Nanomaterial characterization: considerations and needs for hazard assessment and safety evaluation

Nanotechnology is a rapidly emerging field of great interest and promise. As new materials are developed and commercialized, hazard information also needs to be generated to reassure regulators, workers, and consumers that these materials can be used safely. The biological properties of nanomaterials are closely tied to the physical characteristics, including size, shape, dissolution rate, agglomeration state, and surface chemistry, to name a few. Furthermore, these properties can be altered by the medium used to suspend or disperse these water-insoluble particles. However, the current toxicology literature lacks much of the characterization information that allows toxicologists and regulators to develop “rules of thumb” that could be used to assess potential hazards. To effectively develop these rules, toxicologists need to know the characteristics of the particle that interacts with the biological system. This void leaves the scientific community with no options other than to evaluate all materials for all potential hazards. Lack of characterization could also lead to different laboratories reporting discordant results on seemingly the same test material because of subtle differences in the particle or differences in the dispersion medium used that resulted in altered properties and toxicity of the particle. For these reasons, good characterization using a minimal characterization data set should accompany and be required of all scientific publications on nanomaterials.     

Symposium overview computer simulation of inorganic solids

Summary A symposium on Computer Simulation of Inorganic Solids, organised by the Applied Solid State Chemistry Group Trust and by the Polar Solids Group of the Royal Society of Chemistry was held in London, in December 1988. Speakers at the forefront of research in computational techniques for simulation of inorganic solid materials reviewed the range of application of these methods and the prospects for future application to a largely non-specialist audience.The meeting was timely and well supported. The majority of the talks given are presented in this volume. This overview discusses the recent expansion of interest in solid state chemistry and the important role that computer simulation methods have played in this growth. The papers are summarised with especial reference to recent developments in solid state chemistry and materials science.     

Developments in inorganic crystal engineering

The design and synthesis of crystalline materials through the self-assembly of molecular building blocks and the pursuit of functional materials based upon this approach are usually classified under the banner Crystal Engineering. The field is interdisciplinary in nature involving synthetic, materials, structural and theoretical chemists. There are strong ties to modern crystallography which can offer rapid and accurate structure determination and, in particular, insight into molecular and intermolecular geometries. Illustrative examples that chart the development field and provide an assessment of the current state of the art will be reviewed with an emphasis on inorganic chemistry. Broadly speaking, two classes of compounds will be discussed: those based upon molecules or ions linked into networks via noncovalent interactions and those (coordination polymers) in which metal centres are linked using coordination bonds through bridging ligands into extended networks.     

材料化学课程内容与专业课程体系设置的探析

材料化学是材料学与化学等学科交叉、渗透下产生的一门新兴交叉学科,其学科内容还没有得到一致的认同,对应材料化学课程的内容往往与材料化学专业开设的其他课程内容出现重叠.本文通过对材料化学专业要求、核心知识领域以及材料化学学科概念的分析,对材料化学课程内容和材料化学专业课程体系的设置作了初步的探讨.     

Efficient crystallization induced emissive materials based on a simple push-pull molecular structure

Solid state luminescent materials are the subject of ever growing interest both from a scientific and a technological point of view. Aggregation caused quenching (ACQ) processes however represent an obstacle to the development of most luminogens in the condensed phase. This is why particularly fascinating are those materials showing higher emission intensity in the solid state than in solution. Here we report on three 4-dialkylamino-2-benzylidene malonic acid dialkyl esters, very simple push-pull molecules, which are hardly emissive in solution and in the amorphous phase but become good emitters in the crystalline phase according to what has been indicated as crystallization induced emission (CIE). Thanks to combined emission and NMR spectroscopies at different temperatures on the prototype compound 4-dimethylamino-2-benzylidene malonic acid dimethyl ester in solution, we give full evidence that a restricted intramolecular rotation (RIR) phenomenon, in particular the hindered rotation around the aryl main axis of the compound, is at the origin of this behaviour. In addition, solid state photophysical and X-ray diffraction structural characterization allow us to identify J-dimeric interactions as responsible for the particularly intense emission of two of the three compounds. Moreover, by exploiting the compounds' acidochromic properties, applications in sensors and optoelectronics are envisaged.     

