Synthesis and Herbicidal Activities of 3‐(4‐Chloro‐2‐fluoro‐5‐substituted phenyl)benzo[d][1,2,3]triazin‐4(3H)‐one Derivatives

A series of 3‐phenyl benzo[d][1,2,3]triazin‐4(3H)‐one derivatives were synthesized through the condensation of phenol E and alkyl (alkenyl, alkynyl) chlorides (bromides, iodide) or alkyl chloroacetates or N‐alkyl chloroacetamides using K₂CO₃ as the acid acceptor in N,N‐dimethylformamide. Phenol E was prepared from starting material, 5‐amino‐2‐chloro‐4‐fluorophenyl ethyl carbonate, in four steps involving in amidation, reduction, diazotization, and deprotecting‐group reaction. The herbicidal activities of the title compounds were tested against two dicotyledonous plants and two monocotyledonous plants, in which some of them exhibited high herbicidal activities against two dicotyledonous plants in preemergence and postemergence treatments. Moreover, when the dosage was decreased to 180 and 90 g/ha, compounds F1 , F8 , and F9 showed highly selective inhibitory activities against amaranth pigweed, alfalfa, asteraceae, field sowthistle, morning glory, purslane, and velvetleaf in postemergence treatment but had no herbicidal efficacy on rape except F1 , suggesting that it be possible to find a kind of herbicides to inhibit dicotyledonous weeds in the field of dicotyledonous crops with the same genus as aforementioned weeds.     

On a Predator–Prey System with Digestion Delay and Anti-predation Strategy

Journal of Nonlinear Science - Predator–prey interactions are among the most complicated interactions between biological species, in which there may be both direct effect (through predation)...     

In Situ Structural Determination of a Homogeneous Ruthenium Racemization Catalyst and Its Activated Intermediates Using X-Ray Absorption Spectroscopy

The activation process of a known Ru-catalyst, dicarbonyl(pentaphenylcyclopentadienyl)ruthenium chloride, has been studied in detail using time resolved in situ X-ray absorption spectroscopy. The data provide bond lengths of the species involved in the process as well as information about bond formation and bond breaking. On addition of potassium tert-butoxide, the catalyst is activated and an alkoxide complex is formed. The catalyst activation proceeds via a key acyl intermediate, which gives rise to a complete structural change in the coordination environment around the Ru atom. The rate of activation for the different catalysts was found to be highly dependent on the electronic properties of the cyclopentadienyl ligand. During catalytic racemization of 1-phenylethanol a fast-dynamic equilibrium was observed.     

Polyethylenimine‐Based Nanogels for Biomedical Applications

Nanogels (NGs) are 3‐dimensional (3D) networks composed of hydrophilic or amphiphilic polymer chains, allowing for effective and homogeneous encapsulation of drugs, genes, or imaging agents for biomedical applications. Polyethylenimine (PEI), possessing abundant positively charged amine groups, is an ideal platform for the development of NGs. A variety of effective PEI‐based NGs have been designed and much effort has been devoted to study the relationship between the structure and function of the NGs. In particular, PEI‐based NGs can be prepared either using PEI as the major NG component or using PEI as a crosslinker. This review reports the recent progresses in the design of PEI‐based NGs for gene and drug delivery and for bioimaging applications with a target focus to tackle the diagnosis and therapy of cancer.     

Pincer‐Type Platinum(II) Complexes Containing N‐Heterocyclic Carbene (NHC) Ligand: Structures,Photophysical and Anion‐Binding Properties,and Anticancer Activities

Two classes of pincer‐type Pt^II complexes containing tridentate N‐donor ligands ( 1 – 8 ) or C‐deprotonated N^C^N ligands derived from 1,3‐di(2‐pyridyl)benzene ( 10 – 13 ) and auxiliary N‐heterocyclic carbene (NHC) ligand were synthesized. [Pt(trpy)(NHC)]²⁺ complexes 1 – 5 display green phosphorescence in CH₂Cl₂ (Φ: 1.1–5.3 %; τ: 0.3–1.0 μs) at room temperature. Moderate‐to‐intense emissions are observed for 1 – 7 in glassy solutions at 77 K and for 1 – 6 in the solid state. The [Pt(N^C^N)(NHC)]⁺ complexes 10 – 13 display strong green phosphorescence with quantum yields up to 65 % in CHCl₃. The reactions of 1 with a wide variety of anions were examined in various solvents. The tridentate N‐donor ligand of 1 undergoes displacement reaction with CN^? in protic solvents. Similar displacement of the N^C^N ligand by CN^? has been observed for 10 , leading to a luminescence “switch‐off” response. The water‐soluble 7 containing anthracenyl‐functionalized NHC ligand acts as a light “switch‐on” sensor for the detection of CN^? ion with high selectivity. The in vitro cytotoxicity of the Pt^II complexes towards HeLa cells has been evaluated. Complex 12 showed high cytotoxicity with IC₅₀ value of 0.46 μM , whereas 1 – 4 and 6 – 8 are less cytotoxic. The cellular localization of the strongly luminescent complex 12 traced by using emission microscopy revealed that it mainly localizes in the cytoplasmic structures rather than in the nucleus. This complex can induce mitochondria dysfunction and subsequent cell death.     

