新型蒈酸基双酰肼化合物的合成及其生物活性

先将3-蒈烯分子中的碳碳双键氧化开环制得蒈酮酸，再将羰基还原成亚甲基得到蒈酸，酰氯化后与系列酰肼发生N-酰化反应合成了14个新型蒈酸基双酰肼化合物(5a～5n)，其结构经UV-Vis、¹H NMR、¹³C NMR、 FT-IR和MS(ESI)表征，并测试了目标化合物的抑菌和除草活性。结果显示：在用药量为50 μg·mL^-1时，目标化合物对花生褐斑病菌、小麦赤霉病菌、黄瓜枯萎病菌、苹果轮纹病菌、番茄早疫病菌、玉米小斑病菌、西瓜炭疽病菌以及水稻纹枯病菌等8种植物病原菌具有一定的抑制活性，其中化合物蒈酸基α-噻吩甲酰肼5f（R=α-thiophene）对苹果轮纹病菌的抑制率达85.0%，优于阳性对照百菌清。在用药量为100 μg·mL^-1时，化合物蒈酸基3′,4′-二甲氧基苯甲酰肼5j(R=3′,4′-OMe-Ph)、蒈酸基-m-甲氧基苯甲酰肼5d(R=m-OMe-Ph)、蒈酸基-m-甲基苯甲酰肼5b(R=m-Me-Ph)和蒈酸基苯甲酰肼5a(R=Ph)对油菜胚根生长的抑制率分别为88.5%、 86.1%、 85.1%和82.6%（均为A级活性水平），优于阳性对照丙炔氟草胺。     

Effects of double substitution on the thermodynamic stabilities of nitrogen radicals

Ｓｔｕｄｉｅｓｏｎｋｉｎｅｔｉｃｓｏｆｒａｄｉｃａｌｒｅａｃｔｉｏｎｓ[1]ａｎｄｏｎＣＨｂｏｎｄｄｉｓｓｏｃｉａｔｉｏｎｅｎｅｒｇｉｅｓ(ＢＤＥ)[2]ｈａｖｅｓｈｏｗｎｔｈａｔｃａｒｂｏｎｒａｄｉｃａｌｓａｒｅｓｔａｂｉｌｉｚｅｄｂｙｅｉｔｈｅｒａｎｅｌｅｃｔｒｏｎｄｏｎａｔｉｎｇｇｒｏｕｐ(ＥＤＧ)ｏｒａｎｅｌｅｃｔｒｏｎｗｉｔｈｄｒａｗｉｎｇｇｒｏｕｐ(ＥＷＧ),ａｎｄｔｈａｔｉｆａｃａｒｂｏｎｒａｄｉｃａｌｉｓｓｕｂｓｔｉｔｕｔｅｄｗｉｔｈｂｏｔｈａｎＥＤＧａｎｄａｎＥＷＧａｔｔｈｅｓａｍｅｃｅｎ…     

壳聚糖对鞣酸絮凝作用的研究

以壳聚糖为絮凝剂，采用絮凝法除去中药药液中的杂质。以鞣酸为研究对象，从鞣酸浓度，体系温度，ＰＨ絮凝剂用量粘均分子量等方面探讨其絮凝规律，用正交试验优化其絮凝条件，为实施中药药液的絮凝法精制工艺提供参考。     

Nucleation mechanisms and speciation of metal oxide clusters

The self-assembly mechanisms of polyoxometalates (POMs) are still a matter of discussion owing to the difficult task of identifying all the chemical species and reactions involved. We present a new computational methodology that identifies the reaction mechanism for the formation of metal-oxide clusters and provides a speciation model from first-principles and in an automated manner. As a first example, we apply our method to the formation of octamolybdate. In our model, we include variables such as pH, temperature and ionic force because they have a determining effect on driving the reaction to a specific product. Making use of graphs, we set up and solved 2.8 × 10⁵ multi-species chemical equilibrium (MSCE) non-linear equations and found which set of reactions fitted best with the experimental data available. The agreement between computed and experimental speciation diagrams is excellent. Furthermore, we discovered a strong linear dependence between DFT and empirical formation constants, which opens the door for a systematic rescaling.

The self-assembly mechanisms of polyoxometalates (POMs) are still a matter of discussion owing to the difficult task of identifying all the chemical species and reactions involved. The POMSimulator deals with that complexity in an automated manner.     

Enantioselective iodolactonization catalyzed by chiral quaternary ammonium salts derived from cinchonidine

Chiral quaternary ammonium salts derived from cinchonidine have been applied to catalyze the stereoselective iodolactonizations of trans-5-aryl-4-pentenoic acids leading to a mixture of two regioselectively iodolactonized products with fair to excellent yield (37-98%) and moderate enantioselectivity (exo = 42.0% ee, endo = 31.0% ee) under mild conditions. This work is the first example of asymmetric iodolactonization reaction in the presence of less than a stoichiometric amount of chiral reagent.     