Fractals and Related Hierarchical Models in Polymer Science

Polymer science, an interdisciplinary science well-rooted in organic chemistry and in materials science, encompasses an inordinate number and diversity of substance classes and thus has far-reaching applications. Interestingly, polymers also represent a great challenge to the theoreticians, since their theoretical treatment often necessitates appropriate extensions of the classical methods from solid state physics and from statistical physics. Thus, new concepts often have to be invoked when considering the special properties of polymers. In this review we concentrate on one of the modern concepts in the theory of polymers, namely on scaling. Scaling is closely associated with new developments in the field of fractals and of hierarchical structures. Such concepts are invaluable for the modeling of complex geometries and for describing dynamical processes in polymeric materials. Here, we focus on a presentation of these ideas and we outline examples of recent research in which these concepts have been successfully applied.     

Chemistry and Dual Use: From Scientific Integrity to Social Responsibility

Ethical aspects of chemical activity are often exclusively located in the field of scientific integrity and good scientific practice. Yet, there is another dimension of ethics in chemistry that is not covered by research ethics: the impact of chemical scientific and technological progress on society and environment. Here, especially, the dual character of manifestations of chemical progress (new compounds, materials, and processes) is discussed. This essay aims at clarifying the roles, responsibilities, and chances of chemists to contribute to the assessment and management of dual use risks. Its main argument is that the framework for an efficient risk assessment has been established in science and technology governance, based on the sustainability concept. Without having to worry about exceeding their core competences too much – as in ‘Ethics is not my business!’ – chemists’ expertise and knowledge plays a crucial role in tackling the most urging issues of our times as part of a larger interdisciplinary endeavour.     

New trends in nucleic acid based biosensors: University of Florence (Italy), 25-28 October 2003

The Workshop on "New Trends in Nucleic Acids Based Biosensors" was held at the University of Florence (Italy), from 25th to 28th October 2003. The workshop was funded by the European Science Foundation (ESF) within the programme "Functional Genomics" (Programme Area: DNA arrays and chips). This report describes the main arguments discussed during the workshop considering the state of art and the future trends in the field of nucleic acid-based biosensors, with particular attention on the aptamer field.     

Polymers with Metal-Like Conductivity—A Review of their Synthesis,Structure and Properties

Polymers such as polyacetylene, which have an extended π-electron system in their backbone, or like poly(p-phenylene) consist of a sequence of aromatic rings are excellent insulators in their native state and can be transformed by oxidation or reduction in the solid state into conductive CT-complexes which exhibit metal-like conduction characteristics. The chemical and physical processes involved and the reasons for the observed quasimetallic conductivity are not yet fully understood. The real structure of these materials in chemical and physical terms, i. e. their complicated morphology and texture, as well as the results available on the structure-property relationships of the “organic metals” must be considered when discussing their properties. In other words, a discussion of conductive polymers should be based on what is known of the highly conducting CT-complexes of low-molecular weight compounds. The discovery of the highly conducting polymer complexes has opened up a new interdisciplinary field of research which borders on polymer science, solid-state and semiconductor physics and on organic solid-state chemistry. It is hoped that this area will lead to numerous novel materials and technical applications.     

Conclusions of the workshop

The development of analytical techniques for the determination of chemical species has been one of the fastest growing features of the 90's in analytical chemistry. The need for good quality control of these determinations has led the Measurements and Testing Programme (BCR) to organize several series of interlaboratory studies in the field of speciation analysis over the last five years. The state of the art of speciation analysis was discussed at a first workshop in 1990 (Arcachon, F) and, at this stage, it was deemed necessary to discuss the progress achieved and the trends which should be developed in the near future. A workshop on Trends in Speciation Analysis was therefore held in Rome in February 1994, which allowed recommendations to be made based on round-table discussions. This paper gives a summary of these recommendations in the field of inorganic speciation. Projects currently undertaken in the field of inorganic speciation within the Measurements and Testing Programme are also described. An outline of the programme along with the panel of experts participating in this workshop is given in the appendix.     

