WorldWideScience

Sample records for current organic synthesis

  1. Organic Synthesis

    OpenAIRE

    Romea, Pedro

    2014-01-01

    Organic Synthesis is a one-semester course of the fourth year of the Chemistry Degree at the Universitat de Barcelona. This course covers the most important transformations in Organic Chemistry, including a short introduction to the Retrosynthetic Analysis. The aim is to provide a solid knowledge of the main reactions and their mechanism, which could later be improved during Master studies.

  2. Organic Synthesis in Space

    Science.gov (United States)

    Sandford, Scott A.; DeVincenzi, Donald (Technical Monitor)

    2002-01-01

    This talk will review our current understanding of the synthesis of organic molecules in space, with particular emphasis on the synthesis of those compounds that may be of prebiotic interest. The talk will address the possibility that molecules created in the interstellar medium may play a role in the origin and evolution of life on planetary surfaces. The various organic and volatile compounds that are now known or suspected to exist in a variety of space environments (stellar outflows, the diffuse interstellar medium, dense molecular clouds, protostellar nebulae, and planetesimal parent bodies in planetary systems) will be reviewed. This information comes largely from the combined applications of observational infrared and radio spectroscopy, laboratory astrophysical simulations, and theoretical astrochemistry. This will be followed by a discussion of the evidence, largely gathered from the laboratory isotopic study of extraterrestrial materials (meteorites and cosmic dust), that interstellar materials, including organics, can and do survive the transition from the interstellar space into forming stellar systems. Once there, some of this material can be delivered largely unaltered to planetary surfaces where it can play key roles in the origin and subsequent evolution of life.

  3. Organic Synthesis in Space

    Science.gov (United States)

    Sandford, Scott A.; DeVincenzi, Donald (Technical Monitor)

    2002-01-01

    This talk will review our current understanding of the synthesis of organic molecules in space, with particular emphasis on the synthesis of those compounds that may be of prebiotic interest. The talk will address the possibility that molecules created in the interstellar medium may play a role in the origin and evolution of life on planetary surfaces. The various organic and volatile compounds that are now known or suspected to exist in a variety of space environments (stellar outflows, the diffuse interstellar medium, dense molecular clouds, protostellar nebulae, and planetesimal parent bodies in planetary systems) will be reviewed. This information comes largely from the combined applications of observational infrared and radio spectroscopy, laboratory astrophysical simulations, and theoretical astrochemistry. This will be followed by a discussion of the evidence, largely gathered from the laboratory isotopic study of extraterrestrial materials (meteorites and cosmic dust), that interstellar materials, including organics, can and do survive the transition from the interstellar space into forming stellar systems. Once there, some of this material can be delivered largely unaltered to planetary surfaces where it can play key roles in the origin and subsequent evolution of life.

  4. Hydrothermal organic synthesis experiments

    Science.gov (United States)

    Shock, Everett L.

    1992-01-01

    Ways in which heat is useful in organic synthesis experiments are described, and experiments on the hydrothermal destruction and synthesis of organic compounds are discussed. It is pointed out that, if heat can overcome kinetic barriers to the formation of metastable states from reduced or oxidized starting materials, abiotic synthesis under hydrothermal conditions is a distinct possibility. However, carefully controlled experiments which replicate the descriptive variables of natural hydrothermal systems have not yet been conducted with the aim of testing the hypothesis of hydrothermal organic systems.

  5. Mechanochemical organic synthesis.

    Science.gov (United States)

    Wang, Guan-Wu

    2013-09-21

    Recently, mechanical milling using a mixer mill or planetary mill has been fruitfully utilized in organic synthesis under solvent-free conditions. This review article provides a comprehensive overview of various solvent-free mechanochemical organic reactions, including metal-mediated or -catalyzed reactions, condensation reactions, nucleophilic additions, cascade reactions, Diels-Alder reactions, oxidations, reductions, halogenation/aminohalogenation, etc. The ball milling technique has also been applied to the synthesis of calixarenes, rotaxanes and cage compounds, asymmetric synthesis as well as the transformation of biologically active compounds.

  6. Hydrothermal organic synthesis experiments

    Science.gov (United States)

    Shock, Everett L.

    1992-01-01

    The serious scientific debate about spontaneous generation which raged for centuries reached a climax in the nineteenth century with the work of Spallanzani, Schwann, Tyndall, and Pasteur. These investigators demonstrated that spontaneous generation from dead organic matter does not occur. Although no aspects of these experiments addressed the issue of whether organic compounds could be synthesized abiotically, the impact of the experiments was great enough to cause many investigators to assume that life and its organic compounds were somehow fundamentally different than inorganic compounds. Meanwhile, other nineteenth-century investigators were showing that organic compounds could indeed be synthesized from inorganic compounds. In 1828 Friedrich Wohler synthesized urea in an attempt to form ammonium cyanate by heating a solution containing ammonia and cyanic acid. This experiment is generally recognized to be the first to bridge the artificial gap between organic and inorganic chemistry, but it also showed the usefulness of heat in organic synthesis. Not only does an increase in temperature enhance the rate of urea synthesis, but Walker and Hambly showed that equilibrium between urea and ammonium cyanate was attainable and reversible at 100 C. Wohler's synthesis of urea, and subsequent syntheses of organic compounds from inorganic compounds over the next several decades dealt serious blows to the 'vital force' concept which held that: (1) organic compounds owe their formation to the action of a special force in living organisms; and (2) forces which determine the behavior of inorganic compounds play no part in living systems. Nevertheless, such progress was overshadowed by Pasteur's refutation of spontaneous generation which nearly extinguished experimental investigations into the origins of life for several decades. Vitalism was dealt a deadly blow in the 1950's with Miller's famous spark-discharge experiments which were undertaken in the framework of the Oparin

  7. Heterogeneous photocatalysts in organic synthesis

    Science.gov (United States)

    Cherevatskaya, M.; König, B.

    2014-03-01

    The review deals with the application of inorganic semiconductors in organic synthesis. Although the majority of reported reactions still aim at the photocatalytic decomposition of organic compounds, the number of examples in synthetic applications is growing. The principal mechanisms of heterogeneous semiconductor photocatalysis are considered and examples illustrating the use of inorganic semiconductors in organic synthesis are given. The discussion is arranged according to the required excitation wavelength (UV or visible light) and to the new bond that is formed (carbon-carbon or carbon-heteroatom bond). The bibliography includes 47 references.

  8. Matrix Embedded Organic Synthesis

    Science.gov (United States)

    Kamakolanu, U. G.; Freund, F. T.

    2016-05-01

    In the matrix of minerals such as olivine, a redox reaction of the low-z elements occurs. Oxygen is oxidized to the peroxy state while the low-Z-elements become chemically reduced. We assign them a formula [CxHyOzNiSj]n- and call them proto-organics.

  9. Indenylmetal Catalysis in Organic Synthesis.

    Science.gov (United States)

    Trost, Barry M; Ryan, Michael C

    2017-03-06

    Synthetic organic chemists have a long-standing appreciation for transition metal cyclopentadienyl complexes, of which many have been used as catalysts for organic transformations. Much less well known are the contributions of the benzo-fused relative of the cyclopentadienyl ligand, the indenyl ligand, whose unique properties have in many cases imparted differential reactivity in catalytic processes toward the synthesis of small molecules. In this Review, we present examples of indenylmetal complexes in catalysis and compare their reactivity to their cyclopentadienyl analogues, wherever possible. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Biomimetic, Catalytic Oxidation in Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    Shun-lchi Murahashi

    2005-01-01

    @@ 1Introduction Oxidation is one of the most fundamental reactions in organic synthesis. Owing to the current need to develop forward-looking technology that is environmentally acceptable with respect many aspects. The most attractive approaches are biomimetic oxidation reactions that are closely related to the metabolism of living things. The metabolisms are governed by a variety of enzymes such as cytochrome P-450 and flavoenzyme.Simulation of the function of these enzymes with simple transition metal complex catalyst or organic catalysts led to the discovery of biomimetic, catalytic oxidations with peroxides[1]. We extended such biomimetic methods to the oxidation with molecular oxygen under mild conditions.

  11. Diversity-Oriented Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    J. Wu

    2005-01-01

    @@ 1Introduction A goal of chemical genetics is to find small molecules that modulate the individual functions of gene products with high potency and high specificity[1,2]. Natural products and natural product-derived compounds provide many of the most striking examples, particularly in terms of their specificity. It seems unlikely that natural products alone will provide the hypothetical "complete" set of small molecules that would allow the functions of all proteins, as well as their individual domains, to be determined. For chemistry to have its maximal effect on biology, efficient methods based on diversity-oriented organic synthesis for discovering this set of small molecules are in great demand(See Fig. 1).

  12. Green chemistry oriented organic synthesis in water.

    Science.gov (United States)

    Simon, Marc-Olivier; Li, Chao-Jun

    2012-02-21

    The use of water as solvent features many benefits such as improving reactivities and selectivities, simplifying the workup procedures, enabling the recycling of the catalyst and allowing mild reaction conditions and protecting-group free synthesis in addition to being benign itself. In addition, exploring organic chemistry in water can lead to uncommon reactivities and selectivities complementing the organic chemists' synthetic toolbox in organic solvents. Studying chemistry in water also allows insight to be gained into Nature's way of chemical synthesis. However, using water as solvent is not always green. This tutorial review briefly discusses organic synthesis in water with a Green Chemistry perspective.

  13. Synthesis Road Map Problems in Organic Chemistry

    Science.gov (United States)

    Schaller, Chris P.; Graham, Kate J.; Jones, T. Nicholas

    2014-01-01

    Road map problems ask students to integrate their knowledge of organic reactions with pattern recognition skills to "fill in the blanks" in the synthesis of an organic compound. Students are asked to identify familiar organic reactions in unfamiliar contexts. A practical context, such as a medicinally useful target compound, helps…

  14. Synthesis Road Map Problems in Organic Chemistry

    Science.gov (United States)

    Schaller, Chris P.; Graham, Kate J.; Jones, T. Nicholas

    2014-01-01

    Road map problems ask students to integrate their knowledge of organic reactions with pattern recognition skills to "fill in the blanks" in the synthesis of an organic compound. Students are asked to identify familiar organic reactions in unfamiliar contexts. A practical context, such as a medicinally useful target compound, helps…

  15. Microchannel systems for fine organic synthesis

    Science.gov (United States)

    Makarshin, L. L.; Pai, Z. P.; Parmon, V. N.

    2016-02-01

    Characteristic features of application of microchannel systems in organic synthesis are analyzed. The advantages of such systems over conventional chemical engineering equipment, especially for small-scale processes that require fast implementation in industry to obtain small quantities of the product, are shown. Particular examples of successful use of microchannel reactors for various types of organic synthesis are given, primary attention being devoted to the design features of microchannel reactors. The bibliography includes 118 references.

  16. [Current organization of disaster medicine].

    Science.gov (United States)

    Julien, Henri

    2013-12-01

    The concept of disaster medicine, derivedfrom medical management of casualties caused by terrorist attacks or earthquakes, began to be taught in medical school in 1982. It adapts military intervention tactics to civilian practices, and differentiates major disasters (in which preformed teams are sent to the scene) from disasters with limited effects (predefined plans form the backbone of the rescue organization). Management of blast and crush syndromes, triage, care of numerous burn victims, on-site amputation, necrotomy, medicopsychological support, mass decontamination, and rescue management are some of the aspects with which physicians should be familiar. Predefined intervention teams and ad hoc materials have been created to provide autonomous logistic support. Regulations, ethical aspects and managerial methods still need to be refined, and research and teaching must be given a new impetus.

  17. The Solvent Selection framework: solvents for organic synthesis, separation processes and ionic-organic synthesis

    DEFF Research Database (Denmark)

    Mitrofanov, Igor; Sansonetti, Sascha; Abildskov, Jens

    2012-01-01

    problems are presented: 1) solvent selection and design for organic synthesis, 2) solvent screening and design of solvent mixtures for pharmaceutical applications and 3) ionic liquids selection and design as solvents. The application of the framework is highlighted successfully through case studies...... focusing on solvent replacement problem in organic synthesis and solvent mixture design for ibuprofen respectively....

  18. Photocatalysis in organic and polymer synthesis.

    Science.gov (United States)

    Corrigan, Nathaniel; Shanmugam, Sivaprakash; Xu, Jiangtao; Boyer, Cyrille

    2016-11-07

    This review, with over 600 references, summarizes the recent applications of photoredox catalysis for organic transformation and polymer synthesis. Photoredox catalysts are metallo- or organo-compounds capable of absorbing visible light, resulting in an excited state species. This excited state species can donate or accept an electron from other substrates to mediate redox reactions at ambient temperature with high atom efficiency. These catalysts have been successfully implemented for the discovery of novel organic reactions and synthesis of added-value chemicals with an excellent control of selectivity and stereo-regularity. More recently, such catalysts have been implemented by polymer chemists to post-modify polymers in high yields, as well as to effectively catalyze reversible deactivation radical polymerizations and living polymerizations. These catalysts create new approaches for advanced organic transformation and polymer synthesis. The objective of this review is to give an overview of this emerging field to organic and polymer chemists as well as materials scientists.

  19. Organic chemistry: Streamlining drug synthesis

    Science.gov (United States)

    Hawkins, Joel M.

    2015-04-01

    Drug manufacture can benefit from flow synthesis, in which raw materials are fed into a sequence of reactors, producing the drug as a continuous output. A flow strategy that capitalizes on solid catalysts has now been realized. See Letter p.329

  20. Magnetically retrievable catalysts for organic synthesis

    Science.gov (United States)

    The use of magnetic nanoparticles (MNPs) as a catalyst in organic synthesis has become a subject of intense investigation. The recovery of expensive catalysts after catalytic reaction and reusing it without losing its activity is an important feature in the sustainable process de...

  1. Catalytic Radical Domino Reactions in Organic Synthesis.

    Science.gov (United States)

    Sebren, Leanne J; Devery, James J; Stephenson, Corey R J

    2014-02-07

    Catalytic radical-based domino reactions represent important advances in synthetic organic chemistry. Their development benefits synthesis by providing atom- and step-economical methods to complex molecules. Intricate combinations of radical, cationic, anionic, oxidative/reductive, and transition metal mechanistic steps result in cyclizations, additions, fragmentations, ring-expansions, and rearrangements. This Perspective summarizes recent developments in the field of catalytic domino processes.

  2. Magnetically retrievable catalysts for organic synthesis

    Science.gov (United States)

    The use of magnetic nanoparticles (MNPs) as a catalyst in organic synthesis has become a subject of intense investigation. The recovery of expensive catalysts after catalytic reaction and reusing it without losing its activity is an important feature in the sustainable process de...

  3. Current Injection Pumping of Organic Light Emitters

    Science.gov (United States)

    1989-09-28

    MOT-OOO1AF I Current Injection Pumping of Organic Light Emitters Prepared by DI Jeffrey C. Buchholz E L ri: 8 James P. Stec OCT C "t989 Mary C...Schutte Micro -Optics Technologies, Inc. 8608 University Green #5 Middleton, WI 53562 28 September 1989 D,:?UqflON SA2". N’.’ _ Disuibunon Uanu-ted Contract...Title Report Date Current Injection Pumping of Organic Light Emitters 28 September 1989 Authors Jeffrey C. Buchholz, James P. Stec, Mary C. Schutte

  4. Ohmic Heating: An Emerging Concept in Organic Synthesis.

    Science.gov (United States)

    Silva, Vera L M; Santos, Luis M N B F; Silva, Artur M S

    2017-06-12

    The ohmic heating also known as direct Joule heating, is an advanced thermal processing method, mainly used in the food industry to rapidly increase the temperature for either cooking or sterilization purposes. Its use in organic synthesis, in the heating of chemical reactors, is an emerging method that shows great potential, the development of which has started recently. This Concept article focuses on the use of ohmic heating as a new tool for organic synthesis. It presents the fundamentals of ohmic heating and makes a qualitative and quantitative comparison with other common heating methods. A brief description of the ohmic reactor prototype in operation is presented as well as recent examples of its use in organic synthesis at laboratory scale, thus showing the current state of the research. The advantages and limitations of this heating method, as well as its main current applications are also discussed. Finally, the prospects and potential implications of ohmic heating in future research in chemical synthesis are proposed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Asymmetric catalysis in organic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Reilly, S.D.; Click, D.R.; Grumbine, S.K.; Scott, B.L.; Watkins, J.G.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of the project was to prepare new catalyst systems, which would perform chemical reactions in an enantioselective manner so as to produce only one of the possible optical isomers of the product molecule. The authors have investigated the use of lanthanide metals bearing both diolate and Schiff-base ligands as catalysts for the enantioselective reduction of prochiral ketones to secondary alcohols. The ligands were prepared from cheap, readily available starting materials, and their synthesis was performed in a ''modular'' manner such that tailoring of specific groups within the ligand could be carried out without repeating the entire synthetic procedure. In addition, they have developed a new ligand system for Group IV and lanthanide-based olefin polymerization catalysts. The ligand system is easily prepared from readily available starting materials and offers the opportunity to rapidly prepare a wide range of closely related ligands that differ only in their substitution patterns at an aromatic ring. When attached to a metal center, the ligand system has the potential to carry out polymerization reactions in a stereocontrolled manner.

  6. BIOMIMETIC STRATEGIES IN ORGANIC SYNTHESIS. TERPENES

    Directory of Open Access Journals (Sweden)

    V. Kulcitki

    2012-12-01

    Full Text Available The current paper represents an outline of the selected contributions to the biomimetic procedures and approaches for the synthesis of terpenes with complex structure and diverse functionalisation pattern. These include homologation strategies, cyclisations, rearrangements, as well as biomimetic remote functionalisations.

  7. Endogenous Synthesis of Prebiotic Organic Molecules

    Science.gov (United States)

    Miller, Stanley L.

    1996-01-01

    The necessary condition for the synthesis of organic compounds on the primitive earth is the presence of reducing conditions. This means an atmosphere of CH4, CO, or CO2 + H2. The atmospheric nitrogen can be N2 with a trace of NH3, but NH4(+) is needed in the ocean at least for amino acid synthesis. Many attempts have been made to use CO2 + H2O atmospheres for prebiotic synthesis, but these give at best extremely low yields of organic compounds, except in the presence of H2. Even strong reducing agents such as FeS + H2S or the mineral assemblages of the submarine vents fail to give significant yields of organic compounds with CO2. There appears to be a high kinetic barrier to the non-biological reduction of CO2 at low temperatures using geological reducing agents. The most abundant source of energy for prebiotic synthesis is ultraviolet light followed by electric discharges, with electric discharges being more efficient, although it is not clear which was the important energy source. Photochemical process would also make significant contributions. In an atmosphere Of CO2, N2, and H2O with no H2, the production rates of HCN and H2CO would be very low, 0.001 or less than that of a relatively reducing atmosphere. The concentration of organic compounds under these non-reducing conditions would be so low that there is doubt whether the concentration mechanism would be adequate for further steps toward the origin of life. A number of workers have calculated the influx of comets and meteorites on the primitive earth as a source of organic compounds. We conclude that while some organic material was added to the earth from comets and meteorites the amount available from these sources at a given time was at best only a few percent of that from earth bases syntheses under reducing conditions.

  8. Alkoxyallenes as building blocks for organic synthesis.

    Science.gov (United States)

    Zimmer, Reinhold; Reissig, Hans-Ulrich

    2014-05-01

    Alkoxyallenes are unusually versatile C3 building blocks in organic synthesis. Hence this tutorial review summarizes the most important transformations, including subsequent reactions and their applications in the synthesis of relevant compounds, e.g. natural products. The reactivity patterns involved and the synthons derived from alkoxyallenes are presented. Often alkoxyallenes can serve as substitutes of acrolein or acrolein acetals, utilisation of which has already led to interesting products. Most important is the use of lithiated alkoxyallenes which smoothly react with a variety of electrophiles and lead to products with unique substitution patterns. The heterocycles or carbocycles formed are intermediates for the stereoselective synthesis of natural products or for the preparation of other structurally relevant compounds. The different synthons being put into practice by the use of lithiated alkoxyallenes in these variations will be discussed.

  9. Some Aspects of the Catalytic Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    Anil; K.Saikia

    2007-01-01

    1 Results Catalytic reactions are gaining importance due to its low cost, operational simplicity, high efficiency and selectivity. It is also getting much attention in green synthesis. Many useful organic reactions, including the acylation of alcohols and aldehydes, carbon-carbon, carbon-nitrogen, carbon-sulfur bond forming and oxidation reactions are carried out by catalyst. We are exploring the catalytic acylation of alcohols and aldehydes in a simple and efficient manner. Catalytic activation of unr...

  10. Catalytic Radical Domino Reactions in Organic Synthesis

    Science.gov (United States)

    Sebren, Leanne J.; Devery, James J.; Stephenson, Corey R.J.

    2014-01-01

    Catalytic radical-based domino reactions represent important advances in synthetic organic chemistry. Their development benefits synthesis by providing atom- and step-economical methods to complex molecules. Intricate combinations of radical, cationic, anionic, oxidative/reductive, and transition metal mechanistic steps result in cyclizations, additions, fragmentations, ring-expansions, and rearrangements. This Perspective summarizes recent developments in the field of catalytic domino processes. PMID:24587964

  11. New generation of biocatalysts for organic synthesis.

    Science.gov (United States)

    Nestl, Bettina M; Hammer, Stephan C; Nebel, Bernd A; Hauer, Bernhard

    2014-03-17

    The use of enzymes as catalysts for the preparation of novel compounds has received steadily increasing attention over the past few years. High demands are placed on the identification of new biocatalysts for organic synthesis. The catalysis of more ambitious reactions reflects the high expectations of this field of research. Enzymes play an increasingly important role as biocatalysts in the synthesis of key intermediates for the pharmaceutical and chemical industry, and new enzymatic technologies and processes have been established. Enzymes are an important part of the spectrum of catalysts available for synthetic chemistry. The advantages and applications of the most recent and attractive biocatalysts--reductases, transaminases, ammonia lyases, epoxide hydrolases, and dehalogenases--will be discussed herein and exemplified by the syntheses of interesting compounds.

  12. Organic synthesis in experimental impact shocks

    Science.gov (United States)

    McKay, C. P.; Borucki, W. J.

    1997-01-01

    Laboratory simulations of shocks created with a high-energy laser demonstrate that the efficacy of organic production depends on the molecular, not just the elemental composition of the shocked gas. In a methane-rich mixture that simulates a low-temperature equilibrium mixture of cometary material, hydrogen cyanide and acetylene were produced with yields of 5 x 10(17) molecules per joule. Repeated shocking of the methane-rich mixture produced amine groups, suggesting the possible synthesis of amino acids. No organic molecules were produced in a carbon dioxide-rich mixture, which is at odds with thermodynamic equilibrium approaches to shock chemistry and has implications for the modeling of shock-produced organic molecules on early Earth.

  13. Organic synthesis in experimental impact shocks

    Science.gov (United States)

    McKay, C. P.; Borucki, W. J.

    1997-01-01

    Laboratory simulations of shocks created with a high-energy laser demonstrate that the efficacy of organic production depends on the molecular, not just the elemental composition of the shocked gas. In a methane-rich mixture that simulates a low-temperature equilibrium mixture of cometary material, hydrogen cyanide and acetylene were produced with yields of 5 x 10(17) molecules per joule. Repeated shocking of the methane-rich mixture produced amine groups, suggesting the possible synthesis of amino acids. No organic molecules were produced in a carbon dioxide-rich mixture, which is at odds with thermodynamic equilibrium approaches to shock chemistry and has implications for the modeling of shock-produced organic molecules on early Earth.

  14. Current methods for synthesis of gold nanoparticles.

    Science.gov (United States)

    Herizchi, Roya; Abbasi, Elham; Milani, Morteza; Akbarzadeh, Abolfazl

    2016-01-01

    Metal nanoparticles, such as nanoparticles synthesized using gold, have numerous uncommon chemical and physical properties due to the effects of their quantum size and their large surface area, in comparison with other metal atoms or bulk metal. Gold nanoparticles (GNPs), in particular, are very attractive because of their size and shape-dependent properties. Metal nanoparticles have gathered extensive attention due to their uncommon properties and promising applications in photonics, electronics, biochemical sensing, and imaging. This review covers recent advances in the synthesis of GNPs.

  15. Synthesis-Spectroscopy Roadmap Problems: Discovering Organic Chemistry

    Science.gov (United States)

    Kurth, Laurie L.; Kurth, Mark J.

    2014-01-01

    Organic chemistry problems that interrelate and integrate synthesis with spectroscopy are presented. These synthesis-spectroscopy roadmap (SSR) problems uniquely engage second-year undergraduate organic chemistry students in the personal discovery of organic chemistry. SSR problems counter the memorize-or-bust strategy that many students tend to…

  16. Synthesis-Spectroscopy Roadmap Problems: Discovering Organic Chemistry

    Science.gov (United States)

    Kurth, Laurie L.; Kurth, Mark J.

    2014-01-01

    Organic chemistry problems that interrelate and integrate synthesis with spectroscopy are presented. These synthesis-spectroscopy roadmap (SSR) problems uniquely engage second-year undergraduate organic chemistry students in the personal discovery of organic chemistry. SSR problems counter the memorize-or-bust strategy that many students tend to…

  17. Novel Aryne Chemistry in Organic Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhijian [Iowa State Univ., Ames, IA (United States)

    2006-12-12

    Arynes are among the most intensively studied systems in chemistry. However, many aspects of the chemistry of these reactive intermediates are not well understood yet and their use as reagents in synthetic organic chemistry has been somewhat limited, due to the harsh conditions needed to generate arynes and the often uncontrolled reactivity exhibited by these species. Recently, o-silylaryl triflates, which can generate the corresponding arynes under very mild reaction conditions, have been found very useful in organic synthesis. This thesis describes several novel and useful methodologies by employing arynes, which generate from o-silylaryl triflates, in organic synthesis. An efficient, reliable method for the N-arylation of amines, sulfonamides and carbamates, and the O-arylation of phenols and carboxylic acids is described in Chapter 1. Amines, sulfonamides, phenols, and carboxylic acids are good nucleophiles, which can react with arynes generated from a-silylaryl triflates to afford the corresponding N- and O-arylated products in very high yields. The regioselectivity of unsymmetrical arynes has also been studied. A lot of useful, functional groups can tolerate our reaction conditions. Carbazoles and dibenzofurans are important heteroaromatic compounds, which have a variety of biological activities. A variety of substituted carbazoles and dibenzofwans are readily prepared in good to excellent yields starting with the corresponding o-iodoanilines or o-iodophenols and o-silylaryl triflates by a treatment with CsF, followed by a Pd-catalyzed cyclization, which overall provides a one-pot, two-step process. By using this methodology, the carbazole alkaloid mukonine has been concisely synthesized in a very good yield. Insertion of an aryne into a σ-bond between a nucleophile and an electrophile (Nu-E) should potentially be a very beneficial process from the standpoint of organic synthesis. A variety of substituted ketones and sulfoxides have been synthesized in good

  18. Enantioselective biotransformations of nitriles in organic synthesis.

    Science.gov (United States)

    Wang, Mei-Xiang

    2015-03-17

    The hydration and hydrolysis of nitriles are valuable synthetic methods used to prepare carboxamides and carboxylic acids. However, chemical hydration and hydrolysis of nitriles involve harsh reaction conditions, have low selectivity, and generate large amounts of waste. Therefore, researchers have confined the scope of these reactions to simple nitrile substrates. However, biological transformations of nitriles are highly efficient, chemoselective, and environmentally benign, which has led synthetic organic chemists and biotechologists to study these reactions in detail over the last two decades. In nature, biological systems degrade nitriles via two distinct pathways: nitrilases catalyze the direct hydrolysis of nitriles to afford carboxylic acids with release of ammonia, and nitrile hydratases catalyze the conversion of nitriles into carboxamides, which then furnish carboxylic acids via hydrolysis in the presence of amidases. Researchers have subsequently developed biocatalytic methods into useful industrial processes for the manufacture of commodity chemicals, including acrylamide. Since the late 1990s, research by my group and others has led to enormous progress in the understanding and application of enantioselective biotransformations of nitriles in organic synthesis. In this Account, I summarize the important advances in enantioselective biotransformations of nitriles and amides, with a primary focus on research from my laboratory. I describe microbial whole-cell-catalyzed kinetic resolution of various functionalized nitriles, amino- and hydroxynitriles, and nitriles that contain small rings and the desymmetrization of prochiral and meso dinitriles and diamides. I also demonstrate how we can apply the biocatalytic protocol to synthesize natural products and bioactive compounds. These nitrile biotransformations offer an attractive and unique protocol for the enantioselective synthesis of polyfunctionalized organic compounds that are not readily obtainable by

  19. Organic Ion Exchangers. Synthesis, Characterization and Applications

    Institute of Scientific and Technical Information of China (English)

    E. S. Dragan

    2005-01-01

    @@ 1Introduction Organic ion exchangers in beads form are the most widely utilized materials in the purification, concentration and separation processes of inorganic and organic ions in many fields of science and industry[1,2]. Some original contributions in the preparation and characterization of porous organic ion exchangers will be summarized first. The main types of synthetic ion exchangers were obtained by polymer-analogous reactions performed on porous styrene-divinylbenzene copolymers (S-DVB)[3,4] and porous acrylonitrile-DVB copolymers (AN-DVB) [5,6]. Porous S-DVB copolymers were used as substrate for the synthesis of weak and strong base anion exchangers by chloromethylation reaction followed by the reaction with secondary or tertiary amines.Different chloromethylation agents were employed. Weak base anion exchangers with tertiary or primary amine groups were prepared starting from AN-DVB copolymers by aminolyse-hydrolyse reaction with asymmetrical diamines or ethylenediamine (EDA), respectively. Strong base anion exchangers were obtained by quaternization reaction with alkyl halides of the tertiary amine groups. Chelating ion exchangers with iminodiacetic groups were prepared by the carboxymethylation reaction of the primary amine groups above mentioned and of those contained in a vinylamine-ethylacrylate-DVB copolymer, vinylamine units being generated by a Hofmann degradation reaction of the primary amide groups contained in the acrylamide-ethylacrylate-DVB copolymerp[7]. An amphoteric ion exchanger was prepared by the hydrolysis of the ester groups after the Hofmann degradation.

  20. Flow “Fine” Synthesis: High Yielding and Selective Organic Synthesis by Flow Methods

    Science.gov (United States)

    2015-01-01

    Abstract The concept of flow “fine” synthesis, that is, high yielding and selective organic synthesis by flow methods, is described. Some examples of flow “fine” synthesis of natural products and APIs are discussed. Flow methods have several advantages over batch methods in terms of environmental compatibility, efficiency, and safety. However, synthesis by flow methods is more difficult than synthesis by batch methods. Indeed, it has been considered that synthesis by flow methods can be applicable for the production of simple gasses but that it is difficult to apply to the synthesis of complex molecules such as natural products and APIs. Therefore, organic synthesis of such complex molecules has been conducted by batch methods. On the other hand, syntheses and reactions that attain high yields and high selectivities by flow methods are increasingly reported. Flow methods are leading candidates for the next generation of manufacturing methods that can mitigate environmental concerns toward sustainable society. PMID:26337828

  1. Metal–organic framework membranes: from synthesis to separation application

    KAUST Repository

    Qiu, Shilun

    2014-06-26

    Metal-organic framework (MOF) materials, which are constructed from metal ions or metal ion clusters and bridging organic linkers, exhibit regular crystalline lattices with relatively well-defined pore structures and interesting properties. As a new class of porous solid materials, MOFs are attractive for a variety of industrial applications including separation membranes-a rapidly developing research area. Many reports have discussed the synthesis and applications of MOFs and MOF thin films, but relatively few have addressed MOF membranes. This critical review provides an overview of the diverse MOF membranes that have been prepared, beginning with a brief introduction to the current techniques for the fabrication of MOF membranes. Gas and liquid separation applications with different MOF membranes are also included (175 references). This journal is © the Partner Organisations 2014.

  2. Stepwise Synthesis of Metal-Organic Frameworks.

    Science.gov (United States)

    Bosch, Mathieu; Yuan, Shuai; Rutledge, William; Zhou, Hong-Cai

    2017-04-18

    Metal-organic frameworks (MOFs) are a category of porous materials that offer unparalleled control over their surface areas (demonstrated as higher than for any other material), pore characteristics, and functionalization. This allows them to be customized for exceptional performance in a wide variety of applications, most commonly including gas storage and separation, drug delivery, luminescence, or heterogeneous catalysis. In order to optimize biomimicry, controlled separations and storage of small molecules, and detailed testing of structure-property relationships, one major goal of MOF research is "rational design" or "pore engineering", or precise control of the placement of multiple functional groups in pores of chosen sizes and shapes. MOF crystal growth can be controlled through judicious design of stepwise synthetic routes, which can also allow functionalization of MOFs in ways that were previously synthetically inaccessible. Organic chemists have developed a library of powerful techniques over the last century, allowing the total synthesis and detailed customization of complex molecules. Our hypothesis is that total synthesis is also possible for customized porous materials, through the development of similar multistep techniques. This will enable the rational design of MOFs, which is a major goal of many researchers in the field. We have begun developing a library of stepwise synthetic techniques for MOFs, allowing the synthesis of ultrastable MOFs with multiple crystallographically ordered and customizable functional groups at controlled locations within the pores. In order to design MOFs with precise control over pore size and shape, stability, and the placement of multiple different functional groups within the pores at tunable distances from one another, we have concentrated on methods which allow us to circumvent the lack of control inherent to one-pot MOF crystallization. Kinetically tuned dimensional augmentation (KTDA) is an approach using

  3. Fundamentals and applications of organic electrochemistry synthesis, materials, devices

    CERN Document Server

    Fuchigami, Toshio; Inagi, Shinsuke

    2014-01-01

    This textbook is an accessible overview of the broad field of organic electrochemistry, covering the fundamentals and applications of contemporary organic electrochemistry.  The book begins with an introduction to the fundamental aspects of electrode electron transfer and methods for the electrochemical measurement of organic molecules. It then goes on to discuss organic electrosynthesis of molecules and macromolecules, including detailed experimental information for the electrochemical synthesis of organic compounds and conducting polymers. Later chapters highlight new methodology for organic electrochemical synthesis, for example electrolysis in ionic liquids, the application to organic electronic devices such as solar cells and LEDs, and examples of commercialized organic electrode processes. Appendices present useful supplementary information including experimental examples of organic electrosynthesis, and tables of physical data (redox potentials of various organic solvents and organic compounds and phy...

  4. Multistep organic synthesis of modular photosystems

    Science.gov (United States)

    2012-01-01

    Summary Quite extensive synthetic achievements vanish in the online supporting information of publications on functional systems. Underappreciated, their value is recognized by experts only. As an example, we here focus in on the recent synthesis of multicomponent photosystems with antiparallel charge-transfer cascades in co-axial hole- and electron-transporting channels. The synthetic steps are described one-by-one, starting with commercial starting materials and moving on to key intermediates, such as asparagusic acid, an intriguing natural product, as well as diphosphonate “feet”, and panchromatic naphthalenediimides (NDIs), to finally reach the target molecules. These products are initiators and propagators for self-organizing surface-initiated polymerization (SOSIP), a new method introduced to secure facile access to complex architectures. Chemoorthogonal to the ring-opening disulfide exchange used for SOSIP, hydrazone exchange is then introduced to achieve stack exchange, which is a “switching” technology invented to drill giant holes into SOSIP architectures and fill them with functional π-stacks of free choice. PMID:23015840

  5. Patterns in Organometallic Chemistry with Application in Organic Synthesis.

    Science.gov (United States)

    Schwartz, Jeffrey; Labinger, Jay A.

    1980-01-01

    Of interest in this discussion of organometallic complexes are stoichiometric or catalytic reagents for organic synthesis in the complex transformations observed during synthesis for transition metal organometallic complexes. Detailed are general reaction types from which the chemistry or many transition metal organometallic complexes can be…

  6. Peptide synthesis in neat organic solvents with novel thermostable proteases

    NARCIS (Netherlands)

    Toplak, Ana; Nuijens, Timo; Quaedflieg, Peter J L M; Wu, Bian; Janssen, Dick B

    2015-01-01

    Biocatalytic peptide synthesis will benefit from enzymes that are active at low water levels in organic solvent compositions that allow good substrate and product solubility. To explore the use of proteases from thermophiles for peptide synthesis under such conditions, putative protease genes of the

  7. Use of Bromine and Bromo-Organic Compounds in Organic Synthesis.

    Science.gov (United States)

    Saikia, Indranirekha; Borah, Arun Jyoti; Phukan, Prodeep

    2016-06-22

    Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular bromine in organic synthesis is well-known. However, due to the hazardous nature of bromine, enormous growth has been witnessed in the past several decades for the development of solid bromine carriers. This review outlines the use of bromine and different bromo-organic compounds in organic synthesis. The applications of bromine, a total of 107 bromo-organic compounds, 11 other brominating agents, and a few natural bromine sources were incorporated. The scope of these reagents for various organic transformations such as bromination, cohalogenation, oxidation, cyclization, ring-opening reactions, substitution, rearrangement, hydrolysis, catalysis, etc. has been described briefly to highlight important aspects of the bromo-organic compounds in organic synthesis.

  8. Synthesis of fluorinated organic compounds using oxygen difluoride

    Science.gov (United States)

    Toy, M. S.

    1971-01-01

    Oxygen difluoride synthesis is a much simpler, higher-yield procedure than reactions originally followed to synthesize various fluorinated organic compounds. Extreme care is taken in working with oxygen difluoride as its reactions present severe explosion hazard.

  9. Greener and Sustainable Trends in Synthesis of Organics and Nanomaterials

    Science.gov (United States)

    Trends in greener and sustainable process development during the past 25 years are abridged involving the use of alternate energy inputs (mechanochemistry, ultrasound- or microwave irradiation), photochemistry, and greener reaction media as applied to synthesis of organics and na...

  10. Greener and Sustainable Trends in Synthesis of Organics and Nanomaterials

    Science.gov (United States)

    Trends in greener and sustainable process development during the past 25 years are abridged involving the use of alternate energy inputs (mechanochemistry, ultrasound- or microwave irradiation), photochemistry, and greener reaction media as applied to synthesis of organics and na...

  11. Ionic-liquid-supported (ILS) catalysts for asymmetric organic synthesis.

    Science.gov (United States)

    Ni, Bukuo; Headley, Allan D

    2010-04-19

    The asymmetric synthesis of compounds that contain new C-C and C-O bonds remains one of the most important types of synthesis in organic chemistry. Over the years, many different types of catalysts have been designed and used effectively to carry out such transformations. Ionic-liquid-supported (ILS) catalysts represent a new and very effective class of catalysts that are used to facilitate the asymmetric synthesis of such compounds. There are many advantages to using ILS catalysts; they are nontoxic, environmentally benign, and, most important, recyclable. An overview of the design, synthesis, mode of action, and effectiveness of this class of catalysts is reported.

  12. Current Antioxidant Treatments in Organ Transplantation

    Directory of Open Access Journals (Sweden)

    Shaojun Shi

    2016-01-01

    Full Text Available Oxidative stress is one of the key mechanisms affecting the outcome throughout the course of organ transplantation. It is widely believed that the redox balance is dysregulated during ischemia and reperfusion (I/R and causes subsequent oxidative injury, resulting from the formation of reactive oxygen species (ROS. Moreover, in order to alleviate organ shortage, increasing number of grafts is retrieved from fatty, older, and even non-heart-beating donors that are particularly vulnerable to the accumulation of ROS. To improve the viability of grafts and reduce the risk of posttransplant dysfunction, a large number of studies have been done focusing on the antioxidant treatments for the purpose of maintaining the redox balance and thereby protecting the grafts. This review provides an overview of these emerging antioxidant treatments, targeting donor, graft preservation, and recipient as well.

  13. High Critical Current in Metal Organic Derived YBCO Films

    Science.gov (United States)

    2010-10-31

    Contract No. FA9550-07-C-0034 “High Critical Current in Metal Organic Derived YBCO Films” Final Report Prepared for: Dr. Harold...Critical Current in Metal Organic Derived YBCO Films 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...Project focused on optimization of the Metal Organic Deposition (MOD) process for deposition thick, high critical current YBCO films for use in the

  14. Recent developments on ultrasound assisted catalyst-free organic synthesis.

    Science.gov (United States)

    Banerjee, Bubun

    2017-03-01

    Mother Nature needs to be protected from ever increasing chemical pollutions associated with synthetic organic processes. The fundamental challenge for today's methodologists is to make their protocols more environmentally benign and sustainable by avoiding the extensive use of hazardous reagents and solvents, harsh reaction conditions, and toxic metal catalysts. However, the people of the twenty-first century are well aware about the side effects of those hazardous substances used and generated by the chemical processes. As a result, the last decade has seen a tremendous outburst in modifying chemical processes to make them 'sustainable' for the betterment of our environment. Catalysts play a crucial role in organic synthesis and thus they find huge applications and uses. Scientists' continuously trying to modify the catalysts to reduce their toxicity level, but the most benign way is to design an organic reaction without catalyst(s), if possible. It is worthy to mention that the involvement of ultrasound in organic synthesis is sometimes fulfilling this goal. In many occasions the applications of ultrasound can avoid the use of catalysts in organic reactions. Such beneficial features as a whole have motivated the organic chemists to apply ultrasonic irradiation in more heights and as a results, in recent past, there were immense applications of ultrasound in organic reactions for the synthesis of diverse organic scaffolds under catalyst-free condition. The present review summarizes the latest developments on ultrasound assisted catalyst-free organic synthesis reported so far. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Biocatalyzed Regioselective Synthesis in Undergraduate Organic Laboratories: Multistep Synthesis of 2-Arachidonoylglycerol

    Science.gov (United States)

    Johnston, Meghan R.; Makriyannis, Alexandros; Whitten, Kyle M.; Drew, Olivia C.; Best, Fiona A.

    2016-01-01

    In order to introduce the concepts of biocatalysis and its utility in synthesis to organic chemistry students, a multistep synthesis of endogenous cannabinergic ligand 2-arachidonoylglycerol (2-AG) was tailored for use as a laboratory exercise. Over four weeks, students successfully produced 2-AG, purifying and characterizing products at each…

  16. Biocatalyzed Regioselective Synthesis in Undergraduate Organic Laboratories: Multistep Synthesis of 2-Arachidonoylglycerol

    Science.gov (United States)

    Johnston, Meghan R.; Makriyannis, Alexandros; Whitten, Kyle M.; Drew, Olivia C.; Best, Fiona A.

    2016-01-01

    In order to introduce the concepts of biocatalysis and its utility in synthesis to organic chemistry students, a multistep synthesis of endogenous cannabinergic ligand 2-arachidonoylglycerol (2-AG) was tailored for use as a laboratory exercise. Over four weeks, students successfully produced 2-AG, purifying and characterizing products at each…

  17. A Multistep Synthesis for an Advanced Undergraduate Organic Chemistry Laboratory

    Science.gov (United States)

    Chang Ji; Peters, Dennis G.

    2006-01-01

    Multistep syntheses are often important components of the undergraduate organic laboratory experience and a three-step synthesis of 5-(2-sulfhydrylethyl) salicylaldehyde was described. The experiment is useful as a special project for an advanced undergraduate organic chemistry laboratory course and offers opportunities for students to master a…

  18. New Reactions and Strategies in Highly Selective Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Organic synthetic chemistry is a core area of chemical The achievements in research.this field have greatly enhanced our life quality worldwide by providing an impressive range of useful man-made substances, materials and drugs.However, practical organic synthesis requires high selectivity, productivity, atom economy, cost efficiency, operational simplicity, environmental friendliness, and low energy consumption.It is of great importance to conduct intensive research in the development of new organic reactions, new methods and strategies, as well as the synthesis of bioactive important molecules.

  19. Camera-enabled techniques for organic synthesis

    Directory of Open Access Journals (Sweden)

    Steven V. Ley

    2013-05-01

    Full Text Available A great deal of time is spent within synthetic chemistry laboratories on non-value-adding activities such as sample preparation and work-up operations, and labour intensive activities such as extended periods of continued data collection. Using digital cameras connected to computer vision algorithms, camera-enabled apparatus can perform some of these processes in an automated fashion, allowing skilled chemists to spend their time more productively. In this review we describe recent advances in this field of chemical synthesis and discuss how they will lead to advanced synthesis laboratories of the future.

  20. Camera-enabled techniques for organic synthesis

    Science.gov (United States)

    Ingham, Richard J; O’Brien, Matthew; Browne, Duncan L

    2013-01-01

    Summary A great deal of time is spent within synthetic chemistry laboratories on non-value-adding activities such as sample preparation and work-up operations, and labour intensive activities such as extended periods of continued data collection. Using digital cameras connected to computer vision algorithms, camera-enabled apparatus can perform some of these processes in an automated fashion, allowing skilled chemists to spend their time more productively. In this review we describe recent advances in this field of chemical synthesis and discuss how they will lead to advanced synthesis laboratories of the future. PMID:23766820

  1. A different approach to enantioselective organic synthesis

    DEFF Research Database (Denmark)

    Lennartson, Anders; Olsson, Susanne; Sundberg, Jonas

    2009-01-01

    Voilà, optical activity: Both enantiomers of 1-chloroindene have been synthesized in high selectivity from solely achiral starting materials, and without using optically active catalysts (see scheme). These symmetry-breaking syntheses provide a proof-of-concept for a new approach to asymmetric sy...... synthesis. NCS=N-chlorosuccinimide....

  2. Novel synthesis of substituted benzylidenecyclohexanone by microwave assisted organic synthesis

    Science.gov (United States)

    Handayani, Sri; Budimarwanti, Cornelia; Haryadi, Winarto

    2017-03-01

    Benzylidenecyclohexanone derivatives are compounds with wide bioactivity. Usually, it was synthesized from cyclohexanones and benzaldehyde derivatives under base condition. This research presents a rapid and simple method to synthesis substituted benzylidenecyclohexanone. Cyclohexanone was mixed with 4-hydroxybenzaldehyde in acid condition under MAOS for 2 minutes, then it was left to cooled. Brownish purple powder in 81.47% yield was obtained. The product was identified by gas chromatography, then followed by structure elucidation by using NMR spectrophotometer. The novel compound is confirmed as 4-((E)-((1E,3'E)-3'-(4-hydroxybenzylidene)-2'-oxo-[1,1'-bi(cyclohexylidene)]-2,5-dienylidene-4-ylidene) me-thoxy)benzaldehyde.

  3. Direct photocatalysis of supported metal nanostructures for organic synthesis

    Science.gov (United States)

    Wu, Xiayan; Jaatinen, Esa; Sarina, Sarina; Zhu, Huai Yong

    2017-07-01

    Many organic synthesis systems use thermal catalysis to achieve higher product efficiency, and it is of interest to drive reactions by light irradiation at moderate reaction conditions. Other than semiconductors, recent reports have shown that metal nanostructures can be used as direct photocatalysts to drive chemical reactions. In this review, we summarize recent progress in direct photocatalysis in organic synthesis using plasmonic and non-plasmonic metal nanostructures. It starts with a comprehensive introduction to surface plasmons and the role of interband transitions in non-plasmonic metal nanostructures. The application of metal nanostructures in organic synthesis is systematically reviewed, followed by the reaction mechanisms; the role of light-excited energetic electrons, enhanced electromagnetic fields and the photothermal effect are detailed. The influence of light intensity and wavelength is discussed, as well as the critical parameters of photocatalyst design. Finally, the outlook and future opportunities of this new exciting field will be discussed.

  4. Flow "Fine" Synthesis: High Yielding and Selective Organic Synthesis by Flow Methods.

    Science.gov (United States)

    Kobayashi, Shū

    2016-02-18

    The concept of flow "fine" synthesis, that is, high yielding and selective organic synthesis by flow methods, is described. Some examples of flow "fine" synthesis of natural products and APIs are discussed. Flow methods have several advantages over batch methods in terms of environmental compatibility, efficiency, and safety. However, synthesis by flow methods is more difficult than synthesis by batch methods. Indeed, it has been considered that synthesis by flow methods can be applicable for the production of simple gasses but that it is difficult to apply to the synthesis of complex molecules such as natural products and APIs. Therefore, organic synthesis of such complex molecules has been conducted by batch methods. On the other hand, syntheses and reactions that attain high yields and high selectivities by flow methods are increasingly reported. Flow methods are leading candidates for the next generation of manufacturing methods that can mitigate environmental concerns toward sustainable society. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  5. Transitioning organic synthesis from organic solvents to water. What's your E Factor?

    Science.gov (United States)

    Lipshutz, Bruce H.; Ghorai, Subir

    2014-01-01

    Traditional organic chemistry, and organic synthesis in particular, relies heavily on organic solvents, as most reactions involve organic substrates and catalysts that tend to be water-insoluble. Unfortunately, organic solvents make up most of the organic waste created by the chemical enterprise, whether from academic, industrial, or governmental labs. One alternative to organic solvents follows the lead of Nature: water. To circumvent the solubility issues, newly engineered “designer” surfactants offer an opportunity to efficiently enable many of the commonly used transition metal-catalyzed and related reactions in organic synthesis to be run in water, and usually at ambient temperatures. This review focuses on recent progress in this area, where such amphiphiles spontaneously self-aggregate in water. The resulting micellar arrays serve as nanoreactors, obviating organic solvents as the reaction medium, while maximizing environmental benefits. PMID:25170307

  6. Transitioning organic synthesis from organic solvents to water. What's your E Factor?

    Science.gov (United States)

    Lipshutz, Bruce H; Ghorai, Subir

    2014-08-01

    Traditional organic chemistry, and organic synthesis in particular, relies heavily on organic solvents, as most reactions involve organic substrates and catalysts that tend to be water-insoluble. Unfortunately, organic solvents make up most of the organic waste created by the chemical enterprise, whether from academic, industrial, or governmental labs. One alternative to organic solvents follows the lead of Nature: water. To circumvent the solubility issues, newly engineered "designer" surfactants offer an opportunity to efficiently enable many of the commonly used transition metal-catalyzed and related reactions in organic synthesis to be run in water, and usually at ambient temperatures. This review focuses on recent progress in this area, where such amphiphiles spontaneously self-aggregate in water. The resulting micellar arrays serve as nanoreactors, obviating organic solvents as the reaction medium, while maximizing environmental benefits.

