Synthesis of persulfate containing poly (N-vinyl-2-pyrrolidone) (PVP) hydrogels in aqueous solutions by γ-induced radiation

The effect of ⁶⁰Co γ-irradiation on aqueous solutions of poly(N-vinyl-2-pyrrolidone) (PVP) in the presence of persulfate anion has been investigated. The gelation dose of PVP and persulfate containing PVP aqueous solutions has been determined. At low concentrations of persulfate (1.00–3.50%), gelation percentages exhibited a decreasing trend by increasing persulfate content in aqueous solutions of the polymer. The gelation doses of persulfate containing polymer solutions were calculated by the Charlesby–Pinner equation. It was observed that the gelation dose values were shifted to higher values by increasing persulfate concentration in solution. The ratio of the chain scission and crosslinking yields (G(s)/G(x)) was also determined. The results showed that the G(s)/G(x) ratios were smaller than one for PVP aqueous solution system, whereas those obtained for persulfate containing PVP aqueous solutions were higher than unity. The results implied that the chain scission of polymer is more effective than crosslinking in the presence of persulfate. Mechanism of the crosslinking and/or degradation and structure–property relationship of PVP and PVP/persulfate hydrogel systems were investigated by Fourier transformation infeared and thermal analysis (differential scanning calorimetry, thermal gravimetric analysis and differential thermai analysis) methods.     

An extended two‐dimensional copper–molybdate compound with mixed dicarboxyl and organodiamine ligands

The title complex, poly[di‐μ₃‐oxo‐hepta‐μ₂‐oxo‐tetra­oxo­bis(1,10‐phenanthroline)‐μ₄‐terephthalato‐dicopper(II)­tetra­molybdate(VI)], [Cu₂Mo₄(C₈H₄O₄)O₁₃(C₁₂H₈N₂)₂], represents a novel two‐dimensional copper–molybdate compound with mixed ligands. Tetra­nuclear molybdenum oxide clusters are joined through corner‐sharing into a ribbon‐like chain, with [Cu(phen)]²⁺ (phen is 1,10‐phenanthroline) complexes grafted onto either side. The terephthalate ligand lies about an inversion centre and links these chains to form a layer via Cu—O and Mo—O bonds. Face‐to‐face π–π stacking inter­actions between adjacent phen ligands stabilize the structure.     

5，10，15，20-四 [4-(4''-乙基哌嗪基)苯基]卟啉的合成及其与DNA的相互作用

基于卟啉对癌细胞的特殊亲和作用和哌嗪化合物的抗肿瘤、抗病毒作用，设计并合成了具有哌嗪结构的新型卟啉化合物5，10，15，20-四[4-(4'-乙基哌嗪基)苯基]卟啉（TEPPPH₂），其结构经UV-Vis, 元素分析，¹H NMR等手段证明。采用UV-Vis光谱和荧光光谱研究了TEPPPH₂和小牛胸腺DNA 的相互作用模式和结合机理。实验发现，TEPPPH₂能嵌入到DNA的碱基对中，1个小牛胸腺DNA分子对TEPPPH₂分子的最大结合数n约为88，结合常数为8.4×10⁶mol•L^-1 。TEPPPH₂与DNA的结合数和结合常数大于已知的四（4-N-甲基吡啶基）卟啉和Ca/sal-his、Ni/sal–aln型席夫碱抗癌药物。     

ZnHZSM-5上丙烷芳构化的研究-丙烷的活化

研究了HZSM－5、ZnHZSM－5和ZnNaZSM－5上的羟基振动光谱和一氧化碳吸附的红外光谱，以及丙烷的芳构化反应．红外光谱中发现表征强B酸的3610cm－1羟基振动峰相对强度由于锌离子的引入和浸渍氢氧化钠而减小，说明了锌离子和钠离子均进入了分子筛的阳离子位；一氧化碳在锌离子上的吸附峰位在2232cm－1，说明进入阳离子位的锌离子是一种强L酸．反应结果表明，锌离子的引入大大地促进了丙烷的转化和芳烃选择性的提高；在一定范围内，随浸渍氢氧化钠量的增加，丙烷转化率下降，而丙烯的选择性和产率增加，说明了锌组份直接参与了丙烷的脱氢过程．Zn－L酸是丙烷活化脱氢的中心，丙烷在该中心上异裂活化直接脱氢．     

In vitro metabolism study of Strychnos alkaloids using high‐performance liquid chromatography combined with hybrid ion trap/time‐of‐flight mass spectrometry

In this report, the in vitro metabolism of Strychnos alkaloids was investigated using liquid chromatography/high‐resolution mass spectrometry for the first time. Strychnine and brucine were selected as model compounds to determine the universal biotransformations of the Strychnos alkaloids in rat liver microsomes. The incubation mixtures were separated by a bidentate‐C₁₈ column, and then analyzed by on‐line ion trap/time‐of‐flight mass spectrometry. With the assistance of mass defect filtering technique, full‐scan accurate mass datasets were processed for the discovery of the related metabolites. The structural elucidations of these metabolites were achieved by comparing the changes in accurate molecular masses, calculating chemical component using Formula Predictor software and defining sites of biotransformation based upon accurate MSⁿ spectral information. As a result, 31 metabolites were identified, of which 26 metabolites were reported for the first time. These biotransformations included hydroxylation, N‐oxidation, epoxidation, methylation, dehydrogenation, de‐methoxylation, O‐demethylation, as well as hydrolysis reactions. Copyright © 2013 John Wiley & Sons, Ltd.     

N-substituted-3(10H)-acridones as visible-light photosensitizers for organic photoredox catalysis

N-Substituted-3(10H)-acridones have been established as visible-light organic photocatalyst. These photosensitizers are efficient for oxidative coupling reaction of N-aryl tetrahydroisoquinolines with various nucleophiles. Notably, N-methyl-3(10H)-acridone (Ia) is stable and can be effectively prepared. It is a water-soluble and atom-economic catalyst, and thus holds promise for green chemical applications. Mechanistic studies confirm a single electron transfer (SET)-induced radical process and a rate-limiting step. Analysis of the photocatalytic reactivity?structure relationship reveals that the acridones are robust and tunable photosensitizers for photoredox catalysis.     

Indications of bulk property changes from surface ion implantation

In the majority of cases, the effects of ion implantation are confined close to the implant zone but, potentially, the resultant distortions and chemical modifications could catalyse relaxations extending into the bulk substrate. Such possibilities are rarely considered but the present data suggest that high dose ion implantation of ZnO has induced bulk changes. Surface implants with Cu and Tb strongly modified the low temperature bulk thermoluminescence properties generated by X-ray irradiation. Suggestions are proposed for the possible mechanisms for bulk relaxations and structural characteristics, which may indicate where such instability may occur in other lattice structures.