首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 843 毫秒
1.
Water has emerged as a versatile solvent for organic chemistry in recent years. Water as a solvent is not only inexpensive and environmentally benign, but also gives completely new reactivity. The types of organic reactions in water are broad including pericyclic reactions, reactions of carbanion equivalent, reactions of carbocation equivalent, reactions of radicals and carbenes, transition-metal catalysis, oxidations-reductions, which we discuss in this tutorial review. Aqueous organic reactions have broad applications such as synthesis of biological compounds from carbohydrates and chemical modification of biomolecules.  相似文献   

2.
This article provides a concise summary of alkaline earth metal nitrogen chemistry. This important area of s-block metal chemistry is shedding important light on the recent development of alkaline earth metal chemistry, as the preparation of the target compounds utilizes a large variety of synthetic methodology. Further, the compounds have been utilized in a range of applications, including polymerization initiation, catalysis, as solid-state precursors, and even high energy materials.  相似文献   

3.
Photocatalysis has recently opened up new avenues for the generation of radical species under visible light irradiation conditions. A particularly fascinating class of photocatalyzed transformations relies on the activation of stable boron species with visible-light since it allows the creation of boryl and/or carbon radicals through single electron transfer or energy transfer without the need for specific and costly equipment. This new paradigm has found numerous applications in synthetic organic chemistry, catalysis, and macromolecular chemistry. In this minireview, the concepts underlying photoactivation of boron-species as well as applications to the creation of C–H, C–C, C–O, B–C and B–S bond are discussed.  相似文献   

4.
This review provides an overview of the most significant strategies developed in recent years for the preparation of donor-functionalized phosphinines and new developments in this field are highlighted. Selected synthetic procedures for the introduction of additional sulfur-, oxygen-, phosphorus-, and nitrogen-donor groups into the heterocyclic framework are presented. Examples of their coordination chemistry and potential applications in homogeneous catalysis and phosphorus containing molecular materials will be given.  相似文献   

5.
The elaboration of nanoparticles designed for technological applications in various fields such as catalysis, optics, magnetism, electronics… needs the strict control of their characteristics, especially chemical composition, crystalline structure, size, and shape. These characteristics bring the physical properties (color, magnetism, band gap…) of the material, and also the surface to volume ratio of particles which is of high importance when they are used as a chemically active or reactive support, in catalysis for instance. The nanoparticles may have also to be surface functionalized by various species, and/or dispersed in aqueous or non aqueous media. We will show that the aqueous chemistry of metal cations is a very versatile and attractive way for the design of oxide nanomaterials, allowing the control of size, shape, and crystalline structure for polymorphic materials. Aqueous surface chemistry, including adsorption of various species, may be used to modify the morphology of nanoparticles. In some cases, redox processes can be involved to control the morphology of nanoparticles. Technologically important nanomaterials such as titania, alumina, and iron oxides are studied.  相似文献   

6.
After definitions of interfacial coordination chemistry (ICC) and surface organometallic chemistry (SOMC), their main characteristics and applications are compared. The common concepts of ICC and classical coordination chemistry, as well as the specific features of ICC are illustrated through some examples. Finally, possible applications of ICC to catalyst preparation, adsorption and relations to catalysis are given.  相似文献   

7.
目前,纳微结构新材料已成为化工过程强化的重要手段之一.金属-有机骨架材料(metal-organic frameworks,MOFs)是由金属离子与有机配体通过配位键自组装而成的新型纳米多孔材料,有望在储气、分离、催化、传感及制药等领域获得广泛应用.本文以MOF材料为例,结合本课题组的工作,介绍了热力学与计算化学在纳微结构材料构效关系研究与设计中的应用.  相似文献   

8.
The potential of microwave power as a tool to facilitate chemical reactions has not whetted the chemist’s appetite in the past and the phenomenon and uses of microwaves have remained in the comer of spectroscopists and engineers for a long time. The possibility of microwaves initiating chemical changes has nevertheless excited our imagination for the past ten years. We will present the original development of the concept of microwave catalysis/sensitization in chemistry and the coming of age of the techniques as an enabling technology in the industrial world. A number of demonstrated applications ranging from hydrocarbon oxidations to environmental technology will be illustrated, as well as the most recently developed technique and applications of the microwave-induced acoustic phenomenon.  相似文献   