  7. Current Trends in High-Level Synthesis of Asynchronous Circuits

    DEFF Research Database (Denmark)

    Sparsø, Jens

    2009-01-01

    This paper is a survey paper presenting what the author sees as two major and promising trends in the current research in CAD-tools and design-methods for asynchronous circuits. One branch of research builds on top of existing asynchronous CAD-tools that perform syntax directed translation, e.......g. the Haste/TiDE tool from Handshake Solutions or the Balsa tool from the University of Manchester. The aims are to add highlevel synthesis capabilities to these tools and to extend the tools such that a wider range of (higher speed) micro-architectures can be generated. Another branch of research takes...... a conventional synchronous circuit as the starting point, and then adds some form of handshake-based flow-control. One approach keeps the global clock and implements discrete-time asynchronous operation. Another approach substitutes the clocked registers by asynchronous handshake-registers, thus creating truly...

  8. Short Review: Mitigation of Current Environmental Concerns from Methanol Synthesis

    Directory of Open Access Journals (Sweden)

    Andrew Young

    2013-06-01

    Full Text Available Methanol has become a widely used and globally distributed product. Methanol is very important due to the current depletion of fossil fuels. Industrially, methanol produced from the catalytic reaction of synthetic gas composed of hydrogen, carbon monoxide, and carbon dioxide. Methanol production has brought great attention due to carbon dioxide as the main source of greenhouse gas emissions. Combined of reducing CO2 emissions and supplying an alternative fuel source has created the idea of a carbon neutral cycle called “the methanol economy”. The best catalyst for the methanol economy would show a high CO2 conversion and high selectivity for methanol production. This paper investigates research focused on catalyst development for efficient methanol synthesis from hydrogenation of carbon dioxide through added various supports and additives such as silica, zirconium, and palladium. Catalysts that displayed the highest activity included a zirconia and silicon-titanium oxide promoted Cu/Zn/Al2O3 catalyst. Alternative method of catalyst preparation, include the oxalate-gel, solid-state reaction, co-precipitation and combustion method also investigated.  © 2013 BCREC UNDIP. All rights reservedReceived: 10th October 2012; Revised: 7th February 2012; Accepted: 10th February 2013[How to Cite: Young, A., Lesmana, D., Dai, D.J., Wu, H.S. (2013. Short Review: Mitigation of Current En-vironmental Concerns from Methanol Synthesis. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 1-13. (doi:10.9767/bcrec.8.1.4055.1-13][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4055.1-13] | View in  |

  9. Synthesis of unknowns for the interface partial current method

    Energy Technology Data Exchange (ETDEWEB)

    Jatuff, F.E. [Investigacion Aplicada SE (INVAP), San Carlos de Bariloche (Argentina)

    1996-01-01

    A synthesis technique is formulated as an alternative for the standard solution of the low order Interface Partial Current Equations, common in the within-group iteration schemes of Nodal Expansion and Response Matrix methods. This non-linear technique represents each node (mesh) in the iterations by its total partial in-current (j{sup in}), instead of the K partial in-currents at the nodal faces. At the same time, the distribution vector f is introduced, whose elements are the fractions of j{sup in} entering through each face, which are assumed known from the previous fission-source iteration. This simple scheme, with no other non-linear feedback required, gives a nodal formulation of the inner problem with one unknown per node and energy group, while the problem still retains the original number of unknowns. The method has been tested on the IAEA-2D and -3D, and a 2D pressurized water reactor (Biblis) benchmarks. The results show savings of about 15% to 25% of the CPU time, identical convergence despite the irregular nodal discretizations, and compatability to the rest of the iteration strategy. (author).

  10. Peptide synthesis in neat organic solvents with novel thermostable proteases.

    Science.gov (United States)

    Toplak, Ana; Nuijens, Timo; Quaedflieg, Peter J L M; Wu, Bian; Janssen, Dick B

    2015-06-01

    Biocatalytic peptide synthesis will benefit from enzymes that are active at low water levels in organic solvent compositions that allow good substrate and product solubility. To explore the use of proteases from thermophiles for peptide synthesis under such conditions, putative protease genes of the subtilase class were cloned from Thermus aquaticus and Deinococcus geothermalis and expressed in Escherichia coli. The purified enzymes were highly thermostable and catalyzed efficient peptide bond synthesis at 80°C and 60°C in neat acetonitrile with excellent conversion (>90%). The enzymes tolerated high levels of N,N-dimethylformamide (DMF) as a cosolvent (40-50% v/v), which improved substrate solubility and gave good conversion in 5+3 peptide condensation reactions. The results suggest that proteases from thermophiles can be used for peptide synthesis under harsh reaction conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Pathways for abiotic organic synthesis at submarine hydrothermal fields.

    Science.gov (United States)

    McDermott, Jill M; Seewald, Jeffrey S; German, Christopher R; Sylva, Sean P

    2015-06-23

    Arguments for an abiotic origin of low-molecular weight organic compounds in deep-sea hot springs are compelling owing to implications for the sustenance of deep biosphere microbial communities and their potential role in the origin of life. Theory predicts that warm H2-rich fluids, like those emanating from serpentinizing hydrothermal systems, create a favorable thermodynamic drive for the abiotic generation of organic compounds from inorganic precursors. Here, we constrain two distinct reaction pathways for abiotic organic synthesis in the natural environment at the Von Damm hydrothermal field and delineate spatially where inorganic carbon is converted into bioavailable reduced carbon. We reveal that carbon transformation reactions in a single system can progress over hours, days, and up to thousands of years. Previous studies have suggested that CH4 and higher hydrocarbons in ultramafic hydrothermal systems were dependent on H2 generation during active serpentinization. Rather, our results indicate that CH4 found in vent fluids is formed in H2-rich fluid inclusions, and higher n-alkanes may likely be derived from the same source. This finding implies that, in contrast with current paradigms, these compounds may form independently of actively circulating serpentinizing fluids in ultramafic-influenced systems. Conversely, widespread production of formate by ΣCO2 reduction at Von Damm occurs rapidly during shallow subsurface mixing of the same fluids, which may support anaerobic methanogenesis. Our finding of abiogenic formate in deep-sea hot springs has significant implications for microbial life strategies in the present-day deep biosphere as well as early life on Earth and beyond.

  12. Synthesis and Characterization of Novel Organic Semiconductors

    Institute of Scientific and Technical Information of China (English)

    Prashant; Sonar; Samarendra; P.Singh; Ananth; Dodabalapur; Alan; Sellinger

    2007-01-01

    1 Results Development of new organic semiconductors for use in low-cost,large-area applications is very important for growth of the organic electronic industry.Existing non-polymer based organic semiconductors can be roughly classified into linear,star-shaped,branched or lamellar molecules on the basis of their shape[1]. Generally hole (p-type) and electron (n-type) transporting semiconductors have been prepared from electron donating and accepting π-systems respectively[2]. These materials can be used ...

  13. Seed-Mediated Synthesis of Metal-Organic Frameworks.

    Science.gov (United States)

    Xu, Hai-Qun; Wang, Kecheng; Ding, Meili; Feng, Dawei; Jiang, Hai-Long; Zhou, Hong-Cai

    2016-04-27

    The synthesis of phase-pure metal-organic frameworks (MOFs) is of prime importance but remains a significant challenge because of the flexible and diversified coordination modes between metal ions and organic linkers. In this work, we report the synthesis of phase-pure MOFs via a facile seed-mediated approach. For several "accompanying" pairs of Zr-porphyrinic MOFs that are prone to yield mixtures, by fixing all reaction parameters except introducing seed crystals, MOFs in phase-pure forms have been obtained because the stage of MOF nucleation, which generates mixed nuclei, is bypassed. In addition, phase-pure MOF isomers with distinct pore structures have also been prepared through such an approach, revealing its versatility. To the best of our knowledge, this is an initial report on seed-assisted synthesis of phase-pure MOFs.

  14. Spiro[2.4]hepta-4,6-dienes: synthesis and application in organic synthesis

    Science.gov (United States)

    Menchikov, L. G.; Nefedov, O. M.

    2016-03-01

    This review integrates and describes systematically the data in the field of spiro[2.4]hepta-4,6-dienes published in the past 15 years. The changes in the development of studies that took place during this period are noted. The methods for the synthesis, the reactivity details and key chemical transformations of spiro[2.4]hepta-4,6-dienes are considered, with the emphasis on applications of these compounds in organic synthesis. The bibliography includes 207 references.

  15. A biocompatible alkene hydrogenation merges organic synthesis with microbial metabolism.

    Science.gov (United States)

    Sirasani, Gopal; Tong, Liuchuan; Balskus, Emily P

    2014-07-21

    Organic chemists and metabolic engineers use orthogonal technologies to construct essential small molecules such as pharmaceuticals and commodity chemicals. While chemists have leveraged the unique capabilities of biological catalysts for small-molecule production, metabolic engineers have not likewise integrated reactions from organic synthesis with the metabolism of living organisms. Reported herein is a method for alkene hydrogenation which utilizes a palladium catalyst and hydrogen gas generated directly by a living microorganism. This biocompatible transformation, which requires both catalyst and microbe, and can be used on a preparative scale, represents a new strategy for chemical synthesis that combines organic chemistry and metabolic engineering. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Organic nanomaterials: synthesis, characterization, and device applications

    CERN Document Server

    Torres, Tomas

    2013-01-01

    Recent developments in nanoscience and nanotechnology have given rise to a new generation of functional organic nanomaterials with controlled morphology and well-defined properties, which enable a broad range of useful applications. This book explores some of the most important of these organic nanomaterials, describing how they are synthesized and characterized. Moreover, the book explains how researchers have incorporated organic nanomaterials into devices for real-world applications.Featuring contributions from an international team of leading nanoscientists, Organic Nanomaterials is divided into five parts:Part One introduces the fundamentals of nanomaterials and self-assembled nanostructuresPart Two examines carbon nanostructures—from fullerenes to carbon nanotubes to graphene—reporting on properties, theoretical studies, and applicationsPart Three investigates key aspects of some inorganic materials, self-assembled monolayers,...

  17. Synthesis and Chemistry of Organic Geminal Di- and Triazides.

    Science.gov (United States)

    Häring, Andreas P; Kirsch, Stefan F

    2015-11-06

    This review recapitulates all available literature dealing with the synthesis and reactivity of geminal organic di- and triazides. These compound classes are, to a large extent, unexplored despite their promising chemical properties and their simple preparation. In addition, the chemistry of carbonyl diazide (2) and tetraazidomethane (105) is described in separate sections.

  18. ULTRASOUND-ASSISTED ORGANIC SYNTHESIS: ALCOHOL OXIDATION AND OLEFIN EPOXIDATION

    Science.gov (United States)

    Ultrasound-assisted Organic Synthesis: Alcohol Oxidation and Olefin EpoxidationUnnikrishnan R Pillai, Endalkachew Sahle-Demessie , Vasudevan Namboodiri, Quiming Zhao, Juluis EnriquezU.S. EPA , 26 W. Martin Luther King Dr. , Cincinnati, OH 45268 Phone: 513-569-773...

  19. Synthesis and Chemistry of Organic Geminal Di- and Triazides

    Directory of Open Access Journals (Sweden)

    Andreas P. Häring

    2015-11-01

    Full Text Available This review recapitulates all available literature dealing with the synthesis and reactivity of geminal organic di- and triazides. These compound classes are, to a large extent, unexplored despite their promising chemical properties and their simple preparation. In addition, the chemistry of carbonyl diazide (2 and tetraazidomethane (105 is described in separate sections.

  20. Synthesis of Bisphenol Z: An Organic Chemistry Experiment

    Science.gov (United States)

    Gregor, Richard W.

    2012-01-01

    A student achievable synthesis of bisphenol Z, 4,4'-(cyclohexane-1,1-diyl)diphenol, from the acid-catalyzed reaction of phenol with cyclohexanone is presented. The experiment exemplifies all the usual pedagogy for the standard topic of electrophilic aromatic substitution present in the undergraduate organic chemistry curriculum, while providing…

  1. Organic synthesis with olefin metathesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grubbs, R.H. [California Institute of Technology, Pasadena, CA (United States)

    1995-12-31

    Over the past nine years, early transition metal catalysts for the ring opening metathesis polymerization of cyclic olefins have been developed. These catalysts are simple organometallic complexes containing metal carbon multiple bonds that in most cases polymerize olefins by a living process. These catalysts have been used to prepare a family of near monodispersed and structurally homogeneous polymers. A series of group VII ROMP catalysts that allow a wide range of functionality to be incorporated into the polymer side chains have been prepared. The most important member of this family of complexes are the bisphosphinedihalo-ruthenium carbene complexes. These polymerization catalysts can also be used in the synthesis of fine chemicals by ring closing (RCM) and vinyl coupling reactions. The availability of the group VII catalysts allow metathesis to be carried out on highly functionalized substrates such as polypeptides and in unusual environments such as in aqueous emulsions.

  2. Reactivity of organic compounds in catalytic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Minachev, Kh.M.; Bragin, O.V.

    1978-01-01

    A comprehensive review of 1976 Soviet research on catalysis delivered to the 1977 annual session of the USSR Academy of Science Council on Catalysis (Baku 6/16-20/77) covers hydrocarbon reactions, including hydrogenation and hydrogenolysis, dehydrogenation, olefin dimerization and disproportionation, and cyclization and dehydrocyclization (e.g., piperylene cyclization and ethylene cyclotrimerization); catalytic and physicochemical properties of zeolites, including cracking, dehydrogenation, and hydroisomerization catalytic syntheses and conversion of heterocyclic and functional hydrocarbon derivatives, including partial and total oxidation (e.g., of o-xylene to phthalic anhydride); syntheses of thiophenes from alkanes and hydrogen sulfide over certain dehydrogenation catalysts; catalytic syntheses involving carbon oxides ( e.g., the development of a new heterogeneous catalyst for hydroformylation of olefins), and of Co-MgO zeolitic catalysts for synthesis of aliphatic hydrocarbons from carbon dioxide and hydrogen, and fabrication of high-viscosity lubricating oils over bifunctional aluminosilicate catalysts.

  3. CARBOXYLESTERASES IN ENANTIOSELECTIVE SYNTHESIS OF ORGANIC COMPOUNDS

    Directory of Open Access Journals (Sweden)

    E. A. Shesterenko

    2013-02-01

    Full Text Available The classification, structure, and mechanism of catalytic action of carboxylesterase of different origin are presented in the review. The prospects of carboxylesterases application for metabolism and both several drugs and prodrugs activation investigation in vitro are shown. The enzyme usage as biocatalyst of stereoselective hydrolysis and synthesis of a wide range of acyclic, carbocyclic and heterocyclic compounds — esters are also urgent. It was established that enantiomers obtainable with the help of carboxylesterase are characterized by high chemical yields and optical purity; immobilization on different supports stabilizes the enzyme and allows the repeated usage of obtained biocatalysts. The own studies conducted and the enzymatic hydrolysis features of news 3-acylhydroxy-1,4-benzodiasepin-2-ones — potential anxiolytic and hypnotic means, with a help of pig liver microsomal fraction carboxylesterase have been established. For the first time the enantioselective hydrolysis of 3-acetoxy-7-bromo-1-methyl-5-phenyl-1,2-dihydro-3H-1,4-benzdiazepine-2-one was accomplished using free and immobilized in phyllophorine and alginate, stabilized by Ca2+ microsomal fraction. The S-enantiomer of substrate was isolated, which suggests the increased specificity of pig liver microsomal fraction carboxylesterase to its R-enantiomer.

  4. Organic Synthesis in Simulated Interstellar Ice Analogs

    Science.gov (United States)

    Dworkin, Jason P.; Bernstein, Max P.; Sandford, Scott A.; Allamandola, Louis J.; Deamer, David W.; Elsila, Jamie; Zare, Richard N.

    2001-01-01

    Comets and carbonaceous micrometeorites may have been significant sources of organic compounds on the early Earth. Ices on grains in interstellar dense molecular clouds contain a variety of simple molecules as well as aromatic molecules of various sizes. While in these clouds the icy grains are processed by ultraviolet light and cosmic radiation which produces more complex organic molecules. We have run laboratory simulations to identify the types of molecules which could have been generated photolytically in pre-cometary ices. Experiments were conducted by forming various realistic interstellar mixed-molecular ices with and without polycyclic aromatic hydrocarbons (PAHs) at approx. 10 K under high vacuum irradiated with UV light from a hydrogen plasma lamp. The residue that remained after warming to room temperature was analyzed by HPLC, and by laser desorption mass spectrometry. The residue contains several classes of compounds which may be of prebiotic significance.

  5. Synthesis and Characteristics of Organic Bentonite Gel

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The bentonite was modified using Ca-bentonite as a matrix and octadecyl/ hexadecyl ammoniumsized by dispersing it into the dimethyl benzene-methyl alcohol system fully.The optimum process conditions for organic modification were that the coating agent dosage is 22g/L, reaction time is 90 minutes and the pH value of pulp is 10.X-ray diffraction ( XRD ) analysis indicates that the d (001) value of the modified bentonite is 20.532A.The influence of gel temperature on its viscosity characteristic was studied.By analyzing the transmssion electron microscopy (TEM) images and observing the dispersed gel, the nanometer effect of the organic gel was discussed.

  6. Organic Synthesis in Simulated Interstellar Ice Analogs

    Science.gov (United States)

    Dworkin, Jason P.; Bernstein, Max P.; Sandford, Scott A.; Allamandola, Louis J.; Deamer, David W.; Elsila, Jamie; Zare, Richard N.

    2001-01-01

    Comets and carbonaceous micrometeorites may have been significant sources of organic compounds on the early Earth. Ices on grains in interstellar dense molecular clouds contain a variety of simple molecules as well as aromatic molecules of various sizes. While in these clouds the icy grains are processed by ultraviolet light and cosmic radiation which produces more complex organic molecules. We have run laboratory simulations to identify the types of molecules which could have been generated photolytically in pre-cometary ices. Experiments were conducted by forming various realistic interstellar mixed-molecular ices with and without polycyclic aromatic hydrocarbons (PAHs) at approx. 10 K under high vacuum irradiated with UV light from a hydrogen plasma lamp. The residue that remained after warming to room temperature was analyzed by HPLC, and by laser desorption mass spectrometry. The residue contains several classes of compounds which may be of prebiotic significance.

  7. Nitrogen isotopic fractionation during abiotic synthesis of organic solid particles

    CERN Document Server

    Kuga, Maïa; Marty, Bernard; Marrocchi, Yves; Bernard, Sylvain; Rigaudier, Thomas; Fleury, Benjamin; Tissandier, Laurent

    2014-01-01

    The formation of organic compounds is generally assumed to result from abiotic processes in the Solar System, with the exception of biogenic organics on Earth. Nitrogen-bearing organics are of particular interest, notably for prebiotic perspectives but also for overall comprehension of organic formation in the young solar system and in planetary atmospheres. We have investigated abiotic synthesis of organics upon plasma discharge, with special attention to N isotope fractionation. Organic aerosols were synthesized from N2-CH4 and N2-CO gaseous mixtures using low-pressure plasma discharge experiments, aimed at simulating chemistry occurring in Titan s atmosphere and in the protosolar nebula, respectively. Nitrogen is efficiently incorporated into the synthesized solids, independently of the oxidation degree, of the N2 content of the starting gas mixture, and of the nitrogen speciation in the aerosols. The aerosols are depleted in 15N by 15-25 permil relative to the initial N2 gas, whatever the experimental set...

  8. 15 CFR 715.1 - Annual declaration requirements for production by synthesis of unscheduled discrete organic...

    Science.gov (United States)

    2010-01-01

    ... production by synthesis of unscheduled discrete organic chemicals (UDOCs). 715.1 Section 715.1 Commerce and... DISCRETE ORGANIC CHEMICALS (UDOCs) § 715.1 Annual declaration requirements for production by synthesis of unscheduled discrete organic chemicals (UDOCs). (a) Declaration of production by synthesis of UDOCs for...

  9. Current Situations and Countermeasures of Organic Tobacco Development

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Current situations of organic tobacco development at both home and abroad,indicating that organic tobacco is one of the innovation directions for sustainable,healthy,environmental protection and low carbon development of modern tobacco industry.On the basis of foreign cultivation technical system for organic agriculture,the cultivation technical system for organic tobacco is summed up as follows:first,keep the diversity and continuity of space and time;second,ensure closeness of nutrient cycle;third,improve self-regulatory system and protection ability of crops.Then,the development trend of organic tobacco is analyzed and corresponding measures are put forward:establish production base and assessment system for organic tobacco;establish technical system for production of organic tobacco;establish and perfect evaluation system for management,production and supervision of organic tobacco;strengthen popularization of production and concept of organic tobacco;improve management of organic tobacco purchase,industry commerce handover,and redrying.

  10. Earthworm Is a Versatile and Sustainable Biocatalyst for Organic Synthesis

    Science.gov (United States)

    Guan, Zhi; Chen, Yan-Li; Yuan, Yi; Song, Jian; Yang, Da-Cheng; Xue, Yang; He, Yan-Hong

    2014-01-01

    A crude extract of earthworms was used as an eco-friendly, environmentally benign, and easily accessible biocatalyst for various organic synthesis including the asymmetric direct aldol and Mannich reactions, Henry and Biginelli reactions, direct three-component aza-Diels-Alder reactions for the synthesis of isoquinuclidines, and domino reactions for the synthesis of coumarins. Most of these reactions have never before seen in nature, and moderate to good enantioselectivities in aldol and Mannich reactions were obtained with this earthworm catalyst. The products can be obtained in preparatively useful yields, and the procedure does not require any additional cofactors or special equipment. This work provides an example of a practical way to use sustainable catalysts from nature. PMID:25148527

  11. SYNTHESIS OF A NEW ORGANIC AEROGEL

    Institute of Scientific and Technical Information of China (English)

    WU Zhichao; ZHANG Zhicheng; ZHANG Manwei

    1996-01-01

    A new organic aerogel made from (N-hydroxymethyl)-acrylamide (NA) and resorcinol is reported. The acidic solution of NA and resorcinol was irradiated by γ-rays with 1200-1800 Gy dose, then was heated to 60℃ for at least 16hr to form transparent sol-gel.The translucent aerogel can be obtained from the sol-gel with CO2 as supercritical fluid.Synthetic conditions (e.g. acidity of the solution, ratio of NA to resorcinol) are discussed.

  12. Halogen Bonding in Organic Synthesis and Organocatalysis.

    Science.gov (United States)

    Bulfield, David; Huber, Stefan M

    2016-10-01

    Halogen bonding is a noncovalent interaction similar to hydrogen bonding, which is based on electrophilic halogen substituents. Hydrogen-bonding-based organocatalysis is a well-established strategy which has found numerous applications in recent years. In light of this, halogen bonding has recently been introduced as a key interaction for the design of activators or organocatalysts that is complementary to hydrogen bonding. This Concept features a discussion on the history and electronic origin of halogen bonding, summarizes all relevant examples of its application in organocatalysis, and provides an overview on the use of cationic or polyfluorinated halogen-bond donors in halide abstraction reactions or in the activation of neutral organic substrates.

  13. The energetics of organic synthesis inside and outside the cell

    Science.gov (United States)

    Amend, Jan P.; LaRowe, Douglas E.; McCollom, Thomas M.; Shock, Everett L.

    2013-01-01

    Thermodynamic modelling of organic synthesis has largely been focused on deep-sea hydrothermal systems. When seawater mixes with hydrothermal fluids, redox gradients are established that serve as potential energy sources for the formation of organic compounds and biomolecules from inorganic starting materials. This energetic drive, which varies substantially depending on the type of host rock, is present and available both for abiotic (outside the cell) and biotic (inside the cell) processes. Here, we review and interpret a library of theoretical studies that target organic synthesis energetics. The biogeochemical scenarios evaluated include those in present-day hydrothermal systems and in putative early Earth environments. It is consistently and repeatedly shown in these studies that the formation of relatively simple organic compounds and biomolecules can be energy-yielding (exergonic) at conditions that occur in hydrothermal systems. Expanding on our ability to calculate biomass synthesis energetics, we also present here a new approach for estimating the energetics of polymerization reactions, specifically those associated with polypeptide formation from the requisite amino acids. PMID:23754809

  14. The energetics of organic synthesis inside and outside the cell.

    Science.gov (United States)

    Amend, Jan P; LaRowe, Douglas E; McCollom, Thomas M; Shock, Everett L

    2013-07-19

    Thermodynamic modelling of organic synthesis has largely been focused on deep-sea hydrothermal systems. When seawater mixes with hydrothermal fluids, redox gradients are established that serve as potential energy sources for the formation of organic compounds and biomolecules from inorganic starting materials. This energetic drive, which varies substantially depending on the type of host rock, is present and available both for abiotic (outside the cell) and biotic (inside the cell) processes. Here, we review and interpret a library of theoretical studies that target organic synthesis energetics. The biogeochemical scenarios evaluated include those in present-day hydrothermal systems and in putative early Earth environments. It is consistently and repeatedly shown in these studies that the formation of relatively simple organic compounds and biomolecules can be energy-yielding (exergonic) at conditions that occur in hydrothermal systems. Expanding on our ability to calculate biomass synthesis energetics, we also present here a new approach for estimating the energetics of polymerization reactions, specifically those associated with polypeptide formation from the requisite amino acids.

  15. Computer-assisted design of organic synthesis

    Science.gov (United States)

    Kaminaka, H.

    1986-01-01

    The computer programs to design synthetic pathways of organic compounds have been utilized throughout the world since the first system was reported by Corey in 1969, and the LHASA was reported in1972 to become the predominant system. Many programs have been reported mainly in the United States and Europe, and groups of corporations, especially chemical companies, have been trying to improve programs and increase the efficiency of research. In Japan, unfortunately, no concrete movement in this area has been seen. Of course, it goes without saying that these kinds of programs are effective for efficient research, but the remarkable aspect is that these can present unexpected data to the researchers to stimulate them to develop new ideas.

  16. Asymmetric organic/metal(oxide) hybrid nanoparticles: synthesis and applications.

    Science.gov (United States)

    He, Jie; Liu, Yijing; Hood, Taylor C; Zhang, Peng; Gong, Jinlong; Nie, Zhihong

    2013-06-21

    Asymmetric particles (APs) with broken centrosymmetry are of great interest, due to the asymmetric surface properties and diverse functionalities. In particular, organic/metal(oxide) APs naturally combine the significantly different and complementary properties of organic and inorganic species, leading to their unique applications in various fields. In this review article, we highlighted recent advances in the synthesis and applications of organic/metal(oxide) APs. This type of APs is grounded on chemical or physical interactions between metal(oxide) NPs and organic small molecular or polymeric ligands. The synthetic methodologies were summarized in three categories, including the selective surface modifications, phase separation of mixed ligands on the surface of metal(oxide) NPs, and direct synthesis of APs. We further discussed the unique applications of organic/metal(oxide) APs in self-assembly, sensors, catalysis, and biomedicine, as a result of the distinctions between asymmetrically distributed organic and inorganic components. Finally, challenges and future directions are discussed in an outlook section.

  17. Towards waste free organic synthesis using nanostructured hybrid silicas

    Science.gov (United States)

    Ciriminna, Rosaria; Ilharco, Laura M.; Pandarus, Valerica; Fidalgo, Alexandra; Béland, François; Pagliaro, Mario

    2014-05-01

    As catalysis and organic synthesis come together again, the need for stable, selective and truly heterogeneous solid catalysts for clean and efficient synthetic organic chemistry has increased. Hybrid silica glasses obtained by the sol-gel nanochemistry approach can be successfully used for the waste-free synthesis of valued chemicals in various applications. This success derives from the deliberate chemical design of hybrid nanostructures capable of immobilizing and stabilizing organocatalytic species and unstable metal nanoparticles. The highly selective activity along with a broad scope and ease of application of these mesoporous materials to high-throughput reactions opens the route to faster, cleaner and more convenient processes for both small and large scale manufacturing of useful molecules.

  18. Gold-Organic Hybrids: On-Surface Synthesis and Perspectives.

    Science.gov (United States)

    Zhang, Haiming; Chi, Lifeng

    2016-12-01

    Gold-organic hybrids can be prepared on gold substrates by on-surface dehalogenation of molecular precursors with multiple halogen substituents. Various contact geometries of covalent arylAu bonds are achieved by changing the halogen substituents in the bay or peri regions. Scanning tunneling microscopy/spectroscopy (STM/STS) investigations allow a better understanding of the structure/property relationships in various gold-aryl contacts. Recent progress on the synthesis, large-scale alignment, and STS measurement of gold-organic hybrids is described, ending with an emphasis on potential future applications, e.g., as precursors (intermediates) for the synthesis of graphene nanoribbons (GNRs) on insulating surfaces, and as a model system to investigate the role of covalent arylAu bonds in electron transport through gold-GNR contacts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Functionalized Carbosilane Dendritic Species as Soluble Support in Organic Synthesis

    NARCIS (Netherlands)

    Koten, G. van; Hovestad, N.J.; Ford, A.; Jastrzebski, J.T.B.H.

    2000-01-01

    A new methodology, which is compatible with the use of reactive organometallic reagents, has been developed for the use of carbosilane dendrimers as soluble supports in organic synthesis. Hydroxy-functionalized dendritic carbosilanes Si[CH2CH2CH2SiMe2(C6H4CH(R)OH)]4 (G0-OH, R = H or (S)-Me) and Si[C

  20. Ionic Liquids as Tool to Improve Enzymatic Organic Synthesis.

    Science.gov (United States)

    Itoh, Toshiyuki

    2017-08-09

    Ionic liquids (ILs) have now been acknowledged as reaction media for biotransformations. The first three examples were reported in this field in 2000, and since then, numerous applications have been reported for biocatalytic reactions using ILs. Two topics using ILs for enzymatic reactions have been reviewed from the standpoint of biocatalyst mediating organic synthesis; the first is "Biocatalysis in Ionic Liquids" which includes various types of biocatalytic reactions in ILs (section 2): (1) recent examples of lipase-mediated reactions using ILs as reaction media for biodiesel oil production and for sugar ester production, (2) oxidase-catalyzed reactions in ILs, (3) laccase-catalyzed reactions, (4) peroxidase-catalyzed reactions, (4) cytochrome-mediated reactions, (5) microbe-mediated hydrations, (6) protease-catalyzed reactions, (8) whole cell mediated asymmetric reduction of ketones, (10) acylase-catalyzed reactions, (11) glycosylation or cellulase-mediated hydrolysis of polysaccharides, (12) hydroxynitrile lyase-catalyzed reaction, (13) fluorinase or haloalkane dehydrogenase-catalyzed reaction, (14) luciferase-catalyzed reactions, and (15) biocatalytic promiscuity of enzymatic reactions for organic synthesis using ILs. The second is "Enzymes Activated by Ionic Liquids for Organic Synthesis", particularly describing the finding story of activation of lipases by the coating with a PEG-substituted IL (section 3). The author's opinion toward "Future Perspectives of Using ILs for Enzymatic Reactions" has also been discussed in section 4.

  1. Synthesis of Organic Compounds over Selected Types of Catalysts

    Directory of Open Access Journals (Sweden)

    Omar Mohamed Saad Ismail

    2011-05-01

    Full Text Available This study provides an overview for the utilization of different catalytic material in the synthesis of organic compounds for important reactions such as heck reaction, aldol reaction, Diels- Alder and other reactions. Comparisons between multiple catalysts for the same reaction and justifications for developing new catalyzed materials are discussed. The following topics are introduced in this work; (1 solid base catalysts, (2 clay catalysts, (3 palladium catalysts, and (4 catalysts to produce organic compound from CO2. The features of these catalysts a long with the conjugated reactions and their selectivity are explained in details, also, some alternatives for toxic or polluting catalysts used in industry are suggested.

  2. Microbial synthesis of gold nanoparticles: current status and future prospects.

    Science.gov (United States)

    Shedbalkar, Utkarsha; Singh, Richa; Wadhwani, Sweety; Gaidhani, Sharvari; Chopade, B A

    2014-07-01

    Gold nanoparticles have been employed in biomedicine since the last decade because of their unique optical, electrical and photothermal properties. Present review discusses the microbial synthesis, properties and biomedical applications of gold nanoparticles. Different microbial synthesis strategies used so far for obtaining better yield and stability have been described. It also includes different methods used for the characterization and analysis of gold nanoparticles, viz. UV-visible spectroscopy, Fourier transform infrared spectroscopy, X ray diffraction spectroscopy, scanning electron microscopy, ransmission electron microscopy, atomic force microscopy, electron dispersive X ray, X ray photoelectron spectroscopy and cyclic voltametry. The different mechanisms involved in microbial synthesis of gold nanoparticles have been discussed. The information related to applications of microbially synthesized gold nanoparticles and patents on microbial synthesis of gold nanoparticles has been summarized.

  3. Síntese orgânica limpa Clean organic synthesis

    Directory of Open Access Journals (Sweden)

    Antonio Manzolillo Sanseverino

    2000-02-01

    Full Text Available An introduction to the fundamental concepts and main aspects of organic clean synthesis is given, and relevant industrial examples which have implemented the philosophy of cleaner synthesis are also presented. Recent trends in organic synthesis which are environmentally friendly are also discussed.

  4. Síntese orgânica limpa Clean organic synthesis

    OpenAIRE

    Antonio Manzolillo Sanseverino

    2000-01-01

    An introduction to the fundamental concepts and main aspects of organic clean synthesis is given, and relevant industrial examples which have implemented the philosophy of cleaner synthesis are also presented. Recent trends in organic synthesis which are environmentally friendly are also discussed.

  5. Resilience: a transversal occupational skill for current organizations

    Directory of Open Access Journals (Sweden)

    María del Rosario Piñeros-Botero

    2013-12-01

    some studies related to deal the resilience from the transverse occupational skills and the MCclelland approach TO KNOW TO BE AND TO KNOW TO DO, as a structural base for behavior and performance of people. Finally we propose an organizational resilience model that presents its functionality and categorization of profiles in occupational and individual skills that allow encouraging cultural and organizational behavior by means of optimization strategies to current organizations. The term organizations, is going to be used to talk about an industry or enterprise of any kind or financial sector.

  6. Engineering and Applications of fungal laccases for organic synthesis

    Directory of Open Access Journals (Sweden)

    Ballesteros Antonio

    2008-11-01

    Full Text Available Abstract Laccases are multi-copper containing oxidases (EC 1.10.3.2, widely distributed in fungi, higher plants and bacteria. Laccase catalyses the oxidation of phenols, polyphenols and anilines by one-electron abstraction, with the concomitant reduction of oxygen to water in a four-electron transfer process. In the presence of small redox mediators, laccase offers a broader repertory of oxidations including non-phenolic substrates. Hence, fungal laccases are considered as ideal green catalysts of great biotechnological impact due to their few requirements (they only require air, and they produce water as the only by-product and their broad substrate specificity, including direct bioelectrocatalysis. Thus, laccases and/or laccase-mediator systems find potential applications in bioremediation, paper pulp bleaching, finishing of textiles, bio-fuel cells and more. Significantly, laccases can be used in organic synthesis, as they can perform exquisite transformations ranging from the oxidation of functional groups to the heteromolecular coupling for production of new antibiotics derivatives, or the catalysis of key steps in the synthesis of complex natural products. In this review, the application of fungal laccases and their engineering by rational design and directed evolution for organic synthesis purposes are discussed.

  7. Anomalous current transients in organic field-effect transistors

    Science.gov (United States)

    Sharma, A.; Mathijssen, S. G. J.; Cramer, T.; Kemerink, M.; de Leeuw, D. M.; Bobbert, P. A.

    2010-03-01

    Here we study the origin of the gate bias-stress effect in organic p-type transistors. Based on water-mediated exchange between holes in the semiconductor and protons in the gate dielectric, we predict anomalous current transients for a non-constant gate bias, while ensuring accumulation. When applying a strongly negative gate bias followed by a less negative bias a back-transfer of protons to holes and an increase of the current is expected. We verify this counterintuitive behavior experimentally and can quantitatively model the transients with the same parameters as used to describe the threshold voltage shift.

  8. Organic electron donors as powerful single-electron reducing agents in organic synthesis.

    Science.gov (United States)

    Broggi, Julie; Terme, Thierry; Vanelle, Patrice

    2014-01-07

    One-electron reduction is commonly used in organic chemistry for the formation of radicals by the stepwise transfer of one or two electrons from a donor to an organic substrate. Besides metallic reagents, single-electron reducers based on neutral organic molecules have emerged as an attractive novel source of reducing electrons. The past 20 years have seen the blossoming of a particular class of organic reducing agents, the electron-rich olefins, and their application in organic synthesis. This Review gives an overview of the different types of organic donors and their specific characteristics in organic transformations. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Electrical energy sources for organic synthesis on the early earth

    Science.gov (United States)

    Chyba, Christopher; Sagan, Carl

    1991-01-01

    In 1959, Miller and Urey (Science 130, 245) published their classic compilation of energy sources for indigenous prebiotic organic synthesis on the early Earth. Much contemporary origins of life research continues to employ their original estimates for terrestrial energy dissipation by lightning and coronal discharges, 2 × 1019 J yr-1 and 6 × 1019 J yr-1, respectively. However, more recent work in terrestrial lightning and point discharge research suggests that these values are overestimates by factors of about 20 and 120, respectively. Calculated concentrations of amino acids (or other prebiotic organic products) in the early terrestrial oceans due to electrical discharge sources may therefore have been equally overestimated. A review of efficiencies for those experiments that provide good analogues to naturally-occurring lightning and coronal discharges suggests that lightning energy yields for organic synthesis (nmole J-1) are about one order of magnitude higher than those for coronal discharge. Therefore organic production by lightning may be expected to have dominated that due to coronae on early Earth. Limited data available for production of nitric oxide in clouds suggests that coronal emission within clouds, a source of energy heretofore too uncertain to be included in the total coronal energy inventory, is insufficient to change this conclusion. Our recommended valves for lightning and coronal discharge dissipation rates on the early Earth are, respectively, 1 × 1018 J yr-1 and 5 × 1017 J yr-1.

  10. [Organ cryopreservation: current status of research carried out in Grenoble].

    Science.gov (United States)

    Descotes, J L; Payen, E; Rambeaud, J J; Peuridieu, J F; Baudot, A; Odin, J; Mazuer, J; Boutron, P; Delon-Martin, C; Dupeyre, R

    1995-12-01

    After discussing the problem of organ cryopreservation and reviewing the current data available on this subject, the Grenoble project is presented. Physical and biological studies have been combined with experimentation of autologous renal transplantation in rabbits to assess the functional value of the retransplanted organ after treatment and cooling. Renal resistances are measured during perfusion of the kidney with the cryoprotective solution. In order to verify the homogeneity of the cryoprotector concentration in the organ, on NMR spectral imaging test has been developed. A new rapid imaging method now allows real time monitoring of concentration variations during perfusion. In addition to concentration and homogeneity, analysis of local spectra also provides information about the local temperature de the kidney.

  11. α-Imino Esters in Organic Synthesis: Recent Advances.

    Science.gov (United States)

    Eftekhari-Sis, Bagher; Zirak, Maryam

    2017-06-28

    α-Imino esters are useful precursors for the synthesis of a variety of types of natural and unnatural α-amino acid derivatives, with a wide range of biological activities. Due to the adjacent ester group, α-imino esters are more reactive relative to other types of imines and undergo different kinds of reactions, including organometallics addition, metal catalyzed vinylation and alkynylation, aza-Henry, aza-Morita-Baylis-Hillman, imino-ene, Mannich-type, and cycloaddition reactions, as well as hydrogenation and reduction. This review discusses the mechanism, scope, and applications of the reactions of α-imino esters and related compounds in organic synthesis, covering the literature from the last 12 years.

  12. Applications of the Wittig-Still Rearrangement in Organic Synthesis.

    Science.gov (United States)

    Rycek, Lukas; Hudlicky, Tomas

    2017-05-22

    This Review traces the discovery of the Wittig-Still rearrangement and its applications in organic synthesis. Its relationship to Wittig rearrangements is discussed along with detailed analysis of E/Z- and diastereoselectivity. Modifications of the products arising from the Wittig-Still rearrangement are reviewed in the context of increased complexity in intermediates potentially useful in target-oriented synthesis. Early applications of the Wittig-Still rearrangement to modifications of steroids are reviewed as are applications to various terpene and alkaloid natural product targets and miscellaneous compounds. To the best of our knowledge, the literature is covered through December 2016. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Biomineralization-inspired synthesis of functional organic/inorganic hybrid materials: organic molecular control of self-organization of hybrids.

    Science.gov (United States)

    Arakaki, Atsushi; Shimizu, Katsuhiko; Oda, Mayumi; Sakamoto, Takeshi; Nishimura, Tatsuya; Kato, Takashi

    2015-01-28

    Organisms produce various organic/inorganic hybrid materials, which are called biominerals. They form through the self-organization of organic molecules and inorganic elements under ambient conditions. Biominerals often have highly organized and hierarchical structures from nanometer to macroscopic length scales, resulting in their remarkable physical and chemical properties that cannot be obtained by simple accumulation of their organic and inorganic constituents. These observations motivate us to create novel functional materials exhibiting properties superior to conventional materials--both synthetic and natural. Herein, we introduce recent progress in understanding biomineralization processes at the molecular level and the development of organic/inorganic hybrid materials by these processes. We specifically outline fundamental molecular studies on silica, iron oxide, and calcium carbonate biomineralization and describe material synthesis based on these mechanisms. These approaches allow us to design a variety of advanced hybrid materials with desired morphologies, sizes, compositions, and structures through environmentally friendly synthetic routes using functions of organic molecules.

  14. Biodiversity in a changing climate: a synthesis of current and projected trends in the US

    Science.gov (United States)

    Staudinger, Michelle D.; Carter, Shawn L.; Cross, Molly S.; Dubois, Natalie S.; Duffy, J. Emmett; Enquist, Carolyn; Griffis, Roger; Hellmann, Jessica J.; Lawler, Joshua J.; O’Leary, John; Morrison, Scott A.; Sneddon, Lesley; Stein, Bruce A.; Thompson, Laura M.; Turner, Woody

    2013-01-01

    This paper provides a synthesis of the recent literature describing how global biodiversity is being affected by climate change and is projected to respond in the future. Current studies reinforce earlier findings of major climate-change-related impacts on biological systems and document new, more subtle after-effects. For example, many species are shifting their distributions and phenologies at faster rates than were recorded just a few years ago; however, responses are not uniform across species. Shifts have been idiosyncratic and in some cases counterintuitive, promoting new community compositions and altering biotic interactions. Although genetic diversity enhances species' potential to respond to variable conditions, climate change may outpace intrinsic adaptive capacities and increase the relative vulnerabilities of many organisms. Developing effective adaptation strategies for biodiversity conservation will not only require flexible decision-making and management approaches that account for uncertainties in climate projections and ecological responses but will also necessitate coordinated monitoring efforts.

  15. Photocatalytic Anion Oxidation and Applications in Organic Synthesis.

    Science.gov (United States)

    Hering, Thea; Meyer, Andreas Uwe; König, Burkhard

    2016-08-19

    Ions and radicals of the same kind differ by one electron only. The oxidation of many stable inorganic anions yields their corresponding highly reactive radicals, and visible light excitable photocatalysts can provide the required oxidation potential for this transformation. Air oxygen serves as the terminal oxidant, or cheap sacrificial oxidants are used, providing a very practical approach for generating reactive inorganic radicals for organic synthesis. We discuss in this perspective several recently reported examples: Nitrate radicals are obtained by one-electron photooxidation of nitrate anions and are very reactive toward organic molecules. The photooxidation of sulfinate salts yields the much more stable sulfone radicals, which smoothly add to double bonds. A two-electron oxidation of chloride anions to electrophilic chlorine species reacting with arenes in aromatic substitutions extends the method beyond radical reactions. The chloride anion oxidation proceeds via photocatalytically generated peracidic acid as the oxidation reagent. Although the number of reported examples of photocatalytically generated inorganic radical intermediates for organic synthesis is still small, future extension of the concept to other inorganic ions as radical precursors is a clear perspective.

  16. Design of new carbonaceous catalysts and photocatalysts for organic synthesis

    Science.gov (United States)

    Rajpara, Vikul B.

    Pristine and modified carbonaceous materials are introduced as convenient catalysts for oxidation, photooxidation and alkylation of aromatic hydrocarbons. Oxidation reactions have been carried out by air and effect of cyclohexene and light has also been investigated. Availability of the reagents, light source (ambient light), minimum chemical waste, low toxicity and reusability of the catalysts make developed processes green alternatives of traditional methods for the synthesis of industrially important organic compounds. Catalytic performance and selectivity of carbonaceous materials have been linked to their morphology (graphite, carbon black, multi-walled, single-walled carbon nanotubes, fullerene C60) and modification oxidation, conjugation with nanoparticles). The reported study is the first step toward targeted design of new carbonaceous catalysts for organic synthesis. Graphite is known for its electric conductivity and quantum dots are known for transfer of energy to attached molecules and their conjugation may provide a unique hybrid material for photocatalysis of organic reactions. Quantum dots with known number of functional group hold an especially great promise in the field of catalysis. However, controlling the number of functionalities on the surface of quantum dots is very challenging. We demonstrated monofuncationalization of gold nanoparticles using trityl (solid) support. Similar approach was used for the monofunctionalization of quantum dots and our preliminary data showed that quantum dots can be attached and detached from the solid support under mild conditions.

  17. A Retrosynthesis Approach for Biocatalysis in Organic Synthesis.

    Science.gov (United States)

    de Souza, Rodrigo O M A; Miranda, Leandro S M; Bornscheuer, Uwe T

    2017-05-17

    For the planning of an organic synthesis route, the disconnection approach guided by retrosynthetic analysis of possible intermediates and the chemical reactions involved, back to ready available starting materials, is well established. In contrast, such concepts just get developed for biocatalytic routes. In this Review we highlight functional group interconversions catalyzed by enzymes. The article is organized rather by chemical bonds formed-exemplified for C-N, C-O- and C-C-bonds-and not by enzyme classes, covering a broad range of reactions to incorporate the desired functionality in the target molecule. Furthermore, the successful use of biocatalysts, also in combination with chemical steps, is exemplified for the synthesis of various drugs and advanced pharmaceutical intermediates such as Crispine A, Sitagliptin and Atorvastatin. This Review also provides some basic guidelines to choose the most appropriate enzyme for a targeted reaction keeping in mind aspects like commercial availability, cofactor-requirement, solvent tolerance, use of isolated enzymes or whole cell recombinant microorganisms aiming to assist organic chemists in the use of enzymes for synthetic applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. History of Martian volatiles - Implications for organic synthesis.

    Science.gov (United States)

    Fanale, F. P.

    1971-01-01

    A theoretical reconstruction of the history of Martian volatiles indicates that Mars probably possessed a substantial reducing atmosphere at the outset of its history, and that its present tenuous and more oxidized atmosphere is the result of extensive chemical evolution. As a consequence, it is probable that Martian atmospheric chemical conditions, now hostile with respect to abiotic organic synthesis in the gas phase, were initially favorable. Evidence indicating the chronology and degradational history of Martian surface features, surface mineralogy, bulk volatile content, internal mass distribution, and thermal history suggests that Mars catastrophically developed a substantial reducing atmosphere as the result of rapid accretion.

  19. History of Martian volatiles - Implications for organic synthesis.

    Science.gov (United States)

    Fanale, F. P.

    1971-01-01

    A theoretical reconstruction of the history of Martian volatiles indicates that Mars probably possessed a substantial reducing atmosphere at the outset of its history, and that its present tenuous and more oxidized atmosphere is the result of extensive chemical evolution. As a consequence, it is probable that Martian atmospheric chemical conditions, now hostile with respect to abiotic organic synthesis in the gas phase, were initially favorable. Evidence indicating the chronology and degradational history of Martian surface features, surface mineralogy, bulk volatile content, internal mass distribution, and thermal history suggests that Mars catastrophically developed a substantial reducing atmosphere as the result of rapid accretion.

  20. Cyclodextrin-Catalyzed Organic Synthesis: Reactions, Mechanisms, and Applications

    Directory of Open Access Journals (Sweden)

    Chang Cai Bai

    2017-09-01

    Full Text Available Cyclodextrins are well-known macrocyclic oligosaccharides that consist of α-(1,4 linked glucose units and have been widely used as artificial enzymes, chiral separators, chemical sensors, and drug excipients, owing to their hydrophobic and chiral interiors. Due to their remarkable inclusion capabilities with small organic molecules, more recent interests focus on organic reactions catalyzed by cyclodextrins. This contribution outlines the current progress in cyclodextrin-catalyzed organic reactions. Particular emphases are given to the organic reaction mechanisms and their applications. In the end, the future directions of research in this field are proposed.

  1. Synthesis and Characterization of Functionalized Metal-organic Frameworks

    Science.gov (United States)

    Karagiaridi, Olga; Bury, Wojciech; Sarjeant, Amy A.; Hupp, Joseph T.; Farha, Omar K.