Thin-Layer Chromatography with an Isolated Support and Forced Flow of the Mobile Phase

JPC – Journal of Planar Chromatography – Modern TLC -     

有机/无机杂化材料担载季铵盐催化剂的制备及其在相转移催化反应中的应用

利用溶胶-凝胶(S0l-gel)技术制备了新型的有机／无机杂化材料担载的季铵盐催化剂。优化了制备方法、反应条件等多种因素；考察了其作为相转移催化剂在1-溴代正庚烷与碘化钾的亲核取代反应中的应用，转化率最高可达到95％。     

Ni-B和Ni-Ce-B超细非晶态合金的退火晶化及其催化性能

 采用XAFS,XRD和DTA方法研究了Ni－B和Ni－Ce－B超细非晶态合金在退火过程中的结构变化及其结构与催化性能的关系．活性结果表明,在退火温度为623K时,Ni－B和Ni－Ce－B样品的苯加氢催化反应转化率最高,分别为63％和81％,0．3％Ce的掺入提高了Ni－Ce－B的催化活性．DTA结果表明,Ni－B超细非晶态合金在598和653K有两个晶化峰,而Ni－Ce－B样品有548,603,696和801K四个晶化峰．XAFS和XRD结果进一步说明,在573K退火时,Ni－B样品晶化生成晶态Ni3B和纳米晶Ni,此时Ni－Ce－B仅有少量晶态Ni3B生成．在673K退火时,Ni－B样品中的Ni3B开始分解生成晶态Ni,同时纳米晶Ni聚集并形成大颗粒晶态Ni,而Ni－Ce－B样品晶化生成晶态Ni3B和纳米晶Ni．在773K和更高的温度退火处理后,Ni－B样品中Ni的局域环境结构与金属Ni箔基本一致,但Ni－Ce－B样品晶化生成的Ni晶格有较大畸变,同时Ni3B并未分解．说明0．3％的Ce对提高Ni－Ce－B样品的稳定性有显著作用．本文首次报道了Ni－B和Ni－Ce－B超细非晶态合金中苯加氢催化活性中心为纳米晶Ni和类似于金属Ni的Ni－B非晶态合金．     

Influence of ultrasonic field on microcystins produced by bloom-forming algae

Under the background of algae removal and growth inhibition by ultrasonic irradiation, the effects of ultrasonic irradiation on removal of Microcystis, the concentration variation of microcystins (MC) produced by Microcystis in Microcystis suspension, and sonochemical degradation of microcystins in water, were studied in the paper. The results showed that ultrasonic irradiation could efficiently inhibit the growth of Microcystis, and ultrasonic irradiation shorter than 5 min would not introduce the increase of microcystins dissolved in Microcystis suspension simultaneity. Also, microcystins dissolved in Microcystis suspension would not increase as ultrasonic power increasing. Further research showed that microcystins were effectively degraded in ultrasonic fields. After 20 min ultrasonic irradiation at 150 kHz and 30 W, the removal rate of microcystins reached 70%.     

Controlling the cohesion of cement paste

The main source of cohesion in cement paste is the nanoparticles of calcium silicate hydrate (C-S-H), which are formed upon the dissolution of the original tricalcium silicate (C(3)S). The interaction between highly charged C-S-H particles in the presence of divalent calcium counterions is strongly attractive because of ion-ion correlations and a negligible entropic repulsion. Traditional double-layer theory based on the Poisson-Boltzmann equation becomes qualitatively incorrect in these systems. Monte Carlo (MC) simulations in the framework of the primitive model of electrolyte solution is then an alternative, where ion-ion correlations are properly included. In addition to divalent calcium counterions, commercial Portland cement contains a variety of other ions (sodium, potassium, sulfate, etc.). The influence of high concentrations of these ionic additives as well as pH on the stability of the final concrete construction is investigated through MC simulations in a grand canonical ensemble. The results show that calcium ions have a strong physical affinity (in opposition to specific chemical adsorption) to the negatively charged silicate particles of interest (C-S-H, C(3)S). This gives concrete surprisingly robust properties, and the cement cohesion is unaffected by the addition of a large variety of additives provided that the calcium concentration and the C-S-H surface charge are high enough. This general phenomenon is also semiquantitatively reproduced from a simple analytical model. The simulations also predict that the affinity of divalent counterions for a highly and oppositely charged surface sometimes is high enough to cause a "charge reversal" of the apparent surface charge in agreement with electrophoretic measurements on both C(3)S and C-S-H particles.