基于科学态度与社会责任的反向思维教学——以“元素化学”为例

“科学态度与社会责任”是《普通高中课程标准(2017年版)》提出的5大化学学科核心素养之一,但在课堂教学实践中对其的培养却往往流于形式和表面,使得学生并不能真正理解和认同化学学科与社会发展的密切关系。在元素化学的必修课和选修课课堂教学中进行了一系列的“反向思维”教学尝试,通过建立“当某种元素不存在”这一假设来引导学生思考此情境对社会生产生活的影响。通过此教学尝试,让学生在获得元素知识的同时,深刻认识元素价值,并理解化学科学与现代社会发展的重要关系,提升学生的社会使命感与责任感;使学生进一步树立科学利用元素资源和建设现代化祖国的远大志向。     

双体系双波长荧光光度法及其在药物分析中的应用

提出一种新型“双体系双波长荧光光度法”（ＤＳＤＷＦ），并用于性质相近药物苯酚及间苯二酚的同时测定，测定下限为０．０５μｇ／ｍＬ，苯酚与间苯二酚的浓度允许比为１：１０－１０：１。用于模拟复方雷琐辛涂剂的测定，结果满意。     

Natural Product Chemistry: From Plants to Human

Conventionally, natural product chemistry deals with the isolation, characterization, and synthesis of compounds from plants. It a broad sense, natural product chemistry may include all fields of biochemistry. Two projects are presented to illustrate the expanded definition of natural product chemistry. One deals with phosphatidylinositol (PI) and the key enzyme involved in its metabolism, PI-specific phospholipase C. The other project is on the structure-function relationship of human tumor suppressor p16.     

Biofuel Combustion Chemistry: From Ethanol to Biodiesel

Biofuels, such as bio‐ethanol, bio‐butanol, and biodiesel, are of increasing interest as alternatives to petroleum‐based transportation fuels because they offer the long‐term promise of fuel‐source regenerability and reduced climatic impact. Current discussions emphasize the processes to make such alternative fuels and fuel additives, the compatibility of these substances with current fuel‐delivery infrastructure and engine performance, and the competition between biofuel and food production. However, the combustion chemistry of the compounds that constitute typical biofuels, including alcohols, ethers, and esters, has not received similar public attention. Herein we highlight some characteristic aspects of the chemical pathways in the combustion of prototypical representatives of potential biofuels. The discussion focuses on the decomposition and oxidation mechanisms and the formation of undesired, harmful, or toxic emissions, with an emphasis on transportation fuels. New insights into the vastly diverse and complex chemical reaction networks of biofuel combustion are enabled by recent experimental investigations and complementary combustion modeling. Understanding key elements of this chemistry is an important step towards the intelligent selection of next‐generation alternative fuels.     

LiAlH4: From Stoichiometric Reduction to Imine Hydrogenation Catalysis

Imine‐to‐amine conversion with catalytic instead of stoichiometric quantities of LiAlH₄ is demonstrated (85 °C, catalyst loading≥2.5 mol %, pressure≥1 bar). The effects of temperature, pressure, solvent, and catalyst modifications, as well as the substrate scope are discussed. Experimental investigations and preliminary DFT calculations suggest that the catalytically active species is generated in situ: LiAlH₄+Ph(H)C=NtBu→LiAlH₂[N(tBu)CH₂Ph]₂. A cooperative mechanism in which Li and Al both play a prominent role is proposed.     

中学化学实验中的科学风险认知和决策意识

对中学化学实验中的科学风险认知和决策意识进行探索与思考,分析了中学化学实验中科学风险教育的现状,探讨了在化学实验中进行科学风险认知和决策的方式,阐述了在化学实验中培养学生科学风险认知和决策意识的意义。     

抗结冰涂层: 从表面化学到功能化表面

在交通运输、航空航天、电力通信等诸多领域,结冰给人类和社会带来很大危害和安全隐患。现有的抗结冰方法如机械除冰、加热除冰以及喷洒化学试剂等虽然有效,但是存在耗能大和环境污染等问题。在基体表面涂装具有抗结冰性能的功能涂层被认为是一种必要的切实有效的方法,近年来备受关注。本文在介绍了涂层抗结冰原理及基体表面结冰影响因素的基础上,详细综述了近年来各类抗结冰涂层取得的研究成果,主要包括牺牲性涂层、疏冰涂层和超疏水涂层。重点介绍了制备抗结冰涂层所用的材料及方法,并分析了各种抗结冰涂层的优缺点,指出了抗结冰涂层目前存在的问题,最后对抗结冰涂层的发展趋势进行了分析和展望。     

Deep Eutectic Solvents and Multicomponent Reactions: Two Convergent Items to Green Chemistry Strategies

One of the highlights of green chemistry is the development of techniques and procedures with low environmental impact. In the last years, deep eutectic solvents (DES) have become an important alternative to conventional organic solvents. For a period ionic liquids have provoked remarkable interest, but they have been displaced by DES because they show easier preparation methods, lower prices, many of them are biodegradable and compatible with biological systems. In addition, they show adjustable physicochemical properties, high thermal stability, low volatility and are compatible with water. In this paper is reviewed the state of the art of the use of DES paying special attention to the role of reaction media in organic synthesis.     

