲基-4,5-二硝基三唑-1-氧化物(DNMTO);初步探讨了环化反应的机理,研究了反应温度与时间等因素对硝化反应的影响,确定了最佳硝化反应条件.与此同时,利用红外光谱、核磁共振、质谱及元素分析等分析了中间产物和DNMTO的组成和结构.结果表明,目标产物的总收率为16%,纯度为99%;最佳硝化反应温度为100℃,最佳硝化反应时间为0.5h.     

Electrochemical DNA Biosensor Based on Partially Reduced Graphene Oxide Modified Carbon Ionic Liquid Electrode for the Detection of Transgenic Soybean A2704‐12 Gene Sequence

In this work a partially reduced graphene oxide (p‐RGO) modified carbon ionic liquid electrode (CILE) was prepared as the platform to fabricate an electrochemical DNA sensor, which was used for the sensitive detection of target ssDNA sequence related to transgenic soybean A2704‐12 sequence. The CILE was fabricated by using 1‐butylpyridinium hexafluorophosphate as the binder and then p‐RGO was deposited on the surface of CILE by controlling the electroreduction conditions. NH₂ modified ssDNA probe sequences were immobilized on the electrode surface via covalent bonds between the unreduced oxygen groups on the p‐RGO surface and the amine group at the 5′‐end of ssDNA, which was denoted as ssDNA/p‐RGO/CILE and further used to hybridize with the target ssDNA sequence. Methylene blue (MB) was used as electrochemical indicator to monitor the DNA hybridization. The reduction peak current of MB after hybridization was proportional to the concentration of target A2704‐12 ssDNA sequences in the range from 1.0×10^?12 to 1.0×10^?6 mol/L with a detection limit of 2.9×10^?13 mol/L (3σ). The electrochemical DNA biosensor was further used for the detection of PCR products of transgenic soybean with satisfactory results.     

Electrogenerated Fe(I) Porphyrins: Efficient Electrocatalysts for Reductive Dechlorination of DDT in N,N′‐Dimethylformamide

Two iron(I) porphyrins were electrogenerated and then utilized as catalysts for the reductive dechlorination of 1,1‐bis(4‐chlorophenyl)‐2,2,2‐trichloroethane (DDT) in N,N′‐dimethylformamide. No reaction is observed between DDT and the Fe(III) or Fe(II) forms of the porphyrin, but the electrogenerated Fe(I) porphyrin efficiently catalyzes the electroreduction of DDT to give (1,1‐bis(4‐chlorophenyl)‐2,2‐dichloroethane) DDD, (1,1‐bis(4‐chlorophenyl)‐2,2‐dichloroethylene) DDE and (1,1‐bis(4‐chlorophenyl)‐2‐dichloroethane) DDMU as determined by GC‐MS analysis. The reductive dechlorination was monitored by electrochemistry, controlled potential electrolysis and spectroelectrochemistry and a mechanism for the reaction involving the reduced porphyrins and DDT is proposed. Comparisons are also made between the catalytic properties of metalloporphyrins containing iron, cobalt and manganese central metal ions under the same solution conditions.     

稀土镧在腈纶纤维化学镀银中的应用及其电化学性能

采用化学镀法(镀液中加入适量的稀土镧)在硅烷偶联剂改性后的腈纶纤维表面沉积金属银,由粒径分析、X射线衍射、扫描电子显微镜、阴极极化曲线以及循环伏安曲线等方法对其进行表征,研究了硝酸镧对化学镀银沉积速度、镀层质量和电化学性能的影响。结果表明,镀银液中加入适宜的硝酸镧,银的沉积速率和腈纶纤维表面银镀层的表面质量均有不同程度的提高。电化学测试表明,镀银液中增大硝酸镧的浓度(0～0.01 g/L),阴极极化曲线极化度增大,氧化还原峰的电流上升,电沉积的速度加快。     

配合物[Ni（H2B（pyrazolyl）2）2]的非等温热分解动力学研究

在甲醇溶液中用Ni(CH3COO)2.4H2O和NaH2B(pz)2常温下合成出了配合物[Ni(H2B(pz)2)2](pz=pyrazolyl),并用元素分析、红外光谱和X射线衍射等对配合物的结构进行了表征,对此配合物进行了非等温热分解动力学研究.采用了微分Achar和积分Coats-Redfern法分别拟合出配合物2个热分解阶段的动力学方程及相应的动力学参数.配合物第一热分解阶段可能的机理为三维扩散,球形对称,其动力学方程为dα/dT=3(A/β)e-E/RT[(1-α)-1/3-1]-1/2.配合物第二热分解阶段可能的机理为相边界反应,圆柱形对称(n=1/2),其动力学方程为dα/dT=2(A/β)e-E/RT(1-α)1/2.2个反应阶段的表观活化能平均值分别为260.87和176.27kJ/mol,lnA的平均值分别为65.65和37.11s-1.     