    2014-01-01

    Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy. PMID:25225784

  2. Nitrogen isotopic fractionation during abiotic synthesis of organic solid particles

    Science.gov (United States)

    Kuga, Maïa; Carrasco, Nathalie; Marty, Bernard; Marrocchi, Yves; Bernard, Sylvain; Rigaudier, Thomas; Fleury, Benjamin; Tissandier, Laurent

    2014-05-01

    The formation of organic compounds is generally assumed to result from abiotic processes in the Solar System, with the exception of biogenic organics on Earth. Nitrogen-bearing organics are of particular interest, notably for prebiotic perspectives but also for overall comprehension of organic formation in the young Solar System and in planetary atmospheres. We have investigated abiotic synthesis of organics upon plasma discharge, with special attention to N isotope fractionation. Organic aerosols were synthesized from N2-CH4 and N2-CO gaseous mixtures using low-pressure plasma discharge experiments, aimed at simulating chemistry occurring in Titan's atmosphere and in the protosolar nebula, respectively. The nitrogen content, the N speciation and the N isotopic composition were analyzed in the resulting organic aerosols. Nitrogen is efficiently incorporated into the synthesized solids, independently of the oxidation degree, of the N2 content of the starting gas mixture, and of the nitrogen speciation in the aerosols. The aerosols are depleted in 15N by 15-25‰ relative to the initial N2 gas, whatever the experimental setup is. Such an isotopic fractionation is attributed to mass-dependent kinetic effect(s). Nitrogen isotope fractionation upon electric discharge cannot account for the large N isotope variations observed among Solar System objects and reservoirs. Extreme N isotope signatures in the Solar System are more likely the result of self-shielding during N2 photodissociation, exotic effect during photodissociation of N2 and/or low temperature ion-molecule isotope exchange. Kinetic N isotope fractionation may play a significant role in the Titan's atmosphere. On the Titan's night side, 15N-depletion resulting from electron driven reactions may counterbalance photo-induced 15N enrichments occurring on the day's side. We also suggest that the low δ15N values of Archaean organic matter (Beaumont and Robert, 1999) are partly the result of abiotic synthesis of

  3. Modification of Current Feedback Strategies: A Text Synthesis Approach.

    Science.gov (United States)

    1984-03-01

    f c o lorad I Technic Report No. 127 This research was aponsored byiwtut ot Cogniive Science The Air Force Office of Scienlbc Uriverulty of Cooado...SYNTHESIS APPROACH(UA COLORADO ANIA AT BOXLDEN INST OF COONITXE SCIENCE P LANGEB ET AL MAN 84 N6 SIID AORT-408 FS-304 / /0 N EA-1216 OIIATOh E CR E...ADDRESS 10. PROGRAM ELEMENT, PROJECT. TASK AREA & WORK( UNIT NUMIERS Institute of Cognitive Science University of Colorado 61103F Boulder, CO 80309

  4. Organizational leadership: motives and behaviors of leaders in current organizations.

    Science.gov (United States)

    Martí, Margarita; Gil, Francisco; Barrasa, Angel

    2009-05-01

    Organizational leadership is fundamental for the working and development of current organizations. It helps members of an organization to face transcendental challenges. One of the fundamental aspects of leaders is their personal characteristics and behaviour as perceived by their co-workers. Although research has established a relationship between these components, findings have failed to come up with any congruent evidence and further to this the organizations and contexts used are from several decades ago. This article, which forms part of the international GLOBE project, analyses the relationship between motives and behaviour as perceived by co-workers in organizations, using quantitative and qualitative methods and including technological innovations. Using samples from 40 corporate directors and 84 of their co-workers, from different companies, it confirms how the main motives of leaders (power, affiliation and achievement) are related to different behavioral patterns (power to authoritarian, non-dependent and non-social-skill behaviours; affiliation to relationship and dependent behaviors, and achievement to proactive behaviors). It discusses the results with relation to traditional research and suggests practical measures and proposals for future investigations in this area.

  5. Sediments Contamination with Organic Micropollutants: Current State and Perspectives

    Science.gov (United States)

    Popenda, Agnieszka; Włodarczyk-Makuła, Maria

    2016-06-01

    This study focused on the sediment contamination with some organic micropollutants based on the monitoring data together with available literature in Poland. The following persistent organic pollutants (POPs): polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and chlorinated pesticides (CP) were characterized in sediments with respect to current legislations in force. Based on accessible data, higher PAHs, PCBs and CP concentrations were found in river sediments than in lake sediments. Especially, sediments of the Oder River and its tributary in the southern part of Poland, were highly polluted. In order to minimize the risk of the secondary pollution of surface waters, it is necessary to introduce consolidated management system with sediments proceeding. Furthermore, it is also of great importance to elaborate specific regulations concerning conditions of sediments management.

  6. Organic synthesis reactions on-water at the organic-liquid water interface.

    Science.gov (United States)

    Butler, Richard N; Coyne, Anthony G

    2016-10-25

    Organic reactions that occur at the water interface for water-insoluble compounds, and reactions in water solution for water soluble compounds, has added a powerful dimension to prospects for organic synthesis under more beneficial economic and environmental conditions. Many organic molecules are partially soluble in water and reactions that appear as heterogeneous mixtures and suspensions may involve on-water and in-water reaction modes occurring simultaneously. The behavior of water molecules and organic molecules at this interface is discussed in the light of reported theoretical and experimental studies. The on-water catalytic effect, relative to neat reactions or organic solvents, ranges from factors of several hundred times to 1-2 times and it depends on the properties of reactant compounds. In some cases when on-water reactions produce quantitative yields of water-insoluble products they can reach ideal synthetic aspirations.

  7. Dendrimers - from organic synthesis to pharmaceutical applications: an update.

    Science.gov (United States)

    Kalhapure, Rahul S; Kathiravan, Muthu K; Akamanchi, Krishnacharya G; Govender, Thirumala

    2015-01-01

    Dendrimers are a relatively new class of monodisperse polymers, which have tree-like spherical structures with well-defined sizes and shapes. Their unique structure has a significant impact on their physical and chemical properties. Research on dendrimers is of significant interest to scientists from all areas and their utility in various scientific fields, including pharmaceuticals, is expanding. The present review is comprehensive and covers different aspects of dendrimers viz. (1) synthesis, (2) properties and (3) pharmaceutical applications. The emphasis is on their applications as well as the current ongoing research status for drug targeting.

  8. Electrical energy sources for organic synthesis on the early earth

    Science.gov (United States)

    Chyba, Christopher; Sagan, Carl

    1991-01-01

    It is pointed out that much of the contemporary origin-of-life research uses the original estimates of Miller and Urey (1959) for terrestrial energy dissipation by lightning and coronal discharges being equal to 2 x 10 to the 19th J/yr and 6 x 10 to the 19th J/yr, respectively. However, data from experiments that provide analogues to naturally-occurring lightning and coronal discharges indicate that lightning energy yields for organic synthesis (nmole/J) are about one order of magnitude higher than the coronal discharge yields. This suggests that, on early earth, organic production by lightning may have dominated that due to coronal emission. New values are recommended for lightning and coronal discharge dissipation rates on the early earth, 1 x 10 to the 18th J/yr and 5 x 10 to the 17th J/yr, respectively.

  9. Electrical energy sources for organic synthesis on the early earth

    Science.gov (United States)

    Chyba, Christopher; Sagan, Carl

    1991-01-01

    It is pointed out that much of the contemporary origin-of-life research uses the original estimates of Miller and Urey (1959) for terrestrial energy dissipation by lightning and coronal discharges being equal to 2 x 10 to the 19th J/yr and 6 x 10 to the 19th J/yr, respectively. However, data from experiments that provide analogues to naturally-occurring lightning and coronal discharges indicate that lightning energy yields for organic synthesis (nmole/J) are about one order of magnitude higher than the coronal discharge yields. This suggests that, on early earth, organic production by lightning may have dominated that due to coronal emission. New values are recommended for lightning and coronal discharge dissipation rates on the early earth, 1 x 10 to the 18th J/yr and 5 x 10 to the 17th J/yr, respectively.

  10. Synthesis of phthalocyanine derivatives as materials for organic photovoltaic cells

    Science.gov (United States)

    Collazo-Ramos, Aura

    Organic photovoltaics (OPVs) are used to convert sunlight into electricity by using thin films of organic semiconductors. OPVs have the potential to produce low cost, lightweight, flexible devices with an eased manufacturing process. This technology contains the potential to increase the use of clean, sustainable solar energy, helping manage the global energy and environmental crisis that results majorly from the constant use of fossil fuels as an energy source. The ability to modulate the physical properties of organic molecules by tuning their chemical structure is an advantage for OPVs. Phthalocyanines (Pcs) are highly pi-conjugated synthetic porphyrin analogs that have been explored as active layer components in OPVs due to their high extinction coefficients and hole mobilities. The Pc structure can be modified by the introduction of metals in the core and the incorporation of substituents into the periphery. These modifications tend to tune the solubility, photophysical properties and condensed phase organization of Pcs. The research work in this dissertation describes improved methods towards substituted Pc derivatives addressing: (1) the use of mass spectrometry techniques for Pcs characterization, (2) efforts to achieve materials with near-infrared (NIR) absorption, and (3) the potential of Pc as electron-acceptor materials. Herein, the synthesis of a series of asymmetric and symmetric metallated Pcs has been established, which resulted in interesting chemical, photophysical and electrochemical properties. The materials investigated in this thesis increase the potential of Pcs as organic semiconductors for OPVs.

  11. Self-Organizing Maps-based ocean currents forecasting system

    Science.gov (United States)

    Vilibić, Ivica; Šepić, Jadranka; Mihanović, Hrvoje; Kalinić, Hrvoje; Cosoli, Simone; Janeković, Ivica; Žagar, Nedjeljka; Jesenko, Blaž; Tudor, Martina; Dadić, Vlado; Ivanković, Damir

    2016-03-01

    An ocean surface currents forecasting system, based on a Self-Organizing Maps (SOM) neural network algorithm, high-frequency (HF) ocean radar measurements and numerical weather prediction (NWP) products, has been developed for a coastal area of the northern Adriatic and compared with operational ROMS-derived surface currents. The two systems differ significantly in architecture and algorithms, being based on either unsupervised learning techniques or ocean physics. To compare performance of the two methods, their forecasting skills were tested on independent datasets. The SOM-based forecasting system has a slightly better forecasting skill, especially during strong wind conditions, with potential for further improvement when data sets of higher quality and longer duration are used for training.

  12. Trapped-space-charge-limited currents in organics

    Energy Technology Data Exchange (ETDEWEB)

    Paasch, Gernot [IFW Dresden (Germany); Blom, Paul; Mandoc, Magda; Boer, Bert de [University of Groningen (Netherlands)

    2007-07-01

    The Mott-Gurney law for space charge limited current (SCLC) has been modified early to account for the presence of exponentially distributed traps. This expression has been widely used to analyse transport in organic light emitting diodes. However, the theory fails to describe the rather weak temperature dependence observed for electron transport, for instance in PPV derivatives. There we have shown that the trap-limited SCLC law is essentially modified if the density of transport states is of Gaussian type. Here, we discuss the origin of this modification and present a detailed analysis of the modified law. In addition, we derive further modifications for different combinations of densities of states of both the transport states and the trap distribution. As a result, rather different dependencies of the current on voltage, layer thickness and temperature are possible. Consequently, one has to exercise care in order to obtain reliable trap parameters from SCLC.

  13. Recyclable Nanostructured Catalytic Systems in Modern Environmentally Friendly Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Irina Beletskaya

    2010-07-01

    Full Text Available Modern chemical synthesis makes heavy use of different types of catalytic systems: homogeneous, heterogeneous and nano-sized. The latter – nano-sized catalysts – have given rise in the 21st century to a rapidly developing area of research encompassing several prospects and opportunities for new technologies. Catalytic reactions ensure high regio- and stereoselectivity of chemical transformations, as well as better yields and milder reaction conditions. In recent years several novel catalytic systems were developed for selective formation of carbon-heteroatom and carbon-carbon bonds. This review presents the achievements of our team in our studies on various types of catalysts containing metal nanoparticles: palladium-containing diblock copolymer micelles; soluble palladium-containing polymers; metallides on a support; polymeric metal salts and oxides; and, in addition, metal-free organic catalysts based on soluble polymers acting as nanoreactors. Representative examples are given and discussed in light of possible applications to solve important problems in modern organic synthesis.

  14. The visual dimension in organizing, organization, and organization research: Core ideas, current developments, and promising avenues

    OpenAIRE

    Meyer, Renate; Höllerer, Markus; Jancsary, Dennis; Van Leeuwen, Theo

    2013-01-01

    With the unprecedented rise in the use of visuals, and its undeniable omnipresence in organizational contexts, as well as in the individual's everyday life, organization and management science has recently started to pay closer attention to the to date under-theorized "visual mode" of discourse and meaning construction. Building primarily on insights from the phenomenological tradition in organization theory and from social semiotics, this article sets out to consolidate previous scholarly ef...

  15. Synthesis of Two Local Anesthetics from Toluene: An Organic Multistep Synthesis in a Project-Oriented Laboratory Course

    Science.gov (United States)

    Demare, Patricia; Regla, Ignacio

    2012-01-01

    This article describes one of the projects in the advanced undergraduate organic chemistry laboratory course concerning the synthesis of two local anesthetic drugs, prilocaine and benzocaine, with a common three-step sequence starting from toluene. Students undertake, in a several-week independent project, the multistep synthesis of a…

  16. Synthesis of Two Local Anesthetics from Toluene: An Organic Multistep Synthesis in a Project-Oriented Laboratory Course

    Science.gov (United States)

    Demare, Patricia; Regla, Ignacio

    2012-01-01

    This article describes one of the projects in the advanced undergraduate organic chemistry laboratory course concerning the synthesis of two local anesthetic drugs, prilocaine and benzocaine, with a common three-step sequence starting from toluene. Students undertake, in a several-week independent project, the multistep synthesis of a…

  17. Cobalt catalysis involving π components in organic synthesis.

    Science.gov (United States)

    Gandeepan, Parthasarathy; Cheng, Chien-Hong

    2015-04-21

    Over the last three decades, transition-metal-catalyzed organic transformations have been shown to be extremely important in organic synthesis. However, most of the successful reactions are associated with noble metals, which are generally toxic, expensive, and less abundant. Therefore, we have focused on catalysis using the abundant first-row transition metals, specifically cobalt. In this Account, we demonstrate the potential of cobalt catalysis in organic synthesis as revealed by our research. We have developed many useful catalytic systems using cobalt complexes. Overall, they can be classified into several broad types of reactions, specifically [2 + 2 + 2] and [2 + 2] cycloadditions; enyne reductive coupling; reductive [3 + 2] cycloaddition of alkynes/allenes with enones; reductive coupling of alkyl iodides with alkenes; addition of organoboronic acids to alkynes, alkenes, or aldehydes; carbocyclization of o-iodoaryl ketones/aldehydes with alkynes/electron-deficient alkenes; coupling of thiols with aryl and alkyl halides; enyne coupling; and C-H bond activation. Reactions relying on π components, specifically cycloaddition, reductive coupling, and enyne coupling, mostly afford products with excellent stereo- and regioselectivity and superior atom economy. We believe that these cobalt-catalyzed π-component coupling reactions proceed through five-membered cobaltacyclic intermediates formed by the oxidative cyclometalation of two coordinated π bonds of the substrates to the low-valent cobalt species. The high regio- and stereoselectivity of these reactions are achieved as a result of the electronic and steric effects of the π components. Mostly, electron-withdrawing groups and bulkier groups attached to the π bonds prefer to be placed near the cobalt center of the cobaltacycle. Most of these transformations proceed through low-valent cobalt complexes, which are conveniently generated in situ from air-stable Co(II) salts by Zn- or Mn-mediated reduction

  18. TECHNOLOGIES OF SYNTHESIS OF ORGANIC SUBSTANCES BY MICROORGANISMS USING WASTE BIODIESEL PRODUCTION

    Directory of Open Access Journals (Sweden)

    Pirog T. P.

    2015-08-01

    Full Text Available We describe here literature and our experimental data concerning microbial synthesis using waste biodiesel production, mono- and dihydric alcohols (1,3-propanediol, 2,3-butanediol, butanol, ethanol, polyols (mannitol, erythritol, arabitol, organic acids (citric, succinic, lactic, glyceric, polymers and compounds with a complex structure (polysaccharides, polyhydroxyalkanoates, surfactants, cephalosporin, cyanocobalamin. In some mentioned cases recombinant producer strains were used. It was shown that due to the presence of potential inhibitors in the composition of technical (crude glycerol (methanol, sodium and potassium salts, the efficiency of synthesis of most microbial products on such a substrate is lower than on the purified glycerol. However, the need of utilization of this toxic waste (storage and processing of crude glycerol is a serious environmental problem due to the high alkalinity and the content of methanol in it, compensates the lower rates of synthesis of the final product. Furthermore, currently considering the volumes of crude glycerol formed during the production of biodiesel, microbial technologies are preferred for its utilization, allowing realizing biosynthesis of practically valuable metabolites in the environment with the highest possible concentration of this waste. Using of crude glycerol as a substrate will reduce the cost of products of microbial synthesis and increase the profitability of biodiesel production.

  19. Natural Product Total Synthesis in the Organic Laboratory: Total Synthesis of Caffeic Acid Phenethyl Ester (CAPE), a Potent 5-Lipoxygenase Inhibitor from Honeybee Hives

    Science.gov (United States)

    Touaibia, Mohamed; Guay, Michel

    2011-01-01

    Natural products play a critical role in modern organic synthesis and learning synthetic techniques is an important component of the organic laboratory experience. In addition to traditional one-step organic synthesis laboratories, a multistep natural product synthesis is an interesting experiment to challenge students. The proposed three-step…

  20. Natural Product Total Synthesis in the Organic Laboratory: Total Synthesis of Caffeic Acid Phenethyl Ester (CAPE), a Potent 5-Lipoxygenase Inhibitor from Honeybee Hives

    Science.gov (United States)

    Touaibia, Mohamed; Guay, Michel

    2011-01-01

    Natural products play a critical role in modern organic synthesis and learning synthetic techniques is an important component of the organic laboratory experience. In addition to traditional one-step organic synthesis laboratories, a multistep natural product synthesis is an interesting experiment to challenge students. The proposed three-step…

  1. Bioactive molecules: current trends in discovery, synthesis, delivery and testing

    Directory of Open Access Journals (Sweden)

    Yew Beng Kang

    2013-04-01

    Full Text Available Important bioactive molecules are moleculesthat are pharmacologically active derived from naturalsources and through chemical synthesis. Over the yearsmany of such molecules have been discovered throughbioprospective endeavours. The discovery of taxol fromthe pacific yew tree bark that has the ability in stabilisingcellular microtubules represents one of the hallmarks ofsuccess of such endeavours. In recent years, the discoveryprocess has been aided by the rapid developmentof techniques and technologies in chemistry andbiotechnology. The progress in advanced genetics andcomputational biology has also transformed the wayhypotheses are formulated as well as the strategies for drugdiscovery. Of equal importance is the use of advanceddrug delivery vehicles in enhancing the efficacy andbioavailability of bioactive molecules. The availability ofsuitable animal models for testing and validation is yetanother major determinant in increasing the prospect forclinical trials of bioactive molecules.

  2. Characterization of ionic currents of cells of the subfornical organ that project to the supraoptic nuclei

    Science.gov (United States)

    Johnson, R. F.; Beltz, T. G.; Jurzak, M.; Wachtel, R. E.; Johnson, A. K.

    1999-01-01

    The subfornical organ (SFO) is a forebrain structure that converts peripheral blood-borne signals reflecting the hydrational state of the body to neural signals and then through efferent fibers conveys this information to several central nervous system structures. One of the forebrain areas receiving input from the SFO is the supraoptic nucleus (SON), a source of vasopressin synthesis and control of release from the posterior pituitary. Little is known of the transduction and transmission processes by which this conversion of systemic information to brain input occurs. As a step in elucidating these mechanisms, the present study characterized the ionic currents of dissociated cells of the SFO that were identified as neurons that send efferents to the SON. A retrograde tracer was injected into the SON area in eleven-day-old rats. After three days for retrograde transport of the label, the SFOs of these animals were dissociated and plated for tissue culture. The retrograde tracer was used to identify the soma of SFO cells projecting to the SON so that voltage-dependent ionic currents using whole-cell voltage clamp methods could be studied. The three types of currents in labeled SFO neurons were characterized as a 1) rapid, transient inward current that can be blocked by tetrodotoxin (TTX) characteristic of a sodium current; 2) slow-onset sustained outward current that can be blocked by tetraethylammonium (TEA) characteristic of a delayed rectifier potassium current; and 3) remaining outward current that has a rapid-onset and transient characteristic of a potassium A-type current. Copyright 1999 Elsevier Science B.V.

  3. Gold-Catalyzed Cyclization Processes: Pivotal Avenues for Organic Synthesis.

    Science.gov (United States)

    Kumar, Amit; Singh, Sukhdev; Sharma, Sunil K; Parmar, Virinder S; Van der Eycken, Erik V

    2016-02-01

    Over the years, gold catalysis has materialized as an incredible synthetic approach among the scientific community. Due to the trivial reaction conditions and great functional compatibility, these progressions are synthetically expedient, because practitioners can implement them to build intricate architectures from readily amassed building blocks with high bond forming indices. The incendiary growth of gold catalysts in organic synthesis has been demonstrated as one of the most prevailing soft Lewis acids for electrophilic activation of carbon-carbon multiple bonds towards a great assortment of nucleophiles. Nowadays, organic chemists consistently employ gold catalysts to carry out a diverse array of organic transformations to build unprecedented molecular architectures. Despite all these achievements and a plethora of reports, many vital challenges remain. In this account, we describe the reactivity of various gold catalysts towards cyclization processes developed over the years. These protocols give access to a wide scope of polyheterocyclic structures, containing different medium-sized ring skeletons. This is interesting, as the quest for highly selective reactions to assemble diversely functionalized products has attracted much attention. We envisage that these newly developed chemo-, regio-, and diastereoselective protocols could provide an expedient route to architecturally cumbersome heterocycles of importance for the pharmaceutical industry.

  4. Current understanding of organically bound tritium (OBT) in the environment.

    Science.gov (United States)

    Kim, S B; Baglan, N; Davis, P A

    2013-12-01

    It has become increasingly recognized that organically bound tritium (OBT) is the more significant tritium fraction with respect to understanding tritium behaviour in the environment. There are many different terms associated with OBT; such as total OBT, exchangeable OBT, non-exchangeable OBT, soluble OBT, insoluble OBT, tritiated organics, and buried tritium, etc. A simple classification is required to clarify understanding within the tritium research community. Unlike for tritiated water (HTO), the environmental quantification and behaviour of OBT are not well known. Tritiated water cannot bio-accumulate in the environment. However, it is not clear whether or not this is the case for OBT. Even though OBT can be detected in terrestrial biological materials, aquatic biological materials and soil samples, its behaviour is still in question. In order to evaluate the radiation dose from OBT accurately, further study will be required to understand OBT measurements and determine OBT fate in the environment. The relationship between OBT speciation and the OBT/HTO ratio in environmental samples will be useful in this regard, providing information on the previous tritium exposure conditions in the environment and the current tritium dynamics. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  5. Solid-Phase Organic Synthesis and Catalysis: Some Recent Strategies Using Alumina, Silica, and Polyionic Resins

    OpenAIRE

    Basudeb Basu; Susmita Paul

    2013-01-01

    Solid-phase organic synthesis (SPOS) and catalysis have gained impetus after the seminal discovery of Merrifield’s solid-phase peptide synthesis and also because of wide applicability in combinatorial and high throughput chemistry. A large number of organic, inorganic, or organic-inorganic hybrid materials have been employed as polymeric solid supports to promote or catalyze various organic reactions. This review article provides a concise account on our approaches involving the use of (i) al...

  6. Chiral allylic and allenic metal reagents for organic synthesis.

    Science.gov (United States)

    Marshall, James A

    2007-10-26

    This account traces the evolution of our work on the synthesis of chiral allylic and allenic organometal compounds of tin, silicon, zinc, and indium and their application to natural product synthesis over the past quarter century.

  7. Calcium Carbide: A Unique Reagent for Organic Synthesis and Nanotechnology.

    Science.gov (United States)

    Rodygin, Konstantin S; Werner, Georg; Kucherov, Fedor A; Ananikov, Valentine P

    2016-04-01

    Acetylene, HC≡CH, is one of the primary building blocks in synthetic organic and industrial chemistry. Several highly valuable processes have been developed based on this simplest alkyne and the development of acetylene chemistry has had a paramount impact on chemical science over the last few decades. However, in spite of numerous useful possible reactions, the application of gaseous acetylene in everyday research practice is rather limited. Moreover, the practical implementation of high-pressure acetylene chemistry can be very challenging, owing to the risk of explosion and the requirement for complex equipment; special safety precautions need to be taken to store and handle acetylene under high pressure, which limit its routine use in a standard laboratory setup. Amazingly, recent studies have revealed that calcium carbide, CaC2 , can be used as an easy-to-handle and efficient source of acetylene for in situ chemical transformations. Thus, calcium carbide is a stable and inexpensive acetylene precursor that is available on the ton scale and it can be handled with standard laboratory equipment. The application of calcium carbide in organic synthesis will bring a new dimension to the powerful acetylene chemistry.

  8. Organic synthesis toward small-molecule probes and drugs

    Science.gov (United States)

    Schreiber, Stuart L.

    2011-01-01

    Organic synthesis” is a compound-creating activity often focused on biologically active small molecules. This special issue of PNAS explores innovations and trends in the field that are enabling the synthesis of new types of small-molecule probes and drugs. This perspective article frames the research described in the special issue but also explores how these modern capabilities can both foster a new and more extensive view of basic research in the academy and promote the linkage of life-science research to the discovery of novel types of small-molecule therapeutics [Schreiber SL (2009) Chem Bio Chem 10:26–29]. This new view of basic research aims to bridge the chasm between basic scientific discoveries in life sciences and new drugs that treat the root cause of human disease—recently referred to as the “valley of death” for drug discovery. This perspective article describes new roles that modern organic chemistry will need to play in overcoming this challenge. PMID:21464328

  9. Synthesis and study of composite organic silica sorption materials

    Directory of Open Access Journals (Sweden)

    Anna Nikolaevna Shipulya

    2016-03-01

    Full Text Available Currently, one of the promising areas of applied chemistry is research and development of composite absorption materials used as sorbents with a wide range of action, as well as media for biologic preparations and drugs. We have performed research on the development of composite organic silica chitosan-silica based materials with certain composition and biochemical action. Silica was used as the main component, and chitosan - as bio-compatible polymer in the composition of the composite sorbent.

  10. Synthesis of 10-Ethyl Flavin: A Multistep Synthesis Organic Chemistry Laboratory Experiment for Upper-Division Undergraduate Students

    Science.gov (United States)

    Sichula, Vincent A.

    2015-01-01

    A multistep synthesis of 10-ethyl flavin was developed as an organic chemistry laboratory experiment for upper-division undergraduate students. Students synthesize 10-ethyl flavin as a bright yellow solid via a five-step sequence. The experiment introduces students to various hands-on experimental organic synthetic techniques, such as column…

  11. Synthesis of 10-Ethyl Flavin: A Multistep Synthesis Organic Chemistry Laboratory Experiment for Upper-Division Undergraduate Students

    Science.gov (United States)

    Sichula, Vincent A.

    2015-01-01

    A multistep synthesis of 10-ethyl flavin was developed as an organic chemistry laboratory experiment for upper-division undergraduate students. Students synthesize 10-ethyl flavin as a bright yellow solid via a five-step sequence. The experiment introduces students to various hands-on experimental organic synthetic techniques, such as column…

  12. Selenol protecting groups in organic chemistry: special emphasis on selenocysteine Se-protection in solid phase peptide synthesis.

    Science.gov (United States)

    Flemer, Stevenson

    2011-04-18

    The appearance of selenium in organic synthesis is relatively rare, and thus examples in the literature pertaining to the masking of its considerable reactivity are similarly uncommon. Greene's Protecting Groups in Organic Synthesis, the standard reference for the state of the art in this arena, offers no entries for selenium protective methodology, in stark comparison to its mention of the great variety of protecting groups germane to its chalcogen cousin sulfur. This scarcity of Se-protection methods makes it no less interesting and pertinent toward the construction of selenium-containing organic systems which do indeed require the iterative blocking and de-blocking of selenol functionalities. A selenium-containing system which is especially relevant is selenocysteine, as its use in Solid Phase Peptide Synthesis requires extensive protection of its selenol side chain. This review will attempt to summarize the current state of understanding with regard to selenium protection protocol in organic synthesis. Moreover, it will provide a special emphasis on selenocysteine side chain protection, comprising both the breadth of functionality used for this purpose as well as methods of deprotection.

  13. Selenol Protecting Groups in Organic Chemistry: Special Emphasis on Selenocysteine Se-Protection in Solid Phase Peptide Synthesis

    Directory of Open Access Journals (Sweden)

    Stevenson Flemer Jr.

    2011-04-01

    Full Text Available The appearance of selenium in organic synthesis is relatively rare, and thus examples in the literature pertaining to the masking of its considerable reactivity are similarly uncommon. Greene's Protecting Groups in Organic Synthesis, the standard reference for the state of the art in this arena, offers no entries for selenium protective methodology, in stark comparison to its mention of the great variety of protecting groups germane to its chalcogen cousin sulfur. This scarcity of Se-protection methods makes it no less interesting and pertinent toward the construction of selenium-containing organic systems which do indeed require the iterative blocking and de-blocking of selenol functionalities. A selenium-containing system which is especially relevant is selenocysteine, as its use in Solid Phase Peptide Synthesis requires extensive protection of its selenol side chain. This review will attempt to summarize the current state of understanding with regard to selenium protection protocol in organic synthesis. Moreover, it will provide a special emphasis on selenocysteine side chain protection, comprising both the breadth of functionality used for this purpose as well as methods of deprotection.

  14. Magmatic MORB Volatiles, Seafloor Hydrothermal Systems and Abiotic Organic Synthesis

    Science.gov (United States)

    Holloway, J. R.

    2007-12-01

    A plausible model for the origin of the observed C-O-H volatiles observed in MORB glasses is that they were incorporated in primary melts of the upwelling mantle. Based on the observed ferric/ferrous ratios in MORB glass, it is probable that the MORB source mantle contained diamond or graphite, depending on pressure. If true, then during partial mantle melting the graphite/diamond would react with FeO1.5 in garnet/spinel and clinopyroxene to form CO2 which would dissolve in the melt as carbonate ion. Using equation of state models for CO2 activity and ferric/ferrous ratios in the magma it is possible to model the amount of carbonate dissolved in the basaltic magma as a function of the degree of melting (Holloway and O'Day, 2000). The results require that rising MORB magma will become saturated in CO2 at depths much greater than those proposed for MORB magma chambers. Conversely H2O values observed in MORB glasses are far below saturation. However as CO2 reaches saturation and exsolves from the melt the low fO2 imposed by the low ferric/ferrous ratio results in a high H2/H2O ratio in the exsolving supercritical fluid. We have shown that fluids with this composition produce methanol (CH3OH) in the presence of magnetite at seafloor hydrothermal P-T conditions in a flow-through system (Voglesonger, et al., 2001) and that aqueous methanol solutions react in montmorillonite clay interlayers to form a wide variety of complex hydrocarbon molecules, the most abundant being hexamethyl benzene (Williams, et al., 2005). Methyl stearate (C17H35COOCH3) was also observed in moderate amounts. Holloway, J. R. and P. A. O'Day (2000). "Production of CO2 and H2 by Diking-Eruptive Events at Mid-Ocean Ridges: Implications for Abiotic Organic Synthesis and Global Geochemical Cycling." International Geology Review 42: 673-683. Voglesonger, K. M., J. R. Holloway, E. E. Dunn, P. J. Dalla-Betta and P. A. O'Day (2001). "Experimental Abiotic Synthesis of Methanol in Seafloor Hydrothermal

  15. Development of new methods in modern selective organic synthesis: preparation of functionalized molecules with atomic precision

    Science.gov (United States)

    Ananikov, V. P.; Khemchyan, L. L.; Ivanova, Yu V.; Bukhtiyarov, V. I.; Sorokin, A. M.; Prosvirin, I. P.; Vatsadze, S. Z.; Medved'ko, A. V.; Nuriev, V. N.; Dilman, A. D.; Levin, V. V.; Koptyug, I. V.; Kovtunov, K. V.; Zhivonitko, V. V.; Likholobov, V. A.; Romanenko, A. V.; Simonov, P. A.; Nenajdenko, V. G.; Shmatova, O. I.; Muzalevskiy, V. M.; Nechaev, M. S.; Asachenko, A. F.; Morozov, O. S.; Dzhevakov, P. B.; Osipov, S. N.; Vorobyeva, D. V.; Topchiy, M. A.; Zotova, M. A.; Ponomarenko, S. A.; Borshchev, O. V.; Luponosov, Yu N.; Rempel, A. A.; Valeeva, A. A.; Stakheev, A. Yu; Turova, O. V.; Mashkovsky, I. S.; Sysolyatin, S. V.; Malykhin, V. V.; Bukhtiyarova, G. A.; Terent'ev, A. O.; Krylov, I. B.

    2014-10-01

    The challenges of the modern society and the growing demand of high-technology sectors of industrial production bring about a new phase in the development of organic synthesis. A cutting edge of modern synthetic methods is introduction of functional groups and more complex structural units into organic molecules with unprecedented control over the course of chemical transformation. Analysis of the state-of-the-art achievements in selective organic synthesis indicates the appearance of a new trend — the synthesis of organic molecules, biologically active compounds, pharmaceutical substances and smart materials with absolute selectivity. Most advanced approaches to organic synthesis anticipated in the near future can be defined as 'atomic precision' in chemical reactions. The present review considers selective methods of organic synthesis suitable for transformation of complex functionalized molecules under mild conditions. Selected key trends in the modern organic synthesis are considered including the preparation of organofluorine compounds, catalytic cross-coupling and oxidative cross-coupling reactions, atom-economic addition reactions, methathesis processes, oxidation and reduction reactions, synthesis of heterocyclic compounds, design of new homogeneous and heterogeneous catalytic systems, application of photocatalysis, scaling up synthetic procedures to industrial level and development of new approaches to investigation of mechanisms of catalytic reactions. The bibliography includes 840 references.

  16. Nanostructured organic electronic materials: Synthesis and sensor applications

    Science.gov (United States)

    Dua, Vineet

    2009-12-01

    This study is an investigation into (a) the process by which one obtains bulk quantities of nanofibers of parent polythiophene, (b) in-situ deposition of nanofibers of polythiophene on flexible substrate and its application in vapor sensing, and (c) inkjet printing of graphene on flexible substrate and its application as a detector. (a) The 2 nd chapter of the thesis is an extension of "seeding" method from aqueous to organic solvents to synthesize parent polythiophene nanofibers. Bulk quantities of parent polythiophene nanofibers were synthesized in one step using catalytic amounts of freeze dried V2O5. This work is published in Chemistry Letters 2008 37(5), 526--527. (b) The 3rd chapter deals with in-situ films of polythiophene nanofibers on plastic substrates. In this a one step method to directly deposit nanofibers of parent polythiophene on flexible substrate is discussed. These films show a reversible detection of highly oxidizing vapors such as NO2, Cl2 and SO 2 at ppb levels under ambient conditions. This work is published in Macromolecules 2009, 42, 5414--5415. (c) The 4 th chapter describes the synthesis of reduced graphene oxide (RGO) using a mild reducing agent ascorbic acid (Vitamin C) rather than traditionally used harsh reducing agents (N2H4). Dispersions of RGO were inkjet printed on flexible substrate and has been shown to detect aggressive vapors NO2 and Cl2 at ambient conditions. This work is accepted for publication in Angewandte Chemie (Nov 2009).

  17. Selective organic synthesis over metal cation-exchanged clay catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Tateiwa, J.; Uemura, S. [Kyoto University, Kyoto (Japan)

    1997-09-01

    Results of recent studies conducted by the authors are reviewed on the use, as catalysts, of metal cation-exchanged montmorillonite (M{sup n+}-mont), a modified natural clay with a layer structure, and metal cation-exchanged fluor-tetrasilicic mica (M{sup n+}-TSM), a synthetic clay with a layer structure, for the following organic synthesis: (1) Friedel-Crafts alkylation of phenol with 4-hydroxybutan-2-one to produce 4-(4-hydroxyphenyl)butan-2-one (raspberry ketone), (2) rearrangement of alkyl phenyl ethers to corresponding alkylphenols, (3) aromatic alkylation of phenol with aldehydes and ketones to produce corresponding gem-bis(hydroxyphenyl)alkanes (bisphenols) and alkylphenols, respectively, (4) a facile and an almost quantitative substrate-selective acetalization, (5) alkane oxidation with aqueous tert-butyl hydroperoxide, (6) Prins reaction of styrenes with aldehydes using clay as a Bronsted acid, and (7) inter-and intra-molecular carbonyl-ene reaction using clay as a Lewis acid in condition similar to that of Prins reaction. In almost all cases, the clay catalysts could be regenerated and reused several times, after filtration, washing and drying. 42 refs., 20 figs., 3 tabs.

  18. Rapid, Microwave-Assisted Organic Synthesis of Selective V600EBRAF Inhibitors for Preclinical Cancer Research

    Science.gov (United States)

    Buck, Jason R.; Saleh, Sam; Uddin, Md. Imam; Manning, H. Charles

    2012-01-01

    We report a dramatically improved total synthesis of two highly selective V600EBRAF inhibitors, PLX4720 and PLX4032, that leverages microwave-assisted organic synthesis (MAOS). Compared with previously reported approaches, our novel MAOS method significantly reduces overall reaction time without compromising yield. In addition to providing a gram-scale route to these compounds for preclinical oncology research, we anticipate this approach could accelerate the synthesis of azaindoles in high-throughput, library-based formats. PMID:23180892

  19. Some recent work on prebiological synthesis of organic compounds.

    Science.gov (United States)

    Ponnamperuma, C.

    1966-01-01

    Origin of constituents of nucleic acid and protein molecules, noting biological molecules synthesis under conditions similar to those prevailing in prebiotic Earth, following Oparin-Haldane hypothesis

  20. The Synthesis of a Cockroach Pheromone: An Experiment for the Second-Year Organic Chemistry Laboratory

    Science.gov (United States)

    Feist, Patty L.

    2008-01-01

    This experiment describes the synthesis of gentisyl quinone isovalerate, or blattellaquinone, a sex pheromone of the German cockroach that was isolated and identified in 2005. The synthesis is appropriate for the second semester of a second-year organic chemistry laboratory course. It can be completed in two, three-hour laboratory periods and uses…

  1. The Synthesis of a Cockroach Pheromone: An Experiment for the Second-Year Organic Chemistry Laboratory

    Science.gov (United States)

    Feist, Patty L.

    2008-01-01

    This experiment describes the synthesis of gentisyl quinone isovalerate, or blattellaquinone, a sex pheromone of the German cockroach that was isolated and identified in 2005. The synthesis is appropriate for the second semester of a second-year organic chemistry laboratory course. It can be completed in two, three-hour laboratory periods and uses…

  2. A Long Chain Alcohol as Support in Solid Phase Organic Synthesis

    NARCIS (Netherlands)

    Nurlela, Yeni; Minnaard, Adrian J.; Achmad, Sadijah; Wahyuningrum, Deana

    2011-01-01

    The solid phase synthesis is a method by which organic compound synthesis are performed on a support. With this method, the purification can be carried out easily by simple filtration and washing procedures. Long-chain alcohol (C-100 alcohol) can be used as a support because of its insolubility in o

  3. From Polymer to Small Organic Molecules: A Tight Relationship between Radical Chemistry and Solid-Phase Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Danilo Mirizzi

    2011-04-01

    Full Text Available Since Gomberg’s discovery of radicals as chemical entities, the interest around them has increased through the years. Nowadays, radical chemistry is used in the synthesis of 75% of all polymers, inevitably establishing a close relationship with Solid-Phase Organic Synthesis. More recently, the interest of organic chemists has shifted towards the application of usual “in-solution” radical chemistry to the solid-phase, ranging from the use of supported reagents for radical reactions, to the development of methodologies for the synthesis of small molecules or potential libraries. The aim of this review is to put in perspective radical chemistry, moving it away from its origin as a synthetic means for solid supports, to becoming a useful tool for the synthesis of small molecules.

  4. From polymer to small organic molecules: a tight relationship between radical chemistry and solid-phase organic synthesis.

    Science.gov (United States)

    Mirizzi, Danilo; Pulici, Maurizio

    2011-04-18

    Since Gomberg's discovery of radicals as chemical entities, the interest around them has increased through the years. Nowadays, radical chemistry is used in the synthesis of 75% of all polymers, inevitably establishing a close relationship with Solid-Phase Organic Synthesis. More recently, the interest of organic chemists has shifted towards the application of usual "in-solution" radical chemistry to the solid-phase, ranging from the use of supported reagents for radical reactions, to the development of methodologies for the synthesis of small molecules or potential libraries. The aim of this review is to put in perspective radical chemistry, moving it away from its origin as a synthetic means for solid supports, to becoming a useful tool for the synthesis of small molecules.

  5. Recent applications of polymer supported organometallic catalysts in organic synthesis.

    Science.gov (United States)

    Kann, Nina

    2010-09-07

    Recent developments concerning the application of polymer supported organometallic reagents in solid phase synthesis are reviewed, with a special focus on methodology for carbon-carbon formation. Examples of reactions that are covered include the classical Suzuki, Sonogashira and Heck coupings, but also aryl amination, epoxide opening, rearrangements, metathesis and cyclopropanation. Applications in the field of asymmetric synthesis are also discussed.

  6. Recent Applications of Polymer Supported Organometallic Catalysts in Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Nina Kann

    2010-09-01

    Full Text Available Recent developments concerning the application of polymer supported organometallic reagents in solid phase synthesis are reviewed, with a special focus on methodology for carbon-carbon formation. Examples of reactions that are covered include the classical Suzuki, Sonogashira and Heck coupings, but also aryl amination, epoxide opening, rearrangements, metathesis and cyclopropanation. Applications in the field of asymmetric synthesis are also discussed.

  7. Synthesis and Characterization of Metal-Organic Frameworks (MOFs) That Are Difficult to Access De Novo

    Science.gov (United States)

    Karagiaridi, Olga

    Metal-organic frameworks (MOFs) are a class of intriguing hybrid materials, comprised of metal-based nodes joined by organic linkers into a crystalline, porous, three-dimensional lattice. Their signature properties (well-defined surfaces, tailorability and ultra-high porosity) render them promising candidates for many applications, including, but not limited to, gas storage, gas separation, catalysis and sensing. One of the greatest challenges associated with MOF synthesis lies in the fact that obtaining a desired MOF structure that is tailored to perform a specific application is often not trivial. Traditional synthetic pathways termed "de novo synthesis" (typically one-pot reactions between the MOF structural building blocks under solvothermal conditions) often give rise to side products that do not possess the desired structure. To circumvent this problem, we have studied in depth two powerful MOF synthetic techniques -- solvent-assisted linker exchange (SALE) and transmetalation. These are heterogeneous reactions of parent MOF crystals with concentrated solutions of organic linkers and inorganic metal salts, respectively, that lead to the replacement of the linkers or metal nodes within the parent MOFs by the desired components, while the overall framework topology is preserved. The projects described in this dissertation have aimed to apply these techniques to transform simple (unfunctionalized) and easy to synthesize representative materials from various MOF systems to structurally and functionally interesting daughter products. Examples include synthesis of MOFs that are energetically "unfavorable", extension of MOF cages by longer linker incorporation, functionalization of MOF pores and endowment of MOFs with permanent and persistent porosity. Through these projects, we have been able to formulate a set of rules that can be applied to predict the successful outcome of SALE. Since the allure of MOFs lies in their applications, expanding the range of

  8. Microorganisms as efficient biosystem for the synthesis of metal nanoparticles: current scenario and future possibilities.

    Science.gov (United States)

    Salunke, Bipinchandra K; Sawant, Shailesh S; Lee, Sang-Ill; Kim, Beom Soo

    2016-05-01

    Nanoparticles, the elementary structures of nanotechnology, are important materials for fundamental studies and variety of applications. The different sizes and shapes of these materials exhibit unique physical and chemical properties than their bulk materials. There is a great interest in obtaining well-dispersed, ultrafine, and uniform nanoparticles to delineate and utilize their distinct properties. Nanoparticle synthesis can be achieved through a wide range of materials utilizing a number of methods including physical, chemical, and biological processes with various precursors from liquids and solids. There is a growing need to prepare environmentally friendly nanoparticles that do not produce toxic wastes in their process synthesis protocol. This kind of synthesis can be achieved by green environment benign processes, which happen to be mostly of a biological nature. Microorganisms are one of the most attractive and simple sources for the synthesis of different types of nanoparticles. This review is an attempt to provide the up-to-date information on current status of nanoparticle synthesis by different types of microorganisms such as fungi, yeast, bacteria, cyanobacteria, actinomycete, and algae. The probable biosynthesis mechanism and conditions for size/shape control are described. Various applications of microbially synthesized nanoparticles are summarized. They include antibacterial, antifungal, anticancer, larvicidal, medical imaging, biosensor, and catalytic applications. Finally, limitations and future prospects for specific research are discussed.

  9. Iron Catalysis in Organic Synthesis: A Critical Assessment of What It Takes To Make This Base Metal a Multitasking Champion

    OpenAIRE

    Fürstner, Alois

    2016-01-01

    The current status of homogeneous iron catalysis in organic chemistry is contemplated, as are the reasons why this particular research area only recently starts challenging the enduring dominance of the late and mostly noble metals over the field. Centered in the middle of the d-block and able to support formal oxidation states ranging from −II to +VI, iron catalysts hold the promise of being able to encompass organic synthesis at large. They are expected to serve reductive as well as oxidati...

  10. A Safer and Convenient Synthesis of Sulfathiazole for Undergraduate Organic and Medicinal Chemistry Classes

    Science.gov (United States)

    Boyle, Jeff; Otty, Sandra; Sarojini, Vijayalekshmi

    2012-01-01

    A safer method for the synthesis of the sulfonamide drug sulfathiazole, for undergraduate classes, is described. This method improves upon procedures currently followed in several undergraduate teaching laboratories for the synthesis of sulfathiazole. Key features of this procedure include the total exclusion of pyridine, which has potential…

  11. Anodized Aluminum Oxide Templated Synthesis of Metal-Organic Frameworks Used as Membrane Reactors.

    Science.gov (United States)

    Yu, Yifu; Wu, Xue-Jun; Zhao, Meiting; Ma, Qinglang; Chen, Junze; Chen, Bo; Sindoro, Melinda; Yang, Jian; Han, Shikui; Lu, Qipeng; Zhang, Hua

    2017-01-09

    The incorporation of metal-organic frameworks (MOFs) into membrane-shaped architectures is of great importance for practical applications. The currently synthesized MOF-based membranes show many disadvantages, such as poor compatibility, low dispersity, and instability, which severely limit their utility. Herein, we present a general, facile, and robust approach for the synthesis of MOF-based composite membranes through the in situ growth of MOF plates in the channels of anodized aluminum oxide (AAO) membranes. After being used as catalysis reactors, they exhibit high catalytic performance and stability in the Knoevenagel condensation reaction. The high catalytic performance might be attributed to the intrinsic structure of MOF-based composite membranes, which can remove the products from the reaction zone quickly, and prevent the aggregation and loss of catalysts during reaction and recycling process. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Submillisecond organic synthesis: Outpacing Fries rearrangement through microfluidic rapid mixing.

    Science.gov (United States)

    Kim, Heejin; Min, Kyoung-Ik; Inoue, Keita; Im, Do Jin; Kim, Dong-Pyo; Yoshida, Jun-ichi

    2016-05-01

    In chemical synthesis, rapid intramolecular rearrangements often foil attempts at site-selective bimolecular functionalization. We developed a microfluidic technique that outpaces the very rapid anionic Fries rearrangement to chemoselectively functionalize iodophenyl carbamates at the ortho position. Central to the technique is a chip microreactor of our design, which can deliver a reaction time in the submillisecond range even at cryogenic temperatures. The microreactor was applied to the synthesis of afesal, a bioactive molecule exhibiting anthelmintic activity, to demonstrate its potential for practical synthesis and production.

  13. Current challenges in organic photovoltaic solar energy conversion.

    Science.gov (United States)

    Schlenker, Cody W; Thompson, Mark E

    2012-01-01

    Over the last 10 years, significant interest in utilizing conjugated organic molecules for solid-state solar to electric conversion has produced rapid improvement in device efficiencies. Organic photovoltaic (OPV) devices are attractive for their compatibility with low-cost processing techniques and thin-film applicability to flexible and conformal applications. However, many of the processes that lead to power losses in these systems still remain poorly understood, posing a significant challenge for the future efficiency improvements required to make these devices an attractive solar technology. While semiconductor band models have been employed to describe OPV operation, a more appropriate molecular picture of the pertinent processes is beginning to emerge. This chapter presents mechanisms of OPV device operation, based on the bound molecular nature of the involved transient species. With the intention to underscore the importance of considering both thermodynamic and kinetic factors, recent progress in elucidating molecular characteristics that dictate photovoltage losses in heterojunction organic photovoltaics is also discussed.

  14. Organ preconditioning: the past, current status, and related lung studies

    Institute of Scientific and Technical Information of China (English)

    LUH Shi-ping; YANG Pan-chyr

    2006-01-01

    Preconditioning (PC) has emerged as a powerful method for experimentally and clinically attenuating various types of organ injuries. In this paper related clinical and basic research issues on organ preconditioning issues were systemically reviewed.Since lung injuries, including ischemia-reperfusion and others, play important roles in many clinical results, including thromboembolism, trauma, thermal injury, hypovolemic and endotoxin shock, reimplantation response after organ transplantation, and many respiratory diseases in critical care. It is of interest to uncover methods, including the PCs, to protect the lung from the above injuries. However, related studies on pulmonary PC are relatively rare and still being developed, so we will review previous literature on experimental and clinical studies on pulmonary PC in the following paragraphs.

  15. Current approaches in evolution: from molecules to cells and organisms.

    Science.gov (United States)

    Thattai, Mukund; Peisajovich, Sergio G

    2014-11-01

    This is an exciting time to be an evolutionary biologist. Indeed, it is difficult to keep up with all the studies that fall under the broad category of "Evolution" since they span species, traits, and scales of organization. This special issue gives a flavor of exciting new approaches in evolutionary biology, but also emphasizes universal themes. The reviews contained here discuss important aspects of molecular evolution at multiple scales, from individual proteins to complex regulatory networks, as well as from unicellular organisms to macroscopic traits in animals. Though the model systems are diverse, the issues addressed are fundamental: the origin of evolutionary novelties, and the forces that drive them to fixation.

