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Progress in Chemistry 2007, No.09 Previous issue Next issue

In this issue:

Invited Article
Fluorescent Molecular Sensors for Heavy and Transition Metallic Cations with Biological Interests
Zhu Weiping, Xu Yufang,Qian Xuhong**
2007, 19 (9): 1229-1238 |
Published: 24 September 2007
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Abstract
Heavy and transition metallic ions exist widely in the nature. Some of them (such as copper and zinc) play the important roles in the living system, and others (such as mercury, lead and cadmium) have high toxicity to the living plants and animals in the low concentration. This review summarizes the main design principles of the fluorescent sensor for the metallic ions and the progress of the fluorescent molecular sensors for heavy and transition metallic cations with biological interests, especially their design, synthesis, performance and the applications in the living cells.
π-σ Energy Partition and Geometry Optimization under the Restrictions of π-Orbital Interactions
Yu Zhongheng** Bao Peng
2007, 19 (9): 1239-1248 |
Published: 24 September 2007
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Abstract
The history of energy partition is reviewed.It is emphasized that the energy partition is to provide quantum calculation with the chemical meanings. The new methods of energy partition and geometry optimization under restrictions of orbital interactions are introduced, and these are developed in our research group. Based on these two methods, the viewpoint that π- electron delocalization is destabilization have been brought forward.the fundamental causality of classical organic structure theory, a relationship between resonance and molecular conformation, seems to be overturns, and it is confirmed that π-π and σ-σ orbital interactions are the driving forces for distorting NBA away from its planar geometry.A new quantitative method for evaluating aromaticity energy is developed, indicating that the reference molecule (or molecules) is no longer necessary for calculating stabilizing enenrgy for aromatic molecule.The roles of electrostatic and electron delocalization in forming chemical bond are distinguished quantitatively.Substitutent effects and driving forces for distorting strained cyclic molecules are discussied.
Review
Molecular Dynamics Simulations of Self-Assembling
Deng Pingye 1,2,Zhang Donghai 1, Tian Yajun 1, Chen Yunfa 1*, Ding Hui 3
2007, 19 (9): 1249-1257 |
Published: 24 September 2007
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Abstract
The current research about self-assembly by the means of molecular dynamics simulations is briefly reviewed in this paper. Both the methods of computational modeling, and the visual representation of simulating results are briefly described respectively, coupling with their applications in certain topics. Based on the analyzing and discussing of the contributions of previous research，unclosed problems of molecular dynamics simulating self-assembly are proposed. The natural linkage of self-assembly with phase transition or with fluctuation indeed gives the clue of heading path, and consequently, the reports of oscillation in self-assembly and study of frequency depend specific heat are also presented in this paper. Therefore the idea that inspecting the oscillating parameters with respect to frequency depend specific heat in self-assembly might be helpful to understand the process of self–assembly and computational simulations is proposed.
Coumarin-Based Fluorescent Sensors
Ma Wenhui1,2,Peng Xiaojun1**,Xu Qun2,Song Bo1,2
2007, 19 (9): 1258-1266 |
Published: 24 September 2007
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Abstract
Fluorescent sensors can transfer molecular recognition events into fluorescent signals。Of the various kinds of chemosensors，fluorescent sensors offer distinct advantages in terms of sensitivity , selectivity , response time and in situ observation.Monitoring in real-time and real-space the level of analytes is of great interest to many scientists, including chemists, biologists, clinical biochemists and environmentalists. Fluorescent sensors based on coumarin have drawn much attention in recent years .In this paper,the molecular design、mechanism and application of coumarin-based fluorescent sensors for cations、anions and neutral molecules are reviewed. The developing orientation for further research is presented.
Selective Oxidation in Supercritical(Compressed) Carbon Dioxide
Hu Yu,Hou Zhenshan *
2007, 19 (9): 1267-1274 |
Published: 24 September 2007
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Abstract
Supercritical carbon dioxide(SCCO2, Tc= 304K, Pc= 7.38MPa) has been exploited as a reaction medium for catalysis due to its potential advantages such as stability, safety, noninflammability, nontoxicity, low viscosity, high compressibility and high miscibility with many reaction gases，which makes SCCO2 very attractive for processes involving gaseous reactions that often suffer from mass transport limitations. As environmentally benign and economical solvents, supercritical carbon dioxide is properly the solvent that can not be oxidized to other by-products in oxidation reactions. By comparison with traditional organic solvent, the advantages and effects of supercritical carbon dioxide as a solvent on oxidation reaction are extensively described in the literature.The recent developments in selective catalytic oxidation are reviewed in this paper and particular attention is devoted to the selective oxidation of alcohols, ketones, alkanes, alkenes etc. by molecular oxygen as a terminal oxidant.