A Facile Method for Preparation of Superhydrophobic Surfaces with Poly(furfuryl Alcohol)/PTFE Composites

A stable superhydrophobic surface have been fabricated with poly(furfuryl alcohol) (PFA)/polytetrafluoroethylene (PTFE) composite coatings on steel substrates by using a facile method. The observation of field emission scanning electron microscopy revealed that the hierarchical microstructures formed on the surfaces are controlled by varying the curing temperature. This method can be easily operated on substrates of steel, therefore is readily developed to other engineering metal substrates such as aluminum, copper, etc.     

Microwave and Ultrasound Irradiation‐Assisted Synthesis of Novel Disaccharide‐Derived Arylsulfonyl Thiosemicarbazides

The synthesis of 1‐arylsulfonyl‐4‐(1′‐N‐hepta‐O‐acetyl‐β‐lactosyl)thiosemicarbazides by reaction of hepta‐O‐acetyl‐α‐D‐lactosyl isothiocyanate with substituted phenylsulfonyl hydrazines has been shown to occur in less than 1 min under microwave activation and 8 min under ultrasound irradiation at room temperature. It is noteworthy that when ultrasound and microwaves (MW) were utilized, a cleaner reaction accompanied with higher yields was observed.     

Dissociation of Multisubunit Protein–Ligand Complexes in the Gas Phase. Evidence for Ligand Migration

The results of collision-induced dissociation (CID) experiments performed on gaseous protonated and deprotonated ions of complexes of cholera toxin B subunit homopentamer (CTB₅) with the pentasaccharide (β-D-Galp-(1→3)-β-D-GalpNAc-(1→4)[α-D-Neu5Ac-(2→3)]-β-D-Galp-(1→4)-β-D-Glcp (GM1)) and corresponding glycosphingolipid (β-D-Galp-(1→3)-β-D-GalpNAc-(1→4)[α-D-Neu5Ac-(2→3)]-β-D-Galp-(1→4)-β-D-Glcp-Cer (GM1-Cer)) ligands, and the homotetramer streptavidin (S₄) with biotin (B) and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(biotinyl) (Btl), are reported. The protonated (CTB₅ + 5GM1)ⁿ⁺ ions dissociated predominantly by the loss of a single subunit, with the concomitant migration of ligand to another subunit. The simultaneous loss of ligand and subunit was observed as a minor pathway. In contrast, the deprotonated (CTB₅ + 5GM1)^n- ions dissociated preferentially by the loss of deprotonated ligand; the loss of ligand-bound and ligand-free subunit were minor pathways. The presence of ceramide (Cer) promoted ligand migration and the loss of subunit. The main dissociation pathway for the protonated and deprotonated (S₄ + 4B)^n+/– ions, as well as for deprotonated (S₄ + 4Btl)^n– ions, was loss of the ligand. However, subunit loss from the (S₄ + 4B)ⁿ⁺ ions was observed as a minor pathway. The (S₄ + 4Btl)ⁿ⁺ ions dissociated predominantly by the loss of free and ligand-bound subunit. The charge state of the complex and the collision energy were found to have little effect on the relative contribution of the different dissociation channels. Thermally-driven ligand migration between subunits was captured in the results of molecular dynamics simulations performed on protonated (CTB₅ + 5GM1)¹⁵⁺ ions (with a range of charge configurations) at 800 K. Notably, the migration pathway was found to be highly dependent on the charge configuration of the ion. The main conclusion of this study is that the dissociation pathways of multisubunit protein–ligand complexes in the gas phase depend, not only on the native topology of the complex, but also on structural changes that occur upon collisional activation.

Atom Transfer Radical Polymerization of MMA Initiated by 2‐(4‐chloromethyl‐phenyl)‐benzoxazole and Fluorescent Property of PMMA

Atom transfer radical polymerization (ATRP) of MMA was conducted using 2‐(4‐chloromethyl‐phenyl)‐benzoxazole as initiator, CuCl as catalyst, and PMDETA as ligand. The results show that the polymerization is a first order reaction with respect to monomer concentration. The polymerization displayed living character as evidenced by a liner increase of monomer weight with conversation and a relatively narrow distribution (Mn/Mw range from 1.30 to 1.45). The structure of PMMA was analyzed by ¹H‐NMR and proved the polymerization could be controlled to some degree. The optical property of the initiator was well preserved in the resulting PMMA, and the end‐functionalized PMMA exhibited fluorescent emission at 360 nm whether in DMF solution or in film state.     

Polymerization of N,N-Dimethylaminopropyl-Acrylamide Through Hydrogen Transfer Induced by the Propagation of the Polyacrolein Anion

The anionic polymerization of acrolein (AL) with N, N-dimethylamino-propylacrylamide (DMAPA) in the presence of water was investigated in tetrahydrofuran, benzene, and ethanol at 0°C in a nitrogen atmosphere. The resulting polymers were found to be essentially vinyl polymers with one DMAPA attached and an aldehyde side chain. From observations of the polymerization process by ¹H NMR, we find that polymerization was initiated by the hydroxyl anion formed in the thermodynamic equilibrium between the amine of DMAPA and water. The hydrogen transfer reaction of DMAPA was caused by the propagating poly-AL anion. On the other hand, the monomer reactivity ratios and the Q₂-e₂values of DMAPA were determined by the free-radical copolymerization of styrene (St, M₁) with DMAPA and AIBN as initiator.