  16. A Revised Iranian Model of Organ Donation as an Answer to the Current Organ Shortage Crisis.

    Science.gov (United States)

    Hamidian Jahromi, Alireza; Fry-Revere, Sigrid; Bastani, Bahar

    2015-09-01

    Kidney transplantation has become the treatment of choice for patients with end-stage renal disease. Six decades of success in the field of transplantation have made it possible to save thousands of lives every year. Unfortunately, in recent years success has been overshadowed by an ever-growing shortage of organs. In the United States, there are currently more than 100 000 patients waiting for kidneys. However, the supply of kidneys (combined cadaveric and live donations) has stagnated around 17 000 per year. The ever-widening gap between demand and supply has resulted in an illegal black market and unethical transplant tourism of global proportions. While we believe there is much room to improve the Iranian model of regulated incentivized live kidney donation, with some significant revisions, the Iranian Model could serve as an example for how other countries could make significant strides to lessening their own organ shortage crises.

  17. Reactive organometallics from organotellurides: application in organic synthesis

    OpenAIRE

    PRINCIVAL, Jefferson L.; Santos,Alcindo A. Dos; Comasseto,João V

    2010-01-01

    In this paper the preparation of reactive organometallics starting from organotellurides is reviewed. The application of the reactive organometallics prepared in this way in the synthesis of bioactive compounds is commented.

  18. Effect of Electric Field on Spin Polarized Current in Ferromagnetic/ Organic Semiconductor Systems

    Institute of Scientific and Technical Information of China (English)

    MA Yan-Ni; REN Jun-Feng; ZHANG Yu-Bin; LIU De-Sheng; XIE Shi-Jie

    2007-01-01

    Considering the special carriers in organic semiconductors, the spin polarized current under electric field in a ferromagnetic/organic semiconductor system is theoretically studied. Based on the spin-diffusion theory, the current spin polarization under the electric field is obtained. It is found that electric field can enhance the current spin polarization.

  19. Alternating current organic light emitting diodes based on polymer heterojunction

    Institute of Scientific and Technical Information of China (English)

    Yewen Jiang(蒋业文); Haishu Tan(谭海曙); Jianquan Yao(姚建铨)

    2003-01-01

    Most alternating current (ac) polymer EL (electroluminescent) devices to date are based on symmetricalstructure. Here novel alternating current EL devices with asymmetric structure are successfully fabricatedby using a hole type polymer PDDOPV [poly (2,5-bis (dodecyloxy)-phenylenevinylene)] and an electrontype polymer PPQ [poly (phenyl quinoxaline)]. We report that performance of polymer devices withheterojunction in ac operation is not so sensitive to thickness of the two polymer layers as in direct current(dc) operation. This new advantage of ac operation mode over dc means easy production and cheapfacilities in large-scale production in the near future. Different emission spectra are obtained when ourac devices operate in ac mode, forward and reverse bias. Emission spectrum at reverse bias includes twoparts: one is from PDDOPV, the other is from PPQ.

  20. 78 FR 38913 - National Organic Program: Request for an Extension of a Currently Approved Information Collection

    Science.gov (United States)

    2013-06-28

    ... Agricultural Marketing Service National Organic Program: Request for an Extension of a Currently Approved Information Collection AGENCY: Agricultural Marketing Service, USDA. ACTION: Notice and request for comments... Toni Strother, Agricultural Marketing Specialist, National Organic Program, AMS/USDA, 1400...

  1. Current evidence for the organic etiology of spastic dysphonia.

    Science.gov (United States)

    Dedo, H H; Townsend, J J; Izdebski, K

    1978-01-01

    For over 100 years it has been universally assumed in the literature that spastic dysphonia is a functional or psychoneurotic voice disorder. In the last few years, new data have accumulated that support the concept that spastic dysphonia is caused by an organic, rather than a functional, abnormality. Histologic examination of segments of the recurrent laryngeal nerve removed from patients with spastic dysphonia has revealed myelin abnormalities in 30% of the nerves examined. Neurologic examination indicated brain stem or basal ganglia disturbances in some patients who had no apparent nerve disease.

  2. Carbon dioxide capture and use: organic synthesis using carbon dioxide from exhaust gas.

    Science.gov (United States)

    Kim, Seung Hyo; Kim, Kwang Hee; Hong, Soon Hyeok

    2014-01-13

    A carbon capture and use (CCU) strategy was applied to organic synthesis. Carbon dioxide (CO2) captured directly from exhaust gas was used for organic transformations as efficiently as hyper-pure CO2 gas from a commercial source, even for highly air- and moisture-sensitive reactions. The CO2 capturing aqueous ethanolamine solution could be recycled continuously without any diminished reaction efficiency.

  3. Current developments in optical data storage with organic dyes.

    Science.gov (United States)

    Mustroph, Heinz; Stollenwerk, Manfred; Bressau, Volker

    2006-03-20

    The main motivation for the development of digital data storage has been the improvement in play-back quality and the increase in storage capacity. In 1982 Philips and Sony introduced the first technically and economically successful system based on this-the compact disc (CD) and a compatible player. A very broad diversity of optical data recording formats are available today, and a difference is drawn between prerecorded, recordable, and rewritable media. This Review gives an overview of the systems used, the main features of production, and then concentrates on the properties of the organic dyes that are used in recordable systems. Dyestuffs chemistry has gained the reputation of having become a mature field of activity. Is this prejudice or a justified swan song for dyestuffs chemistry? When applications in optical data storage are considered, it is evident that even today progresses such as CD-R and DVD/R would not be feasible without functional dyes.

  4. Organic reaction systems: using microcapsules and microreactors to perform chemical synthesis.

    Science.gov (United States)

    Longstreet, Ashley R; McQuade, D Tyler

    2013-02-19

    The appetite for complex organic molecules continues to increase worldwide, especially in rapidly developing countries such as China, India, and Brazil. At the same time, the cost of raw materials and solvent waste disposal is also growing, making sustainability an increasingly important factor in the production of synthetic life-saving/improving compounds. With these forces in mind, our group is driven by the principle that how we synthesize a molecule is as important as which molecule we choose to synthesize. We aim to define alternative strategies that will enable more efficient synthesis of complex molecules. Drawing our inspiration from nature, we attempt to mimic (1) the multicatalytic metabolic systems within cells using collections of nonenzyme catalysts in batch reactors and (2) the serial synthetic machinery of fatty acid/polyketide biosynthesis using microreactor systems. Whether we combine catalysts in batch to prepare an active pharmaceutical ingredient (API) or use microreactors to synthesize small or polymeric molecules, we strive to understand the mechanism of each reaction while also developing new methods and techniques. This Account begins by examining our early efforts in the development of novel catalytic materials and characterization of catalytic systems and how these observations helped forge our current models for developing efficient synthetic routes. The Account progresses through a focused examination of design principles needed to develop multicatalyst systems using systems recently published by our group as examples. Our systems have been successfully applied to produce APIs as well as new synthetic methods. The multicatalyst section is then juxtaposed with our work in continuous flow multistep synthesis. Here, we discuss the design principles needed to create multistep continuous processes using examples from our recent efforts. Overall, this Account illustrates how multistep organic routes can be conceived and achieved using

  5. Benzothiazines in organic synthesis. An approach to floresolide B

    Science.gov (United States)

    Chen, Yugang; Harmata, Michael

    2011-01-01

    The intramolecular conjugate addition of a sulfoximine carbanion to an α,β-unsaturated ester results in the formation of a benzothiaine bearing a benzylic stereocenter with extremely high fidelity. We have used this methodology to complete a formal total synthesis of the antitumor agent (+)-floresolide B. PMID:21818165

  6. organic template free synthesis of zsm11 from kaolinite clay

    African Journals Online (AJOL)

    user

    from two different mines in Nigeria, namely; Kankara and Onibode. They were both subjected to ... reported the synthesis of zeolite ZSM11 from coal fly ash. Shen et al., [11] .... rod or tubular material attributed to halloysite and clinochlore and ...

  7. Template-Free Synthesis of Hierarchical Porous Metal-Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Yanfeng [ORNL; Qiao, Zhen-an [University of Tennessee, Knoxville (UTK); Fulvio, Pasquale F [ORNL; Dai, Sheng [ORNL; Binder, Andrew J [ORNL; Tian, Chengcheng [ORNL; Nelson, Kimberly M [ORNL; Zhu, Xiang [ORNL

    2013-01-01

    A template-free synthesis of a hierarchical microporous-mesoporous metal-organic framework (MOF) of Zn(II)-2,5-dihydroxy-1,4-benzenedicarboxylate, namely Zn-MOF-74, is reported. The surface morphology and porosity of the bimodal materials can be modified by etching the pore walls with the synthesis solvent under different reaction times and different solvents. This template-free strategy allows for the preparation of stable frameworks with mesopores exceeding 15 nm, which was previously unattained by the synthesis of MOFs by ligand exten-sion method.

  8. Pyrolysis-GCMS Analysis of Solid Organic Products from Catalytic Fischer-Tropsch Synthesis Experiments

    Science.gov (United States)

    Locke, Darren R.; Yazzie, Cyriah A.; Burton, Aaron S.; Niles, Paul B.; Johnson, Natasha M.

    2015-01-01

    Abiotic synthesis of complex organic compounds in the early solar nebula that formed our solar system is hypothesized to occur via a Fischer-Tropsch type (FTT) synthesis involving the reaction of hydrogen and carbon monoxide gases over metal and metal oxide catalysts. In general, at low temperatures (less than 200 C), FTT synthesis is expected to form abundant alkane compounds while at higher temperatures (greater than 200 C) it is expected to product lesser amounts of n-alkanes and greater amounts of alkene, alcohol, and polycyclic aromatic hydrocarbons (PAHs). Experiments utilizing a closed-gas circulation system to study the effects of FTT reaction temperature, catalysts, and number of experimental cycles on the resulting solid insoluble organic products are being performed in the laboratory at NASA Goddard Space Flight Center. These experiments aim to determine whether or not FTT reactions on grain surfaces in the protosolar nebula could be the source of the insoluble organic matter observed in meteorites. The resulting solid organic products are being analyzed at NASA Johnson Space Center by pyrolysis gas chromatography mass spectrometry (PY-GCMS). PY-GCMS yields the types and distribution of organic compounds released from the insoluble organic matter generated from the FTT reactions. Previously, exploratory work utilizing PY-GCMS to characterize the deposited organic materials from these reactions has been reported. Presented here are new organic analyses using magnetite catalyst to produce solid insoluble organic FTT products with varying reaction temperatures and number of experimental cycles.

  9. Discovery, application and protein engineering of Baeyer-Villiger monooxygenases for organic synthesis.

    Science.gov (United States)

    Balke, Kathleen; Kadow, Maria; Mallin, Hendrik; Sass, Stefan; Bornscheuer, Uwe T

    2012-08-21

    Baeyer-Villiger monooxygenases (BVMOs) are useful enzymes for organic synthesis as they enable the direct and highly regio- and stereoselective oxidation of ketones to esters or lactones simply with molecular oxygen. This contribution covers novel concepts such as searching in protein sequence databases using distinct motifs to discover new Baeyer-Villiger monooxygenases as well as high-throughput assays to facilitate protein engineering in order to improve BVMOs with respect to substrate range, enantioselectivity, thermostability and other properties. Recent examples for the application of BVMOs in synthetic organic synthesis illustrate the broad potential of these biocatalysts. Furthermore, methods to facilitate the more efficient use of BVMOs in organic synthesis by applying e.g. improved cofactor regeneration, substrate feed and in situ product removal or immobilization are covered in this perspective.

  10. Preparation and Purification of Zinc Sulphinate Reagents for Organic Synthesis

    Science.gov (United States)

    O’Hara, Fionn; Baxter, Ryan D.; O’Brien, Alexander G.; Collins, Michael R.; Dixon, Janice A.; Fujiwara, Yuta; Ishihara, Yoshihiro; Baran, Phil S.

    2014-01-01

    SUMMARY The present protocol details the synthesis of zinc bis(alkanesulphinate)s that can be used as general reagents for the formation of radical species. The zinc sulphinates described herein have been generated from the corresponding sulphonyl chlorides by treatment with zinc dust. The products may be used crude, or a simple purification procedure may be performed to minimize incorporation of water and zinc chloride. Elemental analysis has been conducted in order to confirm the purity of the zinc sulphinate reagents; reactions with caffeine have also been carried out to verify the reactivity of each batch that has been synthesized. Although the synthesis of the zinc sulphinate salts generally proceeds within 3 h, workup can take up to 24 h and purification can take up to 3 h. Following the steps in this protocol would enable the user to generate a small toolkit of zinc sulphinate reagents over the course of one week. PMID:23640168

  11. Electric Current Activated Combustion Synthesis and Chemical Ovens Under Terrestrial and Reduced Gravity Conditions

    Science.gov (United States)

    Unuvar, C.; Fredrick, D.; Anselmi-Tamburini, U.; Manerbino, A.; Guigne, J. Y.; Munir, Z. A.; Shaw, B. D.

    2004-01-01

    Combustion synthesis (CS) generally involves mixing reactants together (e.g., metal powders) and igniting the mixture. Typically, a reaction wave will pass through the sample. In field activated combustion synthesis (FACS), the addition of an electric field has a marked effect on the dynamics of wave propagation and on the nature, composition, and homogeneity of the product as well as capillary flow, mass-transport in porous media, and Marangoni flows, which are influenced by gravity. The objective is to understand the role of an electric field in CS reactions under conditions where gravity-related effects are suppressed or altered. The systems being studied are Ti+Al and Ti+3Al. Two different ignition orientations have been used to observe effects of gravity when one of the reactants becomes molten. This consequentially influences the position and concentration of the electric current, which in turn influences the entire process. Experiments have also been performed in microgravity conditions. This process has been named Microgravity Field Activated Combustion Synthesis (MFACS). Effects of gravity have been demonstrated, where the reaction wave temperature and velocity demonstrate considerable differences besides the changes of combustion mechanisms with the different high currents applied. Also the threshold for the formation of a stable reaction wave is increased under zero gravity conditions. Electric current was also utilized with a chemical oven technique, where inserts of aluminum with minute amounts of tungsten and tantalum were used to allow observation of effects of settling of the higher density solid particles in liquid aluminum at the present temperature profile and wave velocity of the reaction.

  12. Glycosyl Thioimidates as Versatile Building Blocks for Organic Synthesis

    Science.gov (United States)

    Hasty, S. J.

    2013-01-01

    This review discusses the synthesis and application of glycosyl thioimidates in chemical glycosylation and oligosaccharide assembly. Although glycosyl thioimidates include a broad range of compounds, the discussion herein centers on S-benzothiazolyl (SBaz), S-benzoxazolyl (SBox), S-thiazolinyl (STaz), and S-benzimidazolyl (SBiz) glycosides. These heterocyclic moieties have recently emerged as excellent anomeric leaving groups that express unique characteristics for highly diastereoselective glycosylation and help to provide the streamlined access to oligosaccharides. PMID:24288416

  13. Spin Coulomb Dragging Inhibition of Spin-Polarized Electric Current Injecting into Organic Semiconductors

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun-Qing; QIAO Shi-Zhu; JIA Zhen-Feng; ZHANG Ning-Yu; JI Yan-Ju; PANG Yan-Tao; CHEN Ying; FU Gang

    2008-01-01

    @@ We introduce a one-dimensional spin injection structure comprising a ferromagnetic metal and a nondegenerate organic semiconductor to model electric current polarizations.With this model we analyse spin Coulomb dragging (SCD) effects on the polarization under various electric fields, interface and conductivity conditions.The results show that the SCD inhibits the current polarization.Thus the SCD inhibition should be well considered for accurate evaluation of current polarization in the design of organic spin devices.

  14. Organic Analysis of Catalytic Fischer-Tropsch Type Synthesis Products: Are they Similar to Organics in Chondritic Meteorites?

    Science.gov (United States)

    Yazzie, Cyriah A.; Locke, Darren R.; Johnson, Natasha M.

    2014-01-01

    Fischer-Tropsch Type (FTT) synthesis of organic compounds has been hypothesized to occur in the early solar nebula that formed our Solar System. FTT is a collection of abiotic chemical reactions that convert a mixture of carbon monoxide and hydrogen over nano-catalysts into hydrocarbons and other more complex aromatic compounds. We hypothesized that FTT can generate similar organic compounds as those seen in chondritic meteorites; fragments of asteroids that are characteristic of the early solar system. Specific goals for this project included: 1) determining the effects of different FTT catalyst, reaction temperature, and cycles on organic compounds produced, 2) imaging of organic coatings found on the catalyst, and 3) comparison of organic compounds produced experimentally by FTT synthesis and those found in the ordinary chondrite LL5 Chelyabinsk meteorite. We used Pyrolysis Gas Chromatography Mass Spectrometry (PY-GCMS) to release organic compounds present in experimental FTT and meteorite samples, and Scanning Electron Microscopy (SEM) to take images of organic films on catalyst grains.

  15. Solid-Phase Organic Synthesis and Catalysis: Some Recent Strategies Using Alumina, Silica, and Polyionic Resins

    Directory of Open Access Journals (Sweden)

    Basudeb Basu

    2013-01-01

    Full Text Available Solid-phase organic synthesis (SPOS and catalysis have gained impetus after the seminal discovery of Merrifield’s solid-phase peptide synthesis and also because of wide applicability in combinatorial and high throughput chemistry. A large number of organic, inorganic, or organic-inorganic hybrid materials have been employed as polymeric solid supports to promote or catalyze various organic reactions. This review article provides a concise account on our approaches involving the use of (i alumina or silica, either having doped with metal salts or directly, and (ii polyionic resins to either promote various organic reactions or to immobilize reagents/metal catalysts for subsequent use in hydrogenation and cross-coupling reactions. The reaction parameters, scopes, and limitations, particularly in the context of green chemistry, have been highlighted with pertinent approaches by other groups.

  16. Prebiotic organic matter - Possible pathways for synthesis in a geological context

    Science.gov (United States)

    Chang, S.

    1982-01-01

    Models for the accretion of the earth, core formation, differentiation of the planet into core, mantle, crust, and atmosphere, and prebiotic synthesis of organic materials are reviewed. The development of the Haldane-Oparin and Urey models is traced, and the effect of accretion time on the outgassing process and the composition of the consequent atmosphere is examined. Model prebiotic atmospheres are calculated, the extent of equilibration of the primitive atmosphere is studied and the evolution of the atmosphere prior to organic chemical evolution is reviewed. Finally, experimental progress in synthesis of biological monomers and polymers under presumed early earth conditions is covered.

  17. Microwave Assisted Synthesis of Some Bioactive 1,8-Naphthyridinyl Heterocycles and Development of New Synthetic Methodologies in Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    K. Mogilaiah

    2005-01-01

    @@ 1Introduction Organic synthesis is a powerful discipline, which forms the basis for numerous other areas of research in chemistry and chemical biology. Organic chemists and chemical research in general are under great demand to develop environmentally benign technologies for the synthesis of well-defined precursors and target molecules.It is at this juncture that the microwave assisted technique comes into the picture.Microwave assisted organic reactions have blossomed into an important tool with a variety of applications,particularly after the development of Microwave-induced Organic Reaction Enhancement (MORE) chemistry techniques[1-3]. These techniques require open vessels with little or no solvents and are free of the risk of explosion. MORE chemistry reactions are extremely fast, cleaner than conventional reactions and lead to higher atom economy. Because of short time requirement, ease of workability and eco-friendliness, microwaves provide an alternative green approach to environmentally unacceptable procedures using toxic and expensive reagents. Recently, the use of inorganic solid supports as catalysts[4] have been developed for solvent-free reactions resulting in higher selectivity, milder conditions and easy handling. Clay catalyzed organic reactions are gaining importance owing to their inexpensive nature and special catalytic attributes in heterogeneous reactions[5].

  18. Synthesis of Linearly Fused Benzodipyrrole Based Organic Materials

    Directory of Open Access Journals (Sweden)

    Maarten Vlasselaer

    2016-06-01

    Full Text Available The objective of this review is to give an overview of the synthetic methods to prepare different indolo[3,2-b]carbazoles and similar systems with a potential use in electro-optical devices such as OLEDs (organic light emitting diode, OPVs (organic photovoltaic and OFETs (organic field effect transistor. Some further modifications to the core units and their implications for specific applications are also discussed.

  19. Synthesis of Linearly Fused Benzodipyrrole Based Organic Materials.

    Science.gov (United States)

    Vlasselaer, Maarten; Dehaen, Wim

    2016-06-17

    The objective of this review is to give an overview of the synthetic methods to prepare different indolo[3,2-b]carbazoles and similar systems with a potential use in electro-optical devices such as OLEDs (organic light emitting diode), OPVs (organic photovoltaic) and OFETs (organic field effect transistor). Some further modifications to the core units and their implications for specific applications are also discussed.

  20. Synthesis and characterization of waterborne polyurethane/organic clay nanocomposites

    Institute of Scientific and Technical Information of China (English)

    Zai-feng LI; Sheng-jun WANG; Jin-yan LI

    2008-01-01

    Stable waterborne polyurethane/organic clay latex was synthesized by ultrasonically-assisted mixing with different clay content. Fourier transform infrared (FT-IR) spectra showed that the interaction between NH and C=O was enhanced with low content organic clay loaded. X-ray diffraction (XRD) results implied that the layered organic clay was exfoliated and the crystallization of the hard domain in the waterborne polyurethane (WPU) matrix was enhanced. Transmission electron microscopy (TEM) images show that the layered clay was exfoliated by WPU molecule. The tensile test shows that the mechanical prop-erties were improved by loading organic clay and the desired addition was 1 wt.%.

  1. Iron Catalysis in Organic Synthesis: A Critical Assessment of What It Takes To Make This Base Metal a Multitasking Champion.

    Science.gov (United States)

    Fürstner, Alois

    2016-11-23

    The current status of homogeneous iron catalysis in organic chemistry is contemplated, as are the reasons why this particular research area only recently starts challenging the enduring dominance of the late and mostly noble metals over the field. Centered in the middle of the d-block and able to support formal oxidation states ranging from -II to +VI, iron catalysts hold the promise of being able to encompass organic synthesis at large. They are expected to serve reductive as well as oxidative regimes, can emulate "noble tasks", but are also able to adopt "early" transition metal character. Since a comprehensive coverage of this multidimensional agenda is beyond the scope of an Outlook anyway, emphasis is laid in this article on the analysis of the factors that perhaps allow one to control the multifarious chemical nature of this earth-abundant metal. The challenges are significant, not least at the analytical frontier; their mastery mandates a mindset that differs from the routines that most organic chemists interested in (noble metal) catalysis tend to cultivate. This aspect notwithstanding, it is safe to predict that homogeneous iron catalysis bears the chance to enable a responsible paradigm for chemical synthesis and a sustained catalyst economy, while potentially providing substantial economic advantages. This promise will spur the systematic and in-depth investigations that it takes to upgrade this research area to strategy-level status in organic chemistry and beyond.

  2. Studies on the use of haloperoxidases in organic synthesis.

    NARCIS (Netherlands)

    Franssen, M.C.R.

    1987-01-01

    The subject of this thesis is the use of haloperoxidases in synthetic organic chemistry. Haloperoxidases are enzymes capable of halogenating a variety of organic compounds. They require hydrogen peroxide and halide ions as cosubstrates. The enzymes operate under mild conditions, compared to conventi

  3. Synthesis of Triptorelin Lactate Catalyzed by Lipase in Organic Media

    Science.gov (United States)

    Zhuang, Hong; Wang, Zhi; Wang, Jiaxin; Zhang, Hong; Xun, Erna; Chen, Ge; Yue, Hong; Tang, Ning; Wang, Lei

    2012-01-01

    Triptorelin lactate was successfully synthesized by porcine pancreatic lipase (PPL) in organic solvents. The effects of acyl donor, substrate ratio, organic solvent, temperature, and water activity were investigated. Under the optimum conditions, a yield of 30% for its ester could be achieved in the reaction for about 48 h. PMID:22949842

  4. Synthesis and Application of the Polyether Modified Organic Silicone

    Institute of Scientific and Technical Information of China (English)

    TONG Dong-feng; LIU Jie; ZHAO Chuan-jun

    2014-01-01

    Polyether modified organic silicone was successfully prepared from Eight methyl siloxane, tetramethyl dihydro two siloxane and UPEO. The chemical structure of the Polyether modified organic silicone was characterized by FT-IR. The wettability of treated cotton fabrics was increased. And the softness was improved significantly.

  5. Synthesis of Triptorelin Lactate Catalyzed by Lipase in Organic Media

    Directory of Open Access Journals (Sweden)

    Hong Zhuang

    2012-08-01

    Full Text Available Triptorelin lactate was successfully synthesized by porcine pancreatic lipase (PPL in organic solvents. The effects of acyl donor, substrate ratio, organic solvent, temperature, and water activity were investigated. Under the optimum conditions, a yield of 30% for its ester could be achieved in the reaction for about 48 h.

  6. Studies on the use of haloperoxidases in organic synthesis

    NARCIS (Netherlands)

    Franssen, M.C.R.

    1987-01-01

    The subject of this thesis is the use of haloperoxidases in synthetic organic chemistry. Haloperoxidases are enzymes capable of halogenating a variety of organic compounds. They require hydrogen peroxide and halide ions as cosubstrates. The enzymes operate under mild conditions, compared to

  7. A new metalation complex for organic synthesis and polymerization reactions

    Science.gov (United States)

    Hirshfield, S. M.

    1971-01-01

    Organometallic complex of N,N,N',N' tetramethyl ethylene diamine /TMEDA/ and lithium acts as metalation intermediate for controlled systhesis of aromatic organic compounds and polymer formation. Complex of TMEDA and lithium aids in preparation of various organic lithium compounds.

  8. Organic Matter of the Mulhouse Basin, France: A synthesis

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Hofmann, P.; Huc, A.Y.; Carpentier, B.; Schaeffer, P.; Albrecht, P.; Keely, B.J.; Maxwell, J.R.; Leeuw, J.W. de; Leythaeuser, D.

    1993-01-01

    The lower Oligocene evaporite sequence of the Mulhouse Basin (France) contains organic matter-rich marl deposits. These marls display an overall cyclic variation of sedimentation rate, organic carbon content, hydrogen index and selected molecular parameters over a 30 m thick stratigraphic interval.

  9. Synthesis and Structural Characterization of Carboxylate-Based Metal-Organic Frameworks and Coordination Networks

    Science.gov (United States)

    Calderone, Paul

    Coordination networks (CNs) and metal-organic frameworks (MOFs) are crystalline materials composed of metal ions linked by multifunctional organic ligands. From these connections, infinite arrays of one-, two-, or three-dimensional networks can be formed. Exploratory synthesis and research of novel CNs and MOFs is of current interest because of their many possible industrial applications including gas storage, catalysis, magnetism, and luminescence. A variety of metal centers and organic ligands can be used to synthesize MOFs and CNs under a range of reaction conditions, leading to extraordinary structural diversity. The characteristics of the metals and linkers, such as properties and coordination preferences, play the biggest role in determining the structure and properties of the resulting network. Thus, the choice of metal and linker is dictated by the desired traits of the target network. The pervasive use of transition metal centers in MOF synthesis stems from their well-known coordination behavior with carboxylate-based linkers, thus facilitating design strategies. Conversely, CNs and MOFs based on s-block and lanthanide metals are less studied because each group presents unique challenges to structure prediction. Lanthanide metals have variable coordination spheres capable of accommodating up to twelve atoms, while the bonding in s-block metals takes on a mainly ionic character. In spite of these obstacles, lanthanide and s-block CNs are worthwhile synthetic targets because of their unique properties. Interesting photoluminescent and sensing materials can be developed using lanthanide metals, whereas low atomic weight s-block metals may afford an advantage in gravimetric advantages for gas storage applications. The aim of this research was to expand the current understanding of carboxylate-based CN and MOF synthesis by varying the metals, solvents, and temperatures used. To this end, magnesium-based CNs were examined using a variety of aromatic carboxylate

  10. Organic Fuel Synthesis from Atmospheric Carbon Dioxide and Hydrogen Produced from Water by Electrolysis

    Institute of Scientific and Technical Information of China (English)

    David JOHNSTON

    2009-01-01

    Synthesis of organic fuels from cain dioxide and hydrogen is analysed, in terms of energy recovery efficiency, and the required energy input for electrolysis of water. This electrical energy is related to the thermal energy required in a power station. A method is described to recover heat from energy-producing reactions in the fuel synthesis process, which can then be used to reduce the electrical energy requirement for electrolysis. By co-locating the fuel synthesis plant with a thermal power station, primary (thermal) energy can be used to produce high temperature steam, with a lower electrical requirement for electrolytic production of hydrogen. This can make more efficient use of the primary energy than a thermodynamic engine. Comparison is made with alternative fuels, in terms of energy budget, sustainability, carbon dioxide emissions, etc. The energy security benefits of advanced fuel synthesis are also identified.

  11. High voltage pulsed current in collagen realignment, synthesis, and angiogenesis after Achilles tendon partial rupture

    Directory of Open Access Journals (Sweden)

    Érika P. Rampazo

    2016-01-01

    Full Text Available ABSTRACT Objective To verify the efficacy of high voltage pulsed current in collagen realignment and synthesis and in angiogenesis after the partial rupturing of the Achilles tendon in rats. Method Forty male Wistar rats were randomized into four groups of 10 animals each: sham, cathodic stimulation, anodic stimulation, and alternating stimulation. Their Achilles tendons were submitted to direct trauma by a free-falling metal bar. Then, the treatment was administered for six consecutive days after the injury. In the simulation group, the electrodes were positioned on the animal, but the device remained off for 30 minutes. The other groups used a frequency of 120 pps, sensory threshold, and the corresponding polarity. On the seventh day, the tendons were removed and sent for histological slide preparation for birefringence and Picrosirius Red analysis and for blood vessel quantification. Results No significant difference was observed among the groups regarding collagen realignment (types I or III collagen or quantity of blood vessels. Conclusion High voltage pulsed current for six consecutive days was not effective in collagen realignment, synthesis, or angiogenesis after the partial rupturing of the Achilles tendon in rats.

  12. High voltage pulsed current in collagen realignment, synthesis, and angiogenesis after Achilles tendon partial rupture

    Science.gov (United States)

    Rampazo, Érika P.; Liebano, Richard E.; Pinfildi, Carlos Eduardo; Folha, Roberta A. C.; Ferreira, Lydia M.

    2016-01-01

    ABSTRACT Objective To verify the efficacy of high voltage pulsed current in collagen realignment and synthesis and in angiogenesis after the partial rupturing of the Achilles tendon in rats. Method Forty male Wistar rats were randomized into four groups of 10 animals each: sham, cathodic stimulation, anodic stimulation, and alternating stimulation. Their Achilles tendons were submitted to direct trauma by a free-falling metal bar. Then, the treatment was administered for six consecutive days after the injury. In the simulation group, the electrodes were positioned on the animal, but the device remained off for 30 minutes. The other groups used a frequency of 120 pps, sensory threshold, and the corresponding polarity. On the seventh day, the tendons were removed and sent for histological slide preparation for birefringence and Picrosirius Red analysis and for blood vessel quantification. Results No significant difference was observed among the groups regarding collagen realignment (types I or III collagen) or quantity of blood vessels. Conclusion High voltage pulsed current for six consecutive days was not effective in collagen realignment, synthesis, or angiogenesis after the partial rupturing of the Achilles tendon in rats. PMID:27556387

  13. Synthesis of refractory organic matter in the ionized gas phase of the solar nebula.

    Science.gov (United States)

    Kuga, Maïa; Marty, Bernard; Marrocchi, Yves; Tissandier, Laurent

    2015-06-01

    In the nascent solar system, primitive organic matter was a major contributor of volatile elements to planetary bodies, and could have played a key role in the development of the biosphere. However, the origin of primitive organics is poorly understood. Most scenarios advocate cold synthesis in the interstellar medium or in the outer solar system. Here, we report the synthesis of solid organics under ionizing conditions in a plasma setup from gas mixtures (H2(O)-CO-N2-noble gases) reminiscent of the protosolar nebula composition. Ionization of the gas phase was achieved at temperatures up to 1,000 K. Synthesized solid compounds share chemical and structural features with chondritic organics, and noble gases trapped during the experiments reproduce the elemental and isotopic fractionations observed in primitive organics. These results strongly suggest that both the formation of chondritic refractory organics and the trapping of noble gases took place simultaneously in the ionized areas of the protoplanetary disk, via photon- and/or electron-driven reactions and processing. Thus, synthesis of primitive organics might not have required a cold environment and could have occurred anywhere the disk is ionized, including in its warm regions. This scenario also supports N2 photodissociation as the cause of the large nitrogen isotopic range in the solar system.

  14. Bottom-up synthesis of chiral covalent organic frameworks and their bound capillaries for chiral separation.

    Science.gov (United States)

    Qian, Hai-Long; Yang, Cheng-Xiong; Yan, Xiu-Ping

    2016-07-12

    Covalent organic frameworks (COFs) are a novel class of porous materials, and offer great potential for various applications. However, the applications of COFs in chiral separation and chiral catalysis are largely underexplored due to the very limited chiral COFs available and their challenging synthesis. Here we show a bottom-up strategy to construct chiral COFs and an in situ growth approach to fabricate chiral COF-bound capillary columns for chiral gas chromatography. We incorporate the chiral centres into one of the organic ligands for the synthesis of the chiral COFs. We subsequently in situ prepare the COF-bound capillary columns. The prepared chiral COFs and their bound capillary columns give high resolution for the separation of enantiomers with excellent repeatability and reproducibility. The proposed strategy provides a promising platform for the synthesis of chiral COFs and their chiral separation application.

  15. Harnessing the Power of the Water-Gas Shift Reaction for Organic Synthesis.

    Science.gov (United States)

    Ambrosi, Andrea; Denmark, Scott E

    2016-09-26

    Since its original discovery over a century ago, the water-gas shift reaction (WGSR) has played a crucial role in industrial chemistry, providing a source of H2 to feed fundamental industrial transformations such as the Haber-Bosch synthesis of ammonia. Although the production of hydrogen remains nowadays the major application of the WGSR, the advent of homogeneous catalysis in the 1970s marked the beginning of a synergy between WGSR and organic chemistry. Thus, the reducing power provided by the CO/H2 O couple has been exploited in the synthesis of fine chemicals; not only hydrogenation-type reactions, but also catalytic processes that require a reductive step for the turnover of the catalytic cycle. Despite the potential and unique features of the WGSR, its applications in organic synthesis remain largely underdeveloped. The topic will be critically reviewed herein, with the expectation that an increased awareness may stimulate new, creative work in the area.

  16. Bottom-up synthesis of chiral covalent organic frameworks and their bound capillaries for chiral separation

    Science.gov (United States)

    Qian, Hai-Long; Yang, Cheng-Xiong; Yan, Xiu-Ping

    2016-07-01

    Covalent organic frameworks (COFs) are a novel class of porous materials, and offer great potential for various applications. However, the applications of COFs in chiral separation and chiral catalysis are largely underexplored due to the very limited chiral COFs available and their challenging synthesis. Here we show a bottom-up strategy to construct chiral COFs and an in situ growth approach to fabricate chiral COF-bound capillary columns for chiral gas chromatography. We incorporate the chiral centres into one of the organic ligands for the synthesis of the chiral COFs. We subsequently in situ prepare the COF-bound capillary columns. The prepared chiral COFs and their bound capillary columns give high resolution for the separation of enantiomers with excellent repeatability and reproducibility. The proposed strategy provides a promising platform for the synthesis of chiral COFs and their chiral separation application.

  17. Proton-Coupled Electron Transfer in Organic Synthesis: Fundamentals, Applications, and Opportunities.

    Science.gov (United States)

    Miller, David C; Tarantino, Kyle T; Knowles, Robert R

    2016-06-01

    Proton-coupled electron transfers (PCETs) are unconventional redox processes in which both protons and electrons are exchanged, often in a concerted elementary step. While PCET is now recognized to play a central a role in biological redox catalysis and inorganic energy conversion technologies, its applications in organic synthesis are only beginning to be explored. In this chapter, we aim to highlight the origins, development, and evolution of the PCET processes most relevant to applications in organic synthesis. Particular emphasis is given to the ability of PCET to serve as a non-classical mechanism for homolytic bond activation that is complimentary to more traditional hydrogen atom transfer processes, enabling the direct generation of valuable organic radical intermediates directly from their native functional group precursors under comparatively mild catalytic conditions. The synthetically advantageous features of PCET reactivity are described in detail, along with examples from the literature describing the PCET activation of common organic functional groups.

  18. Novel Metal Organic Framework Synthesis for Spacecraft Oxygen Capture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek and University of Utah propose to develop novel metal organic framework (MOF) material to efficiently capture oxygen in spacecraft cabin environment. The...

  19. A Perspective on the Synthesis, Purification, and Characterization of Porous Organic Cages.

    Science.gov (United States)

    Briggs, Michael E; Cooper, Andrew I

    2017-01-10

    Porous organic cages present many opportunities in functional materials chemistry, but the synthetic challenges for these molecular solids are somewhat different from those faced in the areas of metal-organic frameworks, covalent-organic frameworks, or porous polymer networks. Here, we highlight the practical methods that we have developed for the design, synthesis, and characterization of imine porous organic cages using CC1 and CC3 as examples. The key points are transferable to other cages, and this perspective should serve as a practical guide to researchers who are new to this field.

  20. Synthesis of ordered carbonaceous frameworks from organic crystals.

    Science.gov (United States)

    Nishihara, Hirotomo; Hirota, Tetsuya; Matsuura, Kenta; Ohwada, Mao; Hoshino, Norihisa; Akutagawa, Tomoyuki; Higuchi, Takeshi; Jinnai, Hiroshi; Koseki, Yoshitaka; Kasai, Hitoshi; Matsuo, Yoshiaki; Maruyama, Jun; Hayasaka, Yuichiro; Konaka, Hisashi; Yamada, Yasuhiro; Yamaguchi, Shingi; Kamiya, Kazuhide; Kamimura, Takuya; Nobukuni, Hirofumi; Tani, Fumito

    2017-07-24

    Despite recent advances in the carbonization of organic crystalline solids like metal-organic frameworks or supramolecular frameworks, it has been challenging to convert crystalline organic solids into ordered carbonaceous frameworks. Herein, we report a route to attaining such ordered frameworks via the carbonization of an organic crystal of a Ni-containing cyclic porphyrin dimer (Ni2-CPDPy). This dimer comprises two Ni-porphyrins linked by two butadiyne (diacetylene) moieties through phenyl groups. The Ni2-CPDPy crystal is thermally converted into a crystalline covalent-organic framework at 581 K and is further converted into ordered carbonaceous frameworks equipped with electrical conductivity by subsequent carbonization at 873-1073 K. In addition, the porphyrin's Ni-N4 unit is also well retained and embedded in the final framework. The resulting ordered carbonaceous frameworks exhibit an intermediate structure, between organic-based frameworks and carbon materials, with advantageous electrocatalysis. This principle enables the chemical molecular-level structural design of three-dimensional carbonaceous frameworks.Carbon-based materials are promising alternatives to noble metal catalysts, but their structures are typically disordered and difficult to control. Here, the authors obtain ordered carbonaceous frameworks with advantageous electrocatalytic properties via the carbonization of nickel-containing porphyrin dimer networks.

  1. Synthesis of an Isoindoline-Annulated, Tricyclic Sultam Library via Microwave-Assisted, Continuous-Flow Organic Synthesis (MACOS).

    Science.gov (United States)

    Ullah, Farman; Zang, Qin; Javed, Salim; Porubsky, Patrick; Neuenswander, Benjamin; Lushington, Gerald H; Hanson, Paul R; Organ, Michael G

    2012-01-01

    A microwave-assisted, continuous-flow organic synthesis (MACOS) protocol for the synthesis of an isoindoline-annulat-ed, tricyclic sultam library, utilizing a Heck-aza-Michael (HaM) strategy, is reported. This sequence involves a Heck reaction on vi-nylsulfonamides with batch microwave heating followed by a one-pot, sequential intramolecular aza-Michael cyclization/Boc-deprot-ection using MACOS. Subsequent cyclization with either 1,1'-carbonyldiimidazole or chloromethyl pivalate using MACOS provided an array of tricyclic sultams. This efficient three-step protocol requires only a few hours to produce the target sultams starting from simple starting materials. Using this strategy, a 38-member library of isoindoline-annulated sultams was generated in good to excellent overall yields (53-87%).

  2. Synthesis of an Isoindoline-Annulated, Tricyclic Sultam Library via Microwave-Assisted, Continuous-Flow Organic Synthesis (MACOS)

    Science.gov (United States)

    Ullah, Farman; Zang, Qin; Javed, Salim; Porubsky, Patrick; Neuenswander, Benjamin; Lushington, Gerald H.

    2013-01-01

    A microwave-assisted, continuous-flow organic synthesis (MACOS) protocol for the synthesis of an isoindoline-annulat-ed, tricyclic sultam library, utilizing a Heck–aza-Michael (HaM) strategy, is reported. This sequence involves a Heck reaction on vi-nylsulfonamides with batch microwave heating followed by a one-pot, sequential intramolecular aza-Michael cyclization/Boc-deprot-ection using MACOS. Subsequent cyclization with either 1,1′-carbonyldiimidazole or chloromethyl pivalate using MACOS provided an array of tricyclic sultams. This efficient three-step protocol requires only a few hours to produce the target sultams starting from simple starting materials. Using this strategy, a 38-member library of isoindoline-annulated sultams was generated in good to excellent overall yields (53–87%). PMID:24244052

  3. Current state of ethics literature synthesis: a systematic review of reviews.

    Science.gov (United States)

    Mertz, Marcel; Kahrass, Hannes; Strech, Daniel

    2016-10-03

    Modern standards for evidence-based decision making in clinical care and public health still rely solely on eminence-based input when it comes to normative ethical considerations. Manuals for clinical guideline development or health technology assessment (HTA) do not explain how to search, analyze, and synthesize relevant normative information in a systematic and transparent manner. In the scientific literature, however, systematic or semi-systematic reviews of ethics literature already exist, and scholarly debate on their opportunities and limitations has recently bloomed. A systematic review was performed of all existing systematic or semi-systematic reviews for normative ethics literature on medical topics. The study further assessed how these reviews report on their methods for search, selection, analysis, and synthesis of ethics literature. We identified 84 reviews published between 1997 and 2015 in 65 different journals and demonstrated an increasing publication rate for this type of review. While most reviews reported on different aspects of search and selection methods, reporting was much less explicit for aspects of analysis and synthesis methods: 31 % did not fulfill any criteria related to the reporting of analysis methods; for example, only 25 % of the reviews reported the ethical approach needed to analyze and synthesize normative information. While reviews of ethics literature are increasingly published, their reporting quality for analysis and synthesis of normative information should be improved. Guiding questions are: What was the applied ethical approach and technical procedure for identifying and extracting the relevant normative information units? What method and procedure was employed for synthesizing normative information? Experts and stakeholders from bioethics, HTA, guideline development, health care professionals, and patient organizations should work together to further develop this area of evidence-based health care.

  4. Asymmetric synthesis of amino acid precursors in interstellar complex organics by circularly polarized light

    OpenAIRE

    Takano, Yoshinori; Takahashi, Jun-ichi; Kaneko, Takeo; Marumo, Katsumi; Kobayashi, Kensei

    2007-01-01

    The asymmetric synthesis of amino acid precursors from complex organics have been performed. A gaseous mixture of carbon monoxide, ammonia and water (molecules which are among those identified in the interstellar medium) was irradiated with 3.0 MeV protons to obtain amino acid precursors within high-molecular-weight complex organics of up to 3,000 Da. The amino acid precursor products synthesized were then irradiated with right (R-) or left (L-) ultraviolet circularly polarized light (UV-CPL)...

  5. Enzymatic Synthesis of Dipeptide Derivatives Containing Noncoded Amino Acids in Organic Solvents

    Institute of Scientific and Technical Information of China (English)

    YANG,Hong(杨洪); ZHOU,Chuang(周闯); TIAN,Gui-Ling(田桂玲); YE,Yun-Hua(叶蕴华)

    2002-01-01

    A series of dipeptide derivatives containing non-coded amino acis, N-Boc-4-X-Phe-Ala-NHNHNHPh (X= Cl, Br, I, NO2),were synthesized by using thermoase in organic solvents. The physical data were consistent with the same samples prepared by 3-( diethoxyphosphoryloxy)-1, 2, 3-benzotriazin-4 (3H)-one (DEPBT). Influence of different substituted groups of the non-coded amino acids and different organic solvents on the enzymatic peptide synthesis was studied.

  6. Clean and Efficient Synthesis Using Mechanochemistry: Coordination Polymers, Metal-Organic Frameworks and Metallodrugs

    OpenAIRE

    Friščić, Tomislav; Halasz, Ivan; Štrukil, Vjekoslav; Maksić, Mirjana; Dinnebier, Robert E

    2012-01-01

    This review briefly discusses recent advances and future prospects in the mechanochemical synthesis of coordination compounds by ball milling and grinding, and highlights our contributions to the mechanosynthesis of porous metal-organic frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs), metal-organic pharmaceutical derivatives and metallodrugs using the recently developed mechanochemical methods of liquid-assisted grinding (LAG) and ion- and liquid-assisted grinding (ILAG). The...

  7. Liquid phase oxidation via heterogeneous catalysis organic synthesis and industrial applications

    CERN Document Server

    Clerici, Mario G

    2013-01-01

    Sets the stage for environmentally friendly industrial organic syntheses From basic principles to new and emerging industrial applications, this book offers comprehensive coverage of heterogeneous liquid-phase selective oxidation catalysis. It fully examines the synthesis, characterization, and application of catalytic materials for environmentally friendly organic syntheses. Readers will find coverage of all the important classes of catalysts, with an emphasis on their stability and reusability. Liquid Phase Oxidation via Heterogeneous Catalysis features contributions from an internation

  8. An acid-stable tert-butyldiarylsilyl (TBDAS) linker for solid-phase organic synthesis.

    Science.gov (United States)

    Diblasi, Christine M; Macks, Daniel E; Tan, Derek S

    2005-04-28

    [reaction: see text] A new, robust tert-butyldiarylsilyl (TBDAS) linker has been developed for solid-phase organic synthesis. This linker is stable to both protic and Lewis acidic reaction conditions, overcoming a significant limitation of previously reported silyl linkers. Solid-phase acetal deprotection, olefination, asymmetric allylation, and silyl protecting group deblocking reactions have been demonstrated with TBDAS-linked substrates.

  9. Modulated synthesis of zirconium-metal organic framework (Zr-MOF) for hydrogen storage applications

    CSIR Research Space (South Africa)

    Ren, Jianwei

    2014-01-01

    Full Text Available A modulated synthesis of Zr-metal organic framework (Zr-MOF) with improved ease of handling and decreased reaction time is reported to yield highly crystalline Zr-MOF with well-defined octahedral shaped crystals for practical hydrogen storage...

  10. 1-Isocyano-2-dimethylamino-alkenes: Versatile reagents in diversity-oriented organic synthesis

    NARCIS (Netherlands)

    Dömling, Alexander; Illgen, Katrin

    2005-01-01

    1-Isocyano-2-dimethylamino-alkenes are versatile and multifunctional reagents in organic synthesis. Two useful protocols are given for multicomponent reactions (MCRs) for the assembly of a 6-oxo-1,4,5,6-tetrahydropyrazine-2- carboxylic acid methyl ester derivative and a highly substituted thiazole.

  11. A Simple Assignment that Enhances Students' Ability to Solve Organic Chemistry Synthesis Problems and Understand Mechanisms

    Science.gov (United States)

    Teixeira, Jennifer; Holman, R. W.

    2008-01-01

    Organic chemistry students typically struggle with the retrosynthetic approach to solving synthesis problems because most textbooks present the chemistry grouped by "reactions of the functional group". In contrast, the retrosynthetic approach requires the student to envision "reactions that yield the functional group". A second challenge is the…

  12. Interdisciplinary Learning for Chemical Engineering Students from Organic Chemistry Synthesis Lab to Reactor Design to Separation

    Science.gov (United States)

    Armstrong, Matt; Comitz, Richard L.; Biaglow, Andrew; Lachance, Russ; Sloop, Joseph

    2008-01-01

    A novel approach to the Chemical Engineering curriculum sequence of courses at West Point enabled our students to experience a much more realistic design process, which more closely replicated a real world scenario. Students conduct the synthesis in the organic chemistry lab, then conduct computer modeling of the reaction with ChemCad and…

  13. Synthesis of a Near-Infrared Emitting Squaraine Dye in an Undergraduate Organic Laboratory

    Science.gov (United States)

    Marks, Patrick; Levine, Mindy

    2012-01-01

    Squaraines are a class of organic fluorophores that possess unique photophysical properties, including strong near-infrared absorption and emission. The synthesis of many squaraines involves the condensation of an electron-rich aromatic ring with squaric acid. These reactions are generally refluxed overnight in a benzene-butanol solvent mixture.…

  14. 2005 Nobel Prize in Chemistry: Development of the Olefin Metathesis Method in Organic Synthesis

    Science.gov (United States)

    Casey, Charles P.

    2006-01-01

    The 2005 Nobel Prize in Chemistry was awarded "for the development of the metathesis method in organic synthesis". The discoveries of the laureates provided a chemical reaction used daily in the chemical industry for the efficient and more environmentally friendly production of important pharmaceuticals, fuels, synthetic fibers, and many other…

  15. Sustainable utility of magnetically recyclable nano-catalysts in water: Applications in organic synthesis

    Science.gov (United States)

    Magnetically recyclable nano-catalysts and their use in aqueous media is a perfect combination for the development of greener sustainable methodologies in organic synthesis. It is well established that magnetically separable nano-catalysts avoid waste of catalysts or reagents and...