Conclusions of the workshop

The development of analytical techniques for the determination of chemical species has been one of the fastest growing features of the 90's in analytical chemistry. The need for good quality control of these determinations has led the Measurements and Testing Programme (BCR) to organize several series of interlaboratory studies in the field of speciation analysis over the last five years. The state of the art of speciation analysis was discussed at a first workshop in 1990 (Arcachon, F) and, at this stage, it was deemed necessary to discuss the progress achieved and the trends which should be developed in the near future. A workshop on Trends in Speciation Analysis was therefore held in Rome in February 1994, which allowed recommendations to be made based on round-table discussions. This paper gives a summary of these recommendations in the field of inorganic speciation. Projects currently undertaken in the field of inorganic speciation within the Measurements and Testing Programme are also described. An outline of the programme along with the panel of experts participating in this workshop is given in the appendix.     

组合化学在功能材料合成方面的应用

组合化学方法是当今材料科学和化学领域的研究热点。组合化学方法首先在新药的合成领域得到应用, 很快就以其合成周期短、合成的样品数量大、节约经费等诸多优点而拓展到功能材料的合成等其它领域。组合化学的方法有许多种, 按照反应相的不同可以分为液相中的组合合成法和固相中的组合合成法, 固相组合合成又可以根据所选用的掩模方式的不同而分为二分阴影掩模法、四分阴影掩模法、可移动百叶窗式掩模法等几种, 可以根据材料合成的实际需求加以选择。     

无机固体材料中的忆阻效应

缺陷调控是固体化学中的基本问题,也是决定材料性能的核心要素。基于缺陷调控的忆阻效应将给未来电子信息领域带来全新的变革。本文综述了无机固体材料中忆阻效应的研究进展,主要总结了忆阻效应的产生机制和忆阻材料的类型,结合原子级p-n结的相关工作,提出深入明确电场下缺陷迁移机制将是从无机固体化学角度研究忆阻效应的重要方向。     

无机固体材料中的忆阻效应

缺陷调控是固体化学中的基本问题,也是决定材料性能的核心要素。基于缺陷调控的忆阻效应将给未来电子信息领域带来全新的变革。本文综述了无机固体材料中忆阻效应的研究进展,主要总结了忆阻效应的产生机制和忆阻材料的类型,结合原子级p-n结的相关工作,提出深入明确电场下缺陷迁移机制将是从无机固体化学角度研究忆阻效应的重要方向。     

Report on the 42nd IUVSTA workshop ‘Electron scattering in solids: from fundamental concepts to practical applications’

A summary is given of the workshop entitled ‘Electron Scattering in Solids: from fundamental concepts to practical applications,’ which was held in Debrecen, Hungary, on July 4–8, 2004, under the sponsorship of the International Union of Vacuum Science, Technique, and Applications (IUVSTA). This workshop was held to review the present status and level of understanding of electron‐scattering processes in solids, to identify issues of key importance (hot topics) in the light of the most recent scientific results, and to stimulate discussions leading to a deeper understanding and new solutions of current problems. This report contains summaries of presentations and discussions in sessions on elastic scattering of electrons by atoms and solids, inelastic scattering of electrons in solids, modeling of electron transport in solids and applications, and software. The principal areas of application include Auger‐electron spectroscopy (AES), X‐ray photoelectron spectroscopy, elastic‐peak electron spectroscopy (EPES), reflection electron energy‐loss spectroscopy (REELS), secondary‐electron microscopy, electron‐probe microanalysis (EPMA), and the use of coincidence techniques in electron‐scattering experiments. A major focus of the workshop was determination of the inelastic mean free path of electrons for various surface spectroscopies, particularly corrections for surface and core‐hole effects. Published in 2005 by John Wiley & Sons, Ltd.     

