几点提升结构化学模型实习课效果的举措

为提升结构化学模型实习课的效果,相继采取了建立虚拟模型实习网站,录制模型实习讲解视频以及改造模型实习课为讨论课等几项举措,切实克服了原来实习课所存在的问题,提升了学生在模型实习课中学习分子和晶体结构的效果。     

气球结合球棍模型在化学结构理论教学中的应用*

介绍了气球结合球棍模型在化学结构教学中的应用。气球是价廉易得的杂化轨道教学的完美教具,而结合球棍模型可以辅助认识共轭分子和共轭效应,理解分子轨道理论、分子性质和反应机理。这种让学生亲手操作的体验式学习模式,是一种很好的主动学习法,不仅极大地提升了学生的学习兴趣,更增强了他们对于复杂和抽象知识的理解。     

化学必备品格的内涵及构成要素——基于“学习强国”对化学家报道的分析

基于扎根理论对“学习强国”平台中化学家的报道进行了质性分析,提炼、归纳化学家身上所具有的品格,从而构建了化学必备品格要素的结构体系。该体系以化学学科领域特有的品格、科学领域普遍具有的品格、各个领域普遍具有的品格等3大维度为框架,包括热爱化学、绿色化学意识、批判质疑、严谨求真、求索创新等11个品格要素,这为理解化学必备品格提供了参考。     

化学教学中问题情境的创设

学习活动是一种思维活动,问题情境是思维的本源。本文论述了问题情境的构成要素,以及在化学教学中创设问题情境的原则和途径。     

基于模型与建模的化学学习过程设计

在阐释模型分类、模型功能和建模学习的意义的基础上,以“浓度对化学反应速率的影响”之学习过程设计为例,说明在化学教学中通过确立建模目标、模型参数选择、模型建构及表征、分析、评价、调用、重构等活动,可有效提升学生心智模型与表达模型的内在一致性和有效性,促进学生对化学知识的有效探究和深度理解。     

化学实验操作技能培养的理论探讨

化学实验技能是顺利完成化学实验任务的一种活动方式。化学实验技能涵盖化学实验心智技,能和化学实验动作技能两个方面。     

利用体验式学习软件构建化学实验适时教学空间

适时教学(JiTT)作为一种能有效促进学生自主学习的教学模式,在欧美国家倍受推崇。从适时教学的本质出发,将体验式学习软件与该教学模式相结合,构建了化学实验的适时教学空间,并利用所构建的空间,设计了基于高中化学新课程标准课程内容的教学案例,为理工类课程开展适时教学提供一定的参考。     

《义务教育化学课程标准(2011年版)》“科学探究”内容重大变化解读

义务教育化学课程标准(2011年版)规定了8个基础的学生实验活动,明确了初中生应学习的7项基本技能.对这些重大变化进行了解读与分析,并就“如何完成好学生实验活动、落实化学实验技能的培养”提出了相应的建议.     

一个适用于高中化学新课程标准的实验--微波水热合成法制备纳米Fe2O3

以实验为基础是化学学科的重要特征之一,为此,国家教育部新制订的《普通高中化学课程标准(实验)》(以下简称“新课程标准”)在化学选修课中独立设置了“实验化学”的课程模块,该课程模块围绕“知识与技能”、“过程与方法”、“情感态度与价值观”等三方面的目标,旨在使学生通过实验探究活动掌握基本的化学实验方法和技能、了解化学实验研究的一般过程以及常见物质的制备合成方法和现代仪器在物质研究中的应用。     

中学生化学学习归因结构调查研究

以中学生化学学习归因结构三维模型为理论框架,编制《中学生化学学习归因能力测量问卷》。该问卷由5个因子维度构成,分别是化学学习特定自我概念、化学学习情境认知、化学学习策略认知、化学学习人际认知、化学学习使能认知维度。经过理论预设、内容及项目分析、探索性因素分析、信度分析、专家效度和维度分析、验证性因素分析等过程最终形成正式问卷。问卷整体信度、效度较高,结构效度良好,可以作为中学生化学学习归因能力测量工具。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.