  16. Interdisciplinary Learning for Chemical Engineering Students from Organic Chemistry Synthesis Lab to Reactor Design to Separation

    Science.gov (United States)

    Armstrong, Matt; Comitz, Richard L.; Biaglow, Andrew; Lachance, Russ; Sloop, Joseph

    2008-01-01

    A novel approach to the Chemical Engineering curriculum sequence of courses at West Point enabled our students to experience a much more realistic design process, which more closely replicated a real world scenario. Students conduct the synthesis in the organic chemistry lab, then conduct computer modeling of the reaction with ChemCad and…

  17. 1-Isocyano-2-dimethylamino-alkenes: Versatile reagents in diversity-oriented organic synthesis

    NARCIS (Netherlands)

    Dömling, Alexander; Illgen, Katrin

    2005-01-01

    1-Isocyano-2-dimethylamino-alkenes are versatile and multifunctional reagents in organic synthesis. Two useful protocols are given for multicomponent reactions (MCRs) for the assembly of a 6-oxo-1,4,5,6-tetrahydropyrazine-2- carboxylic acid methyl ester derivative and a highly substituted thiazole.

  18. Synthesis and Characterization of the First Organically Templated Layered Cerium Phosphate Fluoride

    National Research Council Canada - National Science Library

    Ranbo Yu; Dan Wang; Shintaro Ishiwata; Takashi Saito; Masaki Azuma; Mikio Takano; Yunfa Chen; Jinghai Li

    2004-01-01

      A novel organically templated layered cerium phosphate fluoride [(CH2)2(NH3)2]0.5[CeIVF3(HPO4)] has been synthesized by hydrothermal synthesis technology, and characterized by means of single-crystal X-ray diffraction...

  19. Synthesis and Hydrogenation of Disubstituted Chalcones: A Guided-Inquiry Organic Chemistry Project

    Science.gov (United States)

    Mohrig, Jerry R.; Hammond, Christina Noring; Schatz, Paul F.; Davidson, Tammy A.

    2009-01-01

    Guided-inquiry experiments offer the same opportunities to participate in the process of science as classical organic qualitative analysis used to do. This three-week guided-inquiry project involves an aldol-dehydration synthesis of a chalcone chosen from a set of nine, followed by a catalytic transfer hydrogenation reaction using ammonium formate…

  20. Metal organic framework synthesis in the presence of surfactants: towards hierarchical MOFs?

    NARCIS (Netherlands)

    Seoane, B.; Dikhtiarenko, A.; Mayoral, A.; Tellez, C.; Coronas,J.; Kapteijn, F.; Gascon, J.

    2015-01-01

    The effect of synthesis pH and H2O/EtOH molar ratio on the textural properties of different aluminium trimesate metal organic frameworks (MOFs) prepared in the presence of the well-known cationic surfactant cetyltrimethylammonium bromide (CTAB) at 120 °C was studied with the purpose of obtaining a

  1. 2005 Nobel Prize in Chemistry: Development of the Olefin Metathesis Method in Organic Synthesis

    Science.gov (United States)

    Casey, Charles P.

    2006-01-01

    The 2005 Nobel Prize in Chemistry was awarded "for the development of the metathesis method in organic synthesis". The discoveries of the laureates provided a chemical reaction used daily in the chemical industry for the efficient and more environmentally friendly production of important pharmaceuticals, fuels, synthetic fibers, and many other…

  2. Sustainable utility of magnetically recyclable nano-catalysts in water: Applications in organic synthesis

    Science.gov (United States)

    Magnetically recyclable nano-catalysts and their use in aqueous media is a perfect combination for the development of greener sustainable methodologies in organic synthesis. It is well established that magnetically separable nano-catalysts avoid waste of catalysts or reagents and...

  3. High-throughput synthesis and characterization of nanocrystalline porphyrinic zirconium metal-organic frameworks.

    Science.gov (United States)

    Kelty, M L; Morris, W; Gallagher, A T; Anderson, J S; Brown, K A; Mirkin, C A; Harris, T D

    2016-06-14

    We describe and employ a high-throughput screening method to accelerate the synthesis and identification of pure-phase, nanocrystalline metal-organic frameworks (MOFs). We demonstrate the efficacy of this method through its application to a series of porphyrinic zirconium MOFs, resulting in the isolation of MOF-525, MOF-545, and PCN-223 on the nanoscale.

  4. Oxidation of organic pollutants on BDD anodes using modulated current electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Panizza, M. [Department of Chemical and Process Engineering, University of Genoa, P.le J.F. Kennedy 1, 16129 Genova (Italy)], E-mail: marco.panizza@unige.it; Kapalka, Agnieszka [Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Comninellis, Ch. [Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)], E-mail: christos.comninellis@epfl.ch

    2008-01-01

    In this paper, a theoretical model is presented for organic pollutants mineralization at high current efficiency (close to 100%) and low energy consumption on boron-doped diamond electrodes. The model is formulated for a perfect mixed electrochemical reactor operated as a batch recirculation system under multiple current steps, in which the applied current is adjusted during the electrolysis to be close to the limiting value. An experimental validation with the anodic oxidation of 3,4,5-trihydroxybenzoic acid is also provided. The results have shown that multiple current steps electrolysis and continuous current control allowed obtaining high oxidation rate and current efficiency.

  5. A two-dimensional polymer prepared by organic synthesis.

    Science.gov (United States)

    Kissel, Patrick; Erni, Rolf; Schweizer, W Bernd; Rossell, Marta D; King, Benjamin T; Bauer, Thomas; Götzinger, Stephan; Schlüter, A Dieter; Sakamoto, Junji

    2012-02-05

    Synthetic polymers are widely used materials, as attested by a production of more than 200 millions of tons per year, and are typically composed of linear repeat units. They may also be branched or irregularly crosslinked. Here, we introduce a two-dimensional polymer with internal periodicity composed of areal repeat units. This is an extension of Staudinger's polymerization concept (to form macromolecules by covalently linking repeat units together), but in two dimensions. A well-known example of such a two-dimensional polymer is graphene, but its thermolytic synthesis precludes molecular design on demand. Here, we have rationally synthesized an ordered, non-equilibrium two-dimensional polymer far beyond molecular dimensions. The procedure includes the crystallization of a specifically designed photoreactive monomer into a layered structure, a photo-polymerization step within the crystal and a solvent-induced delamination step that isolates individual two-dimensional polymers as free-standing, monolayered molecular sheets.

  6. Synthesis and Resolution of the Atropisomeric 1,1'-Bi-2-Naphthol: An Experiment in Organic Synthesis and 2-D NMR Spectroscopy

    Science.gov (United States)

    Mak, Kendrew K. W.

    2004-01-01

    NMR spectroscopy is presented. It is seen that the experiment regarding the synthesis and resolution of 1,1'-Bi-2-naphtol presents a good experiment for teaching organic synthesis and NMR spectroscopy and provides a strategy for obtaining enantiopure compounds from achiral starting materials.

  7. Synthesis and Resolution of the Atropisomeric 1,1'-Bi-2-Naphthol: An Experiment in Organic Synthesis and 2-D NMR Spectroscopy

    Science.gov (United States)

    Mak, Kendrew K. W.

    2004-01-01

    NMR spectroscopy is presented. It is seen that the experiment regarding the synthesis and resolution of 1,1'-Bi-2-naphtol presents a good experiment for teaching organic synthesis and NMR spectroscopy and provides a strategy for obtaining enantiopure compounds from achiral starting materials.

  8. 75 FR 29967 - National Organic Program Request for an Extension of a Currently Approved Information Collection

    Science.gov (United States)

    2010-05-28

    ...; ] DEPARTMENT OF AGRICULTURE Agricultural Marketing Service National Organic Program Request for an Extension of a Currently Approved Information Collection AGENCY: Agricultural Marketing Service, USDA. ACTION....C. Chapter 35), this notice announces the Agricultural Marketing Service's intention to...

  9. Numerical study on short-circuit current of single layer organic solar cells with Schottkey contacts

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The influence of the cathode work function,carriers mobilities and temperature on the short-circuit current of single layer organic solar cells with Schottkey contacts was numerically studied,and the quantitative dependences of the short-circuit current on these quantities were obtained.The results provide the theoretical foundation for experimental study of single layer organic solar cells with Schottkey contacts.

  10. Carbonyl-bridged energetic materials: biomimetic synthesis, organic catalytic synthesis, and energetic performances.

    Science.gov (United States)

    Feng, Yong-An; Qiu, Hao; Yang, Sa-Sha; Du, Jiang; Zhang, Tong-Lai

    2016-11-01

    In order to obtain high-performance energetic materials, in this work, carbonyl groups (C[double bond, length as m-dash]O) have been newly introduced as sole bridging groups in the field of energetic materials. To this end, two tailored green methods for the synthesis of carbonyl-bridged energetic compounds have been developed for the first time. One is a biomimetic synthesis, in which the conversion route of heme to biliverdin has been used to obtain metal-containing energetic compounds. The other one is an organocatalysis, in which guanidinium serves as an energetic catalyst to afford other energetic compounds. Experimental studies and theoretical calculations have shown that carbonyl-bridged energetic compounds exhibit excellent energetic properties, which is promising for the carbonyl group as a new important and effective linker in energetic materials.

  11. Organic synthesis by quench reactions. [in prebiotic simulation experiment

    Science.gov (United States)

    Park, W. K.; Hochstim, A. R.; Ponnamperuma, C.

    1975-01-01

    Study of the effects of chemical quench reactions on the formation of organic compounds at a water surface under simulated primordial earth conditions. A mixture of gaseous methane and ammonia over a water surface was exposed to an arc discharge between an electrode and the water surface, generating reactive species. Various organic molecules were formed by a subsequent quenching of these species generated on the water surface. The effects of these water-surface quench reactions were assessed by comparing the amounts of synthesized molecules to the amounts which formed during the discharge of an arc above the water level. It is concluded that the quench (or wet) discharge led to faster rates of reactions, higher-molecular-weight organic compounds, and one-order-of-magnitude larger yields than the dry discharge.

  12. Organic synthesis by quench reactions. [in prebiotic simulation experiment

    Science.gov (United States)

    Park, W. K.; Hochstim, A. R.; Ponnamperuma, C.

    1975-01-01

    Study of the effects of chemical quench reactions on the formation of organic compounds at a water surface under simulated primordial earth conditions. A mixture of gaseous methane and ammonia over a water surface was exposed to an arc discharge between an electrode and the water surface, generating reactive species. Various organic molecules were formed by a subsequent quenching of these species generated on the water surface. The effects of these water-surface quench reactions were assessed by comparing the amounts of synthesized molecules to the amounts which formed during the discharge of an arc above the water level. It is concluded that the quench (or wet) discharge led to faster rates of reactions, higher-molecular-weight organic compounds, and one-order-of-magnitude larger yields than the dry discharge.

  13. Synthesis and characterization of a new organic semiconductor material

    Energy Technology Data Exchange (ETDEWEB)

    Tiffour, Imane [Laboratoire de Génie Physique, Département de Physique, Université de Tiaret, Tiaret 14000 (Algeria); Faculté des Sciences et Technologies, Université Mustapha Stambouli, Mascara 29000 (Algeria); Dehbi, Abdelkader [Laboratoire de Génie Physique, Département de Physique, Université de Tiaret, Tiaret 14000 (Algeria); Mourad, Abdel-Hamid I., E-mail: ahmourad@uaeu.ac.ae [Mechanical Engineering Department, Faculty of Engineering, United Arab Emirates University, Al-Ain, P.O. Box 15551 (United Arab Emirates); Belfedal, Abdelkader [Faculté des Sciences et Technologies, Université Mustapha Stambouli, Mascara 29000 (Algeria); LPCMME, Département de Physique, Université d' Oran Es-sénia, 3100 Oran (Algeria)

    2016-08-01

    The objective of this study is to create an ideal mixture of Acetaminophen/Curcumin leading to a new and improved semiconductor material, by a study of the electrical, thermal and optical properties. This new material will be compared with existing semiconductor technology to discuss its viability within the industry. The electrical properties were investigated using complex impedance spectroscopy and optical properties were studied by means of UV-Vis spectrophotometry. The electric conductivity σ, the dielectric constant ε{sub r}, the activation energy E{sub a}, the optical transmittance T and the gap energy E{sub g} have been investigated in order to characterize our organic material. The electrical conductivity of the material is approximately 10{sup −5} S/m at room temperature, increasing the temperature causes σ to increase exponentially to approximately 10{sup −4} S/m. The activation energy obtained for the material is equal to 0.49 ± 0.02 ev. The optical absorption spectra show that the investigating material has absorbance in the visible range with a maximum wavelength (λ{sub max}) 424 nm. From analysis, the absorption spectra it was found the optical band gap equal to 2.6 ± 0.02 eV and 2.46 ± 0.02 eV for the direct and indirect transition, respectively. In general, the study shows that the developed material has characteristics of organic semiconductor material that has a promising future in the field of organic electronics and their potential applications, e.g., photovoltaic cells. - Highlights: • Development of a new organic acetaminophen/Curcumin semiconductor material. • The developed material has characteristics of an organic semiconductor. • It has electrical conductivity comparable to available organic semiconductors. • It has high optical transmittance and low permittivity/dielectric constant.

  14. Nanogold plasmonic photocatalysis for organic synthesis and clean energy conversion.

    Science.gov (United States)

    Wang, Changlong; Astruc, Didier

    2014-01-01

    This review provides the basic concepts, an overall survey and the state-of-the art of plasmon-based nanogold photocatalysis using visible light including fundamental understanding and major applications to organic reactions and clean energy-conversion systems. First, the basic concepts of localized surface plasmon resonance (LSPR) are recalled, then the major preparation methods of AuNP-based plasmonic photocatalysts are reviewed. The major part of the review is dedicated to the latest progress in the application of nanogold plasmonic photocatalysis to organic transformations and energy conversions, and the proposed mechanisms are discussed. In conclusion, new challenges and perspectives are proposed and analyzed.

  15. The role of ionizing radiation in primordial organic synthesis.

    Science.gov (United States)

    Ponnamperuma, C.; Sweeney, M.

    1971-01-01

    Attempt to reveal how ionizing radiation may have been effective in producing the molecules necessary for life. In examining the sequence of events leading to the appearance of the first organisms the problem is considered in two parts: the formation of the small molecules such as amino acids, purines, pyrimidines, and carbohydrates; and the condensation of these molecules to give rise to polypeptides and polynucleotides. It is concluded that in the accumulation of organic compounds on the early earth ionizing radiation was not only a substantial part of the available energy, but was also an effective form of energy.

  16. The role of ionizing radiation in primordial organic synthesis.

    Science.gov (United States)

    Ponnamperuma, C.; Sweeney, M.

    1971-01-01

    Attempt to reveal how ionizing radiation may have been effective in producing the molecules necessary for life. In examining the sequence of events leading to the appearance of the first organisms the problem is considered in two parts: the formation of the small molecules such as amino acids, purines, pyrimidines, and carbohydrates; and the condensation of these molecules to give rise to polypeptides and polynucleotides. It is concluded that in the accumulation of organic compounds on the early earth ionizing radiation was not only a substantial part of the available energy, but was also an effective form of energy.

  17. Advertising or public relations – which is the organizations choice in the current period?

    Directory of Open Access Journals (Sweden)

    Simona Duhalm

    2009-12-01

    Full Text Available In the current period, when the issue of efficient use of financial resources is a central, organizations seeking the best ways to both promote their self-image, and products or services they produce and sell. Between the promotional techniques by the mass communication in which organizations can appeal, the makers have to choose between advertising and public relations activities.

  18. Facile synthesis of zirconia doped hybrid organic inorganic silica membranes

    NARCIS (Netherlands)

    Hove, ten M.; Nijmeijer, A.; Winnubst, A.J.A.

    2015-01-01

    Hybrid organic inorganic silica membranes are interesting candidates for gas-separation applications due to their excellent hydrothermal stability. However, up to now these membranes lack the separation performance required to separate hydrogen from carbon dioxide. In this work a procedure for dopin

  19. Green chemistry principles in organic compound synthesis and analysis

    Directory of Open Access Journals (Sweden)

    Ruchi Verma

    2014-03-01

    Full Text Available The present review focus on various green chemistry approaches which could be utilized in the organic compounds in practical classes for undergraduate level in comparison of conventional methods. These methods avoid the usage of hazardous substances and are environmental friendly.

  20. Experimental Investigation of Organic Synthesis in Hydrothermal Environments

    Science.gov (United States)

    Shock, Everett L.

    1998-01-01

    The results of the investigation were presented at a Astrobiology Institute General Meeting. Seafloor hydrothermal systems may be the most likely locations on the early Earth for the emergence of life. Because of the disequilibrium inherent in such dynamic, mixing environments, abundant chemical energy would have been available for formation of the building blocks of life. In addition, theoretical studies suggest that organic compounds in these conditions would reach metastable states, due to kinetic barriers to the formation of stable equilibrium products (CO2 and methane). The speciation of organic carbon in metastable states is highly dependent on the oxidation state, pH, temperature, pressure and bulk composition of the system. The goal of our research is to investigate the effects of a number external variables on the formation, transformation, and stability of organic compounds at hydrothermal conditions. We have begun experimental work to attempt to control the oxidation state of simulated hydrothermal systems by using buffers composed of mineral powders and gas mixtures. We are also beginning to test the stability of organic compounds under these conditions.

  1. Biodiesel Synthesis and Evaluation: An Organic Chemistry Experiment

    Science.gov (United States)

    Bucholtz, Ehren C.

    2007-01-01

    A new lab esterification reaction based on biodiesel preparation and viscosity, which provides a model experience of industrial process to understand oxidation of vicinal alcohols by periodic acid, is presented. This new desertification experiment and periodate analysis of glycerol for the introductory organic chemistry laboratory provides an…

  2. CO2 mitigation potential in farmland of China by altering current organic matter amendment pattern

    Institute of Scientific and Technical Information of China (English)

    CADISCH; Georg

    2010-01-01

    The estimation of the global warming mitigation potential in terrestrial ecosystems is of great importance for decision makers to adopt measures to increase soil organic carbon (SOC) as well as to reduce greenhouse gas (GHGs) emissions. In this paper, we compiled data published in peer-reviewed journals, and conducted a holistic analysis of the effects of organic matter amendment on soil organic carbon sequestration, methane (CH4) and nitrous oxide (N2O) emissions in paddy and upland systems. Results showed that organic matter amendment increased soil organic carbon content, and apparent conversion rate of organic matter carbon to soil organic carbon in paddies was constant, while that in uplands decreased along with amendment years at 25 years time scale. Organic matter amendment during the rice season led to large CH4-C emissions, e.g on average 99.5 g CH4-C per kg organic carbon input under intermittent flood conditions, and 191.7 g CH4-C per kg organic carbon input under continuous flood conditions, respectively. By alteration of organic matter amendment from rice season to off-rice upland crop season, estimated CH4-C emissions in China could be cut by 3.5 Tg yr-1, accounting for 63% of current CH4-C emissions (5.5 Tg). If organic matter amendment percentage was increased from current 30% to future 50% of organic matter production and by alteration of organic matter amendment from rice season to off-rice upland crop season, the equivalent CO2-C mitigation potential in farmland of China would be 49.2 Tg yr-1 at the 10th year organic matter amendment and 36.0 Tg yr-1 at the 30th year amendment. These findings are important not only for China but also for the other rice production countries to increase farmland global warming mitigation.

  3. Effects of water on reactions for waste treatment, organic synthesis, and bio-refinery in sub- and supercritical water.

    Science.gov (United States)

    Akizuki, Makoto; Fujii, Tatsuya; Hayashi, Rumiko; Oshima, Yoshito

    2014-01-01

    Current research analyzing the effects of water in the field of homogeneous and heterogeneous reactions of organics in sub- and supercritical water are reviewed in this article. Since the physical properties of water (e.g., density, ion product and dielectric constants) can affect the reaction rates and mechanisms of various reactions, understanding the effects that water can have is important in controlling reactions. For homogeneous reactions, the effects of water on oxidation, hydrolysis, aldol condensation, Beckman rearrangement and biomass refining were introduced including recent experimental results up to 100 MPa using special pressure-resistance equipment. For heterogeneous reactions, the effects of ion product on acid/base-catalyzed reactions, such as hydrothermal conversion of biomass-related compounds, organic synthesis in the context of bio-refinery, and hydration of olefins were described and how the reaction paths are controlled by the concentration of water and hydrogen ions was summarized.

  4. Synthesis of Amino Acid Precursors with Organic Solids in Planetesimals with Liquid Water

    Science.gov (United States)

    Kebukawa, Y; Misawa, S.; Matsukuma, J.; Chan, Q. H. S.; Kobayashi, J.; Tachibana, S.; Zolensky, M. E.

    2017-01-01

    Amino acids are important ingredients of life that would have been delivered to Earth by extraterrestrial sources, e.g., comets and meteorites. Amino acids are found in aqueously altered carbonaceous chondrites in good part in the form of precursors that release amino acids after acid hydrolysis. Meanwhile, most of the organic carbon (greater than 70 weight %) in carbonaceous chondrites exists in the form of solvent insoluble organic matter (IOM) with complex macromolecular structures. Complex macromolecular organic matter can be produced by either photolysis of interstellar ices or aqueous chemistry in planetesimals. We focused on the synthesis of amino acids during aqueous alteration, and demonstrated one-pot synthesis of a complex suite of amino acids simultaneously with IOM via hydrothermal experiments simulating the aqueous processing

  5. Synthesis of the Novel Fluoride-containing Organic Silane

    Institute of Scientific and Technical Information of China (English)

    WANG Shuiping; WENG Rui; WANG Chonghui; YANG Ping

    2009-01-01

    A fluoride-containing organic silane was synthesized by the reaction of N-ethyl-N-hydroxy-ethyl perfluorinated octyl sulfonamide(EHPOS),N-β-aminoethyl)-γ-aminopropyl trimethoxy silane(ATS)and cis-butenedioic anhydride(CA).The experimental results show that the yield of product is up to 87%when the molar ratio of EHPOS:CA:ATS is 1:1.05:1.1.EHPOS and CA were maintained at 115℃for 3 hours,then after cooling the reaction solution to 75℃,ATS was added and reacted for an-other 3.5 hours at 145℃.The structure of the productand thermal properties were characterized by Fourier transform infrared(FTIR)and thermogravimetric analysis(TGA),respectively.Results show that fluo-ride-containing organic silane has excellent thermal stability below 185℃.

  6. Zeolite-Based Organic Synthesis (ZeoBOS) of Acortatarin A: First Total Synthesis Based on Native and Metal-Doped Zeolite-Catalyzed Steps.

    Science.gov (United States)

    Wimmer, Eric; Borghèse, Sophie; Blanc, Aurélien; Bénéteau, Valérie; Pale, Patrick

    2017-01-31

    Similarly to polymer-supported assisted synthesis (PSAS), organic synthesis could be envisaged being performed by using zeolites, native or metal-doped, as heterogeneous catalysts. To illustrate this unprecedented Zeolite-Based Organic Synthesis (ZeoBOS), the total synthesis of acortatarin A was achieved through a novel strategy and using five out of eleven synthetic steps catalyzed by H- or metal-doped zeolites as catalysts. Notably, the formation of an yne-pyrrole intermediate with a copper-doped zeolite and the spiroketalization of an alkyne diol with a silver-doped zeolite have been developed as key steps of the synthesis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Current-voltage characteristics of bulk heterojunction organic solar cells: connection between light and dark curves

    Energy Technology Data Exchange (ETDEWEB)

    Boix, Pablo P.; Guerrero, Antonio; Garcia-Belmonte, Germa; Bisquert, Juan [Photovoltaic and Optoelectronic Devices Group, Departament de Fisica, Universitat Jaume I, ES-12071 Castello (Spain); Marchesi, Luis F. [Laboratorio Interdisciplinar de, Eletroquimica e Ceramica (LIEC), Universidade Federal de Sao Carlos (Brazil); Photovoltaic and Optoelectronic Devices Group, Departament de Fisica, Universitat Jaume I, ES-12071 Castello (Spain)

    2011-11-15

    A connection is established between recombination and series resistances extracted from impedance spectroscopy and current-voltage curves of polythiophene:fullerene organic solar cells. Recombination is shown to depend exclusively on the (Fermi level) voltage, which allows construction of the current-voltage characteristics in any required conditions based on a restricted set of measurements. The analysis highlights carrier recombination current as the determining mechanism of organic solar cell performance. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Convolution-based estimation of organ dose in tube current modulated CT

    Science.gov (United States)

    Tian, Xiaoyu; Segars, W. Paul; Dixon, Robert L.; Samei, Ehsan

    2016-05-01

    Estimating organ dose for clinical patients requires accurate modeling of the patient anatomy and the dose field of the CT exam. The modeling of patient anatomy can be achieved using a library of representative computational phantoms (Samei et al 2014 Pediatr. Radiol. 44 460-7). The modeling of the dose field can be challenging for CT exams performed with a tube current modulation (TCM) technique. The purpose of this work was to effectively model the dose field for TCM exams using a convolution-based method. A framework was further proposed for prospective and retrospective organ dose estimation in clinical practice. The study included 60 adult patients (age range: 18-70 years, weight range: 60-180 kg). Patient-specific computational phantoms were generated based on patient CT image datasets. A previously validated Monte Carlo simulation program was used to model a clinical CT scanner (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). A practical strategy was developed to achieve real-time organ dose estimation for a given clinical patient. CTDIvol-normalized organ dose coefficients ({{h}\\text{Organ}} ) under constant tube current were estimated and modeled as a function of patient size. Each clinical patient in the library was optimally matched to another computational phantom to obtain a representation of organ location/distribution. The patient organ distribution was convolved with a dose distribution profile to generate {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} values that quantified the regional dose field for each organ. The organ dose was estimated by multiplying {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} with the organ dose coefficients ({{h}\\text{Organ}} ). To validate the accuracy of this dose estimation technique, the organ dose of the original clinical patient was estimated using Monte Carlo program with TCM profiles explicitly modeled. The

  9. Extra-adrenal glucocorticoid synthesis: immune regulation and aspects on local organ homeostasis.

    Science.gov (United States)

    Talabér, Gergely; Jondal, Mikael; Okret, Sam

    2013-11-05

    Systemic glucocorticoids (GCs) mainly originate from de novo synthesis in the adrenal cortex under the control of the hypothalamus-pituitary-adrenal (HPA)-axis. However, research during the last 1-2 decades has revealed that additional organs express the necessary enzymes and have the capacity for de novo synthesis of biologically active GCs. This includes the thymus, intestine, skin and the brain. Recent research has also revealed that locally synthesized GCs most likely act in a paracrine or autocrine manner and have significant physiological roles in local homeostasis, cell development and immune cell activation. In this review, we summarize the nature, regulation and known physiological roles of extra-adrenal GC synthesis. We specifically focus on the thymus in which GC production (by both developing thymocytes and epithelial cells) has a role in the maintenance of proper immunological function.

  10. 'Thunder' - Shock waves in pre-biological organic synthesis.

    Science.gov (United States)

    Bar-Nun, A.; Tauber, M. E.

    1972-01-01

    Theoretical study of the gasdynamics and chemistry of lightning-produced shock waves in a postulated primordial reducing atmosphere. It is shown that the conditions are similar to those encountered in a previously performed shock-tube experiment which resulted in 36% of the ammonia in the original mixture being converted into amino acids. The calculations give the (very large) energy rate of about 0.4 cal/sq cm/yr available for amino acid production, supporting previous hypotheses that 'thunder' could have been responsible for efficient large-scale production of organic molecules serving as precursors of life.

  11. Synthesis of Carbon Nanotubes and Volatile Organic Compounds Detection

    Directory of Open Access Journals (Sweden)

    Sobri S.

    2016-01-01

    Full Text Available In this work, the adsorption effect of volatile organic compounds (chloroacetophenone, acetonitrile and hexane towards the change of resistance of CNTs pellet as sensor signal was investigated. CNTs used in this research were synthesized using Floating Catalyst – Chemical Vapor Deposition (FC-CVD method in optimum condition. The synthesized CNTs were characterized using Scanning Electron Microscopy (SEM, Transmission Electron Microscopy (TEM and Raman Spectroscopy. The variation of resistance changes towards the tested gases were recorded using a multimeter. CNTs sensor pellet showed good responses towards the tested gases, however, the sensitivity, response time and recovery time of sensor pellet need to be optimized.

  12. 'Thunder' - Shock waves in pre-biological organic synthesis.

    Science.gov (United States)

    Bar-Nun, A.; Tauber, M. E.

    1972-01-01

    Theoretical study of the gasdynamics and chemistry of lightning-produced shock waves in a postulated primordial reducing atmosphere. It is shown that the conditions are similar to those encountered in a previously performed shock-tube experiment which resulted in 36% of the ammonia in the original mixture being converted into amino acids. The calculations give the (very large) energy rate of about 0.4 cal/sq cm/yr available for amino acid production, supporting previous hypotheses that 'thunder' could have been responsible for efficient large-scale production of organic molecules serving as precursors of life.

  13. Synthesis and application of monodisperse oligo(oxyethylene)-grafted polystyrene resins for solid-phase organic synthesis.

    Science.gov (United States)

    Lumpi, Daniel; Braunshier, Christian; Horkel, Ernst; Hametner, Christian; Fröhlich, Johannes

    2014-07-14

    In a preliminary investigation by our group, we found that poly(styrene-oxyethylene) graft copolymers (PS-PEG), for example, TentaGel resins, are advantageous for gel-phase (13)C NMR spectroscopy. Because of the solution-like environment provided by the PS-PEG resins, good spectral quality of the attached moiety can be achieved, which is useful for nondestructive on-resin analysis. The general drawbacks of such resins are low loading capacities and the intense signal in the spectra resulting from the PEG linker (>50 units). Here, we describe the characterization of solvent-dependent swelling and reaction kinetics on a new type of resin for solid-phase organic synthesis (SPOS) that allows an accurate monitoring by gel-phase NMR without the above disadvantages. A series of polystyrene-oligo(oxyethylene) graft copolymers containing monodisperse PEG units (n = 2-12) was synthesized. A strong correlation between the linker (PEG) length and the line widths in the (13)C gel-phase spectra was observed, with a grafted PEG chain of 8 units giving similar results in terms of reactivity and gel-phase NMR monitoring to TentaGel resin. Multistep on-resin reaction sequences were performed to prove the applicability of the resins in solid-phase organic synthesis.

  14. Structural versatility of Metal-organic frameworks: Synthesis and Characterization

    KAUST Repository

    Alsadun, Norah S.

    2017-05-01

    Metal-Organic Frameworks (MOFs), an emerging class of porous crystalline materials, have shown promising properties for diverse applications such as catalysis, gas storage and separation. The high degree of tunability of MOFs vs other solid materials enable the assembly of advanced materials with fascinating properties for specific applications. Nevertheless, the precise control in the construction of MOFs at the molecular level remains challenging. Particularly, the formation of pre-targeted multi-nuclear Molecular Building Block (MBB) precursors to unveil materials with targeted structural characteristics is captivating. The aim of my master project in the continuous quest of the group of Prof. Eddaoudi in exploring different synthetic pathways to control the assembly of Rare Earth (RE) based MOF. After giving a general overview about MOFs, I will discuss in this thesis the results of my work on the use of tri-topic oriented organic carboxylate building units with the aim to explore the assembly/construction of new porous RE based MOFs. In chapter 2 will discuss the assembly of 3-c linkers with RE metals was then evaluated based on symmetry and angularity of the three connected linkers. The focus of chapter 3 is cerium based MOFs and heterometallic system, based on 3-c ligands with different length and symmetry. Overall, the incompatibility of 3-c ligands with the 12-c cuo MBB did not allow to any formation of higher neuclearity (˃6), but it has resulted in affecting the connectivity of the cluster.

  15. Rational design, synthesis, purification, and activation of metal-organic framework materials.

    Science.gov (United States)

    Farha, Omar K; Hupp, Joseph T

    2010-08-17

    The emergence of metal-organic frameworks (MOFs) as functional ultrahigh surface area materials is one of the most exciting recent developments in solid-state chemistry. Now constituting thousands of distinct examples, MOFs are an intriguing class of hybrid materials that exist as infinite crystalline lattices with inorganic vertices and molecular-scale organic connectors. Useful properties such as large internal surface areas, ultralow densities, and the availability of uniformly structured cavities and portals of molecular dimensions characterize functional MOFs. Researchers have effectively exploited these unusual properties in applications such as hydrogen and methane storage, chemical separations, and selective chemical catalysis. In principle, one of the most attractive features of MOFs is the simplicity of their synthesis. Typically they are obtained via one-pot solvothermal preparations. However, with the simplicity come challenges. In particular, MOF materials, especially more complex ones, can be difficult to obtain in pure form and with the optimal degree of catenation, the interpenetration or interweaving of identical independent networks. Once these two issues are satisfied, the removal of the guest molecules (solvent from synthesis) without damaging the structural integrity of the material is often an additional challenge. In this Account, we review recent advances in the synthetic design, purification, and activation of metal-organic framework materials. We describe the rational design of a series of organic struts to limit framework catenation and thereby produce large pores. In addition, we demonstrate the rapid separation of desired MOFs from crystalline and amorphous contaminants cogenerated during synthesis based on their different densities. Finally, we discuss the mild and efficient activation of initially solvent-filled pores with supercritical carbon dioxide, yielding usable channels and high internal surface areas. We expect that the

  16. Organ dose conversion coefficients for tube current modulated CT protocols for an adult population

    Science.gov (United States)

    Fu, Wanyi; Tian, Xiaoyu; Sahbaee, Pooyan; Zhang, Yakun; Segars, William Paul; Samei, Ehsan

    2016-03-01

    In computed tomography (CT), patient-specific organ dose can be estimated using pre-calculated organ dose conversion coefficients (organ dose normalized by CTDIvol, h factor) database, taking into account patient size and scan coverage. The conversion coefficients have been previously estimated for routine body protocol classes, grouped by scan coverage, across an adult population for fixed tube current modulated CT. The coefficients, however, do not include the widely utilized tube current (mA) modulation scheme, which significantly impacts organ dose. This study aims to extend the h factors and the corresponding dose length product (DLP) to create effective dose conversion coefficients (k factor) database incorporating various tube current modulation strengths. Fifty-eight extended cardiac-torso (XCAT) phantoms were included in this study representing population anatomy variation in clinical practice. Four mA profiles, representing weak to strong mA dependency on body attenuation, were generated for each phantom and protocol class. A validated Monte Carlo program was used to simulate the organ dose. The organ dose and effective dose was further normalized by CTDIvol and DLP to derive the h factors and k factors, respectively. The h factors and k factors were summarized in an exponential regression model as a function of body size. Such a population-based mathematical model can provide a comprehensive organ dose estimation given body size and CTDIvol. The model was integrated into an iPhone app XCATdose version 2, enhancing the 1st version based upon fixed tube current modulation. With the organ dose calculator, physicists, physicians, and patients can conveniently estimate organ dose.

  17. Organic light emitting devices synthesis, properties and applications

    CERN Document Server

    Müllen, Klaus; Mllen, Klaus; Mü Llen, Klaus; Mullen, Klaus

    2006-01-01

    This high-class book reflects a decade of intense research, culminating in excellent successes over the last few years. The contributions from both academia as well as the industry leaders combine the fundamentals and latest research results with application know-how and examples of functioning displays. As a result, all the four important aspects of OLEDs are covered: - syntheses of the organic materials - physical theory of electroluminescence and device efficiency - device conception and construction - characterization of both materials and devices. The whole is naturally rounded off with a look at what the future holds in store. The editor, Klaus Muellen, is director of the highly prestigious MPI for polymer research in Mainz, Germany, while the authors include Nobel Laureate Alan Heeger, one of the most notable founders of the field, Richard Friend, as well as Ching Tang, Eastman Kodak's number-one OLED researcher, known throughout the entire community for his key publications.

  18. Trophic magnification of organic chemicals: A global synthesis

    Science.gov (United States)

    Walters, David; Jardine, T.D.; Cade, Brian S.; Kidd, K.A.; Muir, D.C.G.; Leipzig-Scott, Peter C.

    2016-01-01

    Production of organic chemicals (OCs) is increasing exponentially, and some OCs biomagnify through food webs to potentially toxic levels. Biomagnification under field conditions is best described by trophic magnification factors (TMFs; per trophic level change in log-concentration of a chemical) which have been measured for more than two decades. Syntheses of TMF behavior relative to chemical traits and ecosystem properties are lacking. We analyzed >1500 TMFs to identify OCs predisposed to biomagnify and to assess ecosystem vulnerability. The highest TMFs were for OCs that are slowly metabolized by animals (metabolic rate kM  0.2 day–1). This probabilistic model provides a new global tool for screening existing and new OCs for their biomagnification potential.

  19. DNA display III. Solid-phase organic synthesis on unprotected DNA.

    Directory of Open Access Journals (Sweden)

    David R Halpin

    2004-07-01

    Full Text Available DNA-directed synthesis represents a powerful new tool for molecular discovery. Its ultimate utility, however, hinges upon the diversity of chemical reactions that can be executed in the presence of unprotected DNA. We present a solid-phase reaction format that makes possible the use of standard organic reaction conditions and common reagents to facilitate chemical transformations on unprotected DNA supports. We demonstrate the feasibility of this strategy by comprehensively adapting solid-phase 9-fluorenylmethyoxycarbonyl-based peptide synthesis to be DNA-compatible, and we describe a set of tools for the adaptation of other chemistries. Efficient peptide coupling to DNA was observed for all 33 amino acids tested, and polypeptides as long as 12 amino acids were synthesized on DNA supports. Beyond the direct implications for synthesis of peptide-DNA conjugates, the methods described offer a general strategy for organic synthesis on unprotected DNA. Their employment can facilitate the generation of chemically diverse DNA-encoded molecular populations amenable to in vitro evolution and genetic manipulation.

  20. Evaluating reaction pathways of hydrothermal abiotic organic synthesis at elevated temperatures and pressures using carbon isotopes

    Science.gov (United States)

    Fu, Qi; Socki, Richard A.; Niles, Paul B.

    2015-04-01

    Experiments were performed to better understand the role of environmental factors on reaction pathways and corresponding carbon isotope fractionations during abiotic hydrothermal synthesis of organic compounds using piston cylinder apparatus at 750 °C and 5.5 kbars. Chemical compositions of experimental products and corresponding carbon isotopic values were obtained by a Pyrolysis-GC-MS-IRMS system. Alkanes (methane and ethane), straight-chain saturated alcohols (ethanol and n-butanol) and monocarboxylic acids (formic and acetic acids) were generated with ethanol being the only organic compound with higher δ13C than CO2. CO was not detected in experimental products owing to the favorable water-gas shift reaction under high water pressure conditions. The pattern of δ13C values of CO2, carboxylic acids and alkanes are consistent with their equilibrium isotope relationships: CO2 > carboxylic acids > alkanes, but the magnitude of the fractionation among them is higher than predicted isotope equilibrium values. In particular, the isotopic fractionation between CO2 and CH4 remained constant at ∼31‰, indicating a kinetic effect during CO2 reduction processes. No "isotope reversal" of δ13C values for alkanes or carboxylic acids was observed, which indicates a different reaction pathway than what is typically observed during Fischer-Tropsch synthesis under gas phase conditions. Under constraints imposed in experiments, the anomalous 13C isotope enrichment in ethanol suggests that hydroxymethylene is the organic intermediate, and that the generation of other organic compounds enriched in 12C were facilitated by subsequent Rayleigh fractionation of hydroxymethylene reacting with H2 and/or H2O. Carbon isotope fractionation data obtained in this study are instrumental in assessing the controlling factors on abiotic formation of organic compounds in hydrothermal systems. Knowledge on how environmental conditions affect reaction pathways of abiotic synthesis of organic

  1. Ionic liquids as an electrolyte for the electro synthesis of organic compounds.

    Science.gov (United States)

    Kathiresan, Murugavel; Velayutham, David

    2015-12-25

    The use of ionic liquids (ILs) as a solvent and an electrolyte for electro organic synthesis has been reviewed. To date several ILs exist, however the ILs based on tetraalkylammonium, pyrrolidinium, piperidinium and imidazolium cations with BF4(-), PF6(-), and TFSI anions have been widely used and explored the most. Electro organic synthesis in ionic liquid media leading to the synthesis of a wide range of organic compounds has been discussed. Anodic oxidation or cathodic reduction will generate radical cation or anion intermediates, respectively. These radicals can undergo self coupling or coupling with other molecules yielding organic compounds of interest. The cation of the IL is known to stabilize the radical anion extensively. This stabilization effect has a specific impact on the electrochemical CO2 reduction and coupling to various organics. The relative stability of the intermediates in IL leads to the formation of specific products in higher yields. Electrochemical reduction of imidazolium or thiazolium based ILs generates N-heterocyclic carbenes that have been shown to catalyze a wide range of base or nucleophile catalyzed organic reactions in IL media, an aspect that falls into the category of organocatalysis. Electrochemical fluorination or selective electrochemical fluorination is another fascinating area that delivers selectively fluorinated organic products in Et3N·nHF or Et4NF·nHF adducts (IL) via anodic oxidation. Oxidative polymerization in ILs has been explored the most; although morphological changes were observed compared to the conventional methods, polymers were obtained in good yields and in some cases ILs were used as dopants to improve the desired properties.

  2. Chemical coagulation-based processes for trace organic contaminant removal: current state and future potential.

    Science.gov (United States)

    Alexander, Jonathan T; Hai, Faisal I; Al-Aboud, Turki M

    2012-11-30

    Trace organic contaminants have become an increasing cause of concern for governments and water authorities as they attempt to respond to the potential challenges posed by climate change by implementing sustainable water cycle management practices. The augmentation of potable water supplies through indirect potable water reuse is one such method currently being employed. Given the uncertainty surrounding the potential human health impacts of prolonged ingestion of trace organic contaminants, it is vital that effective and sustainable treatment methods are utilized. The purpose of this article is to provide a comprehensive literature review of the performance of the chemical coagulation process in removing trace organic contaminants from water. This study evaluated the removal data collated from recent research relating to various trace organic contaminants during the coagulation process. It was observed that there is limited research data relating to the removal of trace organic contaminants using coagulation. The findings of this study suggest that there is a gap in the current research investigating the potential of new types of coagulants and exploring coagulation-based hybrid processes to remove trace organic contaminants from water. The data analysed in this study regarding removal efficiency suggests that, even for the significantly hydrophobic compounds, hydrophobicity is not the sole factor governing removal of trace organic contaminants by coagulation. This has important implications in that the usual practice of screening coagulants based on turbidity (suspended solid) removal proves inadequate in the case of trace organic contaminant removal. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. A scalable synthesis of a mesoporous metal-organic framework called NU-1000.

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Timothy C.; Vermeulen, Nicolaas A.; Kim, In Soo; Martinson, Alex B. F.; Stoddart, J. Fraser; Hupp, Joseph T.; Farha, Omar K.

    2016-01-01

    The synthesis of NU-1000, a mesoporous metal-organic framework (MOF), can be conducted efficiently on a multigram scale from inexpensive starting materials. NU-1000 has been reported as an excellent candidate for gas separation and catalysis. In particular, it is ideal for the catalytic deactivation of nerve agents and shows great promise as a new generic platform for a wide range of applications. Multiple post-synthetic modification protocols have been developed using NU-1000 as the parent material, making it a potentially useful scaffold for several catalytic applications. The procedure for the preparation of NU-1000 can be scaled up reliably and is suitable for the production of 50 grams of the requisite organic linker and ?? grams of NU-1000. The entire synthesis is performed without purification by column chromatography and can be completed within 10 days.

  4. Graphene-like single-layered covalent organic frameworks: synthesis strategies and application prospects.

    Science.gov (United States)

    Liu, Xuan-He; Guan, Cui-Zhong; Wang, Dong; Wan, Li-Jun

    2014-10-29

    Two-dimensional (2D) nanomaterials, such as graphene and transition metal chalcogenides, show many interesting dimension-related materials properties. Inspired by the development of 2D inorganic nanomaterials, single-layered covalent organic frameworks (sCOFs), featuring atom-thick sheets and crystalline extended organic structures with covalently bonded building blocks, have attracted great attention in recent years. With their unique graphene-like topological structure and the merit of structural diversity, sCOFs promise to possess novel and designable properties. However, the synthesis of sCOFs with well-defined structures remains a great challenge. Herein, the recent development of the bottom-up synthesis methods of 2D sCOFs, such as thermodynamic equilibrium control methods, growth-kinetics control methods, and surface-assisted covalent polymerization methods, are reviewed. Finally, some of the critical properties and application prospects of these materials are outlined.

  5. STUDY OF SYNTHESIS AND CHARACTERIZATION OF METAL-ORGANIC FRAMEWORKS MOF-5 AS HYDROGEN STORAGE MATERIAL

    Directory of Open Access Journals (Sweden)

    Prapti Rahayu

    2016-03-01

    Full Text Available Metal-organic frameworks (MOFs are porous coordination polymer containing bi-or polidentate organic linker coordinated with inorganic part, such as metal oxide cluster or metal cation as node which called as secondary building unit (SBU to form infinite structure. Due to high porosity and surface area, good thermal stability as well as the availability of unsaturated metal center or the linker influence attracts the interaction with gases, thus MOFs have potential to be applied as hydrogen storage material. One type of MOFs that have been widely studied is [Zn4O(benzene-1,4-dicarboxylate3], namely, MOF-5.Various synthesis method have been developed to obtain optimum results. Characterization of MOF-5 from various synthesis method such as crystallinity, capacity, stability, and quantum dot behavior of MOF-5 have been summarized in this review.

  6. Analytical Model for Voltage-Dependent Photo and Dark Currents in Bulk Heterojunction Organic Solar Cells

    OpenAIRE

    2016-01-01

    A physics-based explicit mathematical model for the external voltage-dependent forward dark current in bulk heterojunction (BHJ) organic solar cells is developed by considering Shockley-Read-Hall (SRH) recombination and solving the continuity equations for both electrons and holes. An analytical model for the external voltage-dependent photocurrent in BHJ organic solar cells is also proposed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (...

  7. KH in Paraffin - KH(P): A Useful Base for Organic Synthesis

    Science.gov (United States)

    Taber, Douglass F.; Nelson, Christopher G.

    2011-01-01

    The preparation of KH as a one:one homogenate with paraffin, termed KH(P), is reported. KH(P), a solid at room temperature, is stable without special handling. On suspension in THF with a phosphonium salt, KH(P) rapidly generates the ylide. Wittig condensation with aromatic, aliphatic and α, β-unsaturated aldehydes proceeds with high Z-selectivity. KH(P) should be a generally useful base for organic synthesis. PMID:17081034

  8. Enhanced Singlet Oxygen Generation in Oxidized Graphitic Carbon Nitride for Organic Synthesis.

    Science.gov (United States)

    Wang, Hui; Jiang, Shenlong; Chen, Shichuan; Li, Dandan; Zhang, Xiaodong; Shao, Wei; Sun, Xianshun; Xie, Junfeng; Zhao, Zhi; Zhang, Qun; Tian, Yupeng; Xie, Yi

    2016-08-01

    Experimental data reveal that the incorporation of carbonyl groups into polymer matrix can significantly enhance singlet oxygen ((1) O2 ) generation and suppress production of other reactive oxygen species. Excitonic processes investigated by phosphorescence spectroscopy reveal enhanced triplet-exciton generation in the modified g-C3 N4 , which facilitate (1) O2 generation through an energy transfer process. Benefiting from this, the modified g-C3 N4 shows excellent conversion and selectivity in organic synthesis.

  9. Solid-Phase Organic Synthesis of Aryl Vinyl Ethers Using Sulfone-Linking Strategy

    Institute of Scientific and Technical Information of China (English)

    余腊妹; 汤妮; 盛寿日; 陈茹冰; 刘晓玲; 蔡明中

    2012-01-01

    A novel facile solid-phase organic synthesis of aryl vinyl ethers by reaction of polystyrene-supported 2-phenylsulfonylethanol with phenols under Mitsunobu conditions and subsequent elimination reaction with DBU has been developed. The advantages of this method include straightforward operation, good yield and high purity of the products. Alternatively, a typical example of Suzuki coupling reaction on-resin was further applied to prepare 4-phenylphenyl vinyl ether for extending this method.

  10. Benefits of Using a Problem-Solving Scaffold for Teaching and Learning Synthesis in Undergraduate Organic Chemistry I

    Science.gov (United States)

    Sloop, Joseph C.; Tsoi, Mai Yin; Coppock, Patrick

    2016-01-01

    A problem-solving scaffold approach to synthesis was developed and implemented in two intervention sections of Chemistry 2211K (Organic Chemistry I) at Georgia Gwinnett College (GGC). A third section of Chemistry 2211K at GGC served as the control group for the experiment. Synthesis problems for chapter quizzes and the final examination were…

  11. Solution-Phase Synthesis of Dipeptides: A Capstone Project That Employs Key Techniques in an Organic Laboratory Course

    Science.gov (United States)

    Marchetti, Louis; DeBoef, Brenton

    2015-01-01

    A contemporary approach to the synthesis and purification of several UV-active dipeptides has been developed for the second-year organic laboratory. This experiment exposes students to the important technique of solution-phase peptide synthesis and allows an instructor to highlight the parallel between what they are accomplishing in the laboratory…

  12. Simplified Application of Material Efficiency Green Metrics to Synthesis Plans: Pedagogical Case Studies Selected from "Organic Syntheses"

    Science.gov (United States)

    Andraos, John

    2015-01-01

    This paper presents a simplified approach for the application of material efficiency metrics to linear and convergent synthesis plans encountered in organic synthesis courses. Computations are facilitated and automated using intuitively designed Microsoft Excel spreadsheets without invoking abstract mathematical formulas. The merits of this…

  13. Solution-Phase Synthesis of Dipeptides: A Capstone Project That Employs Key Techniques in an Organic Laboratory Course

    Science.gov (United States)

    Marchetti, Louis; DeBoef, Brenton

    2015-01-01

    A contemporary approach to the synthesis and purification of several UV-active dipeptides has been developed for the second-year organic laboratory. This experiment exposes students to the important technique of solution-phase peptide synthesis and allows an instructor to highlight the parallel between what they are accomplishing in the laboratory…

  14. Simplified Application of Material Efficiency Green Metrics to Synthesis Plans: Pedagogical Case Studies Selected from "Organic Syntheses"

    Science.gov (United States)

    Andraos, John

    2015-01-01

    This paper presents a simplified approach for the application of material efficiency metrics to linear and convergent synthesis plans encountered in organic synthesis courses. Computations are facilitated and automated using intuitively designed Microsoft Excel spreadsheets without invoking abstract mathematical formulas. The merits of this…

  15. Use of organic precursors and graphenes in the controlled synthesis of carbon-containing nanomaterials for energy storage and conversion.