PCBs Treatment by Sub-Supercritical Water Catalytic Oxidation, Thermolysis and Reduction
Wei Chaohai**,Yan Bo,Hu Chengsheng
2007, 19 (9): 1275-1281 |
Published: 24 September 2007
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Abstract
The major sources and environmental hazards of PCBs are briefly introduced. The reaction pathways and decomposition efficiencies of PCBs in Supercritical Water (SCW) are reviewed in terms of Supercritical Water Oxidation (SCWO), Supercritical Water Thermolysis (SCWT), and Subcritical Water Reduction (SCWR). The mechanisms of decomposition and dechlorination of PCBs on account of the action of cosolvent with methanol or benzene, alkali catalyst with sodium carbonate or sodium hydroxide and oxidant with sodium nitrate and sodium nitrite are summarized. The diffirences about the promotion mechanism of methanol to PCBs decomposition are found between SCWO and SCWT. The dechlorination reaction was accelerated due to the decrease of HCl which produced in the dechlorination process by the neutralisation of HCl with alkali catalyst. The corrosion problem of reactor and cost-effectiveness during the process of SCWO PCBs are discussed. The research trends for the future in SCWO PCBs are proposed.
Nitrogen Doped TiO2 Photocatalysts with Visible-Light Activity
Fang Xiaoming**, Zhang Zhengguo, Chen Qinglin
2007, 19 (9): 1282-1290 |
Published: 24 September 2007
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Abstract
Anion-doped TiO2 photocatalysts are considered the second-generation photocatalytic materials, which nitrogen doped TiO2 is the representative. The methods for preparing nitrogen doped TiO2 were systematically reviewed, and some controversy concerning the origin of visible-light responses for N-doped TiO2 and the state of N doped in TiO2 matrix were expanded in this paper. The methods for preparing nitrogen doped TiO2 powders mainly include the heat treatment under NH3 flow, the hydrolytic precipitation, the sol-gel process and the mechanochemical method. The methods for preparing nitrogen doped TiO2 films mainly include magnetron sputtering, pulsed laser deposition and metal-organic chemical vapor deposition. several different mechanisms for the visible-light activity of N-doped TiO2 have been proposed, which are the mixing of N 2p and O 2p orbits, the formation of an N-induced isolated narrow band, the presence of oxygen vacancies, and the sensitization by paramagnetic impurity. The controversy concerning the state of N doped in TiO2 matrix lies in the assignment of the peak feature in the XPS N 1s spectrum foTiO2r nitrogen doped TiO2. Finally, the problems involved studies on nitrogen doped TiO2 photocatalysts and the future developing trends are presented.
Mixed Cationic and Anionic Surfactants Systems
Nan Yanqing**,Hao Lisheng
2007, 19 (9): 1291-1300 |
Published: 24 September 2007
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Abstract
Because of the strong static attraction between the oppositely charged head groups,the mixed cationic and anionic surfactant systems possess strong synergistic effect and high surface activity, can form rich microstructures in aqueous solution and exhibit complicated phase behavior. In this paper, we have reviewed recent progresses in the studies about surface (interface) properties, the preparation and stability of vesicles, the formation and properties of wormlike micelles, and the properties and applications on extraction of aqueous two-phase systems. The studies about the theory investigation (such as pseudo-phase separation model, thermodynamic cell model, molecular thermodynamics and molecular simulation etc.), and the usage as templates of nanomaterial synthesis of mixed cationic/anionic surfactant systems have been reviewed also.　For the research of the aqueous two-phase systems, some questions need to be solved are indicated.
Anode Electrocatalysts for Direct Methanol Fuel Cells
Tang Zhicheng 1,2,Lv Gongxuan1**
2007, 19 (9): 1301-1312 |
Published: 24 September 2007
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Abstract
Direct methanol fuel cell（DMFC） has attracted much attention for their potential applications as clean and mobile power sources due to its advantages of low operating temperature (<100℃), easy transportation and storage of the fuel, high energy efficiency and low exhaustion, and the fast start-up of fuel. Anode electrocatalysts are the main components of direct methanol fuel cell. The progress of anode electrocatalysts for direct methanol fuel cell in the recent three years is reviewed in this paper. The preparation methods of electrocatalysts, the preparation and application of the novel carbon materials, the kinds of electrocatalysts are described in detailed. The trend of future research in the area of anode electrocatalysts is suggested, the existed problem are pointed out.
