Theoretical aspects of communication in chemistry

Successful searching for publications on the basis of subject obeys rules whose relations to thermodynamics are unmistakable. As a collection of literature grows, the degree of order required increases, since the patience, time, and memory used by man to compensate for lack of order cannot keep pace. The high degrees of order that are necessary nowadays in scientific literature cannot be attained by traditional documentation methods. If modern techniques are used to improve communication, the conceptual basis of such a documentation method must be revised and adapted to suit the new possibilities. The conditions in chemistry are relatively favorable for the effective use of modern technical and conceptual methods, since the terminology has been developed further than in most other sciences.     

Application and new possibilities of automation in liquid chromatography

Summary The different steps of automation of an HPLC system are discussed. With automatic sample injection, a higher through put and a better reproducibility can be achieved than with manual injection.Peak processing systems are necessary to manage the flood of data. Post run optimization of the integration parameters are possible with a computer system. Data systems provide an enormous flexibility to produce different kinds of reports, summaries and graphs and to perform statistical calculations.The assay and purity control of a peptide hormone injection (Lys⁸-Vasopressin) is shown as an example of automated HPLC. Reversed phase gradient elution with UV and reaction detection is used.     

Heavy Grignard reagents: challenges and possibilities of aryl alkaline earth metal compounds

Compounds of the type aryl--M--X, with M=Ca, Sr, Ba and X as any kind of ligand (such as halide, phosphanide, amide, aryl), are presented. The low reactivity of the heavy alkaline earth metals calcium, strontium, and barium enforces an activation prior to use for the direct synthesis. The insertion of these metals into C--I bonds of aryl iodides (direct synthesis) yields aryl metal iodides and has to be performed at low temperatures and in THF. Aryl alkaline-earth-metal compounds show some characteristics: 1) the ease of ether cleavage enforces low reaction temperatures, 2) for Sr and Ba the Schlenk equilibrium is shifted towards homoleptic MI2 and MPh2, 3) high solubility of diaryl alkaline-earth-metal derivatives in THF even at low temperatures initiated quantum chemical investigations on the aggregation behavior, and 4) a strong low field shift of the 13C resonances of the ipso carbon atoms in NMR spectra was observed. First results from quantum chemical calculations on diaryl dicalcium(I) suggest a long Ca--Ca bond with a considerable Ca--Ca bond dissociation energy. Initial results on a selection of applications such as metallation, metathesis, and addition reactions of aryl calcium compounds are presented as well.     

Chemical communication between solids placed at distance: Sol-gel entrapped acids and bases

Chemical reactions between “far-away” components are quite common in the living world and in geological processes, and are affected by communicating shuttling molecules and ions. Surprisingly, there has been little attention in the chemical literature to model these natural processes by bench-laboratory heterogeneous reactions. Towards that goal we report the study of chemical communication between solid acids and bases placed at distance. The porous solids were prepared by entrapping various acids and bases in silica sol-gel matrices. We recall that while, of course, dissolved acids and bases titrate each other, when solid acids and bases are placed in the same pot, titration can be affected only through an ion-exchange process. This property is used here to cause the two distantly placed solids to communicate with each other. In particular, we use here the entrapped acids as senders of messenger-hydronium ions and as receivers of hydroxyl ions, and entrapped bases as senders of messenger-hydroxyls. We demonstrate the possibility to control the parameters of the communication between these solids.     

化学系统性思维的背景、应用与特征*

当今地球与社会系统所面临的可持续发展、气候变化、环境退化等全球性挑战问题,用还原主义方法不足以应对,需要化学教育等领域的工作者采用系统性思维方法。梳理了国外学者在应用化学系统性思维理解化学学科系统复杂性、化学学习系统层级性、化学教育系统整合性的研究进展。概述了化学系统性思维具有重视跨学科关联、整体综合思考目标系统问题、强调可持续发展的全球观念等特征。建议加强化学教育内外部系统的协作,注重各学段化学课程与教学的跨学科、系统性,重视学生解决化学问题的认识方式差异。     

化学系统性思维的表征手段与改革实践*

化学系统性思维强调化学子系统之间,以及化学系统与其他学科系统之间的关系,有助于学习者整合、应用化学知识解释化学现象、解决化学问题。内外交织的多个不同系统很容易让学生迷失在纷繁复杂的概念体系中,需要借助SOCME,OPM,BOTG,CLD,SFD等可视化图形工具厘清各个系统之间的关系,以表征化学系统性思维。在明确化学系统性思维内涵的基础上,开展“化学平衡”教学改革,探索绿色化学课程建设,开展游戏化学习、服务性学习、深度学习、项目学习、工作坊或研讨会,有助于化学系统性思维培养实践的改革与落地。横向关联化学系统与其他学科系统的关系,纵向深入分析化学子系统之间的关系,是进一步开展化学系统性思维教学的关键。这就需要多学科的协同攻关,既要关注化学知识的社会应用,也要抓住化学学科本质和特征,才可以围绕化学概念和社会问题,建构纵横交织的多系统影响关系,促进学生化学系统性思维的发展。     

大学化学实验安全教育和管理的创新与实践

在常规的安全教育和管理基础上,近年来中国科学技术大学化学实验教学中心进一步从硬件环境建设到在线安全课程(慕课)设置、从反应绿色化到高危实验虚拟化、从大型仪器管理到药品管理等方面,切实开展了一系列工作,建立了一套较为完整的安全教育与管理体系,以实现对学生安全意识和防护意识的全面提升。     

Research on analytical chemistry in Brazil: an overview

An overview is presented of the beginnings, evolution and current status of research on analytical chemistry in Brazil. Among the various fields of chemistry two decades ago, Analytical Chemistry was considered one of the least developed in Brazil. In the last 15 years, however, research and development in this field have expanded considerably and today it is one of the most highly developed fields of Chemistry in Brazil. This paper offers a general overview of this evolution and some suggestions for possible routes for the future of analytical chemistry in Brazil.     

Teaching metrology and quality in chemistry based on methods of mathematical statistics and e-learning

Chemistry students do not usually have the necessary background in mathematical statistics to study metrology and quality principles in chemistry. Even when the students have studied mathematical statistics, it is helpful to refresh their statistical knowledge, focusing on specific applications to metrology and quality in chemistry. Therefore, when planning a course for teaching metrology and quality it is important to achieve a harmonized interaction of metrological and quality issues with the supporting statistical issues. Additional possibilities for learning the relevant subjects originate from the Internet (e-learning). Such a lecture course developed and delivered during the five years since 2003 at the Hebrew University of Jerusalem is discussed in the paper.     

基于中学“新课改”的大学 “无机化学”教学改革探索

伴随新一轮中学课程改革的全面展开,中学化学教学从内容和形式上都发生了很大变化,与之紧密衔接的大学“无机化学”教学改革需随之展开,结合“无机化学”教学实践,本文从知识、方法上总结了大学“无机化学”教学改革的经验及需解决的瓶颈问题。