    Science.gov (United States)

    Yang, Shubin; Bachman, Robert E; Feng, Xinliang; Müllen, Klaus

    2013-01-15

    The development of high-performance electrochemical energy storage and conversion devices, including supercapacitors, lithium-ion batteries, and fuel cells, is an important step on the road to alternative energy technologies. Carbon-containing nanomaterials (CCNMs), defined here as pure carbon materials and carbon/metal (oxide, hydroxide) hybrids with structural features on the nanometer scale, show potential application in such devices. Because of their pronounced electrochemical activity, high chemical and thermal stability and low cost, researchers are interested in CCNMs to serve as electrodes in energy-related devices. Various all-carbon materials are candidates for electrochemical energy storage and conversion devices. Furthermore, carbon-based hybrid materials, which consist of a carbon component with metal oxide- or metal hydroxide-based nanostructures, offer the opportunity to combine the attractive properties of these two components and tune the behavior of the resulting materials. As such, the design and synthesis of CCNMs provide an attractive route for the construction of high-performance electrode materials. Studies in these areas have revealed that both the composition and the fabrication protocol employed in preparing CCNMs influence the morphology and microstructure of the resulting material and its electrochemical performance. Consequently, researchers have developed several synthesis strategies, including hard-templated, soft-templated, and template-free synthesis of CCNMs. In this Account, we focus on recent advances in the controlled synthesis of such CCNMs and the potential of the resulting materials for energy storage or conversion applications. The Account is divided into four major categories based on the carbon precursor employed in the synthesis: low molecular weight organic or organometallic molecules, hyperbranched or cross-linked polymers consisting of aromatic subunits, self-assembling discotic molecules, and graphenes. In each case

  16. Design and synthesis of organic-inorganic hybrid capsules for biotechnological applications.

    Science.gov (United States)

    Shi, Jiafu; Jiang, Yanjun; Wang, Xiaoli; Wu, Hong; Yang, Dong; Pan, Fusheng; Su, Yanlei; Jiang, Zhongyi

    2014-08-07

    Organic-inorganic hybrid capsules, which typically possess a hollow lumen and a hybrid wall, have emerged as a novel and promising class of hybrid materials and have attracted enormous attention. In comparison to polymeric capsules or inorganic capsules, the hybrid capsules combine the intrinsic physical/chemical properties of the organic and inorganic moieties, acquire more degrees of freedom to manipulate multiple interactions, create hierarchical structures and integrate multiple functionalities. Thus, the hybrid capsules exhibit superior mechanical strength (vs. polymeric capsules) and diverse functionalities (vs. inorganic capsules), which may give new opportunities to produce high-performance materials. Much effort has been devoted to exploring innovative and effective methods for the synthesis of hybrid capsules that exhibit desirable performance in target applications. This tutorial review firstly presents a brief description of the capsular structure and hybrid materials in nature, then classifies the hybrid capsules into molecule-hybrid capsules and nano-hybrid capsules based upon the size of the organic and inorganic moieties in the capsule wall, followed by a detailed discussion of the design and synthesis of the hybrid capsules. For each kind of hybrid capsule, the state-of-the-art synthesis methods are described in detail and a critical comment is embedded. The applications of these hybrid capsules in biotechnological areas (biocatalysis, drug delivery, etc.) have also been summarized. Hopefully, this review will offer a perspective and guidelines for the future research and development of hybrid capsules.

  17. Convolution-based estimation of organ dose in tube current modulated CT.

    Science.gov (United States)

    Tian, Xiaoyu; Segars, W Paul; Dixon, Robert L; Samei, Ehsan

    2016-05-21

    Estimating organ dose for clinical patients requires accurate modeling of the patient anatomy and the dose field of the CT exam. The modeling of patient anatomy can be achieved using a library of representative computational phantoms (Samei et al 2014 Pediatr. Radiol. 44 460-7). The modeling of the dose field can be challenging for CT exams performed with a tube current modulation (TCM) technique. The purpose of this work was to effectively model the dose field for TCM exams using a convolution-based method. A framework was further proposed for prospective and retrospective organ dose estimation in clinical practice. The study included 60 adult patients (age range: 18-70 years, weight range: 60-180 kg). Patient-specific computational phantoms were generated based on patient CT image datasets. A previously validated Monte Carlo simulation program was used to model a clinical CT scanner (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). A practical strategy was developed to achieve real-time organ dose estimation for a given clinical patient. CTDIvol-normalized organ dose coefficients ([Formula: see text]) under constant tube current were estimated and modeled as a function of patient size. Each clinical patient in the library was optimally matched to another computational phantom to obtain a representation of organ location/distribution. The patient organ distribution was convolved with a dose distribution profile to generate [Formula: see text] values that quantified the regional dose field for each organ. The organ dose was estimated by multiplying [Formula: see text] with the organ dose coefficients ([Formula: see text]). To validate the accuracy of this dose estimation technique, the organ dose of the original clinical patient was estimated using Monte Carlo program with TCM profiles explicitly modeled. The discrepancy between the estimated organ dose and dose simulated using TCM Monte Carlo program was quantified. We further compared the

  18. Quaternary Organic Amines Inhibit Na,K Pump Current in a Voltage-dependent Manner

    OpenAIRE

    2004-01-01

    The effects of organic quaternary amines, tetraethylammonium (TEA) chloride and benzyltriethylammonium (BTEA) chloride, on Na,K pump current were examined in rat cardiac myocytes superfused in extracellular Na+-free solutions and whole-cell voltage-clamped with patch electrodes containing a high Na+-salt solution. Extracellular application of these quaternary amines competitively inhibited extracellular K+ (K+ o) activation of Na,K pump current; however, the concentration for half maximal inh...

  19. Metal Organic Frameworks: Explorations and Design Strategies for MOF Synthesis

    KAUST Repository

    AbdulHalim, Rasha

    2016-11-27

    Metal-Organic Frameworks (MOFs) represent an emerging new class of functional crystalline solid-state materials. In the early discovery of this now rapidly growing class of materials significant challenges were often encountered. However, MOFs today, with its vast structural modularity, reflected by the huge library of the available chemical building blocks, and exceptional controlled porosity, stand as the most promising candidate to address many of the overbearing societal challenges pertaining to energy and environmental sustainability. A variety of design strategies have been enumerated in the literature which rely on the use of predesigned building blocks paving the way towards potentially more predictable structures. The two major design strategies presented in this work are the molecular building block (MBB) and supermolecular building block (SBB) -based approaches for the rationale assembly of functional MOF materials with the desired structural features. In this context, we targeted two highly connected MOF platforms, namely rht-MOF and shp-MOF. These two MOF platforms are classified based on their topology, defined as the underlying connectivity of their respective net, as edge transitive binodal nets; shp being (4,12)-connected net and rht being (3,24)-connected net. These highly connected nets were deliberately targeted due to the limited number of possible nets for connecting their associated basic building units. Two highly porous materials were designed and successfully constructed; namely Y-shp-MOF-5 and rht-MOF-10. The Y-shp-MOF-5 features a phenomenal water stability with an exquisite behavior when exposed to water, positioning this microporous material as the best adsorbent for moisture control applications. The shp-MOF platform proved to be modular to ligand functionalization and thus imparting significant behavioral changes when hydrophilic and hydrophobic functionalized ligands were introduced on the resultant MOF. On the other hand, rht

  20. Using the Power of Organic Synthesis for Engineering the Interactions of Nanoparticles with Biological Systems.

    Science.gov (United States)

    Mizuhara, Tsukasa; Moyano, Daniel F; Rotello, Vincent M

    2016-02-01

    The surface properties of nanoparticles (NPs) dictate their interaction with the outside world. The use of precisely designed molecular ligands to control NP surface properties provides an important toolkit for modulating their interaction with biological systems, facilitating their use in biomedicine. In this review we will discuss the application of the atom-by-atom control provided by organic synthesis to the generation of engineered nanoparticles, with emphasis on how the functionalization of NPs with these "small" organic molecules (Mw < 1,000) can be used to engineer NPs for a wide range of applications.

  1. Integrated process of distillation with side reactors for synthesis of organic acid esters

    Science.gov (United States)

    Panchal, Chandrakant B; Prindle, John C; Kolah, Aspri; Miller, Dennis J; Lira, Carl T

    2015-11-04

    An integrated process and system for synthesis of organic-acid esters is provided. The method of synthesizing combines reaction and distillation where an organic acid and alcohol composition are passed through a distillation chamber having a plurality of zones. Side reactors are used for drawing off portions of the composition and then recycling them to the distillation column for further purification. Water is removed from a pre-reactor prior to insertion into the distillation column. An integrated heat integration system is contained within the distillation column for further purification and optimizing efficiency in the obtaining of the final product.

  2. Gold nanoparticle (AuNPs) and gold nanopore (AuNPore) catalysts in organic synthesis.

    Science.gov (United States)

    Takale, Balaram S; Bao, Ming; Yamamoto, Yoshinori

    2014-04-07

    Organic synthesis using gold has gained tremendous attention in last few years, especially heterogeneous gold catalysis based on gold nanoparticles has made its place in almost all organic reactions, because of the robust and green nature of gold catalysts. In this context, gold nanopore (AuNPore) with a 3D metal framework is giving a new dimension to heterogeneous gold catalysts. Interestingly, AuNPore chemistry is proving better than gold nanoparticles based chemistry. In this review, along with recent advances, major discoveries in heterogeneous gold catalysis are discussed.

  3. Long-Term Stable Organic Photodetectors with Ultra Low Dark Currents for High Detectivity Applications

    Science.gov (United States)

    Kielar, Marcin; Dhez, Olivier; Pecastaings, Gilles; Curutchet, Arnaud; Hirsch, Lionel

    2016-12-01

    Printed organic photodetectors can transform plastic, paper or glass into smart surfaces. This innovative technology is now growing exponentially due to the strong demand in human-machine interfaces. To date, only niche markets are targeted since organic sensors still present reduced performances in comparison with their inorganic counterparts. Here we demonstrate that it is possible to engineer a state-of-the-art organic photodetector approaching the performances of Si-based photodiodes in terms of dark current, responsivity and detectivity. Only three solution-processed layers and two low-temperature annealing steps are needed to achieve the performance that is significantly better than most of the organic photodetectors reported so far. We also perform a long-term ageing study. Lifetimes of over 14,000 hours under continuous operation are more than promising and demonstrate that organic photodetectors can reach a competitive level of stability for successful commercialization of this new and promising technology.

  4. Synthesis and gas adsorption study of porous metal-organic framework materials

    Science.gov (United States)

    Mu, Bin

    Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) have become the focus of intense study over the past decade due to their potential for advancing a variety of applications including air purification, gas storage, adsorption separations, catalysis, gas sensing, drug delivery, and so on. These materials have some distinct advantages over traditional porous materials such as the well-defined structures, uniform pore sizes, chemically functionalized sorption sites, and potential for postsynthetic modification, etc. Thus, synthesis and adsorption studies of porous MOFs have increased substantially in recent years. Among various prospective applications, air purification is one of the most immediate concerns, which has urgent requirements to improve current nuclear, biological, and chemical (NBC) filters involving commercial and military purposes. Thus, the major goal of this funded project is to search, synthesize, and test these novel hybrid porous materials for adsorptive removal of toxic industrial chemicals (TICs) and chemical warfare agents (CWAs), and to install the benchmark for new-generation NBC filters. The objective of this study is three-fold: (i) Advance our understanding of coordination chemistry by synthesizing novel MOFs and characterizing these porous coordination polymers; (ii) Evaluate porous MOF materials for gasadsorption applications including CO2 capture, CH4 storage, other light gas adsorption and separations, and examine the chemical and physical properties of these solid adsorbents including thermal stability and heat capacity of MOFs; (iii) Evaluate porous MOF materials for next-generation NBC filter media by adsorption breakthrough measurements of TICs on MOFs, and advance our understanding about structureproperty relationships of these novel adsorbents.

  5. Evidence for organic synthesis in high temperature aqueous media - facts and prognosis

    Science.gov (United States)

    Simoneit, Bernd R. T.

    1995-01-01

    Hydrothermal systems are common along the active tectonic areas of the earth. Potential sites being studied for organic matter alteration and possible organic synthesis are spreading ridges, off-axis systems, back-arc activity, hot spots, volcanism, and subduction. Organic matter alteration, primarily reductive and generally from immature organic detritus, occurs in these high temperature and rapid fluid flow hydrothermal regimes. Hot circulating water (temperature range - warm to greater than 400 C) is responsible for these molecular alterations, expulsion and migration. Compounds that are obviously synthesized are minor components because they are generally masked by the pyrolysis products formed from contemporary natural organic precursors. The reactivity of organic compounds in hot water (200-350 C) has been studied in autoclaves, and supercritical water as a medium for chemistry has also been evaluated. This high temperature aqueous organic chemistry and the strong reducing conditions of the natural systems suggest this as an important route to produce organic compounds on the primitive earth. Thus a better understanding of the potential syntheses of organic compounds in hydrothermal systems will require investigations of the chemistry of condensation, autocatalysis, catalysis and hydrolysis reactions in aqueous mineral buffered systems over a range of temperatures from warm to greater than 400 C.

  6. Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites

    Science.gov (United States)

    Vollmer, Christian; Kepaptsoglou, Demie; Leitner, Jan; Busemann, Henner; Spring, Nicole H.; Ramasse, Quentin M.; Hoppe, Peter; Nittler, Larry R.

    2014-01-01

    Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight 15N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C–O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C–O bonding environments and nanoglobular organics with dominant aromatic and C–N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid. PMID:25288736

  7. Evidence for organic synthesis in high temperature aqueous media - facts and prognosis

    Science.gov (United States)

    Simoneit, Bernd R. T.

    1995-01-01

    Hydrothermal systems are common along the active tectonic areas of the earth. Potential sites being studied for organic matter alteration and possible organic synthesis are spreading ridges, off-axis systems, back-arc activity, hot spots, volcanism, and subduction. Organic matter alteration, primarily reductive and generally from immature organic detritus, occurs in these high temperature and rapid fluid flow hydrothermal regimes. Hot circulating water (temperature range - warm to greater than 400 C) is responsible for these molecular alterations, expulsion and migration. Compounds that are obviously synthesized are minor components because they are generally masked by the pyrolysis products formed from contemporary natural organic precursors. The reactivity of organic compounds in hot water (200-350 C) has been studied in autoclaves, and supercritical water as a medium for chemistry has also been evaluated. This high temperature aqueous organic chemistry and the strong reducing conditions of the natural systems suggest this as an important route to produce organic compounds on the primitive earth. Thus a better understanding of the potential syntheses of organic compounds in hydrothermal systems will require investigations of the chemistry of condensation, autocatalysis, catalysis and hydrolysis reactions in aqueous mineral buffered systems over a range of temperatures from warm to greater than 400 C.

  8. Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites.

    Science.gov (United States)

    Vollmer, Christian; Kepaptsoglou, Demie; Leitner, Jan; Busemann, Henner; Spring, Nicole H; Ramasse, Quentin M; Hoppe, Peter; Nittler, Larry R

    2014-10-28

    Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight (15)N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C-O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C-O bonding environments and nanoglobular organics with dominant aromatic and C-N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid.

  9. Potential for galactic cosmic ray stimulated organic synthesis at the poles of the Moon and Mercury

    Science.gov (United States)

    Crites, S.; Lucey, P. G.; Lawrence, D. J.

    2013-12-01

    The poles of the Moon are a unique environment. Urey (1952) was the first to point out that because of the Moon's low obliquity, polar topographic lows would be permanently shaded from sunlight. The Diviner Lunar Radiometer has confirmed temperatures as low as 29 K in some of these permanently shadowed regions, cold enough to trap and retain many volatile compounds including water ice. Evidence for the presence of volatiles and in particular water ice at the poles of the Moon continues to accumulate from measurements such as radar observations and neutron spectrometer results, and the LCROSS impactor detected abundant water ice as well as a variety of organic compounds including C2H4, CH3OH, and CH4. Laboratory measurements have demonstrated that a proton irradiation dose of 1-10 eV/molecule can stimulate organic synthesis in simple mixtures of C, H, O, and N-bearing ices (Moore and Hudson 1998). We use the radiation transport code MCNPX to model the proton flux and radiation dose from galactic cosmic rays at the poles of the Moon to compare with these experiments in order to establish the plausibility of in-situ organic synthesis. We validate our model against measurements from the Cosmic Ray Telescope for the Effects of Radiation experiment on Lunar Reconnaissance Orbiter and find them in good agreement within a 25% margin. We report doses from protons in the narrow energy band of 0.1 to 1 MeV to directly compare to experiments as well as dose from protons of all energies, dose from protons and alpha particles, and an estimate of dose from protons, alpha particles, and heavy ions. Since the actual water content of the polar cold traps is not known, we model a range of water contents between 0.1 wt% and 30 wt% H2O as well as a number of layered cases but find that the water content does not significantly affect dose deposited. We find an energy deposition rate from GCR protons of 7.9 eV/molecule-Gyr, indicating that only about 125 Myr are required to reach the

  10. Selenol Protecting Groups in Organic Chemistry: Special Emphasis on Selenocysteine Se-Protection in Solid Phase Peptide Synthesis

    OpenAIRE

    Stevenson Flemer Jr.

    2011-01-01

    The appearance of selenium in organic synthesis is relatively rare, and thus examples in the literature pertaining to the masking of its considerable reactivity are similarly uncommon. Greene's Protecting Groups in Organic Synthesis, the standard reference for the state of the art in this arena, offers no entries for selenium protective methodology, in stark comparison to its mention of the great variety of protecting groups germane to its chalcogen cousin sulfur. This scarcity of Se-protecti...

  11. High current, low voltage carbon nanotube enabled vertical organic field effect transistors.

    Science.gov (United States)

    McCarthy, Mitchell A; Liu, Bo; Rinzler, Andrew G

    2010-09-08

    State-of-the-art performance is demonstrated from a carbon nanotube enabled vertical field effect transistor using an organic channel material. The device exhibits an on/off current ratio >10(5) for a gate voltage range of 4 V with a current density output exceeding 50 mA/cm(2). The architecture enables submicrometer channel lengths while avoiding high-resolution patterning. The ability to drive high currents and inexpensive fabrication may provide the solution for the so-called OLED backplane problem.

  12. Design, Synthesis and Characterization of Functional Metal-Organic Framework Materials

    KAUST Repository

    Alamer, Badriah

    2015-06-01

    Over the past few decades, vast majority of industrial and academic research throughout the world has witnessed the emergence of materials that can serve as ideal candidates for potential utility in desired applications, and these materials are known as Metal Organic Framework (MOFs). This exceptional new family of porous materials is fabricated by linkage of metal ions or clusters and organic linkers via strong bonds. MOFs have been awarded with remarkable interest and widely studied due to their inherent structural methodology (e.g. use of various metals, expanded library of organic building blocks with different geometry and functionality particularly frameworks designed from carboxylate organic linkers) and unquestionably unique structural and chemical features for many practical applications. (i.e. gas storage/separation, catalysis, drug delivery etc). Simply, metal organic frameworks epitomize the beauty of porous chemical structures. From a design perspective, the introduction of the Molecular Building Block (MBB) approach is actively being pursued pathway by researchers toward the construction of MOFs by employing inorganic building blocks and organic linkers and taking advantage of not only their multiple coordination modes and geometries but also the way in which they are reticulated to generate final framework. In this thesis, research studies will be directed toward (i) the investigation of the relationship between experimental parameters and synthesis of well-known fcu –MOF, (ii) rational design and synthesis of new rare earth (RE) based MOFs, (ii) isoreticular materials based on particular MBB ([M3O(RCO2)6]), M= p-and d-block metals, and (iv) zeolite- like metal organic framework assembled from single-metal ion based MBB ([MN2(CO2)4]) via 2-, 3-,and 4-connected organic linkers. Consequently, the porosity, chemical and thermal stability, and gas sorption properties will be evaluated and detailed.

  13. Forecasting Performance in Organizations: An Application of Current-Value Human Resources Accounting. Final Report.

    Science.gov (United States)

    Pecorella, Patricia A.; And Others

    A methodology to describe current-value human resources accounting (HRA) was developed to aid management in decision making and provide information about the effects of organizational policies and practices on the value of the organizations' human resources. A two-phase activity was designed to investigate the nature of the relationship between…

  14. High current density in light-emitting transistors of organic single crystals

    NARCIS (Netherlands)

    Takenobu, Taishi; Bisri, Satria Zulkarnaen; Takahashi, Tetsuo; Yahiro, Masayuki; Adachi, Chihaya; Iwasa, Yoshihiro

    2008-01-01

    We measured the external electroluminescence quantum efficiency (eta(ext)) in light-emitting field-effect transistors (LETs) made of organic single crystals and found that, in the ambipolar transport region, eta(ext) is not degraded up to several hundreds A/cm(2) current-density range, which is 2 or

  15. Immobilization of trypsin in organic and aqueous media for enzymatic peptide synthesis and hydrolysis reactions.

    Science.gov (United States)

    Stolarow, Julia; Heinzelmann, Manuel; Yeremchuk, Wladimir; Syldatk, Christoph; Hausmann, Rudolf

    2015-08-19

    Immobilization of enzymes onto different carriers increases enzyme's stability and reusability within biotechnological and pharmaceutical applications. However, some immobilization techniques are associated with loss of enzymatic specificity and/or activity. Possible reasons for this loss are mass transport limitations or structural changes. For this reason an immobilization method must be selected depending on immobilisate's demands. In this work different immobilization media were compared towards the synthetic and hydrolytic activities of immobilized trypsin as model enzyme on magnetic micro-particles. Porcine trypsin immobilization was carried out in organic and aqueous media with magnetic microparticles. The immobilization conditions in organic solvent were optimized for a peptide synthesis reaction. The highest carrier activity was achieved at 1 % of water (v/v) in dioxane. The resulting immobilizate could be used over ten cycles with activity retention of 90 % in peptide synthesis reaction in 80 % (v/v) ethanol and in hydrolysis reaction with activity retention of 87 % in buffered aqueous solution. Further, the optimized method was applied in peptide synthesis and hydrolysis reactions in comparison to an aqueous immobilization method varying the protein input. The dioxane immobilization method showed a higher activity coupling yield by factor 2 in peptide synthesis with a maximum activity coupling yield of 19.2 % compared to aqueous immobilization. The hydrolysis activity coupling yield displayed a maximum value of 20.4 % in dioxane immobilization method while the aqueous method achieved a maximum value of 38.5 %. Comparing the specific activity yields of the tested immobilization methods revealed maximum values of 5.2 % and 100 % in peptide synthesis and 33.3 % and 87.5 % in hydrolysis reaction for the dioxane and aqueous method, respectively. By immobilizing trypsin in dioxane, a beneficial effect on the synthetic trypsin activity resilience

  16. Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

    Directory of Open Access Journals (Sweden)

    Alexander O. Terent'ev

    2014-01-01

    Full Text Available The present review describes the current status of synthetic five and six-membered cyclic peroxides such as 1,2-dioxolanes, 1,2,4-trioxolanes (ozonides, 1,2-dioxanes, 1,2-dioxenes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes. The literature from 2000 onwards is surveyed to provide an update on synthesis of cyclic peroxides. The indicated period of time is, on the whole, characterized by the development of new efficient and scale-up methods for the preparation of these cyclic compounds. It was shown that cyclic peroxides remain unchanged throughout the course of a wide range of fundamental organic reactions. Due to these properties, the molecular structures can be greatly modified to give peroxide ring-retaining products. The chemistry of cyclic peroxides has attracted considerable attention, because these compounds are used in medicine for the design of antimalarial, antihelminthic, and antitumor agents.

  17. Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products.

    Science.gov (United States)

    Terent'ev, Alexander O; Borisov, Dmitry A; Vil', Vera A; Dembitsky, Valery M

    2014-01-08

    The present review describes the current status of synthetic five and six-membered cyclic peroxides such as 1,2-dioxolanes, 1,2,4-trioxolanes (ozonides), 1,2-dioxanes, 1,2-dioxenes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes. The literature from 2000 onwards is surveyed to provide an update on synthesis of cyclic peroxides. The indicated period of time is, on the whole, characterized by the development of new efficient and scale-up methods for the preparation of these cyclic compounds. It was shown that cyclic peroxides remain unchanged throughout the course of a wide range of fundamental organic reactions. Due to these properties, the molecular structures can be greatly modified to give peroxide ring-retaining products. The chemistry of cyclic peroxides has attracted considerable attention, because these compounds are used in medicine for the design of antimalarial, antihelminthic, and antitumor agents.

  18. Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

    Science.gov (United States)

    Borisov, Dmitry A; Vil’, Vera A; Dembitsky, Valery M

    2014-01-01

    Summary The present review describes the current status of synthetic five and six-membered cyclic peroxides such as 1,2-dioxolanes, 1,2,4-trioxolanes (ozonides), 1,2-dioxanes, 1,2-dioxenes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes. The literature from 2000 onwards is surveyed to provide an update on synthesis of cyclic peroxides. The indicated period of time is, on the whole, characterized by the development of new efficient and scale-up methods for the preparation of these cyclic compounds. It was shown that cyclic peroxides remain unchanged throughout the course of a wide range of fundamental organic reactions. Due to these properties, the molecular structures can be greatly modified to give peroxide ring-retaining products. The chemistry of cyclic peroxides has attracted considerable attention, because these compounds are used in medicine for the design of antimalarial, antihelminthic, and antitumor agents. PMID:24454562

  19. Metal-organic gel templated synthesis of magnetic porous carbon for highly efficient removal of organic dyes.

    Science.gov (United States)

    Wang, Luhuan; Ke, Fei; Zhu, Junfa

    2016-03-21

    Magnetic porous carbon composites are promising materials in various applications, such as adsorbents, supercapacitors and catalyst supports, due to their high surface area, thermal and chemical stability, and easy separation. However, despite the increasing number of reports of magnetic porous carbon composites, the preparation of these materials with environmentally friendly procedures still remains a great challenge. Herein, we report a facile method to prepare a magnetic porous carbon composite with high surface area from a Fe-based metal-organic gel (MOG) template, an extended structure of a metal-organic framework (MOF). The obtained magnetic porous carbon composite was applied to remove organic dyes from an aqueous solution by selecting methyl orange (MO) as a model molecule. It exhibits excellent adsorption capacity (182.82 mg g(-1)), fast adsorption kinetics (8.13 × 10(-3) g mg(-1) min(-1)), and a perfect magnetic separation performance for the MO removal. This study demonstrates a new way to achieve clean synthesis of magnetic porous carbon materials, and opens a new door for the application of MOGs in organic dye removal.

  20. Blue green alga mediated synthesis of gold nanoparticles and its antibacterial efficacy against Gram positive organisms

    Energy Technology Data Exchange (ETDEWEB)

    Uma Suganya, K.S. [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Govindaraju, K., E-mail: govindtu@gmail.com [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Ganesh Kumar, V.; Stalin Dhas, T.; Karthick, V. [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Singaravelu, G. [Nanoscience Division, Department of Zoology, Thiruvalluvar University, Vellore 632115 (India); Elanchezhiyan, M. [Department of Microbiology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai 600113 (India)

    2015-02-01

    Biofunctionalized gold nanoparticles (AuNPs) play an important role in design and development of nanomedicine. Synthesis of AuNPs from biogenic materials is environmentally benign and possesses high bacterial inhibition and bactericidal properties. In the present study, blue green alga Spirulina platensis protein mediated synthesis of AuNPs and its antibacterial activity against Gram positive bacteria is discussed. AuNPs were characterized using Ultraviolet–visible (UV–vis) spectroscopy, Fluorescence spectroscopy, Fourier Transform-Infrared (FTIR) spectroscopy, Raman spectroscopy, High Resolution-Transmission Electron Microscopy (HR-TEM) and Energy Dispersive X-ray analysis (EDAX). Stable, well defined AuNPs of smaller and uniform shape with an average size of ∼ 5 nm were obtained. The antibacterial efficacy of protein functionalized AuNPs were tested against Gram positive organisms Bacillus subtilis and Staphylococcus aureus. - Highlights: • Size controlled synthesis of gold nanoparticles from blue green alga Spirulina platensis • Stability of gold nanoparticles at different temperatures • Potent antibacterial efficacy against Gram positive organisms.

  1. A new era for organic synthesis-highlights of the recent progress

    Institute of Scientific and Technical Information of China (English)

    WU Yikang; WU Yu-Lin

    2007-01-01

    The major progress in organic synthesis since 2005 is briefly surveyed in two parts.The first part deals with some of the most impressive advances in the synthetic methodology,which includes:(1) metal-mediated synthetic reactions,with an emphasis on the olefin metathesis and gold-mediated reactions;(2) free radical-based organic synthesis;(3) synthetic transformations performed in a "one-pot" manner involving either tandem reactions or multicomponent reactions;(4) asymmetric reactions catalyzed by metal and organo-catalysts.The major advances in total synthesis of some complex natural products with significant biological activities are presented in the second part,with detailed illustrations of ten selected molecules,including dragmacidin F,abyssomicin C,11-acetoxy-4-deoxyasbestinin D,pentacycloanammoxic acid,UCS 1025A,(-)-merrilactone A,nigellamine A2,( +)-saxitoxin,and Tamiflu (an artificially designed natural product-like molecule).An array of complicated structures of the natural products synthesized over the last two years is also listed to serve as a convenient lead to the original literature for the prospective interested readers.

  2. Synthesis of alkyl esters by cutinase in miniemulsion and organic solvent media.

    Science.gov (United States)

    de Barros, Dragana P C; Fonseca, Luís P; Cabral, Joaquim M S; Weiss, Clemens K; Landfester, Katharina

    2009-05-01

    The main objective of this work was studying and testing the nature and influence of reaction media (organic solvent vs. miniemulsion system) on the synthesis of alkyl esters catalyzed by Fusarium solani pisi cutinase. Ester synthesis and cutinase selectivity for different chain length of acids and alcohols (ethyl and hexyl) were evaluated. In iso-octane, after 1 h of reaction, cutinase exhibits rates of esterification between 0.24 micromol x mg(-)1 x min(-1) for ethyl oleate and 1.15 micromol x mg(-)1 x min(-1) for ethyl butyrate, while in a miniemulsion system the rates were from 0.05 for ethyl heptanoate to 0.76 micromol x mg(-1) x min(-1) for ethyl decanoate. The reaction rate for the synthesis of hexyl esters in a miniemulsion system was from 0.19 for hexyl heptanoate to 1.07 micromol x mg(-)1 x min(-1) for hexyl decanoate. High conversion yields of 95% at equilibrium after 8 h of reaction in iso-octane for pentanoic acid (C(5)) with ethanol at equimolar concentration (0.1 M) was achieved. Additionally, this work showed that a significant and unexpected shift in cutinase selectivity occurred towards longer chain length carboxylic acids (C(8)-C(10)) in miniemulsion system as compared to organic solvent (iso-octane) and previous studies in reverse micellar systems. The possibility of working with higher concentration of substrates, without inhibitory effect on the enzyme, was another advantage of the miniemulsion system.

  3. Controlled synthesis of organic nanophotonic materials with specific structures and compositions.

    Science.gov (United States)

    Cui, Qiu Hong; Zhao, Yong Sheng; Yao, Jiannian

    2014-10-29

    Organic nanomaterials have drawn great interest for their potential applications in high-speed miniaturized photonic integration due to their high photoluminescence quantum efficiency, structural processability, ultrafast photoresponse, and excellent property engineering. Based on the rational design on morphological and componential levels, a series of organic nanomaterials have been controllably synthesized in recent years, and their excitonic/photonic behaviors has been fine-tuned to steer the light flow for specific optical applications. This review presents a comprehensive summary of recent breakthroughs in the controlled synthesis of organic nanomaterials with specific structures and compositions, whose tunable photonic properties would provide a novel platform for multifunctional applications. First, we give a general overview of the tailored construction of novel nanostructures with various photonic properties. Then, we summarize the design and controllable synthesis of composite materials for the modulation of their functionalities. Subsequently, special emphasis is put on the fabrication of complex nanostructures towards wide applications in isolated photonic devices. We conclude with our personal viewpoints on the development directions in the novel design and controllable construction of organic nanomaterials for future applications in highly integrated photonic devices and chips.

  4. DNA-Based Synthesis and Assembly of Organized Iron Oxide Nanostructures

    Science.gov (United States)

    Khomutov, Gennady B.

    Organized bio-inorganic and hybrid bio-organic-inorganic nanostructures consisting of iron oxide nanoparticles and DNA complexes have been formed using methods based on biomineralization, interfacial and bulk phase assembly, ligand exchange and substitution, Langmuir-Blodgett technique, DNA templating and scaffolding. Interfacially formed planar DNA complexes with water-insoluble amphiphilic polycation or intercalator Langmuir monolayers were prepared and deposited on solid substrates to form immobilized DNA complexes. Those complexes were then used for the synthesis of organized DNA-based iron oxide nanostructures. Planar net-like and circular nanostructures of magnetic Fe3O4 nanoparticles were obtained via interaction of cationic colloid magnetite nanoparticles with preformed immobilized DNA/amphiphilic polycation complexes of net-like and toroidal morphologies. The processes of the generation of iron oxide nanoparticles in immobilized DNA complexes via redox synthesis with various iron sources of biological (ferritin) and artificial (FeCl3) nature have been studied. Bulk-phase complexes of magnetite nanoparticles with biomolecular ligands (DNA, spermine) were formed and studied. Novel nano-scale organized bio-inorganic nanostructures - free-floating sheet-like spermine/magnetite nanoparticle complexes and DNA/spermine/magnetite nanoparticle complexes were synthesized in bulk aqueous phase and the effect of DNA molecules on the structure of complexes was discovered.

  5. Structure-directing effects of ionic liquids in the ionothermal synthesis of metal–organic frameworks

    Directory of Open Access Journals (Sweden)

    Thomas P. Vaid

    2017-07-01

    Full Text Available Traditional synthesis of metal–organic frameworks (MOFs involves the reaction of a metal-containing precursor with an organic linker in an organic solvent at an elevated temperature, in what is termed a `solvothermal' reaction. More recently, many examples have been reported of MOF synthesis in ionic liquids (ILs, rather than an organic solvent, in `ionothermal' reactions. The high concentration of both cations and anions in an ionic liquid allows for the formation of new MOF structures in which the IL cation or anion or both are incorporated into the MOF. Most commonly, the IL cation is included in the open cavities of the MOF, countering the anionic charge of the MOF framework itself and acting as a template around which the MOF structure forms. Ionic liquids can also serve other structure-directing roles, for example, when an IL containing a single enantiomer of a chiral anion leads to a homochiral MOF, even though the IL anion is not itself incorporated into the MOF. A comprehensive review of ionothermal syntheses of MOFs, and the structure-directing effects of the ILs, is given.

  6. Structure-directing effects of ionic liquids in the ionothermal synthesis of metal–organic frameworks

    Science.gov (United States)

    Kelley, Steven P.; Rogers, Robin D.

    2017-01-01

    Traditional synthesis of metal–organic frameworks (MOFs) involves the reaction of a metal-containing precursor with an organic linker in an organic solvent at an elevated temperature, in what is termed a ‘solvothermal’ reaction. More recently, many examples have been reported of MOF synthesis in ionic liquids (ILs), rather than an organic solvent, in ‘ionothermal’ reactions. The high concentration of both cations and anions in an ionic liquid allows for the formation of new MOF structures in which the IL cation or anion or both are incorporated into the MOF. Most commonly, the IL cation is included in the open cavities of the MOF, countering the anionic charge of the MOF framework itself and acting as a template around which the MOF structure forms. Ionic liquids can also serve other structure-directing roles, for example, when an IL containing a single enantiomer of a chiral anion leads to a homochiral MOF, even though the IL anion is not itself incorporated into the MOF. A comprehensive review of ionothermal syntheses of MOFs, and the structure-directing effects of the ILs, is given. PMID:28875025

  7. Structure-directing effects of ionic liquids in the ionothermal synthesis of metal-organic frameworks.

    Science.gov (United States)

    Vaid, Thomas P; Kelley, Steven P; Rogers, Robin D

    2017-07-01

    Traditional synthesis of metal-organic frameworks (MOFs) involves the reaction of a metal-containing precursor with an organic linker in an organic solvent at an elevated temperature, in what is termed a 'solvothermal' reaction. More recently, many examples have been reported of MOF synthesis in ionic liquids (ILs), rather than an organic solvent, in 'ionothermal' reactions. The high concentration of both cations and anions in an ionic liquid allows for the formation of new MOF structures in which the IL cation or anion or both are incorporated into the MOF. Most commonly, the IL cation is included in the open cavities of the MOF, countering the anionic charge of the MOF framework itself and acting as a template around which the MOF structure forms. Ionic liquids can also serve other structure-directing roles, for example, when an IL containing a single enantiomer of a chiral anion leads to a homochiral MOF, even though the IL anion is not itself incorporated into the MOF. A comprehensive review of ionothermal syntheses of MOFs, and the structure-directing effects of the ILs, is given.

  8. Carbon Isotope Systematics in Mineral-Catalyzed Hydrothermal Organic Synthesis Processes at High Temperature and Pressures

    Science.gov (United States)

    Fu, Qi; Socki, R. A.; Niles, Paul B.

    2011-01-01

    Observation of methane in the Martian atmosphere has been reported by different detection techniques. Reduction of CO2 and/or CO during serpentization by mineral surface catalyzed Fischer-Tropsch Type (FTT) synthesis may be one possible process responsible for methane generation on Mars. With the evidence a recent study has discovered for serpentinization in deeply buried carbon rich sediments, and more showing extensive water-rock interaction in Martian history, it seems likely that abiotic methane generation via serpentinization reactions may have been common on Mars. Experiments involving mineral-catalyzed hydrothermal organic synthesis processes were conducted at 750 C and 5.5 Kbars. Alkanes, alcohols and carboxylic acids were identified as organic compounds. No "isotopic reversal" of delta C-13 values was observed for alkanes or carboxylic acids, suggesting a different reaction pathway than polymerization. Alcohols were proposed as intermediaries formed on mineral surfaces at experimental conditions. Carbon isotope data were used in this study to unravel the reaction pathways of abiotic formation of organic compounds in hydrothermal systems at high temperatures and pressures. They are instrumental in constraining the origin and evolution history of organic compounds on Mars and other planets.

  9. Synthesis of Vitamin E Succinate from Candida rugosa Lipase in Organic Medium

    Institute of Scientific and Technical Information of China (English)

    JIANG Xiang-jun; HU Yi; JIANG Ling; GONG Ji-hong; HUANG He

    2013-01-01

    A screening of commercially available lipases for the synthesis of vitamin E succinate showed that lipase from Candida rugosa presented the highest yield.The synthesis of vitamin E succinate in organic solvents with different lgP values ranging from-1.3 to 3.5 was investigated.Of particular interest was that dimethyl sulfoxide (DMSO) with the lowest lgP exhibited the highest yield among all the organic solvents used.It suggests that lgP is incapable of satisfactorily predicting the biocompatibility of organic solvents due to the complexity of enzymatic reaction with hydrophilic and hydrophobic substrates in organic solvent.Effects of different operating conditions,such as molar ratio of substrate,enzyme concentration,reaction temperature,mass transfer,and reaction time were also studied.Under the optimum conditions of 10 g/L enzyme,a stirring rate of 100 r/min,a substrate molar ratio of 5:1 at 55 C for 18 h,a satisfactory yield(46.95%) was obtained.The developed method has a potential to be used for efficient enzymatic production of vitamin E succinate.

  10. sp(2)-sp(3) diboranes: astounding structural variability and mild sources of nucleophilic boron for organic synthesis.

    Science.gov (United States)

    Dewhurst, Rian D; Neeve, Emily C; Braunschweig, Holger; Marder, Todd B

    2015-06-14

    Despite the widespread use of organoborane reagents in organic synthesis and catalysis, a major challenge still remains: very few boron-centered nucleophiles exist for the direct construction of B-C bonds. Perhaps the most promising emerging solution to this problem is the use of sp(2)-sp(3) diboranes, in which one boron atom of a conventional diborane(4) is quaternised by either a neutral or anionic nucleophile. These compounds, either isolated or generated in situ, serve as relatively mild and convenient sources of the boryl anion [BR2](-) for use in organic synthesis and have already proven their efficacy in metal-free as well as metal-catalysed borylation reactions. This Feature article documents the history of sp(2)-sp(3) diborane synthesis, their properties and surprising structural variability, and their burgeoning utility in organic synthesis.

  11. Microwave-Assisted Organic Synthesis in the Organic Teaching Lab: A Simple, Greener Wittig Reaction

    Science.gov (United States)

    Martin, Eric; Kellen-Yuen, Cynthia

    2007-01-01

    A greener, microwave-assisted Wittig reaction has been developed for the second-semester organic teaching laboratory. Utilizing this microwave technique, a variety of styrene derivatives have been successfully synthesized from aromatic aldehydes in good yields (41-68%). The reaction not only occurs under neat reaction conditions, but also employs…

  12. Silicon-containing alka-1,3-dienes and their functional derivatives in organic synthesis

    Science.gov (United States)

    Stadnichuk, M. D.; Voropaeva, T. I.

    1995-01-01

    Data on the synthesis and chemical reactions of silicon-containing 1,3-dienes are surveyed for the first time in the present review. It is shown that the addition reactions of 1- and 2-triorganosilylalka-1,3-dienes and their derivatives are the most interesting and promising in fine organic synthesis. The application of the trialkylsilyl group as a protecting group and as a new reaction centre, which makes it possible to obtain carbon-carbon or carbon-heteroatom bonds, is examined. It has been found that the double bonds remote from the silicon atom are the most reactive in addition reactions and that regardless of the nature of the reagent the attacking species always binds to the terminal carbon atom of the buta-1,3-diene fragment. The bibliography includes 329 references.

  13. Quantification of DNA synthesis in multicellular organisms by a combined DAPI and BrdU technique.

    Science.gov (United States)

    Knobloch, Jürgen; Kunz, Werner; Grevelding, Christoph G

    2002-12-01

    The development of a novel method to detect and quantify mitotic activity in multicellular organisms is reported. The method is based on the combinatorial use of 4',6-diamidino-2-phenylindole (DAPI) as a dye for the specific staining of DNA and the thymidine analog 5-bromo-2'-deoxyuridine (BrdU) as a marker for DNA synthesis. It is shown that on nitrocellulose filters, the amount of DNA can be determined by DAPI as a prerequisite for the subsequent quantification of mitotic activity by BrdU. As a model system to prove the applicability of this technique, the blood fluke Schistosoma mansoni has been used. It is demonstrated that the DNA synthesis rate is higher in adult female schistosomes than in adult males. Furthermore, dimethyl sulfoxide, a widely used solvent for many mitogens and inhibitors of mitosis, has no influence on mitotic activity in adult schistosomes.

  14. Little Thermodynamic Penalty for the Synthesis of Ultraporous Metal Organic Frameworks.

    Science.gov (United States)

    Akimbekov, Zamirbek; Navrotsky, Alexandra

    2016-02-16

    Many metal-organic frameworks (MOFs) of ultrahigh porosity (with molar volumes more than ten times greater than those of the corresponding dense phases) have been synthesized. However, the number of possible structures far exceeds those that have been made. It is logical to ask if there are energetic barriers to the stability of ultraporous MOFs or whether there is little thermodynamic penalty to their formation. Herein, we show that although the molar volumes of MOF-177 and UMCM-1 reach ultrahigh values, their energetic metastability is in the same range (of 7-36 kJ mol(-1)) as that seen previously for other porous materials. These findings suggest that there is little thermodynamic penalty for the synthesis of structures with varying porosity, and hence, ultraporous frameworks are energetically accessible. Therefore, innovative synthesis methods have the possibility to overcome the drawbacks of conventional approaches and greatly extend the number, porosity, and properties of new framework materials.

  15. Blue green alga mediated synthesis of gold nanoparticles and its antibacterial efficacy against Gram positive organisms.

    Science.gov (United States)

    Suganya, K S Uma; Govindaraju, K; Kumar, V Ganesh; Dhas, T Stalin; Karthick, V; Singaravelu, G; Elanchezhiyan, M

    2015-02-01

    Biofunctionalized gold nanoparticles (AuNPs) play an important role in design and development of nanomedicine. Synthesis of AuNPs from biogenic materials is environmentally benign and possesses high bacterial inhibition and bactericidal properties. In the present study, blue green alga Spirulina platensis protein mediated synthesis of AuNPs and its antibacterial activity against Gram positive bacteria is discussed. AuNPs were characterized using Ultraviolet-visible (UV-vis) spectroscopy, Fluorescence spectroscopy, Fourier Transform-Infrared (FTIR) spectroscopy, Raman spectroscopy, High Resolution-Transmission Electron Microscopy (HR-TEM) and Energy Dispersive X-ray analysis (EDAX). Stable, well defined AuNPs of smaller and uniform shape with an average size of ~ 5 nm were obtained. The antibacterial efficacy of protein functionalized AuNPs were tested against Gram positive organisms Bacillus subtilis and Staphylococcus aureus.

  16. Modulation by Amino Acids: Toward Superior Control in the Synthesis of Zirconium Metal-Organic Frameworks.

    Science.gov (United States)

    Gutov, Oleksii V; Molina, Sonia; Escudero-Adán, Eduardo C; Shafir, Alexandr

    2016-09-12

    The synthesis of zirconium metal-organic frameworks (Zr MOFs) modulated by various amino acids, including l-proline, glycine, and l-phenylalanine, is shown to be a straightforward approach toward functional-group incorporation and particle-size control. High yields in Zr-MOF synthesis are achieved by employing 5 equivalents of the modulator at 120 °C. At lower temperatures, the method provides a series of Zr MOFs with increased particle size, including many suitable for single-crystal X-ray diffraction studies. Furthermore, amino acid modulators can be incorporated at defect sites in Zr MOFs with an amino acid/ligand ratio of up to 1:1, depending on the ligand structure and reaction conditions. The MOFs obtained through amino acid modulation exhibit an improved CO2 -capture capacity relative to nonfunctionalized materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Analytical Model for Voltage-Dependent Photo and Dark Currents in Bulk Heterojunction Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Mesbahus Saleheen

    2016-05-01

    Full Text Available A physics-based explicit mathematical model for the external voltage-dependent forward dark current in bulk heterojunction (BHJ organic solar cells is developed by considering Shockley-Read-Hall (SRH recombination and solving the continuity equations for both electrons and holes. An analytical model for the external voltage-dependent photocurrent in BHJ organic solar cells is also proposed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (EHPs, carrier trapping, and carrier drift and diffusion in the photon absorption layer. Modified Braun’s model is used to compute the electric field-dependent dissociation efficiency of the bound EHPs. The overall net current is calculated considering the actual solar spectrum. The mathematical models are verified by comparing the model calculations with various published experimental results. We analyze the effects of the contact properties, blend compositions, charge carrier transport properties (carrier mobility and lifetime, and cell design on the current-voltage characteristics. The power conversion efficiency of BHJ organic solar cells mostly depends on electron transport properties of the acceptor layer. The results of this paper indicate that improvement of charge carrier transport (both mobility and lifetime and dissociation of bound EHPs in organic blend are critically important to increase the power conversion efficiency of the BHJ solar cells.

  18. Tin Oxide Nanoparticles: Synthesis, Characterization and Study their Particle Size at Different Current Density

    Directory of Open Access Journals (Sweden)

    Karzan A. Omar

    2013-11-01

    Full Text Available Tin oxide nanoparticles are prepared by electrochemical reduction method using tetrapropylammonium bromide (TPAB and tetrabutylammonium bromide (TBAB as structure directing agent in an organic medium viz. tetrahydrofuran (THF and acetonitrile (ACN in 4:1 ratio by optimizing current density and molar concentration of the ligand. The reduction process takes place under an inert atmosphere of nitrogen over a period of 2 h. Such nanoparticles are prepared by using a simple electrolysis cell in which the sacrificial anode as a commercially available in tin metal sheet and platinum (inert sheet act as a cathode. The parameters such as current density, solvent polarity, distance between electrodes and concentration of stabilizers are used to control the size of nanoparticles. The synthesized tin oxide nanoparticles are characterized by using UV–Visible, FT-IR and SEM–EDS analysis techniques. UV-Visible spectroscopy has revealed the optical band gap to be 4.13, 4.16 and 4.24 ev for (8, 10 and 12 mA/cm2 and the effect of current density on theirs particle size, respectively.

  19. Open Augmented Reality Standards: Current Activities in Standards- Development Organizations%Open Augmented Reality Standards: Current Activities in Standards- Development Organizations

    Institute of Scientific and Technical Information of China (English)

    Christine Perey

    2012-01-01

    Augmented reality (AR) has emerged from research laboratories and is now being accepted in other domains as an attractive way of visualizing information. Before AR can be used in the mass market, there are a number of obstacles that need to be overcome. Several of these can be overcome by adopting open standards. A global grassroots community seeking open, interoperable AR content and experiences began to take shape in early 2010. This community is working collaboratively to reduce the barriers to the flow of data from content provider to AR end user. Standards development organizations and industry groups that provide open interfaces for AR meet regularly to provide updates, identify complementary work, and seek harmonization. The community also identifies deployer and implementer needs, communicates requirements, and discusses emerging challenges that could be resolved with standards. In this article, we describe current activities in international standards-development organizations. We summarize the AR standards gap analysis and shed light on special considerations for using standards in mobile AR.