Layered Li-Ni-Co-Mn-O as Cathode Materials for Lithium Ion Battery
Tang Aidong,Wang Haiyan,Huang Kelong**,Tan Bin,Wang Xiaoling.
2007, 19 (9): 1313-1321 |
Published: 24 September 2007
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Abstract
Research progress of layered Li-Ni-Co-Mn-O as cathode materials for lithium ion batteries in recent years were reviewed and emphasis was replaced on their synthesis ways, electrochemical performance , as well as doped and surface-modification studies. Now LiNi1/3Co1/3Mn1/3O2has been commercialized and it will substitute LiCoO2 finally because of its excellent characters and less cost.
Preparation of Macro-mesostructured Pseudoboehmite and γ-Al2O3with High Surface Area
Cai Weiquan1** Yu Xiaofeng2
2007, 19 (9): 1322-1330 |
Published: 24 September 2007
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Abstract
As a very important catalyst support, adsorbent and separate material, the preparation of macro-mesostructured γ-Al2O3 is very important, especially for catalytic conversion of petroleum heavy cuts and residues. However, while increasing the pore volumes, the surface areas decrease for most conventional preparation methods of macro-mesostructured γ-Al2O3. The methods and their mechanisms to prepare macro-mesostructured pseudoboehmite and γ-Al2O3 with high surface areas are reviewed in this paper, including controlling the precipitation process of pseudoboehmite, the precipitation processing techniques of the precipitated pseudoboehmite and the introducing pore forming additives or sintering additives. These preparation ways include pH swing method, organic reagent as reaction media, surfactant assembly, microwave-assisted heating, hydrothermal processing of pseudoboehmite or γ-Al2O3 directly, displacement water in wet precipitate by organic solvent, unconventional drying method and control of pore structure with pore forming additives or sintering additives. Finally, development trend for preparation techniques of macro-mesostructured pseudoboehmite and γ-Al2O3 is also suggested.
Nonhydrodesulfurization Technologies of Light Oil
An Gaojun,Zhou Tongna,Chai Yongming, Zhang Jingcheng, Liu Yunqi, Liu Chenguang
2007, 19 (9): 1331-1344 |
Published: 24 September 2007
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Abstract
Due to increasingly stringent regulations for the environmental protection purpose, the requirement for the productive technology of the low sulfur and ultra-low sulfur clean oil is becoming higher. The conventional hydrodesulfurization technologies have several problems, such as higher investment and operating cost. Consequently, the investigation of nonhydrogenation technologies is becoming popular, because these novel technologies have the advantages of lower investment and much milder operating conditions. Several nonhydrodesulfurization technologies and processes of light oil were introduced in this paper, mainly including oxidative desulfurization, adsorptive desulfurization and biodesulfurization. In addition, the technologies of desulfurization by extraction, complexation, catalytic cracking, alkylation, membrane separation and ionic liquid were also described briefly.The opinions with respect to the future application trend of nonhydrodesulfurization of light oil are proposed.
Application of Functional Metal-Organic Framework Materials
Mu Cuizhi,Xu Feng*,Lei Wei
2007, 19 (9): 1345-1356 |
Published: 24 September 2007
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Abstract
Metal-organic framework (MOFs) materials have drawn great attention because of their unique structures. It owns great advantages compared to inorganic or organic materials and becomes one of most popular research topics in functional materials field. This review briefly summarized the new application and progress of MOFs materials in the area of separation and purification, catalysis, micro-reactor and ion exchange. In addition, several trends of designing MOFs as functional material are also presented.
Carbasugars Synthesis from Non-Carbohydrate Sources
Zhao Chuansheng,Zhang Weihong**,Zeng Xian,Feng Yaqing
2007, 19 (9): 1357-1370 |
Published: 24 September 2007
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Abstract
Carbasugars, carbocyclic analogues of true sugars, are compounds in which the ring-oxygen of furanoid or pyranoid sugars is replaced by methylene groupe. As carbohydrate mimics, carbasugars are currently attracting great interest because their reactivity and stability differs enormously from those of carbohydrates. In this paper, recent development in furanoid and pyranoid carbasugars synthesis from non-carbohydrate sources is reviewed. Synthesis with carbocyclic compounds, such as cyclodienylsilane, quinic acid and norbornene etc, as starting materials is discussed in detail.