The Dirac Electron: From Quantum Chemistry to Holistic Cosmology

The Dirac equation, which was derived by combining the relativistic invariance condition with the quantum probability principle, showed its fecundity by explaining the half‐integer spin of fermions and by predicting antiparticles. In previous papers, we conjectured that the spinning motion of the electron was that of a massless charge moving at light velocity, this internal motion being responsible for the electron rest mass involved in external motions and interactions. Implications of this concept on basic properties such as time, mass, electric charge, and magnetic moment were investigated. The present paper is a recollection of these ideas aimed at their possible impact on quantum chemistry and holistic cosmology.     

From Polyhalides to Polypseudohalides: Chemistry Based on Cyanogen Bromide

Pseudohalogens are defined as molecular entities that resemble the halogens in their chemistry. While our understanding of polyhalogen chemistry has increased over the last years, research on polypseudohalogen compounds is lacking. The pseudohalogen BrCN possesses a highly pronounced σ‐hole at the bromine side of the molecule, inducing strong halogen bonding. This allows the synthesis and characterization of new polypseudohalogen anions, as shown by the single‐crystal X‐ray diffraction of [PNP][Br(BrCN)] and [PNP][Br(BrCN)₃]. Both the nearly linear anion [Br(BrCN)]^? and the distorted pyramidal anion [Br(BrCN)₃]^? were characterized by Raman spectroscopy and quantum‐chemical calculations. The behavior of the polypseudohalogen compounds in solution and as room‐temperature ionic liquids (RT‐ILs) using the [NBu₄]⁺ cation was studied by ¹³C and ¹⁵N NMR spectroscopy. These types of ILs are capable of dissolving elemental gold and offer themselves as promising compounds in metal recycling.     

Micro-Solvated DMABN: Excited State Quantum Dynamics and Dual Fluorescence Spectra

In this work, we report a complete analysis by theoretical and spectroscopic methods of the short-time behaviour of 4-(dimethylamino)benzonitrile (DMABN) in the gas phase as well as in cyclohexane, tetrahydrofuran, acetonitrile, and water solution, after excitation to the La state. The spectroscopic properties of DMABN were investigated experimentally using UV absorption and fluorescence emission spectroscopy. The computational study was developed at different electronic structure levels and using the Polarisable Continuum Model (PCM) and explicit solvent molecules to reproduce the solvent environment. Additionally, excited state quantum dynamics simulations in the diabatic picture using the direct dynamics variational multiconfigurational Gaussian (DD-vMCG) method were performed, the largest quantum dynamics “on-the-fly” simulations performed with this method until now. The comparison with fully converged multilayer multiconfigurational time-dependent Hartree (ML-MCTDH) dynamics on parametrised linear vibronic coupling (LVC) potentials show very similar population decays and evolution of the nuclear wavepacket. The ring C=C stretching and three methyl tilting modes are identified as the responsible motions for the internal conversion from the La to the Lb states. No major differences are observed in the ultrafast initial decay in different solvents, but we show that this effect depends strongly on the level of electronic structure used.     

The Use of Dual Cyclodextrin Chiral Selector Systems in the Enantioseparation of Pharmaceuticals by Capillary Electrophoresis: An Overview

Cyclodextrin (CD) derivatives are the most efficient and frequently used chiral selectors (CSs) in capillary electrophoresis (CE). There are situations when the use of a single CD as CS is not enough to obtain efficient chiral discrimination of the enantiomers; in these cases, sometimes this problem can be resolved using a dual CD system. The use of dual CD systems can often dramatically enhance enantioseparation selectivity and can be applied for the separation of many analytes of pharmaceutical interest for which enantioseparation by CE with another CS systems can be problematic. Usually in a dual CD system an anionic CD is used together with a neutral one, but there are situations when the use of a cationic CD with a neutral one or the use of two neutral CDs or even two ionized CDs can be an efficient solution. In the current review we present general aspects of the use of dual CD systems in the analysis of pharmaceutical substances. Several examples of applications of the use of dual CD systems in the analysis of pharmaceuticals are selected and discussed. Theoretical aspects regarding the separation of enantiomers through simultaneous interaction with the two CSs are also explained. Finally, advantages, disadvantages, potential and new direction in this chiral analysis field are highlighted.     