Analysis of IBAD silicon oxynitride film for anti-reflection coating application

A SOI-based optoelectronic device needs a high-quality anti-reflection coating on both faces of the device to minimize the optical reflectance from the face. In this work amorphous silicon oxynitride films were deposited on silicon substrates by ion beam assisted deposition (IBAD). The main purpose was to use silicon oxynitride film as single layer anti-reflection coating for SOI-based optoelectronic devices. This application is primarily based on the ability to tune the silicon oxynitride optical functions to the values optimal by changing deposition parameters. The chemical information was measured by X-ray photoelectron spectroscopy (XPS). Spectroscopic ellipsometry (SE) was applied to measure the refractive index and thickness. Single-side polished silicon substrate that was coated with silicon oxynitride film exhibited low reflectance. Double-side polished silicon substrate that was coated with silicon oxynitride film exhibited high transmittance. The results suggested silicon oxynitride film was a very attractive single layer anti-reflection coating for SOI-based optoelectronic device.     

Pt/ZnO 在室温水相无碱条件下绿色催化苯甲醇选择性氧化

醇类化合物选择性氧化是有机合成中一个非常重要的反应, 在精细化工领域具有重要应用. 而以水为绿色溶剂, 分子氧为绿色氧化剂实现醇类化合物选择性氧化是绿色化学领域的一大挑战. Pt 催化剂由于其优异的活化氧气和 C-H 键的能力在该反应中得到了广泛应用. 但是, 常规的 Pt 催化剂通常需要在较高温度和较高氧气压力以及加碱的条件下才能发挥作用, 从而引起了催化剂腐蚀等一系列问题. 从绿色化学角度出发, 进一步优化 Pt 催化剂, 让其能够在室温无碱条件下以空气为氧化剂选择性氧化醇类合成羰基化合物具有重要的研究价值和应用前景.本文通过化学还原法制备了 Pt/ZnO 催化剂, 系统研究了该催化剂在水相无碱条件下选择性氧化苯甲醇生成苯甲醛反应中的催化性能. X 射线电子衍射和透射电镜等结果表明, Pt 颗粒较小(3.2 ± 0.3 nm), 均匀分散在 ZnO 载体上; X 射线光电子能谱表明 ZnO 载体能够稳定 Pt 纳米颗粒表面的 Pt0物种. 上述催化剂在水相苯甲醇选择性氧化反应中, 在室温下即可催化空气高选择性氧化苯甲醇到苯甲醛 (选择性>99%), 并表现出比 Pt/SiO2, Pt/Al2O3, Pt/TiO2, Pt/Ca(Mg)-ZSM-5 等催化剂更为优异的催化活性. 这可归结于 Pt 和 ZnO 之间的协同作用. 该协同作用通过动力学实验和密度泛函理论计算 (DFT)得到了证实. 氧分压实验表明, 在以空气为氧化剂时, O2的活化并不是限制 Pt/ZnO 催化活性的关键因素, 而动力学同位素效应实验则证实了苯甲醇的 C-H 键活化是整个反应的决速步骤. 通过构建不同的理论模型, 分别计算了 Pt/ZnO 界面处以及纯 Pt 位点上苯甲醇选择性氧化的反应过程. 结果表明, 苯甲醇和氧气分子倾向于分别在 ZnO 和 Pt 上进行吸附, 随后由吸附的氧气分子来活化苯甲醇中的 C-H 键, 进而生成苯甲醛和水. 而当 ZnO 不参与苯甲醇的吸附活化时, 整个反应的活化能会大大提高, 表明 ZnO 和 Pt 之间的协同作用对于整个反应至关重要. 此外, Pt/ZnO 表现出非常优异的稳定性, 循环使用 4 次后, 催化剂结构以及催化活性没有显著变化.进一步向 Pt/ZnO 催化剂中引入少量 Bi 元素对 Pt 的电子结构进行修饰, 可以将 Pt/ZnO 的催化活性提高 3 倍. 所制备的 Pt/Bi-ZnO 复合物是目前报道的相同条件下催化苯甲醇选择性氧化反应转化频率 (45.1 h-1)最高的催化剂.