  20. A Research Module for the Organic Chemistry Laboratory: Multistep Synthesis of a Fluorous Dye Molecule.

    Science.gov (United States)

    Slade, Michael C; Raker, Jeffrey R; Kobilka, Brandon; Pohl, Nicola L B

    2014-01-14

    A multi-session research-like module has been developed for use in the undergraduate organic teaching laboratory curriculum. Students are tasked with planning and executing the synthesis of a novel fluorous dye molecule and using it to explore a fluorous affinity chromatography separation technique, which is the first implementation of this technique in a teaching laboratory. Key elements of the project include gradually introducing students to the use of the chemical literature to facilitate their searching, as well as deliberate constraints designed to force them to think critically about reaction design and optimization in organic chemistry. The project also introduces students to some advanced laboratory practices such as Schlenk techniques, degassing of reaction mixtures, affinity chromatography, and microwave-assisted chemistry. This provides students a teaching laboratory experience that closely mirrors authentic synthetic organic chemistry practice in laboratories throughout the world.

  1. Effects of dissolved organic matter on the growth and pigments synthesis of Spirulina platensis ( Arthrospira )

    Institute of Scientific and Technical Information of China (English)

    MA Zengling; GAO Kunshan; WATANABE Teruo

    2006-01-01

    Excessive accumulation of dissolved organic matter (DOM) in the culture ponds of Spirulina platensis is usually considered to be one of the potential factors affecting the production of S. platensis, however, we are not quite aware of effects of DOM on the growth and pigments synthesis of S. platensis. In the present study, S. platensis was grown in batch or semi-continuous cultures using the filtrate in the culture ponds that had not been renewed for years. It was found that disssolved organic carbon up to 60 mg/L did not bring about an inhibitory effect on the growth of S. platensis, but increased the contents of chlorophyll a and phycocyanin instead. However, further accumulation of dissolved organic matter could decrease the content of chlorophyll a.

  2. A Research Module for the Organic Chemistry Laboratory: Multistep Synthesis of a Fluorous Dye Molecule

    Science.gov (United States)

    2014-01-01

    A multi-session research-like module has been developed for use in the undergraduate organic teaching laboratory curriculum. Students are tasked with planning and executing the synthesis of a novel fluorous dye molecule and using it to explore a fluorous affinity chromatography separation technique, which is the first implementation of this technique in a teaching laboratory. Key elements of the project include gradually introducing students to the use of the chemical literature to facilitate their searching, as well as deliberate constraints designed to force them to think critically about reaction design and optimization in organic chemistry. The project also introduces students to some advanced laboratory practices such as Schlenk techniques, degassing of reaction mixtures, affinity chromatography, and microwave-assisted chemistry. This provides students a teaching laboratory experience that closely mirrors authentic synthetic organic chemistry practice in laboratories throughout the world. PMID:24501431

  3. Metal-organic frameworks: structure, properties, methods of synthesis and characterization

    Science.gov (United States)

    Butova, V. V.; Soldatov, M. A.; Guda, A. A.; Lomachenko, K. A.; Lamberti, C.

    2016-03-01

    This review deals with key methods of synthesis and characterization of metal-organic frameworks (MOFs). The modular structure affords a wide variety of MOFs with different active metal sites and organic linkers. These compounds represent a new stage of development of porous materials in which the pore size and the active site structure can be modified within wide limits. The set of experimental methods considered in this review is sufficient for studying the short-range and long-range order of the MOF crystal structure, determining the morphology of samples and elucidating the processes that occur at the active metal site in the course of chemical reactions. The interest in metal-organic frameworks results, first of all, from their numerous possible applications, ranging from gas separation and storage to chemical reactions within the pores. The bibliography includes 362 references.

  4. Recent Developments of Metal and Metal Oxide Nanocatalysts in Organic Synthesis.

    Science.gov (United States)

    Makawana, Jigar A; Sangani, Chetan B; Yao, Yong-Fang; Duan, Yong-Tao; Lv, Peng-Cheng; Zhu, Hai-Liang

    2016-01-01

    Recently, various nanomaterials have been used in many organic transformations as efficient catalysts. The development of new catalysts by nanoscale design has emerged as a fertile field for research and innovation. The ability of nanotechnology to enhance catalytic activity opens the potential to replace expensive catalysts with lower amounts of inexpensive nanocatalysts. Besides, development of efficient and environmentally friendly synthetic methodologies for the synthesis of compound libraries of medicinal scaffolds is an attractive area of research in both academic and pharmaceutical industry. According to above reports and needs, this review deals with applications of nanoparticles as catalysts in various organic syntheses. We detail the topic of organic transformations using nanoparticles: Metal Nanoparticles and Metal Oxide Nanoparticles. In the latter part, different Metal Oxide Nanoparticles, such as ZnO Nanoparticle, TiO2 Nanoparticle, and CuO Nanoparticle are discussed.

  5. Environmentally friendly synthesis of organic-soluble silver nanoparticles for printed electronics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwi Jong; Jun, Byung Ho; Choi, Junrak; Lee, Young Il; Joung, Jaewoo; Oh, Yong Soo [eMD Center, Samsung Electro-Mechanics, Suwon, Kyunggi-Do 443-743 (Korea, Republic of)

    2007-08-22

    In this study, we attempted to synthesize organic-soluble silver nanoparticles in the concentrated organic phase with an environmentally friendly method. The fully organic phase system contains silver acetate as a silver precursor, oleic acid as both a medium and a capping molecule, and tin acetate as a reducing agent. Monodisperse silver nanoparticles with average diameters of ca. 5 nm can be easily synthesized at large scale. Only a small usage of tin acetate (<0.05 eq.mol) resulted in a high synthesis yield (>90%). Also, it was investigated that the residual tin atom does not exist in the synthesized silver nanoparticles. This implied that tin acetate acts as a reducing catalyst.

  6. Tetracene dicarboxylic imide and its disulfide: synthesis of ambipolar organic semiconductors for organic photovoltaic cells.

    Science.gov (United States)

    Okamoto, Toshihiro; Suzuki, Tsuyoshi; Tanaka, Hideyuki; Hashizume, Daisuke; Matsuo, Yutaka

    2012-01-02

    We have designed and synthesized a new donor/acceptor-type tetracene derivative by the introduction of dicarboxylic imide and disulfide groups as electron-withdrawing and -donating units, respectively. The prepared compounds, tetracene dicarboxylic imide (TI) and its disulfide (TIDS) have high chemical and electrochemical stability as well as long-wavelength absorptions of up to 886 nm in the thin films. The crystal packing structure of TIDS molecules features face-to-face π-stacking, derived from dipole-dipole interactions. Notably, TIDS exhibited ambipolar properties of both electron-donating and -accepting natures in p-n and p-i-n heterojunction organic thin-film photovoltaic devices. Accordingly, TI and TIDS are expected to be promising compounds for designing new organic semiconductors.

  7. Synthesis of current knowledge on post-fire seeding for soil stabilization and invasive species control

    Science.gov (United States)

    Beyers, Jan L.; Pyke, David A.; Wirth, Troy

    2015-01-01

    The General Accounting Office has identified a need for better information on the effectiveness of post-fire emergency stabilization and rehabilitation methods used by the U.S. Forest Service and Department of Interior (DOI) agencies. Since reviews were published on treatment effectiveness in the early 2000s, treatment choices have changed and increased monitoring has been done. Greater use of native species has added substantially to burned area emergency response (BAER) treatment costs, for example, but quantitative data on this treatment were scarce in earlier reviews. We synthesized current information on the effectiveness of post-fire seeding for both soil stabilization and for prevention of the spread of invasive species in rangelands. We reviewed published literature (peer-reviewed and “gray”) and agency monitoring reports, as well as compiled and analyzed quantitative data in agency files. Products of this review include a web-accessible database of monitoring reports and published information, a scientific journal paper summarizing findings of scientific studies, an annotated bibliography of peer-reviewed papers, a summary report published as a General Technical Report that will be available online (in progress), and presentations to scientific meetings and BAER/ESR team training sessions and workshops. By combining results from studies done by Forest Service and DOI agency personnel with research studies published since the initial reviews, we presented a comprehensive synthesis of seeding effectiveness knowledge that complements the review of other hillslope treatments published by other researchers. This information will help federal land managers make more cost-effective decisions on post-fire stabilization and rehabilitation treatments.

  8. Numerical Analysis on Current Transport Characteristics in Single Layer Organic Electroluminescent Devices

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new model to describe I-V characteristics of organic light-emitting devices (OLEDs) is developed based on experimental results. The dependence of I-V characteristics on energy barrier, trap density and carrier mobility is analyzed. The result shows that this model combines the Fowler-Nordheim tunnel theory and the trap charge limited current theory with exponential trap distribution (TCL), and it describes the current transport characteristics of OLEDs more comprehensively. The I-V characteristics follow Fowler-Nordheim theory when the energy barrier is high, the trap density is small and the carrier mobility is large.In other cases they follow the TCL theory.

  9. On Calculating the Current-Voltage Characteristic of Multi-Diode Models for Organic Solar Cells

    CERN Document Server

    Roberts, Ken

    2016-01-01

    We provide an alternative formulation of the exact calculation of the current-voltage characteristic of solar cells which have been modeled with a lumped parameters equivalent circuit with one or two diodes. Such models, for instance, are suitable for describing organic solar cells whose current-voltage characteristic curve has an inflection point, also known as an S-shaped anomaly. Our formulation avoids the risk of numerical overflow in the calculation. It is suitable for implementation in Fortran, C or on micro-controllers.

  10. Synthesis of Zeolites Using the ADOR (Assembly-Disassembly-Organization-Reassembly) Route.

    Science.gov (United States)

    Wheatley, Paul S; Čejka, Jiří; Morris, Russell E

    2016-04-03

    Zeolites are an important class of materials that have wide ranging applications such as heterogeneous catalysts and adsorbents which are dependent on their framework topology. For new applications or improvements to existing ones, new zeolites with novel pore systems are desirable. We demonstrate a method for the synthesis of novel zeolites using the ADOR route. ADOR is an acronym for Assembly, Disassembly, Organization and Reassembly. This synthetic route takes advantage of the assembly of a relatively poorly stable that which can be selectively disassembled into a layered material. The resulting layered intermediate can then be organized in different manners by careful chemical manipulation and then reassembled into zeolites with new topologies. By carefully controlling the organization step of the synthetic pathway, new zeolites with never before seen topologies are capable of being synthesized. The structures of these new zeolites are confirmed using powder X-ray diffraction and further characterized by nitrogen adsorption and scanning electron microscopy. This new synthetic pathway for zeolites demonstrates its capability to produce novel frameworks that have never been prepared by traditional zeolite synthesis techniques.

  11. Scalable synthesis and post-modification of a mesoporous metal-organic framework called NU-1000.

    Science.gov (United States)

    Wang, Timothy C; Vermeulen, Nicolaas A; Kim, In Soo; Martinson, Alex B F; Stoddart, J Fraser; Hupp, Joseph T; Farha, Omar K

    2016-01-01

    The synthesis of NU-1000, a highly robust mesoporous (containing pores >2 nm) metal-organic framework (MOF), can be conducted efficiently on a multigram scale from inexpensive starting materials. Tetrabromopyrene and (4-(ethoxycarbonyl)phenyl)boronic acid can easily be coupled to prepare the requisite organic strut with four metal-binding sites in the form of four carboxylic acids, while zirconyl chloride octahydrate is used as a precursor for the well-defined metal oxide clusters. NU-1000 has been reported as an excellent candidate for the separation of gases, and it is a versatile scaffold for heterogeneous catalysis. In particular, it is ideal for the catalytic deactivation of nerve agents, and it shows great promise as a new generic platform for a wide range of applications. Multiple post-synthetic modification protocols have been developed using NU-1000 as the parent material, making it a potentially useful scaffold for several catalytic applications. The procedure for the preparation of NU-1000 can be scaled up reliably, and it is suitable for the production of 50 g of the tetracarboxylic acid containing organic linker and 200 mg-2.5 g of NU-1000. The entire synthesis is performed without purification by column chromatography and can be completed within 10 d.

  12. Some considerations on the current debate about typing resolution in solid organ transplantation

    OpenAIRE

    Vogiatzi, Paraskevi

    2016-01-01

    Background The shortage of suitable organs and achieved tolerance are uncontested main concerns in transplantation. Long waiting lists for deceased donors and limited numbers of living donors are the current scenarios. Kidney grafts from living donors have better overall survival compared to cadaveric and require less aggressive immunosuppressive regimens. The human leukocyte antigen (HLA) labs have the key role to test the recipient and donors compatibility based on typing and antibody profi...

  13. A note on the prebiotic synthesis of organic acids in carbonaceous meteorites

    Science.gov (United States)

    Kerridge, John F.

    1991-01-01

    Strong similarities between monocarboxylic and hydrocarboxylic acids in the Murchison meteorite suggest corresponding similarities in their origins. However, various lines of evidence apparently implicate quite different precursor compounds in the synthesis of the different acids. These seeming inconsistencies can be resolved by postulating that the apparent precursors also share a related origin. Pervasive D enrichment indicates that this origin was in a presolar molecular cloud. The organic acids themselves were probably synthesized in an aqueous environment on an asteroidal parent body, the hydroxy (and amino) acids by means of the Strecker cyanohydrin reaction.

  14. Zeolite-like metal–organic frameworks (ZMOFs): design, synthesis, and properties

    KAUST Repository

    Eddaoudi, Mohamed

    2014-10-24

    This review highlights various design and synthesis approaches toward the construction of ZMOFs, which are metal–organic frameworks (MOFs) with topologies and, in some cases, features akin to traditional inorganic zeolites. The interest in this unique subset of MOFs is correlated with their exceptional characteristics arising from the periodic pore systems and distinctive cage-like cavities, in conjunction with modular intra- and/or extra-framework components, which ultimately allow for tailoring of the pore size, pore shape, and/or properties towards specific applications.

  15. Regioselective enzymatic synthesis of non-steroidal anti-inflammatory drugs containing glucose in organic media.

    Science.gov (United States)

    Wang, Na; Liu, Bo Kai; Wu, Qi; Wang, Jun Liang; Lin, Xian Fu

    2005-06-01

    Enzymatic transesterification of glucose with the vinyl ester of non-steroidal anti-inflammatory drugs (NSAIDs) was in organic media performed for synthesis of novel NSAIDs-glucose conjugates. Glucose was regioselectively acylated at the 6-hydroxyl group. The indomethacin-glucose conjugate and ketoprofen-glucose conjugate were produced by the catalysis of alkaline protease from Bacillus subtilis in the respective yields of 42% (over 48 h) and 63% (over 40 h). The etodolac-glucose conjugate was obtained in 26% yield (over 144 h) by lipase from Candida antarctica.

  16. Interface modification and material synthesis of organic light-emitting diodes using plasma technology

    Science.gov (United States)

    Liang, Rongqing; Ou, Qiongrong; Yang, Cheng; He, Kongduo; Yang, Xilu; Zhong, Shaofeng; plasma application Team

    2015-09-01

    Organic light-emitting diodes (OLEDs), due to their unique properties of solution processability, compatibility with flexible substrates and with large-scale printing technology, attract huge interest in the field of lighting. The integration of plasma technology into OLEDs provides a new route to improve their performance. Here we demonstrate the modification of indium-tin-oxide (ITO) work function by plasma treatment, synthesis of thermally activated delayed fluorescence (TADF) materials using plasma grafting (polymerisation), and multi-layer solution processing achieved by plasma cross-linking.

  17. Metal-organic framework templated synthesis of porous inorganic materials as novel sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, Kathryn M. L.; Lin, Wenbin; Abney, Carter W.

    2017-03-21

    A novel metal-organic framework (MOF) templated process for the synthesis of highly porous inorganic sorbents for removing radionuclides, actinides, and heavy metals is disclosed. The highly porous nature of the MOFs leads to highly porous inorganic sorbents (such as oxides, phosphates, sulfides, etc) with accessible surface binding sites that are suitable for removing radionuclides from high level nuclear wastes, extracting uranium from acid mine drainage and seawater, and sequestering heavy metals from waste streams. In some cases, MOFs can be directly used for removing these metal ions as MOFs are converted to highly porous inorganic sorbents in situ.

  18. Synthesis of zinc oxide nanocrystals by thermal decomposition of Zn-oleate in organic medium

    Institute of Scientific and Technical Information of China (English)

    Beng; S.ONG; Rafik; O.LOUTFY

    2008-01-01

    We report the synthesis of uniform-sized hexagonal ZnO nanocrystals by the thermolysis of Zn-oleate complex,which was prepared from the reaction of inexpensive and environmentally friendly reagents such as zinc nitrate and sodium oleate.Two organic compounds with different boiling points,octadecene and octylether,were selected as the medium for thermolysis of Zn-oleate complex.Under optimized reaction conditions,we were able to synthesize ZnO nanoparticles with the size being about 10 nm.X-ray diffraction and transmission electron micrograph(TEM) images confirmed the high crystallinity of the nanocrystals.

  19. Nobel Prize in Chemistry. Development of the Olefin Metathesis Method in Organic Synthesis

    Science.gov (United States)

    Casey, Charles P.

    2006-02-01

    The 2005 Nobel Prize in Chemistry was awarded to Yves Chauvin of the Institut Français du Pétrole, Robert H. Grubbs of CalTech, and Richard R. Schrock of MIT "for development of the metathesis method in organic synthesis". The discoveries of the laureates provided a chemical reaction now used daily in the chemical industry for the efficient and more environmentally friendly production of important pharmaceuticals, fuels, synthetic fibers, and many other products. This article tells the story of how olefin metathesis became a truly useful synthetic transformation and a triumph for mechanistic chemistry, and illustrates the importance of fundamental research. See JCE Featured Molecules .

  20. [Synthesis and applications of chiral metal-organic framework in the selective separation of enantiomers].

    Science.gov (United States)

    Qi, Xiaoyue; Li, Xianjiang; Bai, Yu; Liu, Huwei

    2016-01-01

    Chirality is a universal phenomenon in nature. Chiral separation is vitally important in drug development, agricultural chemistry, pharmacology, environmental science, biology and many other fields. Chiral metal-organic frameworks (MOFs) are a new group of porous materials with special topology and designable pore structures, as well as their high specific surface area, porosity, excellent thermal stability, solvent resistance, etc. Thus, chiral MOFs are promising with various applications in the field of analytical chemistry. This review summarizes the synthesis strategies of chiral MOFs and their applications in the selective separation of enantiomers, as well as related mechanism.

  1. Metal-organic framework templated synthesis of porous inorganic materials as novel sorbents

    Science.gov (United States)

    Taylor-Pashow, Kathryn M. L.; Lin, Wenbin; Abney, Carter W.

    2017-03-21

    A novel metal-organic framework (MOF) templated process for the synthesis of highly porous inorganic sorbents for removing radionuclides, actinides, and heavy metals is disclosed. The highly porous nature of the MOFs leads to highly porous inorganic sorbents (such as oxides, phosphates, sulfides, etc) with accessible surface binding sites that are suitable for removing radionuclides from high level nuclear wastes, extracting uranium from acid mine drainage and seawater, and sequestering heavy metals from waste streams. In some cases, MOFs can be directly used for removing these metal ions as MOFs are converted to highly porous inorganic sorbents in situ.

  2. Synthesis and characterization of organic-inorganic hybrids formed between conducting polymers and crystalline antimonic acid

    Directory of Open Access Journals (Sweden)

    Beleze Fábio A.

    2001-01-01

    Full Text Available In this paper we report the synthesis and characterization of novel organic-inorganic hybrid materials between the crystalline antimonic acid (CAA and two conductive polymers: polypyrrole and polyaniline. The hybrids were obtained by in situ oxidative polymerization of monomers by the Sb(V present in the pyrochlore-like CAA structure. The materials were characterized by infrared and Raman spectroscopy, X-ray diffraction, cyclic voltammetry, CHN elemental analysis and electronic paramagnetic resonance spectroscopy. The results showed that both polymers were formed in their oxidized form, with the CAA structure acting as a counter anion.

  3. Applications of Continuous-Flow Photochemistry in Organic Synthesis, Material Science, and Water Treatment.

    Science.gov (United States)

    Cambié, Dario; Bottecchia, Cecilia; Straathof, Natan J W; Hessel, Volker; Noël, Timothy

    2016-09-14

    Continuous-flow photochemistry in microreactors receives a lot of attention from researchers in academia and industry as this technology provides reduced reaction times, higher selectivities, straightforward scalability, and the possibility to safely use hazardous intermediates and gaseous reactants. In this review, an up-to-date overview is given of photochemical transformations in continuous-flow reactors, including applications in organic synthesis, material science, and water treatment. In addition, the advantages of continuous-flow photochemistry are pointed out and a thorough comparison with batch processing is presented.

  4. Synthesis of zinc oxide nanocrystals by thermal decomposition of Zn-oleate in organic medium

    Institute of Scientific and Technical Information of China (English)

    LI ChenSha; LI YuNing; WU YiLiang; Beng S. ONG; Rafik O. LOUTFY

    2008-01-01

    We report the synthesis of uniform-sized hexagonal ZnO nanocrystals by the thermolysis of Zn-oleate complex, which was prepared from the reaction of inex-pensive and environmentally friendly reagents such as zinc nitrate and sodium oleate. Two organic compounds with different boiling points, octadecene and oc-tylether, were selected as the medium for thermolysis of Zn-oleate complex. Under optimized reaction conditions, we were able to synthesize ZnO nanoparticles with the size being about 10 nm. X-ray diffraction and transmission electron micrograph (TEM) images confirmed the high crystallinity of the nanocrystals.

  5. Innovative Catalysis in Organic Synthesis Oxidation, Hydrogenation, and C-X Bond Forming Reactions

    CERN Document Server

    Andersson, Pher G

    2012-01-01

    Authored by a European team of leaders in the field, this book compiles innovative approaches for C-X bond forming processes frequently applied in organic synthesis. It covers all key types of catalysis, including homogeneous, heterogeneous, and organocatalysis, as well as mechanistic and computational studies. Special attention is focused on the improvement of efficiency and sustainability of important catalytic processes, such as selective oxidations, hydrogenation and cross-coupling reactions.The result is a valuable resource for both advanced researchers in academia and industry, as well a

  6. Pelvic organ prolapse in women: how is it diagnosed and treated currently?

    Directory of Open Access Journals (Sweden)

    Paweł Milart

    2015-09-01

    Full Text Available The aim of the paper was to summarize the current opinions about the management of pelvic organ prolapse in women. Food and Drug Administration safety announcements from 2008 and 2011 triggered the discussion about the methods of treatment of pelvic organ prolapse and the used materials and a partial return to the methods which had been totally criticized before the implementation of meshes. The decrease in mesh usage is also observed. The studies did not demonstrate the prevalence of any particular surgical procedure. The amount of studies concerning the evaluation and the treatment of pelvic organ prolapse ensures that the quality of care provided to women with urogynecological problems is continuously increasing.

  7. Current progress and future perspectives for organic/inorganic perovskite solar cells

    Directory of Open Access Journals (Sweden)

    Pablo P. Boix

    2014-01-01

    Full Text Available The recent emergence of efficient solar cells based on organic/inorganic lead halide perovskite absorbers promises to transform the fields of dye-sensitized, organic, and thin film solar cells. Solution processed photovoltaics incorporating perovskite absorbers have achieved efficiencies of 15% [1] in solid-state device configurations, superseding liquid dye sensitized solar cell (DSC, evaporated and tandem organic solar cells, as well as various thin film photovoltaics; thus establishing perovskite solar cells as a robust candidate for commercialization. Since the first reports in late 2012, interest has soared in the innovative device structures as well as new materials, promising further improvements. However, identifying the basic working mechanisms, which are still being debated, will be crucial to design the optimum device configuration and maximize solar cell efficiencies. Here we distill the current state-of-the-art and highlight the guidelines to ascertain the scientific challenges as well as the requisites to make this technology market-viable.

  8. Resident Involvement in Professional Otolaryngology Organizations: Current Trends in the United States.

    Science.gov (United States)

    Wong, Kevin; Jang, Minyoung; Gilad, Amir; Levi, Jessica R

    2017-08-01

    Involvement by residents in professional medical organizations can enrich their training, but little data exist regarding the number and types of involvement opportunities available to otolaryngology residents. We sought to fill this gap in knowledge by quantifying the extent to which major otolaryngology-related organizations in the United States provide involvement opportunities to otolaryngology residents. Our analysis included 23 organizations and subspecialty societies. Results showed that many opportunities exist for residents to attend conferences and present research; however, fewer involvement and funding opportunities existed in any other leadership, health policy, or service-learning experiences. These findings were consistent across general and subspecialty societies. Given the many purported benefits of resident involvement in otolaryngology outside of the standard training environment, future efforts may be warranted to increase the number and type of involvement opportunities currently available in professional societies.

  9. A Student-Centered First-Semester Introductory Organic Laboratory Curriculum Facilitated by Microwave-Assisted Synthesis (MAOS)

    Science.gov (United States)

    Russell, Cianán B.; Mason, Jeremy D.; Bean, Theodore G.; Murphree, S. Shaun

    2014-01-01

    An instructional laboratory curriculum for a first-semester introductory organic chemistry course has been developed using microwave-assisted organic synthesis (MAOS). Taking advantage of short reaction times, materials were developed to facilitate collaborative experimental design, analysis, and debriefing of results during the normal laboratory…

  10. Benign by design: catalyst-free in-water, on-water green chemical methodologies in organic synthesis

    Science.gov (United States)

    The development of organic synthesis under sustainable conditions is a primary goal of practicing green chemists who want to prevent pollution and design safer pathways. Although, it is challenging to avoid the use of catalysts, or solvents in all the organic reactions but progre...

  11. A Student-Centered First-Semester Introductory Organic Laboratory Curriculum Facilitated by Microwave-Assisted Synthesis (MAOS)

    Science.gov (United States)

    Russell, Cianán B.; Mason, Jeremy D.; Bean, Theodore G.; Murphree, S. Shaun

    2014-01-01

    An instructional laboratory curriculum for a first-semester introductory organic chemistry course has been developed using microwave-assisted organic synthesis (MAOS). Taking advantage of short reaction times, materials were developed to facilitate collaborative experimental design, analysis, and debriefing of results during the normal laboratory…

  12. Saccharin Derivative Synthesis via [1,3] Thermal Sigmatropic Rearrangement: A Multistep Organic Chemistry Experiment for Undergraduate Students

    Science.gov (United States)

    Fonseca, Custódia S. C.

    2016-01-01

    Saccharin (1,2-benzisothiazole-3-one 1,1-dioxide) is an artificial sweetener used in the food industry. It is a cheap and easily available organic compound that may be used in organic chemistry laboratory classes for the synthesis of related heterocyclic compounds and as a derivatizing agent. In this work, saccharin is used as a starting material…

  13. Lifetimes of organic photovoltaics: Design and synthesis of single oligomer molecules in order to study chemical degradation mechanisms

    DEFF Research Database (Denmark)

    Alstrup, J.; Norrman, K.; Jørgensen, M.

    2006-01-01

    Degradation mechanisms in organic and polymer photovoltaics are addressed through the study of an organic photovoltaic molecule based on a single phenylene-vinylene-type oligomer molecule. The synthesis of such a model compound with different end-groups is presented that allows for assignment...

  14. Benign by design: catalyst-free in-water, on-water green chemical methodologies in organic synthesis

    Science.gov (United States)

    The development of organic synthesis under sustainable conditions is a primary goal of practicing green chemists who want to prevent pollution and design safer pathways. Although, it is challenging to avoid the use of catalysts, or solvents in all the organic reactions but progre...

  15. Synthesis of magnetic metal-organic framework (MOF) for efficient removal of organic dyes from water

    Science.gov (United States)

    Zhao, Xiaoli; Liu, Shuangliu; Tang, Zhi; Niu, Hongyun; Cai, Yaqi; Meng, Wei; Wu, Fengchang; Giesy, John P.

    2015-07-01

    A novel, simple and efficient strategy for fabricating a magnetic metal-organic framework (MOF) as sorbent to remove organic compounds from simulated water samples is presented and tested for removal of methylene blue (MB) as an example. The novel adsorbents combine advantages of MOFs and magnetic nanoparticles and possess large capacity, low cost, rapid removal and easy separation of the solid phase, which makes it an excellent sorbent for treatment of wastewaters. The resulting magnetic MOFs composites (also known as MFCs) have large surface areas (79.52 m2 g-1), excellent magnetic response (14.89 emu g-1), and large mesopore volume (0.09 cm3 g-1), as well as good chemical inertness and mechanical stability. Adsorption was not drastically affected by pH, suggesting π-π stacking interaction and/or hydrophobic interactions between MB and MFCs. Kinetic parameters followed pseudo-second-order kinetics and adsorption was described by the Freundlich isotherm. Adsorption capacity was 84 mg MB g-1 at an initial MB concentration of 30 mg L-1, which increased to 245 mg g-1 when the initial MB concentration was 300 mg L-1. This capacity was much greater than most other adsorbents reported in the literature. In addition, MFC adsorbents possess excellent reusability, being effective after at least five consecutive cycles.

  16. Metal-Organic Framework Synthesis System Based on Fuzzy Predictive Control via Network Transmission

    Directory of Open Access Journals (Sweden)

    Jui-Ho Chen

    2014-01-01

    Full Text Available The purpose of this study is to construct metal-organic framework (MOF synthesis heating systems based on fuzzy method for monitoring and automatic control. In this study, the temperature sensing module for measurements sensed values that it through a wireless ZigBee chips and wired DAQ device for real-time data transmission. Because MOF synthesis, often due to different modes of heating or heating instability caused by its nucleation and crystal growth rate, is an important influence, leading to different crystallinity, the use of fuzzy theory to predict the temperature parameter and instant heating MOF synthesis parameters can be adjusted to improve the accuracy of the system. The research system to RS-232 interface module for infrared emission control packets issued and automated control of the furnace through the infrared receiver module. This study is based on a terminal interface window of Visual Basic programming and LabView graphical diagram for control system design. Finally, this research, through a number of experiments to validate the use of fuzzy system development methods and networks, can improve the accuracy of the reaction efficiency MOF sensing and control the heating system.

  17. Arctic Synthesis Collaboratory: A Virtual Organization for Transformative Research and Education on a Changing Arctic

    Science.gov (United States)

    Warnick, W. K.; Wiggins, H. V.; Hinzman, L.; Holland, M.; Murray, M. S.; Vörösmarty, C.; Loring, A. J.

    2008-12-01

    About the Arctic Synthesis Collaboratory The Arctic Synthesis Collaboratory concept, developed through a series of NSF-funded workshops and town hall meetings, is envisioned as a cyber-enabled, technical, organizational, and social-synthesis framework to foster: • Interactions among interdisciplinary experts and stakeholders • Integrated data analysis and modeling activities • Training and development of the arctic science community • Delivery of outreach, education, and policy-relevant resources Scientific Rationale The rapid rate of arctic change and our incomplete understanding of the arctic system present the arctic community with a grand scientific challenge and three related issues. First, a wealth of observations now exists as disconnected data holdings, which must be coordinated and synthesized to fully detect and assess arctic change. Second, despite great strides in the development of arctic system simulations, we still have incomplete capabilities for modeling and predicting the behavior of the system as a whole. Third, policy-makers, stakeholders, and the public are increasingly making demands of the science community for forecasts and guidance in mitigation and adaptation strategies. Collaboratory Components The Arctic Synthesis Collaboratory is organized around four integrated functions that will be established virtually as a distributed set of activities, but also with the advantage of existing facilities that could sponsor some of the identified activities. Community Network "Meeting Grounds:" The Collaboratory will link distributed individuals, organizations, and activities to enable collaboration and foster new research initiatives. Specific activities could include: an expert directory, social networking services, and virtual and face-to-face meetings. Data Integration, Synthesis, and Modeling Activities: The Collaboratory will utilize appropriate tools to enable the combination of data and models. Specific activities could include: a web

  18. Novelmetal-organic photocatalysts: Synthesis, characterization and decomposition of organic dyes

    Science.gov (United States)

    Gopal Reddy, N. B.; Murali Krishna, P.; Kottam, Nagaraju

    2015-02-01

    An efficient method for the photocatalytic degradation of methylene blue in an aqueous medium was developed using metal-organic complexes. Two novel complexes were synthesized using, Schiff base ligand, N‧-[(E)-(4-ethylphenyl)methylidene]-4-hydroxybenzohydrazide (HL) and Ni(II) (Complex 1)/Co(II) (Complex 2) chloride respectively. These complexes were characterized using microanalysis, various spectral techniques. Spectral studies reveal that the complexes exhibit square planar geometry with ligand coordination through azomethine nitrogen and enolic oxygen. The effects of catalyst dosage, irradiation time and aqueous pH on the photocatalytic activity were studied systematically. The photocatalytic activity was found to be more efficient in the presence of Ni(II) complexes than the Co(II) complex. Possible mechanistic aspects were discussed.

  19. Microbiologically produced carboxylic acids used as building blocks in organic synthesis.

    Science.gov (United States)

    Aurich, Andreas; Specht, Robert; Müller, Roland A; Stottmeister, Ulrich; Yovkova, Venelina; Otto, Christina; Holz, Martina; Barth, Gerold; Heretsch, Philipp; Thomas, Franziska A; Sicker, Dieter; Giannis, Athanassios

    2012-01-01

    Oxo- and hydroxy-carboxylic acids are of special interest in organic synthesis. However, their introduction by chemical reactions tends to be troublesome especially with regard to stereoselectivity. We describe herein the biotechnological preparation of selected oxo- and hydroxycarboxylic acids under "green" conditions and their use as promising new building blocks. Thereby, our biotechnological goal was the development of process fundamentals regarding the variable use of renewable raw materials, the development of a multi purpose bioreactor and application of a pilot plant with standard equipment for organic acid production to minimize the technological effort. Furthermore the development of new product isolation procedures, with the aim of direct product recovery, capture of products or single step operation, was necessary. The application of robust and approved microorganisms, also genetically modified, capable of using a wide range of substrates as well as producing a large spectrum of products, was of special importance. Microbiologically produced acids, like 2-oxo-glutaric acid and 2-oxo-D-gluconic acid, are useful educts for the chemical synthesis of hydrophilic triazines, spiro-connected heterocycles, benzotriazines, and pyranoic amino acids. The chiral intermediate of the tricarboxylic acid cycle, (2R,3S)-isocitric acid, is another promising compound. For the first time our process provides large quantities of enantiopure trimethyl (2R,3S)-isocitrate which was used in subsequent chemical transformations to provide new chiral entities for further usage in total synthesis and pharmaceutical research.Oxo- and hydroxy-carboxylic acids are of special interest in organic synthesis. However, their introduction by chemical reactions tends to be troublesome especially with regard to stereoselectivity. We describe herein the biotechnological preparation of selected oxo- and hydroxycarboxylic acids under "green" conditions and their use as promising new building

  20. Synthesis and characterization of monodispersed inorganic/organic core/shell microspheres with fluorescence

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kai; HAN Kun; ZHANG Xuehai; YANG Bai

    2005-01-01

    @@ In recent years, the semiconductor nanocrystals (NCs) have attracted great interest due to their potentials in photonics, electronics, magnetics and catalysis, and the monodispersed organic or inorganic microspheres doped NCs display predominant characteristics in the fabrication and study for photonic crystals[1,2], and considerable effort has been devoted to the design and synthesis of CdTe NCs doped colloid with well fluorescence[3-8]. For example, CdTe NCs were fabricated on the surfaces of silica or polymer microspheres by the methods of layer-by-layer assembly, and CdTe NCs were also doped into inorganic or organic microspheres through sol-gel process or swell- ing.

  1. Selective organic synthesis through generation and reactivity control of hyper-coordinate metal species.

    Science.gov (United States)

    Hiyama, Tamejiro

    2008-01-01

    This paper is a review of my 40 years of research at Kyoto, Sagamihara, and Yokohama, all based on the generation of hyper-coordinate metal species such as ate complexes and pentacoordinate silicates. The topics are: (i) carbenoid reagents for carbon-carbon bond-forming reactions, (ii) nucleophilic substitution at acetal carbons using aluminate reagents, (iii) preparation of magnesium enolates and its reaction with nitriles, (iv) Cr(II) reagents for reduction of organic halides and highly selective carbon-carbon bond formation, (v) organic synthesis with organosilion reagents/fluoride ions, (vi) cross-coupling reaction of organosilicon compounds, and (vii) silicon-based conjugate addition to alpha,beta-unsaturated carbonyl acceptors.

  2. [Emission characteristics and hazard assessment analysis of volatile organic compounds from chemical synthesis pharmaceutical industry].

    Science.gov (United States)

    Li, Yan; Wang, Zhe-Ming; Song, Shuang; Xu, Zhi-Rong; Xu, Ming-Zhu; Xu, Wei-Li

    2014-10-01

    In this study, volatile organic compounds (VOCs) released from chemical synthesis pharmaceutical industry in Taizhou, Zhejiang province were analyzed quantitatively and qualitatively. The total volatile organic compounds (TVOCs) was in the range of 14.9-308.6 mg · m(-3). Evaluation models of ozone formation potentials (OFP) and health risk assessment were adopted to preliminarily assess the environmental impact and health risk of VOCs. The results showed that the values of OFP of VOCs were in the range of 3.1-315.1 mg · m(-3), based on the maximum incremental reactivity, the main principal contribution was toluene, tetrahydrofuran (THF), acetic ether etc. The non-carcinogenic risk and the carcinogen risk fell in the ranges of 9.48 x 10(-7)-4.98 x 10(-4) a(-1) and 3.17 x 10(-5)- 6.33 x 10(-3). The principal contribution of VOCs was benzene, formaldehyde and methylene chloride.

  3. Nanoscale luminescent lanthanide-based metal–organic frameworks: properties, synthesis, and applications

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Dongqin; Song, Yonghai; Wang, Li, E-mail: lwanggroup@aliyun.com [Jiangxi Normal University, Key Laboratory of Functional Small Organic Molecule, Ministry of Education, Key Laboratory of Chemical Biology, Jiangxi Province, College of Chemistry and Chemical Engineering (China)

    2015-07-15

    Nanoscale luminescent lanthanide-based metal–organic frameworks (NLLn-MOFs) possess superior optical and physical properties such as higher luminescent lifetime, quantum yield, high stability, high surface area, high agent loading, and intrinsic biodegradability, and therefore are regarded as a novel generation of luminescent material compared with bulk lanthanide-based metal–organic frameworks (Ln-MOFs). Traditional luminescent Ln-MOFs have been well studied; however, NLLn-MOFs taking the advantages of nanomaterials have attracted extensive investigations for applications in optical imaging in living cells, light-harvesting, and sensing. In this review, we provide a survey of the latest progresses made in developing NLLn-MOFs, which contains the fundamental optical features, synthesis, and their potential applications. Finally, the future prospects and challenges of the rapidly growing field are summarized.

  4. Sustainable Utility of Magnetically Recyclable Nano-Catalysts in Water: Applications in Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Manoj B. Gawande

    2013-10-01

    Full Text Available Magnetically recyclable nano-catalysts and their use in aqueous media is a perfect combination for the development of greener sustainable methodologies in organic synthesis. It is well established that magnetically separable nano-catalysts avoid waste of catalysts or reagents and it is possible to recover >95% of catalysts, which is again recyclable for subsequent use. Water is the ideal medium to perform the chemical reactions with magnetically recyclable nano-catalysts, as this combination adds tremendous value to the overall benign reaction process development. In this review, we highlight recent developments inthe use of water and magnetically recyclable nano-catalysts (W-MRNs for a variety of organic reactions namely hydrogenation, condensation, oxidation, and Suzuki–Miyaura cross-coupling reactions, among others.

  5. Thiophene fused azacoronenes: regioselective synthesis, self organization, charge transport, and its incorporation in conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yi; He, Bo

    2015-09-15

    A regioselective synthesis of an azacoronene fused with two peripheral thiophene groups has been realized through a concise synthetic route. The resulting thienoazacoronene (TAC) derivatives show high degree of self-organization in solution, in single crystals, in the bulk, and in spuncast thin films. Spuncast thin film field-effect transistors of the TACs exhibited mobilities up to 0.028 cm.sup.2V.sup.-1 S.sup.-1, which is among the top field effect mobilities for solution processed discotic materials. Organic photovoltaic devices using TAC-containing conjugated polymers as the donor material exhibited a high open-circuit voltage of 0.89 V, which was ascribable to TAC's low-lying highest occupied molecular orbital energy level.

  6. Direct photocatalysis for organic synthesis by using plasmonic-metal nanoparticles irradiated with visible light.

    Science.gov (United States)

    Xiao, Qi; Jaatinen, Esa; Zhu, Huaiyong

    2014-11-01

    Recent advances in direct-use plasmonic-metal nanoparticles (NPs) as photocatalysts to drive organic synthesis reactions under visible-light irradiation have attracted great interest. Plasmonic-metal NPs are characterized by their strong interaction with visible light through excitation of the localized surface plasmon resonance (LSPR). Herein, we review recent developments in direct photocatalysis using plasmonic-metal NPs and their applications. We focus on the role played by the LSPR of the metal NPs in catalyzing organic transformations and, more broadly, the role that light irradiation plays in catalyzing the reactions. Through this, the reaction mechanisms that these light-excited energetic electrons promote will be highlighted. This review will be of particular interest to researchers who are designing and fabricating new plasmonic-metal NP photocatalysts by identifying important reaction mechanisms that occur through light irradiation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Thiophene fused azacoronenes: regioselective synthesis, self organization, charge transport, and its incorporation in conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yi; He, Bo

    2015-09-15

    A regioselective synthesis of an azacoronene fused with two peripheral thiophene groups has been realized through a concise synthetic route. The resulting thienoazacoronene (TAC) derivatives show high degree of self-organization in solution, in single crystals, in the bulk, and in spuncast thin films. Spuncast thin film field-effect transistors of the TACs exhibited mobilities up to 0.028 cm.sup.2V.sup.-1 S.sup.-1, which is among the top field effect mobilities for solution processed discotic materials. Organic photovoltaic devices using TAC-containing conjugated polymers as the donor material exhibited a high open-circuit voltage of 0.89 V, which was ascribable to TAC's low-lying highest occupied molecular orbital energy level.

  8. Confined-Pyrolysis as an Experimental Method for Hydrothermal Organic Synthesis

    Science.gov (United States)

    Leif, Roald N.; Simoneit, Bernd R. T.

    1995-01-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  9. Confined-pyrolysis as an experimental method for hydrothermal organic synthesis

    Science.gov (United States)

    Leif, Roald N.; Simoneit, Bernd R. T.

    1995-10-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic compounds and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  10. Confined-Pyrolysis as an Experimental Method for Hydrothermal Organic Synthesis

    Science.gov (United States)

    Leif, Roald N.; Simoneit, Bernd R. T.

    1995-01-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  11. Microwave-Assisted Solid Phase Organic Synthesis.Application to Indole Library Construction

    Institute of Scientific and Technical Information of China (English)

    DAI Wei-Min; SUN Li-Ping; GUO Dian-Shun; HUANG Xiang-Hong

    2004-01-01

    Microwave-assisted organic synthesis (MAOS) has attained increasing popularity due to recent advancement in the instrumentation of microwave technology. Now, MAOS can be performed under controlled temperature and pressure to yield reproducible results. For combinatorial chemistry,the dramatically increased reaction rate under microwave irradiation at high temperature provides an ideal solution to those sluggish reactions, in particular the combinatorial reactions carried out on solid supports. In this presentation, we describe our results on microwave-assisted solid-phase organic synthesis (MASPOS) applied to the construction of indole libraries such as 5. Compounds 4 were synthesized on the Rink amide resins using IRORI MicroKanTM reactors encoded with a radio-frequency (Rf) tag. The resin-bound terminal alkynes 2, prepared via the amide bond, were cross-coupled with the nitroaryl triflate under the conditions adopted from the solution reactions developed by us1,2. The nitro group of 3 was then reduced and sulfonylated to give 4. Ring closure reactions within 4 with Cu(OAc)2 were examined initially in refluxing DCE for 24 h, but no indole product was detected after cleavage from the resin. Therefore, the same reactions were carried out under microwave irradiation at 200 ℃ for 10 min on a Personal Chemistry Emrys Creator, the desired indoles 5 were obtained in 60-95% overall yields calculated from 1 and in >90% purities in most cases3. It is necessary to mention that the IRORI microreactors cannot tolerate the high temperature and the resin-bound 4 must be transferred to the reaction vials for the microwave-assisted ring closure reactions. A traceless synthesis of an indole library via MASPOS will be discussed as well.4

  12. Deep Carbon Cycling in the Deep Hydrosphere: Abiotic Organic Synthesis and Biogeochemical Cycling

    Science.gov (United States)

    Sherwood Lollar, B.; Sutcliffe, C. N.; Ballentine, C. J.; Warr, O.; Li, L.; Ono, S.; Wang, D. T.

    2014-12-01

    Research into the deep carbon cycle has expanded our understanding of the depth and extent of abiotic organic synthesis in the deep Earth beyond the hydrothermal vents of the deep ocean floor, and of the role of reduced gases in supporting deep subsurface microbial communities. Most recently, this research has expanded our understanding not only of the deep biosphere but the deep hydrosphere - identifying for the first time the extreme antiquity (millions to billions of years residence time) of deep saline fracture waters in the world's oldest rocks. Energy-rich saline fracture waters in the Precambrian crust that makes up more than 70% of the Earth's continental lithosphereprovide important constraints on our understanding of the extent of the crust that is habitable, on the time scales of hydrogeologic isolation (and conversely mixing) of fluids relevant to the deep carbon cycle, and on the geochemistry of substrates that sustain both abiotic organic synthesis and biogeochemical cycles driven by microbial communities. Ultimately the chemistry and hydrogeology of the deep hydrosphere will help define the limits for life in the subsurface and the boundary between the biotic-abiotic fringe. Using a variety of novel techniques including noble gas analysis, clumped isotopologues of methane, and compound specific isotope analysis of CHNOS, this research is addressing questions about the distribution of deep saline fluids in Precambrian rocks worldwide, the degree of interconnectedness of these potential biomes, the habitability of these fluids, and the biogeographic diversity of this new realm of the deep hydrosphere.

  13. Zr-based metal-organic frameworks: design, synthesis, structure, and applications.

    Science.gov (United States)

    Bai, Yan; Dou, Yibo; Xie, Lin-Hua; Rutledge, William; Li, Jian-Rong; Zhou, Hong-Cai

    2016-04-21

    Among the large family of metal-organic frameworks (MOFs), Zr-based MOFs, which exhibit rich structure types, outstanding stability, intriguing properties and functions, are foreseen as one of the most promising MOF materials for practical applications. Although this specific type of MOF is still in its early stage of development, significant progress has been made in recent years. Herein, advances in Zr-MOFs since 2008 are summarized and reviewed from three aspects: design and synthesis, structure, and applications. Four synthesis strategies implemented in building and/or modifying Zr-MOFs as well as their scale-up preparation under green and industrially feasible conditions are illustrated first. Zr-MOFs with various structural types are then classified and discussed in terms of different Zr-based secondary building units and organic ligands. Finally, applications of Zr-MOFs in catalysis, molecule adsorption and separation, drug delivery, and fluorescence sensing, and as porous carriers are highlighted. Such a review based on a specific type of MOF is expected to provide guidance for the in-depth investigation of MOFs towards practical applications.

  14. Tracking of the organic species during the synthesis of cobalt-based nanoparticles in non-aqueous solution

    Science.gov (United States)

    Staniuk, M.; Niederberger, M.; Koziej, D.

    2014-08-01

    In this work we investigate the organic products of the synthesis of Co-based nanoparticles in benzyl alcohol. Our GC and in situ IR studies provide the experimental proofs for the formation of benzaldehyde, toluene and isopropanol in the reaction solution. These organic products can be correlated with formation of cobalt-based nanoparticles with oxidation state from 0 to 3+. These results shine the light on the complexity of organic and inorganic reactions in solution during crystallization of nanoparticles.

  15. Demonstration of high current carbon nanotube enabled vertical organic field effect transistors at industrially relevant voltages

    Science.gov (United States)

    McCarthy, Mitchell

    The display market is presently dominated by the active matrix liquid crystal display (LCD). However, the active matrix organic light emitting diode (AMOLED) display is argued to become the successor to the LCD, and is already beginning its way into the market, mainly in small size displays. But, for AMOLED technology to become comparable in market share to LCD, larger size displays must become available at a competitive price with their LCD counterparts. A major issue preventing low-cost large AMOLED displays is the thin-film transistor (TFT) technology. Unlike the voltage driven LCD, the OLEDs in the AMOLED display are current driven. Because of this, the mature amorphous silicon TFT backplane technology used in the LCD must be upgraded to a material possessing a higher mobility. Polycrystalline silicon and transparent oxide TFT technologies are being considered to fill this need. But these technologies bring with them significant manufacturing complexity and cost concerns. Carbon nanotube enabled vertical organic field effect transistors (CN-VFETs) offer a unique solution to this problem (now known as the AMOLED backplane problem). The CN-VFET allows the use of organic semiconductors to be used for the semiconductor layer. Organics are known for their low-cost large area processing compatibility. Although the mobility of the best organics is only comparable to that of amorphous silicon, the CN-VFET makes up for this by orienting the channel vertically, as opposed to horizontally (like in conventional TFTs). This allows the CN-VFET to achieve sub-micron channel lengths without expensive high resolution patterning. Additionally, because the CN-VFET can be easily converted into a light emitting transistor (called the carbon nanotube enabled vertical organic light emitting transistor---CN-VOLET) by essentially stacking an OLED on top of the CN-VFET, more potential benefits can be realized. These potential benefits include, increased aperture ratio, increased OLED

  16. Some considerations on the current debate about typing resolution in solid organ transplantation.

    Science.gov (United States)

    Vogiatzi, Paraskevi

    2016-01-01

    The shortage of suitable organs and achieved tolerance are uncontested main concerns in transplantation. Long waiting lists for deceased donors and limited numbers of living donors are the current scenarios. Kidney grafts from living donors have better overall survival compared to cadaveric and require less aggressive immunosuppressive regimens. The human leukocyte antigen (HLA) labs have the key role to test the recipient and donors compatibility based on typing and antibody profile. The current standard molecular procedure in solid organ transplantation is low-resolution typing, at the antigen level. In this commentary, the merits of high versus low degree of typing resolution in solid organ transplantation are discussed. Critical questions and reasons to bring high-resolution typing as a routine test in health system are considered. Specifically, with the introduction of the next-generation sequencing (NGS) in HLA, the pros and cons in living donation and benefits after deceased donation are critically evaluated. NGS has the potential to improve the transplant rates and the overall graft survival. Alternative strategies to increase in demanding the number of transplants are briefly highlighted.