Chemistry of Pentafluorosulfanyl Derivatives and Related Analogs: From Synthesis to Applications

Pentafluorosulfanyl (SF₅)-containing compounds and corresponding analogs are a highly valuable class of fluorine-containing building blocks owing to their unique properties. The reason for that is the set of peculiar and tremendously beneficial characteristics they can impart on molecules once introduced onto them. Despite this, their application in distinct scientific fields remains modest, given the extremely harsh reaction conditions needed to access such compounds. The recent synthetic approaches via S−F, and C−SF₅ bond formation as well as the use of SF₅-containing building blocks embody a “stairway-to-heaven” loophole in the synthesis of otherwise-inaccessible chemical scaffolds only a few years ago. Herein, we report and evaluate the properties of the SF₅ group and analogs, by summarizing synthetic methodologies available to access them as well as following applications in material science and medicinal chemistry since 2015.     

Evaluation of the Use of QSARS for Priority Setting and Risk Assessment

Abstract

Impending changes in EEC legislation have accelerated the need to define the principles and practical considerations of the use of QSARs in priority setting and risk assessment. It is important to delineate the limitations of this approach and to review whether and how this information should be used in the risk assessment. The value and limitations of QSARs for use in priority setting and risk assessment will not be discussed in detail since the European Chemical Industry Ecology and Toxicology Centre (ECETOC) has only recently established a Task Force to tackle this issue. The terms of reference of the Task Force are: (1) compare the predictions obtained with QSARs to measured data using ECETOC databases and other sources of data and comment on the validity and applicability of such QSARs; (2) identify and review software packages which are available for accessing and using appropriate QSARs; (3) identify those aspects of environmental distribution, fate and effects where the further development of QSARs is desirable and feasible; and (4) provide a scientific basis for ECETOC's contribution to the activities of the European Chemicals Bureau (ECB) in this area. In this short paper, only an initial and personal evaluation is made of when and where to use QSARs in the priority setting and risk assessment process within the regulatory framework. Some critical remarks and suggestions are provided to guide future developments and integration of QSARs in the risk assessment process.     

Advances in Anion Supramolecular Chemistry: From Recognition to Chemical Applications

Since the start of this millennium, remarkable progress in the binding and sensing of anions has been taking place, driven in part by discoveries in the use of hydrogen bonding, as well as the previously under‐exploited anion–π interactions and halogen bonding. However, anion supramolecular chemistry has developed substantially beyond anion recognition, and now encompasses a diverse range of disciplines. Dramatic advance has been made in the anion‐templated synthesis of macrocycles and interlocked molecular architectures, while the study of transmembrane anion transporters has flourished from almost nothing into a rapidly maturing field of research. The supramolecular chemistry of anions has also found real practical use in a variety of applications such as catalysis, ion extraction, and the use of anions as stimuli for responsive chemical systems.     

限域化学：碳基功能材料从基础研究到应用

限域化学研究的是对象在纳米尺度限域空间内的化学行为。限域空间内的化学环境不同于常规本体溶液,因而会出现许多奇特的现象,如反应选择性增强、活性增加、稳定性提高。本文结合笔者课题组近年来的工作,对限域化学领域碳基功能材料的限域策略,包括限域界面诱导、限域化学组装印刷及三维多孔受限体系作简要介绍,并阐述了其在催化、储能方面的应用。最后提出了限域化学未来发展面临的主要挑战,期望能为此领域研究提供参考。     

Chemistry of tetracyanoethylene (TCNE): From TCNE to dicyanomethylacetate

In the presence of CoCl₂ · 6H₂O, the reaction of TCNE (tetracyanoethylene) with CH₃OH forms a dicyanomethylacetate molecule, which has been obtained as one solvent molecule in one new compound {[Co(bpy)₂CN₂][(NC)₂C-CO₂CH₃]} · 2H₂O (1). It was characterized by IR spectra, UV-Vis spectra, and cyclic voltammogram. Its structure was determined by X-ray crystallography: 1 crystallizes in P2(1)/n with a = 13.3368(17), b = 12.5299(16), c = 16.074(2) Å, α = 90, β = 94.6320(10), γ = 90°, and Z = 2.     

从生活世界到科学世界——新课程理念下化学教学范式的重要转型

把化学带到生活中去,加强与社会生活的联系,使化学教学贴近学生的社会生活实际,让学生以社会生活为背景学习化学知识,并使其了解化学在现代社会生活中的价值,是20世纪90年代以来世界中学化学课程改革的重要趋势,也是当前我国基础教育课程改革中化学教学范式的重要转型。落实从生活世界向科学世界的化学教学范式的转变,完整地体现化学课程的价值,是当前我国中学化学课程改革所面临的一项重要任务。     

从原子论到原子-分子论:科学思想的传播与进化

本文研究了原子-分子论形成的历史过程,对原子论和分子论在各阶段的传播和进化情况进行了客观的分析和评价,认为从原子论到原子-分子论的演变是一种修正式的进化,并对道尔顿和阿伏加德罗也做了客观的评价。