Organic Electrical Bistability Devices
Shi Shengwei,Peng Junbiao**
2007, 19 (9): 1371-1380 |
Published: 24 September 2007
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Abstract
Organic Electrical Bistability Devices (OEBDs) show the advantages in low-cost,easy processing, small size, fast response, low power and high storage density.OEBDs have attracted more and more considerable attention due to their wide potential applications in information storage and logic circuit. But the mechanism of OEBDs still hasn’t been well understood, and some fundamental questions such as new concepts and theories, and new structures, methods, technology and materials involved during the fabrication and processing need to be further investigated. In this paper, recent progress of OEBDs is reviewed, and potential applications in electrical switching memory and scientific problems of OEBDs are also discussed here.
Progress in Fluorescent Polymers
Wu Zhaoqiang1**, Meng Lingzhi2
2007, 19 (9): 1381-1392 |
Published: 24 September 2007
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Abstract
During the past two decades, research on fluorescent polymers has attracted increasing interests because of their important application prospect in the fields of life science and medicine. The latest research progress in fluorescent polymers is summarized as follows.(1) Classification of fluorescent polymers.Although there are different methods to classify fluorescent polymers, according to its solubility, fluorescent polymers can be divided into three types which is hydrophobic, hydrophilic and amphiphilic, individually; (2) Five methods of design and synthesis of fluorescent polymers: fluorescent polymers can be synthesized by using fluorescent compounds as initiator, fluorescent compounds as chain transfer agents, polymerization of fluorescent functional monomer, chemical bonds between fluorescent compounds and polymers, polymerization of none fluorescent functional monomer; (3) Applications of fluorescent polymers: fluorescent polymers are functional macromolecules with important application prospect. Their applications in the fields of fluorescent chemosensor, fluorescent molecular thermometers, fluorescent imaging, drug delivery carriers and fluorescent probe are briefly introduced in this paper.
The Electric-Field-Sensitive Hydrogels
Shang Jing,Chen Xin**,Shao Zhengzhong
2007, 19 (9): 1393-1399 |
Published: 24 September 2007
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Abstract
Electric-field-sensitive hydrogel is one kind of intelligent hydrogels that exhibits swelling, shrinking or bending behavior on the application of an electric field. The main advantage of such a kind of hydrogel is that it can transform electrical energy into mechanical energy. In this paper, the recent research on electric-field-sensitive hydrogels is reviewed, in which the preparation and deformation mechanism of hydrogels are introduced. It is generally thought that the deformation of the hydrogel in an electric field is due to the change of osmotic pressure based upon the voltage-induced motion of ions in the electrolyte solution and may be influenced by a number of factors, including pH, ionic strength of the bath solution, as well as the electric potential imposed across the hydrogels. At last, the applications of such an electric-field-sensitive hydrogel, for example, in the fields of energy transducing devices, artificial muscles, and controlled drug delivery system are also presented.
Polymer Dispersed Liquid Crystal Films
Dou Yanli1,Zhang Wanxi1,Qin Chuangye2,Xu Jingwei2*
2007, 19 (9): 1400-1405 |
Published: 24 September 2007
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Abstract
Polymer dispersed liquid crystal films(PDLC) consist of low molecular liquid crystal dispersed in a polymer matrix, which have drawn much attention in recent years. Based on the strong optical anisotropy and dielectric anisotropy of liquid crystal, polymer dispersed liquid crystal films find a wide application in electrooptical industry. The preparation methods and study methods have been introduced in this paper. As film-formation material, polymer provides a stable network for liquid crystal, and plays an auxiliary but very important role in various polymer dispersed liquid crystal devices, the effect of polymer’s structure and polymer curing process on the electrooptical properties of polymer dispersed liquid crystal films have been discussed.
The Investigation of Living/Controlled Free Radical Polymerization under γ-ray Irradiation
Ge Xueping, Bai Ruke**
2007, 19 (9): 1406-1412 |
Published: 24 September 2007
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Abstract
The progress in the investigation of controlled/living free radical polymerizations under γ-ray irradiation condition was reviewed. Although γ-ray initiated polymerization is uncontrolled in conventional condition, controlled/living free radical polymerization has been successfully carried out under γ-ray irradiation in the presence of thio-compounds, such as dithioesters or trithiocarbonates. The molecular weight of the obtained polymers in the process can be controlled with narrow distribution and increases linearly with monomer conversion. Block copolymers can be prepared by this approach. The organic thio-compound plays a key role in controlling polymerization and the effect of the thio-compound structures is remarkable on the polymerization behavior under γ-ray irradiation. The remarkable advantage of the polymerization is that it can be performed at room temperature or much lower temperature without adding initiator. Macrocyclic polymers have been obtained in the presence of cyclic thio-compound. And moreover the controlled/living free radical polymerizations of azide monomers, which are sensitive to the thermal condition or UV light, have been achieved first time.