9.
A survey of some recent developments and past achievements in low-valent main group chemistry is presented. Some emerging implications of this area of chemistry in materials science, catalysis and new reagent development are also discussed.  相似文献   

10.
相转移催化在杂环化学中的应用   总被引:4,自引:0,他引:4  
就近几年来相转移催化(PTC)在杂环化学中的应用,包括杂环化合物的合成,杂环化合物的化学修饰及杂环的转变进行了综述。  相似文献   

11.
This review covers new data on the use of phase transfer catalysis in the chemistry of heterocyclic compounds. The following reactions are considered: alkylation, acylation, reactions with dihalocarbenes, preparations of ethers and esters, the formation of halo derivatives, oxidation and reduction, and isotope exchange. The advantages of phase transfer catalysis are examined and the prospects for its further development in heterocyclic chemistry are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1443–1459, November, 1983.  相似文献   

12.
This article represents a survey of current aluminum chemistry and some predictions regarding what type of aluminum chemistry will be conducted in the year 2000 and after. Because of the abundance and availability of aluminum in the earth, research incorporating this element will always be of importance to applications that impact on daily life. Indeed, applied chemistry is the primary goal of most aluminum research. It is likely that three broad areas of aluminum chemistry, catalysis, materials synthesis, and biological studies, will see substantial activity in the future. The use of aluminum in materials will continue in step with the growth of materials science, in general. In contrast, the use of aluminum compounds in catalysis and in effecting synthetic transformations will see a spectacular increase. This is a result of an increased understanding of the chemistry of aluminum, and the availability of a wide range of compounds containing aluminum which was been achieved over the past few decades during a period of increased attention to Main Group chemistry. In the coming years a clear understanding of the influence of aluminum on biological systems will almost certainly be obtained based upon the quality and amount of effort that has focused on this area in recent times.  相似文献   

13.
多金属氧酸盐(POM)是一类由过渡金属与氧原子桥连而成的阴离子簇合物,由于其特殊的分子结构及优异的物理化学性质,使其在催化、医药、材料科学、表面化学、超分子化学等领域有广泛的应用价值。 POM在稀的水溶液中能够发生自聚集,形成类似两亲分子溶液中的“有序聚集体结构”,赋予其新的结构和性质,以期开发出新型纳米器件及在催化、药物等领域得到应用。 本文介绍了POM的主要结构、性质和近年来的应用,阐述了其在溶液中自聚集行为的研究状况和新进展。  相似文献   

14.
This tutorial review presents the synthesis, chemistry and applications of functionalised N-heterocyclic carbenes NHC and their transition metal complexes. Functionalised NHC comprise those carrying a phosphino-, amino-, imino- or oxygen-containing functionality on the imidazole sidechain. Main applications have been the modification of catalysts and their immobilisation by fixation on a polymeric support using the functional group. Whereas the functionalisation of the NHC has not improved their performance in catalysis, new developments have occurred in the use of imidazole-containing biomolecules such as L-histidine or caffeine as precursors for NHC.  相似文献   

15.
Surface organometallic chemistry is an area of heterogeneous catalysis which has recently emerged as a result of a comparative analysis of homogeneous and heterogeneous catalysis. The chemical industry has often favored heterogeneous catalysis, but the development of better catalysts has been hindered by the presence of numerous kinds of active sites and also by the low concentration of active sites. These factors have precluded a rational improvement of these systems, hence the empirical nature of heterogeneous catalysis. Catalysis is primarily a molecular phenomenon, and it must involve well-defined surface organometallic intermediates and/or transition states. Thus, one must be able to construct a well-defined active site, test its catalytic performance, and assess a structure-activity relationship, which will be used, in turn-as in homogeneous catalysis-to design better catalysts.By the transfer of the concepts and tools of molecular organometallic chemistry to surfaces, surface organometallic chemistry can generate well-defined surface species by understanding the reaction of organometallic complexes with the support, which can be considered as a rigid ligand. This new approach to heterogeneous catalysis can bring molecular insight to the design of new catalysts and even allow the discovery of new reactions (Ziegler-Natta depolymerization and alkane metathesis). After more than a century of existence, heterogeneous catalysis can still be improved and will play a crucial role in solving current problems. It offers an answer to economical and environmental problems faced by industry in the production of molecules (agrochemicals, petrochemicals, pharmaceuticals, polymers, basic chemicals).  相似文献   