高温固体氧化物燃料电池（SOFC）进展

固体氧化物燃料电池(SOFC) 采用的是全固体的电池结构, 不存在液体电解质带来的腐蚀和流失等问题, 而且具有燃料适应性广等突出优点, 近几年发展非常迅速, 已经展示出作为集中或分散发电新技术的前景。本文较详细地介绍了固体氧化物燃料电池的特点、工作原理和关键电池材料的研制, 并全面阐述了国内外发展现状和发展趋势。     

Reversible Topotactic Redox Reactions of Solids by Electron/Ion Transfer

Solids having suitable structural and electronic properties are able to form intercalation compounds by reversible redox reactions at room temperature via topotactic electron/ion transfer processes. The host lattices range from inorganic solids with different structural dimensionality to organic molecular solids. Similarly, depending on the host lattice type, the guest species may vary from protons and metal ions to large inorganic and organic molecular ions. The possibilities of a systematic “tailoring” of new stable or metastable compounds, the controlled modification of physical properties of solids, and the technical application of electronic/ionic conductors, provide a wide and attractive field for academic and applied research in an interdisciplinary area that involves solid state chemistry and physics, molecular chemistry, electrochemistry, and interface science.     

The urgent requirement for new radioanalytical certified reference materials for nuclear safeguards, forensics, and consequence management

A multi-agency workshop was held from 25 to 27 August 2009, at the National Institute of Standards and Technology (NIST), to identify and prioritize the development of radioanalytical Certified Reference Materials (CRMs, generally provided by National Metrology Institutes; Standard Reference Materials, a CRM issued by NIST) for field and laboratory nuclear measurement methods to be used to assess the consequences of a domestic or international nuclear event. Without these CRMs, policy makers concerned with detecting proliferation and trafficking of nuclear materials, attribution and retribution following a nuclear event, and public health consequences of a nuclear event would have difficulty making decisions based on analytical data that would stand up to scientific, public, and judicial scrutiny. The workshop concentrated on three areas: post-incident Improvised Nuclear Device (IND) nuclear forensics, safeguard materials characterization, and consequence management for an IND or a Radiological Dispersion Device detonation scenario. The workshop identified specific CRM requirements to fulfill the needs for these three measurement communities. Of highest priority are: (1) isotope dilution mass spectrometry standards, specifically ²³³U, ^236gNp, ²⁴⁴Pu, and ²⁴³Am, used for quantitative analysis of the respective elements that are in critically short supply and in urgent need of replenishment and certification; (2) CRMs that are urgently needed for post-detonation debris analysis of actinides and fission fragments, and (3) CRMs used for destructive and nondestructive analyses for safeguards measurements, and radioisotopes of interest in environmental matrices.     

Molecular spintronics

The electron spin made its debut in the device world only two decades ago but today our ability of detecting the spin state of a moving electron underpins the entire magnetic data storage industry. This technological revolution has been driven by a constant improvement in our understanding on how spins can be injected, manipulated and detected in the solid state, a field which is collectively named Spintronics. Recently a number of pioneering experiments and theoretical works suggest that organic materials can offer similar and perhaps superior performances in making spin-devices than the more conventional inorganic metals and semiconductors. Furthermore they can pave the way for radically new device concepts. This is Molecular Spintronics, a blossoming research area aimed at exploring how the unique properties of the organic world can marry the requirements of spin-devices. Importantly, after a first phase, where most of the research was focussed on exporting the concepts of inorganic spintronics to organic materials, the field has moved to a more mature age, where the exploitation of the unique properties of molecules has begun to emerge. Molecular spintronics now collects a diverse and interdisciplinary community ranging from device physicists to synthetic chemists to surface scientists. In this critical review, I will survey this fascinating, rapidly evolving, field with a particular eye on new directions and opportunities. The main differences and challenges with respect to standard spintronics will be discussed and so will be the potential cross-fertilization with other fields (177 references).     

Copper(II) complexes with aroylhydrazones

The coordination chemistry of copper(II) with tridentate aroylhydrazones is briefly discussed in this article. Two types of aroylhydrazones derived from aroylhydrazines and ortho-hydroxy aldehydes or 2-pyridine-carboxaldehyde have been used. The characterization of the complexes has been performed with the help of various physico-chemical techniques. Solid state structural patterns have been established by X-ray crystallography. In the solid state, structural varieties of these complexes are seen to range from monomeric, dimeric, polymeric and one-dimensional self-assembly via hydrogen bonds and π-π interactions. EPR spectroscopy and variable temperature magnetic susceptibility measurements have been used to reveal the nature of the coordination geometry and magnetic characteristics of these complexes.