Dimerization reaction of isobutene
Xu Zehui1,2* Fang Dingye2
2007, 19 (9): 1413-1418 |
Published: 24 September 2007
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Abstract
Because Methyl tert-butyl ether (MTBE) is soluble in water and has been occasionally found its way into ground water from leaking storage tanks, MTBE was environmentally limited as gasoline additive and its production and application prospects is negatively affected. Producing isooctane by MTBE decomposition, dimerization of isobutene(IB) and hydrogenation of diisobutene became the main way for the exiting MTBE units abroad to produce other products. The catalyst for IB dimerization, reactive site, reactive mechanism and dynamics research date was reviewed in this paper and try to explain the mechanism of selectivity enhancing by adding Tertiary butyl alcohol during IB dimerization and provide reference for the study of dimerization afterwards.
Nanomaterials Preparation in the supercritical fluid system
Xu Qun, Ni Wei
2007, 19 (9): 1419-1427 |
Published: 24 September 2007
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Abstract
The development of nano science and technology will produce a deep and essential revolution of science and technology. During this process, nanomaterials will play an important and foundational role. This paper gives an overview on a newly arisen green and environmentally friendly solvent, supercritical fluid and its application in the preparation process of nanomaterials from semi-zero-dimensional particles to three-dimensional materials and from inorganic nanomaterials to organic polymeric nanomaterials. Not only different methods about supercritical CO2 used in nanomaterials preparation are introduced, but also the unique properties of supercritical CO2 and its advantages during the preparation process, such as swelling effect, plasticizing effect and low surface tension, etc., are also referred. In addition, the potential applications of supercritical fluids in nanomaterial fabrications in the future are expected.
Preparation of Thin Film Composite Membrane by Interfacial Polymerization Method
Tang Beibei1 Xu Tongwen2 Wu Peiyi1**
2007, 19 (9): 1428-1435 |
Published: 24 September 2007
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Abstract
The recent research progress on the preparation of the thin film composite membrane by interfacial polymerization method is reviewed.The membrane formation mechanism by interfacial polymerization method is described. The reaction of interfacial polymerization in composite membrane preparation based on the species of monomers is classified. The details of the research progress about the preparation of the thin film composite membrane by interfacial polymerization method are especially discussed. Furthermore, some problems in the research and the research prospects are also discussed.
Preparation and Application of Membrane with Cyclodextrins
Zhou Zhijun, Cai Rongxi, Liu Nengjun, Zhang Lin**, Chen Huanlin
2007, 19 (9): 1436-1442 |
Published: 24 September 2007
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Abstract
In this paper, the structure and property of cyclodextrins(CDs) with hydrophilic external and a hydrophobic internal cavities are presented. For the special molecular structure of CDs, the characteristics and performances of membranes will be improved by introducing CDs and their derivatives into the membrane. The preparation methods of membranes with CDs and their applications are reviewed, including separation of isomers, transfer of metal ions, controlled release of drug, drug testing and analysis, hydrolyzation of esters etc. The study on molecular conduit of CDs has been summarized. Based on these reviews, the prospect of membrane with CDs is discussed.
Nanoparticle-Stabilized Emulsions and Their Applications in Preparation of Nanostructures
He Yongjun1** Qi Suitao2 Zhao Shiyong1
2007, 19 (9): 1443-1448 |
Published: 24 September 2007
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Abstract
With a brief introduction to normal emulsions, microemulsions and solid-stabilized emulsions, nanoparticle-stabilized emulsions and their applications for the preparation of nanostructures are reviewed emphatically. With special three phases (oil, solid and water), three interfaces (oil/water, oil/solid and water/solid) and size-tunable droplets, nanoparticle-stabilized emulsions have been used as medium for the syntheses of various nanostructures. However, the effect of the nanoparticles on the stability of the emulsion, and the mechanism of the reactions in nanoparticle-stabilized emulsion still remain to be further addressed.