16.
Air and water stable ionic liquids in physical chemistry   总被引:1,自引:0,他引:1  
Ionic liquids are defined today as liquids which solely consist of cations and anions and which by definition must have a melting point of 100 degrees C or below. Originating from electrochemistry in AlCl(3) based liquids an enormous progress was made during the recent 10 years to synthesize ionic liquids that can be handled under ambient conditions, and today about 300 ionic liquids are already commercially available. Whereas the main interest is still focussed on organic and technical chemistry, various aspects of physical chemistry in ionic liquids are discussed now in literature. In this review article we give a short overview on physicochemical aspects of ionic liquids, such as physical properties of ionic liquids, nanoparticles, nanotubes, batteries, spectroscopy, thermodynamics and catalysis of/in ionic liquids. The focus is set on air and water stable ionic liquids as they will presumably dominate various fields of chemistry in future.  相似文献   

17.
We examine the main results from the work of O.M. Poltorak, who made a significant contribution in the theory of enzymatic catalysis and introduced many new terms and concepts in physical chemistry.  相似文献   

18.
The use of N-heterocyclic carbenes (NHCs) in the chemistry of iron is stimulating important new applications of one of the most ubiquitous ligand types in modern organometallic chemistry. A series of reports has shown how the flexible and modifiable stereo-electronic properties of NHC ligands can be combined with iron in a range of oxidation states to create opportunities for studying unique structures, bonding and reactivity. Of particular interest are the roles of iron NHC complexes in: the stabilization of unusual oxidation states and coordination environments; the activation of small molecules; homogeneous catalysis; and bio-mimetic chemistry. Our feature article summarizes the key developments in the field.  相似文献   

19.
In recent years, research in organophosphorus chemistry has mainly focused in designing newer and better phosphorus ligands for synthesizing novel metal complexes with improved catalytic activities. Aminophosphines [tricoordinate phosphorus(III)–nitrogen systems] are considered as versatile compounds owing to the presence of nitrogen centres which, in principle, can influence additional reactivity features. They are quite sensitive to air and moisture due to the presence of polar P? N bond(s). In spite of this, research in aminophosphine chemistry is gaining momentum day‐by‐day and this is due mainly to one reason: their rich behaviour as ligands in metal complex chemistry and subsequently in catalysis. Their role as synthons in inorganic heterocyclic chemistry has also helped produce new types of heterocycles. In this paper, the chemistry of simple acyclic aminophosphines (synthesis, characterization, reactivity and applications) is covered and particular focus is given to their ability to form chalcogenides along with their role played as ligands in coordination chemistry and as synthons in inorganic heterocyclic chemistry. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

20.
One-dimensional fibrous nanostructures may exhibit unique mechanical, optical, magnetic, and electronic properties as a result of their nanoscale dimensions. Various approaches have been used to prepare nanofibers (e.g., electrospinning, vapor deposition), but this review focuses on the research and development of self-assembled nanofibers formed through coordination chemistry. By employing metal–ligand interactions that extend along the backbone of the aggregates, nanofibrous, often gel-forming, materials with appealing properties have been formed. Other fibers formed through electrostatic interactions between charged coordination complexes are also discussed. The optical, electronic, and magnetic properties conferred upon the materials by the embedded coordination complexes render the nanofibers useful for applications in the fields of catalysis, sensors, and gas storage, and potentially for developing nanosized devices.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号