  17. Synthesis of nanoporous carbohydrate metal-organic framework and encapsulation of selected organic compounds

    Science.gov (United States)

    Al-Ghamdi, Saleh

    Cyclodextrin metal organic frameworks (CDMOFs) with different types of cyclodextrins (CDs) (i.e., Alpha, Beta and Gamma-CD) and coordination potassium ion sources (KOH) CDMOF-a and (C7H5KO2) CDMOF-b were synthesized and fully characterized. The physical and thermal properties of the successfully produced CDMOFs were evaluated using N2 gas sorption, thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The N2 gas sorption isotherm revealed high uptake into the micropores (330 cm3.g -1 for Gamma-CDMOF-a) to macropore (125 cm3.g -1 for Gamma-CDMOF-b) structures with isotherm types I and II for Gamma-CDMOFs and Alpha-CDMOFs, respectively. The Langmuir specific surface area (SSA) of Gamma-CDMOF-a (1376 m2.g-1) was significantly higher than the SSA of Alpha-CDMOF-a (289 m2.g -1) and Beta-CDMOF-a (54 m2.g-1). The TGA of dehydrated CDMOF crystals showed the structures were thermally stable up to 300 °C. The XRD of the Gamma-CDMOFs and Alpha-CDMOFs showed a highly face-centered-cubic symmetrical structure. An Aldol condensation reaction occurred during the encapsulation of acetaldehyde, hexanal, trans-2-hexenal, and ethanol into Gamma-CDMOF-a, with a SSA of 1416 m2.g -1. However, Gamma-CDMOF-b with a SSA of 499 m2.g -1 was successfully used to encapsulate acetaldehyde. The maximum release of acetaldehyde from CDMOF-b was 53 mug of acetaldehyde per g of CDMOF, which is greater than previously reported acetaldehyde encapsulation on Beta-CD inclusion complexes.

  18. Synthesis and characterization of organic semiconducting polymers containing dithienylfluorenone for use in organic photovoltaic cells.

    Science.gov (United States)

    Byun, Yun-Sun; Kim, Ji-Hoon; Park, Jong Baek; Hwang, Do-Hoon

    2014-08-01

    2,7-Bis(5-bromo-4-hexylthiophen-2-yl)-9H-fluoren-9-one (DTFO) was synthesized as a new electron-accepting material in semiconducting polymers for use in photovoltaic devices. The synthesized DTFO was polymerized with two different electron-donating counter monomers: 2,7-dibromo-9,9-dioctyl-9H-fluorene (DOF) and 2,6-bis(trimethyltin)-4,8-di(2-ethylhexyloxyl)benzo [1,2-b:4,5-b']dithiophene (BDT). Two alternating copolymers, poly(DTFO-alt-DOF) and poly(DTFO-alt-BDT), were synthesized through the Suzuki and Stille coupling polymerizations, respectively. The synthesized polymers exhibited good solubility in common solvents and show good thermal stability up to 350 °C. The optical band gap energies of poly(DTFO-alt-DOF) and poly(DTFO-alt-BDT) were determined to be 2.44 and 2.23 eV, respectively. The positions of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the polymers were determined by cyclic voltammetry (CV). One of these devices showed a power conversion efficiency of 0.50%, with an open-circuit voltage of 0.67 V, a short-circuit current of 2.34 mA/cm2, and a fill factor of 0.30 under air mass (AM) 1.5 global (1.5 G) illumination conditions (100 mW/cm2).

  19. The formation, properties and impact of secondary organic aerosol: current and emerging issues

    Directory of Open Access Journals (Sweden)

    M. Hallquist

    2009-02-01

    Full Text Available Secondary organic aerosol (SOA accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with a description of the current state of knowledge on the global SOA budget and the atmospheric degradation mechanisms for SOA precursors. The topic of gas-particle partitioning theory is followed by an account of the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail; molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.

  20. The formation, properties and impact of secondary organic aerosol: current and emerging issues

    Directory of Open Access Journals (Sweden)

    J. Wildt

    2009-07-01

    Full Text Available Secondary organic aerosol (SOA accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with an update on the current state of knowledge on the global SOA budget and is followed by an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail: molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.

  1. Dramatic effects of chlorine addition on expanding synthesis conditions for fluorine-free metal-organic decomposition YBa2Cu3O y films

    Science.gov (United States)

    Motoki, Takanori; Ikeda, Shuhei; Honda, Genki; Nagaishi, Tatsuoki; Nakamura, Shin-ichi; Shimoyama, Jun-ichi

    2017-02-01

    The synthesis conditions of fluorine-free metal-organic decomposition (FF-MOD)-processed YBa2Cu3O y (YBCO) films on buffered metallic substrates have been systematically investigated. Chlorine addition to the starting solution was found to be quite effective for expanding the synthesis conditions of highly c-axis-oriented YBCO films. YBCO films showing a high critical current, ˜100 A/cm (77 K, ˜0 T), were successfully obtained by sintering at 740 °C, which is ˜50 °C lower than the typical sintering temperature for FF-MOD-processed YBCO films. This strongly indicated that chlorine addition is promising for the development of long and homogeneous YBCO tapes even by sintering at a low temperature of ˜740 °C.

  2. Controlled Synthesis of Organic/Inorganic van de Waals Solid for Tunable Light-matter Interactions

    CERN Document Server

    Niu, Lin; Cong, Chunxiao; Wu, Chunyang; Wu, Di; Chang, Tay-Rong; Wang, Hong; Zeng, Qingsheng; Zhou, Jiadong; Wang, Xingli; Fu, Wei; Yu, Peng; Fu, Qundong; Zhang, Zhuhua; Yakobson, Boris I; Tay, Beng Kang; Jeng, Horng-Tay; Lin, Hsin; Sum, Tze Chien; Jin, Chuanhong; He, Haiyong; Yu, Ting; Liu, Zheng

    2015-01-01

    Van de Waals (vdW) solids, as a new type of artificial materials that consisting of alternative layers bonded by weak interactions, have shed light on fantastic optoelectronic devices. As a result, a large variety of shining vdW devices have been engineered via layer-by-layer stacking of two-dimensional materials, although shadowed by the difficulties of fabrication. Alternatively, direct growth of vdW solids have been proved a scalable and swift way towards vdW solids, reflected by the successful synthesis of graphene/h-BN and transition metal dichalcogenides (TMDs) vertical heterostructures from controlled vapor deposition. Enlightened by it, with a three-step deposition and reaction, we realize high-quality organic and inorganic vdW solids, using methylammonium lead halide as the organic part (organic perovskite) and 2D monolayers inorganic as counterpart. Being a perfect light absorbent, the electrons and holes generated in organic perovskite couple with its inorganic 2D companions, and behave dramaticall...

  3. Organic-Stabilizer-Free Polyol Synthesis of Silver Nanowires for Electrode Applications.

    Science.gov (United States)

    Sim, Hwansu; Bok, Shingyu; Kim, Bongsung; Kim, Minha; Lim, Guh-Hwan; Cho, Sung Min; Lim, Byungkwon

    2016-09-19

    The polyol reduction of a Ag precursor in the presence of an organic stabilizer, such as poly(vinylpyrrolidone), is a widely used method for the production of Ag nanowires (NWs). However, organic capping molecules introduce insulating layers around each NW. Herein we demonstrate that Ag NWs can be produced in high yield without any organic stabilizers simply by introducing trace amounts of NaCl and Fe(NO3 )3 during low-temperature polyol synthesis. The heterogeneous nucleation and growth of Ag NWs on initially formed AgCl particles, combined with oxidative etching of unwanted Ag nanoparticles, resulted in the selective formation of long NWs with an average length of about 40 μm in the absence of a capping or stabilizing effect provided by surface-adsorbing molecules. These organic-stabilizer-free Ag NWs were directly used for the fabrication of high-performance transparent or stretchable electrodes without a complicated process for the removal of capping molecules from the NW surface.

  4. Synthesis of Perylene Imide Diones as Platforms for the Development of Pyrazine Based Organic Semiconductors.

    Science.gov (United States)

    de Echegaray, Paula; Mancheño, María J; Arrechea-Marcos, Iratxe; Juárez, Rafael; López-Espejo, Guzmán; López Navarrete, J Teodomiro; Ramos, María Mar; Seoane, Carlos; Ortiz, Rocío Ponce; Segura, José L

    2016-11-18

    There is a great interest in peryleneimide (PI)-containing compounds given their unique combination of good electron accepting ability, high abosorption in the visible region, and outstanding chemical, thermal, and photochemical stabilities. Thus, herein we report the synthesis of perylene imide derivatives endowed with a 1,2-diketone functionality (PIDs) as efficient intermediates to easily access peryleneimide (PI)-containing organic semiconductors with enhanced absorption cross-section for the design of tunable semiconductor organic materials. Three processable organic molecular semiconductors containing thiophene and terthiophene moieties, PITa, PITb, and PITT, have been prepared from the novel PIDs. The tendency of these semiconductors for molecular aggregation have been investigated by NMR spectroscopy and supported by quantum chemical calculations. 2D NMR experiments and theoretical calculations point to an antiparallel π-stacking interaction as the most stable conformation in the aggregates. Investigation of the optical and electrochemical properties of the materials is also reported and analyzed in combination with DFT calculations. Although the derivatives presented here show modest electron mobilities of ∼10(-4) cm(2)V(-1)s(-1), these preliminary studies of their performance in organic field effect transistors (OFETs) indicate the potential of these new building blocks as n-type semiconductors.

  5. Progammed synthesis of magnetic mesoporous silica coated carbon nanotubes for organic pollutant adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Yue; Zhang, Min, E-mail: congmingyang123@163.com; Xia, Peixiong; Wang, Linlin; Zheng, Jing; Li, Weizhen; Xu, Jingli, E-mail: xujingli@sues.edu.cn

    2016-05-15

    Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis method and were characterized by TEM, XRD, FTIR, TGA, N{sub 2} adsorption–desorption and VSM. The well-designed mesoporous magnetic nanotubes had a large specific area, a highly open mesoporous structure and high magnetization. Firstly, SiO{sub 2}-coated maghemite/CNTs nanoparticles (CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites) were synthesized by the combination of high temperature decomposition process and an sol–gel method, in which the iron acetylacetonate as well as TEOS acted as the precursor for maghemite and SiO{sub 2}, respectively. The CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites revealed a core–shell structure, Then, CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was obtained by extracting cetyltrimethylammonium bromide (CTAB) via an ion-exchange procedure. The resulting composites show not only a magnetic response to an externally applied magnetic field, but also can be a good adsorbent for the organic pollutant in the ambient temperature. - Graphical abstract: Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis, which can be a good adsorbent for the organic pollutant in the ambient temperature. - Highlights: • The surface of CNTs/Fe{sub 3}O{sub 4} is hydrophilic, which facilitates the silica coating. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was synthesized by a facile method. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} can be a good adsorbent for the organic pollutant.

  6. Optical Generation of Ballistic and Diffusive Spin Currents in Organic-Inorganic Lead Halide Perovskites

    Science.gov (United States)

    Li, Junwen; Haney, Paul

    Organic-inorganic halide perovskite solar cells have attracted enormous attention in recent years due to their remarkable photovoltaic power conversion efficiency. These materials should exhibit interesting spin-dependent properties as well, owing to the strong spin-orbit coupling and the broken inversion symmetry present at room temperature. In this work, we consider the spin-dependent optical response of CH3NH3PbI3 on two distinct time scales. We first use density functional theory to compute the ballistic spin current injected by absorption of linearly polarized light. This spin current persists on a time scale of the momentum relaxation time. We then consider diffusive transport of photogenerated charge and spin for a thin perovskite layer with a passivated surface and an Ohmic, non-selective back contact. The spin densities and spin currents are evaluated by solving the drift-diffusion equations for a 3-dimensional Rashba model. We comment on the applications of optically excited spin densities and spin currents in these materials.

  7. Modeling space-charge-limited currents in organic semiconductors: Extracting trap density and mobility

    KAUST Repository

    Dacuña, Javier

    2011-11-28

    We have developed and have applied a mobility edge model that takes drift and diffusion currents to characterize the space-charge-limited current in organic semiconductors into account. The numerical solution of the drift-diffusion equation allows the utilization of asymmetric contacts to describe the built-in potential within the device. The model has been applied to extract information of the distribution of traps from experimental current-voltage measurements of a rubrene single crystal from Krellner showing excellent agreement across several orders of magnitude in the current. Although the two contacts are made of the same metal, an energy offset of 580 meV between them, ascribed to differences in the deposition techniques (lamination vs evaporation) was essential to correctly interpret the shape of the current-voltage characteristics at low voltage. A band mobility of 0.13cm 2V-1s-1 for holes is estimated, which is consistent with transport along the long axis of the orthorhombic unit cell. The total density of traps deeper than 0.1 eV was 2.2×1016cm -3. The sensitivity analysis and error estimation in the obtained parameters show that it is not possible to accurately resolve the shape of the trap distribution for energies deeper than 0.3 eV or shallower than 0.1 eV above the valence-band edge. The total number of traps deeper than 0.3 eV, however, can be estimated. Contact asymmetry and the diffusion component of the current play an important role in the description of the device at low bias and are required to obtain reliable information about the distribution of deep traps. © 2011 American Physical Society.

  8. Organic Analysis of Catalytic Fischer-Tropsch Synthesis Products and Ordinary Chondrite Meteorites by Stepwise Pyrolysis-GCMS: Organics in the Early Solar Nebula

    Science.gov (United States)

    Locke, Darren R.; Yazzie, Cyriah A.; Burton, Aaron S.; Niles, Paul B.; Johnson, Natasha M.

    2014-01-01

    Abiotic generation of complex organic compounds, in the early solar nebula that formed our solar system, is hypothesized by some to occur via Fischer-Tropsch (FT) synthesis. In its simplest form, FT synthesis involves the low temperature (synthesis has been utilized in the gas-to-liquid process to convert syngas, produced from coal, natural gas, or biomass, into paraffin waxes that can be cracked to produce liquid diesel fuels. In general, the effect of increasing reaction temperature (>300degC) produces FT products that include lesser amounts of n-alkanes and greater alkene, alcohol, and polycyclic aromatic hydrocarbon (PAH) compounds. We have begun to experimentally investigate FT synthesis in the context of abiotic generation of organic compounds in the early solar nebula. It is generally thought that the early solar nebula included abundant hydrogen and carbon monoxide gases and nano-particulate matter such as iron and metal silicates that could have catalyzed the FT reaction. The effect of FT reaction temperature, catalyst type, and experiment duration on the resulting products is being investigated. These solid organic products are analyzed by thermal-stepwise pyrolysis-GCMS and yield the types and distribution of hydrocarbon compounds released as a function of temperature. We show how the FT products vary by reaction temperature, catalyst type, and experimental duration and compare these products to organic compounds found to be indigenous to ordinary chondrite meteorites. We hypothesize that the origin of organics in some chondritic meteorites, that represent an aggregation of materials from the early solar system, may at least in part be from FT synthesis that occurred in the early solar nebula.

  9. Passive strain-induced matrix synthesis and organization in shape-specific, cartilaginous neotissues.

    Science.gov (United States)

    MacBarb, Regina F; Paschos, Nikolaos K; Abeug, Reedge; Makris, Eleftherios A; Hu, Jerry C; Athanasiou, Kyriacos A

    2014-12-01

    Tissue-engineered musculoskeletal soft tissues typically lack the appropriate mechanical robustness of their native counterparts, hindering their clinical applicability. With structure and function being intimately linked, efforts to capture the anatomical shape and matrix organization of native tissues are imperative to engineer functionally robust and anisotropic tissues capable of withstanding the biomechanically complex in vivo joint environment. The present study sought to tailor the use of passive axial compressive loading to drive matrix synthesis and reorganization within self-assembled, shape-specific fibrocartilaginous constructs, with the goal of developing functionally anisotropic neotissues. Specifically, shape-specific fibrocartilaginous neotissues were subjected to 0, 0.01, 0.05, or 0.1 N axial loads early during tissue culture. Results found the 0.1-N load to significantly increase both collagen and glycosaminoglycan synthesis by 27% and 67%, respectively, and to concurrently reorganize the matrix by promoting greater matrix alignment, compaction, and collagen crosslinking compared with all other loading levels. These structural enhancements translated into improved functional properties, with the 0.1-N load significantly increasing both the relaxation modulus and Young's modulus by 96% and 255%, respectively, over controls. Finite element analysis further revealed the 0.1-N uniaxial load to induce multiaxial tensile and compressive strain gradients within the shape-specific neotissues, with maxima of 10.1%, 18.3%, and -21.8% in the XX-, YY-, and ZZ-directions, respectively. This indicates that strains created in different directions in response to a single axis load drove the observed anisotropic functional properties. Together, results of this study suggest that strain thresholds exist within each axis to promote matrix synthesis, alignment, and compaction within the shape-specific neotissues. Tailoring of passive axial loading, thus, presents

  10. Room-temperature sol–gel synthesis of organic ligand-capped ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zobel, Mirijam, E-mail: mirijam.zobel@fau.de; Chatterjee, Haimantee [Friedrich-Alexander University Erlangen-Nürnberg (FAU), Department of Physics, Lehrstuhl für Kristallographie und Strukturphysik (Germany); Matveeva, Galina; Kolb, Ute [Johannes Gutenberg-Universität, Institut für Physikalische Chemie (Germany); Neder, Reinhard B., E-mail: reinhard.neder@fau.de [Friedrich-Alexander University Erlangen-Nürnberg (FAU), Department of Physics, Lehrstuhl für Kristallographie und Strukturphysik (Germany)

    2015-05-15

    Powders of zinc oxide nanoparticles with individual particle sizes below 10 nm in diameter are readily produced in base-induced sol–gel processes from ethanolic solutions of zinc acetate dihydrate. These particles are covered with acetate molecules and without further stabilization, they grow when stored as a powder. Here, we present three organic ligands, which reproducibly stabilize individual particle sizes <5 nm within the agglomerated powders for extended periods of time, up to months. Citric acid and 1,5-diphenyl-1,3,5-pentanetrione result in average diameters of 3 nm, whereas dimethyl-L-tartrate stabilizes 2.1 nm. X-ray diffraction and pair distribution function analysis were used to investigate the structural properties of the particles. TEM data confirm the individual particle size and crystallinity and show that the particles are agglomerated without structural coherence. Besides the introduction of these novel ligands for ZnO nanoparticles, we investigated, in particular, the influence of each synthesis step onto the final nanoparticle size in the powder. Previous studies often reported the employed synthesis parameters, but did not motivate the reasoning for their choice based on detailed experimental observations. Herein, we regard separately the steps of (i) the synthesis of the colloids, (ii) their precipitation, and (iii) the drying of the resulting gel to understand the role of the ligands therein. ZnO particles only covered with acetate grow to 5 nm during the drying process, whereas particles with any of the additional ligands retain their colloidal size of 2–3 nm. This clearly shows the efficient binding and effect of the presented ligands.

  11. Chemical vs. biotechnological synthesis of C13-apocarotenoids: current methods, applications and perspectives.

    Science.gov (United States)

    Cataldo, Vicente F; López, Javiera; Cárcamo, Martín; Agosin, Eduardo

    2016-07-01

    Apocarotenoids are natural compounds derived from the oxidative cleavage of carotenoids. Particularly, C13-apocarotenoids are volatile compounds that contribute to the aromas of different flowers and fruits and are highly valued by the Flavor and Fragrance industry. So far, the chemical synthesis of these terpenoids has dominated the industry. Nonetheless, the increasing consumer demand for more natural and sustainable processes raises an interesting opportunity for bio-production alternatives. In this regard, enzymatic biocatalysis and metabolically engineered microorganisms emerge as attractive biotechnological options. The present review summarizes promising bioengineering approaches with regard to chemical production methods for the synthesis of two families of C13-apocarotenoids: ionones/dihydroionones and damascones/damascenone. We discuss each method and its applicability, with a thorough comparative analysis for ionones, focusing on the production process, regulatory aspects, and sustainability.

  12. Synthesis of Organic Matter of Prebiotic Chemistry at the Protoplanetary Disc

    Science.gov (United States)

    Snytnikov, Valeriy; Stoynovskaya, Olga; Rudina, Nina

    We have carried out scanning electron microscopic examination of CM carbonaceous chondrites meteorites Migey, Murchison, Staroe Boriskino aged more than 4.56 billion years (about 50 million years from the beginning of the formation of the Solar system). Our study confirmed the conclusion of Rozanov, Hoover and other researchers about the presence of microfossils of bacterial origin in the matrix of all these meteorites. Since the time of the Solar system formation is 60 - 100 million years, the primary biocenosis emerged in the protoplanetary disc of the Solar system before meteorites or simultaneously with them. It means that prebiological processes and RNA world appeared even earlier in the circumsolar protoplanetary disc. Most likely, this appearance of prebiotic chemistry takes place nowday in massive and medium-massive discs of the observed young stellar objects (YSO) class 0 and I. The timescale of the transition from chemical to biological evolution took less than 50 million years for the Solar system. Further evolution of individual biocenosis in a protoplanetary disc associated with varying physico-chemical conditions during the formation of the Solar system bodies. Biocenosis on these bodies could remove or develop under the influence of many cosmic factors and geological processes in the case of Earth. To complete the primary biosphere formation in short evolution time - millions of years - requires highly efficient chemical syntheses. In industrial chemistry for the efficient synthesis of ammonia, hydrogen cyanide, methanol and other organic species, that are the precursors to obtain prebiotic compounds, catalytic reactors of high pressure are used. Thus (1) necessary amount of the proper catalyst in (2) high pressure areas of the disc can trigger these intense syntheses. The disc contains the solids with the size from nanoparticle to pebble. Iron and magnesium is catalytically active ingredient for such solids. The puzzle is a way to provide hydrogen

  13. Zirconocene and Si-tethered diynes: a happy match directed toward organometallic chemistry and organic synthesis.

    Science.gov (United States)

    Zhang, Wen-Xiong; Zhang, Shaoguang; Xi, Zhenfeng

    2011-07-19

    Characterizing reactive organometallic intermediates is critical for understanding the mechanistic aspects of metal-mediated organic reactions. Moreover, the isolation of reactive organometallic intermediates can often result in the ability to design new synthetic methods. In this Account, we outline synthetic methods that we developed for a variety of diverse Zr/Si organo-bimetallic compounds and Si/N heteroatom-organic compounds through the detailed study of zirconacyclobutene-silacyclobutene fused compounds. Two basic components are involved in this chemistry. The first is the Si-tethered diyne, which owes its rich reactive palette to the combination of the Si-C bond and the C≡C triple bond. The second is the low-valent zirconocene species Cp(2)Zr(II), which has proven very useful in organic synthesis. The reaction of these two components affords the zirconacyclobutene-silacyclobutene fused compound, which is the key reactive Zr/Si organo-bimetallic intermediate discussed here. We discuss the three types of reactions that have been developed for the zirconacyclobutene-silacyclobutene fused intermediate. The reaction with nitriles (the C≡N triple bond) is introduced in the first section. In this one-pot reaction, up to four different components can be combined: the Si-tethered diyne can be reacted with three identical nitriles, with differing nitriles, or with a nitrile and other unsaturated organic substrates such as formamides, isocyanides, acid chlorides, aldehydes, carbodiimides, and azides. Several unexpected multiring, fused Zr/Si organo-bimetallic intermediates were isolated and characterized. A wide variety of N-heterocycles, such as 5-azaindole, pyrrole, and pyrroloazepine derivatives, were obtained. We then discuss the reaction with alkynes (the C≡C triple bond). A consecutive skeletal rearrangement, differing from that observed in the reactions with nitriles, takes place in this reaction. Finally, we discuss the reaction with the C═X substrates

  14. A dynamic Monte Carlo study of anomalous current voltage behaviour in organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Feron, K., E-mail: Krishna.Feron@csiro.au; Fell, C. J. [Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308 (Australia); CSIRO Energy Flagship, Newcastle, NSW 2300 (Australia); Zhou, X.; Belcher, W. J.; Dastoor, P. C. [Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308 (Australia)

    2014-12-07

    We present a dynamic Monte Carlo (DMC) study of s-shaped current-voltage (I-V) behaviour in organic solar cells. This anomalous behaviour causes a substantial decrease in fill factor and thus power conversion efficiency. We show that this s-shaped behaviour is induced by charge traps that are located at the electrode interface rather than in the bulk of the active layer, and that the anomaly becomes more pronounced with increasing trap depth or density. Furthermore, the s-shape anomaly is correlated with interface recombination, but not bulk recombination, thus highlighting the importance of controlling the electrode interface. While thermal annealing is known to remove the s-shape anomaly, the reason has been not clear, since these treatments induce multiple simultaneous changes to the organic solar cell structure. The DMC modelling indicates that it is the removal of aluminium clusters at the electrode, which act as charge traps, that removes the anomalous I-V behaviour. Finally, this work shows that the s-shape becomes less pronounced with increasing electron-hole recombination rate; suggesting that efficient organic photovoltaic material systems are more susceptible to these electrode interface effects.

  15. Synthesis and Characterization of an Iron Nitride Constructed by a Novel Template of Metal Organic Framework

    Directory of Open Access Journals (Sweden)

    Suyan Liu

    2015-01-01

    Full Text Available An iron nitride with high surface area was synthesized from an iron-based metal organic framework (Fe-MOF in this work. During the synthesis process, the Fe-MOF of MIL-53 served as a hard template, a template to impart a certain degree of morphology for iron oxide products and to form porosities for iron nitride products. Moreover, it played the roles of iron sources for the synthesis of the final iron oxides and the iron nitrides. The physicochemical properties of the materials were characterized by a series of technologies including XRD, SEM, and N2-adsorption/desorption. The results showed that the iron nitride synthesized from MIL-53 was α-Fe2-3N. And, the α-Fe2-3N showed the morphology with loosely aggregated particles which favored the formation of rich interparticle porosities. As a result, the surface area of the α-Fe2-3N was larger than those of samples using α-Fe2O3 as precursors and its value was 41 m2/g. In addition, the results agreed that both raw material properties (such as crystallinity and surface areas and nitriding approaches had significant effects on the surface areas of iron nitrides. Also the results were proved by the iron oxide synthesized with different methods. This new synthetic strategy could be a general approach for the preparation of late transition metal nitrides with peculiar properties.

  16. Synthesis of metal-organic framework films by pore diffusion method

    Science.gov (United States)

    Murayama, Naohiro; Nishimura, Yuki; Kajiro, Hiroshi; Kishida, Satoru; Kinoshita, Kentaro; Tottori Univ Team; Nippon Steel; Sumitomo Metal Co. Collaboration; Tottori Integrated Frontier Resaerch Center (Tifrec) Collaboration; Tottori University Electronic Display Resaerch Center (Tedrec) Collaboration

    Metal-organic frameworks (MOFs) presents high controllability in designing the nano-scale pore, and this enable molecular storages, catalysts, gas sensors, gas separation membranes, and electronic devices for next-generation. Therefore, a simple method for film synthesis of MOFs compared with conventional methods [1] is strongly required. In this paper, we provide pore diffusion method, in which a substrate containing constituent metals of MOF is inserted in solution that includes only linker molecules of MOF. As a result, 2D growth of MOF was effectively enhanced, and the formation of flat and dense MOF films was attained. The growth time, t, dependence of film thickness, d, can be expressed by the relation of d = Aln(t + 1) + B, where A and B are constants. It means that ionized coppers diffuse through the pores of MOFs and the synthesis reaction proceeds at the MOF/solvent interface. We demonstrated the fabrication of a HKUST-1/Cu-TPA hetero structure by synthesizing a Cu-TPA film continuously after the growth of a HKUST-1 film on the CuOx substrate.

  17. Chemoenzymatic Synthesis of Cellular Adhesion Tripeptide RGD Precursor in Organic Media

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Chemoenzymatic synthesis of tripeptide Bz-RGD-(OEt)2 was conducted in this study. First, the free dipeptide Gly-Asp was synthesized via a novel chemical method, wherein only L-aspartic acid was used and was followed by the esterification of Gly-Asp. The formation of the linkage between the third amino acid Bz-Arg-OEt and Gly-Asp-(OEt)2 was completed by using the enzymatic method in organic media. The effects of several factors such as pH, the water content, triethylamine(TEA), the molar ratio of the substrates, and the reaction time on the yield of Bz-RGD-(OEt)2 were examined. It was obtained that the optimum conditions for Bz-RGD-(OEt)2 synthesis in an ethanol/Tris-HCl buffer system(volume ratio 93:7) were as follows; pH=8.0; temperature, 30 ℃; reaction time, 7 h. The tripeptide yield was 75.2%.

  18. Choline acetyltransferase and organic cation transporters are responsible for synthesis and propionate-induced release of acetylcholine in colon epithelium.

    Science.gov (United States)

    Bader, Sandra; Klein, Jochen; Diener, Martin

    2014-06-15

    Acetylcholine is not only a neurotransmitter, but is found in a variety of non-neuronal cells. For example, the enzyme choline acetyltransferase (ChAT), catalyzing acetylcholine synthesis, is expressed by the colonic epithelium of different species. These cells release acetylcholine across the basolateral membrane after luminal exposure to propionate, a short-chain fatty acid. The functional consequence is the induction of chloride secretion, measurable as increase in short-circuit current (Isc) in Ussing chamber experiments. It is unclear how acetylcholine is produced and released by colonic epithelium. Therefore, the aim of the present study was the identification (on mRNA and protein level) and functional characterization (in Ussing chamber experiments combined with HPLC detection of acetylcholine) of transporters/enzymes in the cholinergic system of rat colonic epithelium. Immunohistochemical staining as well as RT-PCR revealed the expression of high-affinity choline transporter, ChAT, carnitine acetyltransferase (CarAT), vesicular acetylcholine transporter (VAChT), and organic cation transporters (OCT 1, 2, 3) in colonic epithelium. In contrast to blockade of ChAT with bromoacetylcholine, inhibition of CarAT with mildronate did not inhibit the propionate-induced increase in Isc, suggesting a predominant synthesis of epithelial acetylcholine by ChAT. Although being expressed, blockade of VAChT with vesamicol was ineffective, whereas inhibition of OCTs with omeprazole and corticosterone inhibited propionate-induced Isc and the release of acetylcholine into the basolateral compartment. In summary, OCTs seem to be involved in regulated acetylcholine release by colonic epithelium, which is assumed to be involved in chemosensing of luminal short-chain fatty acids by the intestinal epithelium. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. [Exploitation of the chemistry of magnesium carbenoids and their use in organic synthesis].

    Science.gov (United States)

    Satoh, Tsuyoshi

    2009-09-01

    Synthetic organic chemistry is a base of medicinal chemistry and the exploitation of new methods for carbon-carbon bond formation is of most importance in synthetic organic chemistry. Carbenes and carbenoids have long been known to be highly reactive carbon species that show a variety of unique reactivity. However, those reactive species are not fully used in organic synthesis. The reasons are as follows: one is the precursors for the generation of carbenes and carbenoids are quite limited and the other is that the reactivity of the species is too high to control. In order to solve the problem mentioned above, we used alpha-haloalkyl (or alkenyl) aryl sulfoxides as the precursors and used sulfoxide-magnesium exchange reaction for generation of much mild magnesium carbenoids. alpha-Haloalkyl (or alkenyl) aryl sulfoxides are quite easily synthesized in high overall yields. Magnesium carbenoids, cyclopropylmagnesium carbenoids, cyclobutylmagnesium carbenoids, magnesium beta-oxido carbenoids, and magnesium alkylidene carbenoids are generated at low temperature from the corresponding sulfoxides with a Grignard reagent in quantitative yields. They were found to be stable usually at below -60 degrees C for at least 30 min. The each magnesium carbenoids have their own unique reactivities and we could find many unprecedented reactions from these reactive species. Recent results for the developments of new synthetic methods based on the chemistry of magnesium carbenoids are described.

  20. Synthesis of Pt3Ni Microspheres with High Performance for Rapid Degradation of Organic Dyes

    Science.gov (United States)

    Wang, Min; Yang, Yushi; Long, Jia; Mao, Zhou; Qiu, Tong; Wu, Qingzhi; Chen, Xiaohui

    2015-05-01

    In this study, Pt3Ni microspheres consisted of nanoparticles were synthesized without addition of surfactants via the solvothermal route. The obtained sample was characterized by X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometer (ICP-AES), X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscopy (FESEM). Furthermore, the catalytic performance of as-synthesized Pt3Ni microspheres was evaluated on the degradation of different organic dyes (methylene blue, methyl orange, Congo red, and rhodamine B). The results show that different dyes were rapidly decomposed by Pt3Ni microspheres in different pathways. Among different dyes, the formation and further degradation of the intermediates was observed during the degradation of methylene blue and methyl orange, suggesting the indirect degradation process of these dyes. This study provides not only a promising catalyst for the removal of organic contaminants for environment remediation, but also new insights for Pt3Ni alloy as a high-performance catalyst in organic synthesis.

  1. Synthesis of Pt3Ni microspheres with high performance for rapid degradation of organic dyes.

    Science.gov (United States)

    Wang, Min; Yang, Yushi; Long, Jia; Mao, Zhou; Qiu, Tong; Wu, Qingzhi; Chen, Xiaohui

    2015-12-01

    In this study, Pt3Ni microspheres consisted of nanoparticles were synthesized without addition of surfactants via the solvothermal route. The obtained sample was characterized by X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometer (ICP-AES), X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscopy (FESEM). Furthermore, the catalytic performance of as-synthesized Pt3Ni microspheres was evaluated on the degradation of different organic dyes (methylene blue, methyl orange, Congo red, and rhodamine B). The results show that different dyes were rapidly decomposed by Pt3Ni microspheres in different pathways. Among different dyes, the formation and further degradation of the intermediates was observed during the degradation of methylene blue and methyl orange, suggesting the indirect degradation process of these dyes. This study provides not only a promising catalyst for the removal of organic contaminants for environment remediation, but also new insights for Pt3Ni alloy as a high-performance catalyst in organic synthesis.

  2. Organic chemistry. Nanomole-scale high-throughput chemistry for the synthesis of complex molecules.

    Science.gov (United States)

    Buitrago Santanilla, Alexander; Regalado, Erik L; Pereira, Tony; Shevlin, Michael; Bateman, Kevin; Campeau, Louis-Charles; Schneeweis, Jonathan; Berritt, Simon; Shi, Zhi-Cai; Nantermet, Philippe; Liu, Yong; Helmy, Roy; Welch, Christopher J; Vachal, Petr; Davies, Ian W; Cernak, Tim; Dreher, Spencer D

    2015-01-02

    At the forefront of new synthetic endeavors, such as drug discovery or natural product synthesis, large quantities of material are rarely available and timelines are tight. A miniaturized automation platform enabling high-throughput experimentation for synthetic route scouting to identify conditions for preparative reaction scale-up would be a transformative advance. Because automated, miniaturized chemistry is difficult to carry out in the presence of solids or volatile organic solvents, most of the synthetic "toolkit" cannot be readily miniaturized. Using palladium-catalyzed cross-coupling reactions as a test case, we developed automation-friendly reactions to run in dimethyl sulfoxide at room temperature. This advance enabled us to couple the robotics used in biotechnology with emerging mass spectrometry-based high-throughput analysis techniques. More than 1500 chemistry experiments were carried out in less than a day, using as little as 0.02 milligrams of material per reaction.

  3. Synthesis of copper nanostructures on silica-based particles for antimicrobial organic coatings

    Science.gov (United States)

    Palza, Humberto; Delgado, Katherine; Curotto, Nicolás

    2015-12-01

    Sol-gel based silica nanoparticles of 100 nm were used to interact with copper ions from the dissolution of CuCl2 allowing the synthesis of paratacamite (Cu2(OH)3Cl) nanocrystals of around 20 nm. The method produced well dispersed copper nanostructures directly supported on the surface of the SiO2 particles and was generalized by using a natural zeolite microparticle as support with similar results. These hybrid Cu based nanoparticles released copper ions when immersed in water explaining their antimicrobial behavior against Escherichia coli and Staphylococcus aureus as measured by the minimum inhibitory and minimum bactericidal concentrations (MIC and MBC). Noteworthy, when these nanostructured particles were mixed with an organic coating the resulting film eliminated until a 99% of both bacteria at concentrations as low as 0.01 wt%.

  4. Synthesis and Characterization of Highly Efficient Nickel Nanocatalysts and Their Use in Degradation of Organic Dyes

    Directory of Open Access Journals (Sweden)

    Nazar Hussain Kalwar

    2014-01-01

    Full Text Available The present study describes the synthesis of highly active and ordered structures of nickel nanocatalysts by a facile, green, and economically viable approach. The study reveals efficient catalytic activity for the degradation of a number of toxic organic dyes, such as eosin-B (EB, rose bengal (RB, eriochrome black-T (ECBT, and methylene blue (MB. The stable ordered nickel nanostructure (Ni NSs arrays were prepared via a modified hydrazine reduction route with unique and controlled morphologies in a lyotropic liquid crystalline medium using a nonionic surfactant (Triton X-100. Characterization and optimization studies for the fabricated Ni NSs involving their surface binding interactions, size, and morphologies were carried out using UV-Vis spectroscopy, Fourier transform infrared (FTIR spectroscopy, X-ray diffraction (XRD, and scanning electron microscopy (SEM.

  5. Oxide-based inorganic/organic and nanoporous spherical particles: synthesis and functional properties

    Science.gov (United States)

    Shiba, Kota; Tagaya, Motohiro; Tilley, Richard D.; Hanagata, Nobutaka

    2013-04-01

    This paper reviews the recent progress in the preparation of oxide-based and heteroatom-doped particles. Surfactant-templated oxide particles, e.g. silica and titania, are possible candidates for various potential applications such as adsorbents, photocatalysts, and optoelectronic and biological materials. We highlight nanoporous oxides of one element, such as silicon or titanium, and those containing multiple elements, which exhibit properties that are not achieved with individual components. Although the multicomponent nanoporous oxides possess a number of attractive functions, the origin of their properties is hard to determine due to compositional/structural complexity. Particles with a well-defined size and shape are keys for a quantitative and detailed discussion on the unique complex properties of the particles. From this viewpoint, we review the synthesis techniques of the oxide particles, which are functionalized with organic molecules or doped with heteroatoms, the physicochemical properties of the particles and the possibilities for their photofunctional applications as complex systems.

  6. Plausible role of nanoparticle contamination in the synthesis and properties of organic electronic materials

    Science.gov (United States)

    Ananikov, Valentine P.

    2016-12-01

    Traceless transition metal catalysis (Pd, Ni, Cu, etc.) is very difficult to achieve. Metal contamination in the synthesized products is unavoidable and the most important questions are: How to control metal impurities? What amount of metal impurities can be tolerated? What is the influence of metal impurities? In this brief review, the plausible origins of nanoparticle contamination are discussed in the framework of catalytic synthesis of organic electronic materials. Key factors responsible for increasing the probability of contamination are considered from the point of view of catalytic reaction mechanisms. The purity of the catalyst may greatly affect the molecular weight of a polymer, reaction yield, selectivity and several other parameters. Metal contamination in the final polymeric products may induce some changes in the electric conductivity, charge transport properties, photovoltaic performance and other important parameters.

  7. Organic phase synthesis of noble metal-zinc chalcogenide core-shell nanostructures.

    Science.gov (United States)

    Kumar, Prashant; Diab, Mahmud; Flomin, Kobi; Rukenstein, Pazit; Mokari, Taleb

    2016-10-15

    Multi-component nanostructures have been attracting tremendous attention due to their ability to form novel materials with unique chemical, optical and physical properties. Development of hybrid nanostructures that are composed of metal-semiconductor components using a simple approach is of interest. Herein, we report a robust and general organic phase synthesis of metal (Au or Ag)-Zinc chalcogenide (ZnS or ZnSe) core-shell nanostructures. This synthetic protocol also enabled the growth of more compositionally complex nanostructures of Au-ZnSxSe1-x alloys and Au-ZnS-ZnSe core-shell-shell. The optical and structural properties of these hybrid nanostructures are also presented.

  8. Direct Arylation Strategies in the Synthesis of π-Extended Monomers for Organic Polymeric Solar Cells

    Directory of Open Access Journals (Sweden)

    Andrea Nitti

    2016-12-01

    Full Text Available π-conjugated macromolecules for organic polymeric solar cells can be rationally engineered at the molecular level in order to tune the optical, electrochemical and solid-state morphology characteristics, and thus to address requirements for the efficient solid state device implementation. The synthetic accessibility of monomers and polymers required for the device is getting increasing attention. Direct arylation reactions for the production of the π-extended scaffolds are gaining importance, bearing clear advantages over traditional carbon-carbon forming methodologies. Although their use in the final polymerization step is already established, there is a need for improving synthetic accessibility to implement them also in the monomer synthesis. In this review, we discuss recent examples highlighting this useful strategy.

  9. Mechanoassisted Synthesis of Sulfonated Covalent Organic Frameworks with High Intrinsic Proton Conductivity.

    Science.gov (United States)

    Peng, Yongwu; Xu, Guodong; Hu, Zhigang; Cheng, Youdong; Chi, Chenglong; Yuan, Daqiang; Cheng, Hansong; Zhao, Dan

    2016-07-20

    It is challenging to introduce pendent sulfonic acid groups into modularly built crystalline porous frameworks for intrinsic proton conduction. Herein, we report the mechanoassisted synthesis of two sulfonated covalent organic frameworks (COFs) possessing one-dimensional nanoporous channels decorated with pendent sulfonic acid groups. These COFs exhibit high intrinsic proton conductivity as high as 3.96 × 10(-2) S cm(-1) with long-term stability at ambient temperature and 97% relative humidity (RH). In addition, they were blended with nonconductive polyvinylidene fluoride (PVDF) affording a series of mixed-matrix membranes (MMMs) with proton conductivity up to 1.58 × 10(-2) S cm(-1) and low activation energy of 0.21 eV suggesting the Grotthuss mechanism for proton conduction. Our study has demonstrated the high intrinsic proton conductivity of COFs shedding lights on their wide applications in proton exchange membranes.

  10. Accessing Stereochemically Rich Sultams via Microwave-Assisted, Continuous Flow Organic Synthesis (MACOS) Scale-out

    Science.gov (United States)

    Organ, Michael G.; Hanson, Paul R.; Rolfe, Alan; Samarakoon, Thiwanka B.; Ullah, Farman

    2011-01-01

    The generation of stereochemically-rich benzothiaoxazepine-1,1′-dioxides for enrichment of high-throughput screening collections is reported. Utilizing a microwave-assisted, continuous flow organic synthesis platform (MACOS), scale-out of core benzothiaoxazepine-1,1′-dioxide scaffolds has been achieved on multi-gram scale using an epoxide opening/SNAr cyclization protocol. Diversification of these sultam scaffolds was attained via a microwave-assisted intermolecular SNAr reaction with a variety of amines. Overall, a facile, 2-step protocol generated a collection of benzothiaoxazepine-1,1′-dioxides possessing stereochemical complexity in rapid fashion, where all 8 stereoisomers were accessed from commercially available starting materials. PMID:22116791

  11. Synthesis and characterization of tunable coumarin- linked glasses as new class of organic/inorganic phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Luridiana, Alberto; Pretta, Gianluca; Secci, Francesco; Frongia, Angelo [Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Complesso universitario di Monserrato, SS 554, bivio per Sestu, Monserrato (Canada) (Italy); Chiriu, Daniele; Carbonaro, Carlo Maria; Corpino, Riccardo [Dipartimento di Fisica, Università degli Studi di Cagliari, Complesso universitario di Monserrato, SS 554, bivio per Sestu, Monserrato (Canada) (Italy); Ricci, Pier Carlo, E-mail: carlo.ricci@dsf.unica.it [Dipartimento di Fisica, Universitá degli Studi di Cagliari, S.P. Monserrato-Sestu Km 0,700, 09042 Monserrato (Canada) (Italy)

    2014-10-21

    It is well known that stilbene with a trans conformation is highly fluorescent. From the viewpoint of molecular structure, coumarins bear a carbon-carbon double bond which is fixed as trans conformation as in trans-stilbene through a lactone structure. This can help to avoid the trans-cis transformation of the double bond under ultraviolet (UV) irradiation as observed in stilbene compounds and results in strong fluorescence and high fluorescence quantum yield and photostability in most of coumarin derivatives. Herein we report some preliminary results about the synthesis and spectroscopic characterization of tunable coumarins and the development of a new linkage protocol for the obtainment of monolayer coumarin-covalently linked glasses. The resulting organic/inorganic coumarin/silica based Self-Assembled Monolayer (SMA) film is proposed as new phosphors for the substituting of critical raw materials, like rare earths, in photonics applications.

  12. Synthesis of 5'-O-DMT-2'-O-TBS Mononucleosides Using an Organic Catalyst.

    Science.gov (United States)

    Lee, Sunggi; Blaisdell, Thomas P; Kasaplar, Pinar; Sun, Xixi; Tan, Kian L

    2014-06-24

    This unit describes a highly effective method to produce 5'-O-DMT-2'-O-TBS mononucleosides selectively using a small organic catalyst. This methodology avoids the tedious protection/deprotection strategy necessary to differentiate the 2'- and 3'-hydroxyl groups in a ribonucleoside. The catalyst was synthesized in two steps, starting from the condensation of valinol and cyclopentyl aldehyde, followed by anionic addition of N-methylimidazole. Ring closure of the amino alcohol with N,N-dimethylformamide dimethyl acetal in methanol furnishes the catalyst. All four 2'-O-TBS protected mono-nucleosides, U, A(Bz), G(Ib), and C(Ac), were produced in a single step using 10 to 20 mol% of the catalyst at room temperature with excellent yields and selectivity. Further transformation to phosphoramidite demonstrates the utility of this protocol in the preparation of monomers useful for automated synthesis of RNA.

  13. Synthesis of TiO2 nanocrystals with a high affinity for amine organic compounds.

    Science.gov (United States)

    Gonçalves, Ricardo H; Schreiner, Wido Herwig; Leite, Edson R

    2010-07-20

    This article describes a different approach to the colloidal synthesis of TiO(2) nanocrystals using a polymer melt as a solvent. This approach allowed us to obtain a colloidal dispersion with a high degree of stability in a polymeric solvent, resulting in a transparent colloid. Using this method, it was possible to obtain the TiO(2) nanocrystal with Brønsted acid sites and polymer chains chemically anchored on the nanocrystal surface. The acid surface of those nanocrystals has the chemical property to react in the presence of amine organic compounds and to maintain the colloidal stability. In this way, TiO(2) nanocrystals were combined with a molecular probe containing amine functional groups such as polyaniline. Through the combination of the molecular probe and inorganic nanocrystals, we obtained a hybrid material with interesting chemical, optical, and electronic behavior, making it a promising material for photovoltaic, photochromic, and sensor devices.

  14. Sonochemical Synthesis of Photoluminescent Nanoscale Eu(III-Containing Metal-Organic Frameworks

    Directory of Open Access Journals (Sweden)

    Cheng-an TAO

    2015-11-01

    Full Text Available Nanoscale lanthanide-containing metal-organic frameworks (MOFs have more and more interest due to their great properties and potential applications, but how to construct them easily is still challenging. Here, we present a facile and rapid synthesis of Eu(III-containing Nanoscale MOF (denoted as NMOF under ultrasonic irradiation. The effect of the ratio and the addition order of metal ions and linkers on the morphology and size of MOFs was investigated. It is found that both of the ratio and the addition order can affect the morphology and size of 1.4-benzenedicarboxylic acid(H2BDC -based MOFs, but they show no evident influence on that of H2aBDC-based MOFs. The former exhibit typical emission bands of Eu(III ions, while the latter only show the photoluminescent properties of ligands.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.9695

  15. Sonochemical Synthesis of Photoluminescent Nanoscale Eu(III-Containing Metal-Organic Frameworks

    Directory of Open Access Journals (Sweden)

    Cheng-an TAO

    2015-11-01

    Full Text Available Nanoscale lanthanide-containing metal-organic frameworks (MOFs have more and more interest due to their great properties and potential applications, but how to construct them easily is still challenging. Here, we present a facile and rapid synthesis of Eu(III-containing Nanoscale MOF (denoted as NMOF under ultrasonic irradiation. The effect of the ratio and the addition order of metal ions and linkers on the morphology and size of MOFs was investigated. It is found that both of the ratio and the addition order can affect the morphology and size of 1.4-benzenedicarboxylic acid(H2BDC -based MOFs, but they show no evident influence on that of H2aBDC-based MOFs. The former exhibit typical emission bands of Eu(III ions, while the latter only show the photoluminescent properties of ligands.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.9695

  16. An Efficient Synthesis Strategy for Metal-Organic Frameworks: Dry-Gel Synthesis of MOF-74 Framework with High Yield and Improved Performance

    Science.gov (United States)

    Das, Atanu Kumar; Vemuri, Rama Sesha; Kutnyakov, Igor; McGrail, B. Peter; Motkuri, Radha Kishan

    2016-06-01

    Vapor-assisted dry-gel synthesis of the metal-organic framework-74 (MOF-74) structure, specifically Ni-MOF-74 produced from synthetic precursors using an organic-water hybrid solvent system, showed a very high yield (>90% with respect to 2,5-dihydroxyterepthalic acid) and enhanced performance. The Ni-MOF-74 obtained showed improved sorption characteristics towards CO2 and the refrigerant fluorocarbon dichlorodifluoromethane. Unlike conventional synthesis, which takes 72 hours using the tetrahydrofuran-water system, this kinetic study showed that Ni-MOF-74 forms within 12 hours under dry-gel conditions with similar performance characteristics, and exhibits its best performance characteristics even after 24 hours of heating. In the dry-gel conversion method, the physical separation of the solvent and precursor mixture allows for recycling of the solvent. We demonstrated efficient solvent recycling (up to three times) that resulted in significant cost benefits. The scaled-up manufacturing cost of Ni-MOF-74 synthesized via our dry-gel method is 45% of conventional synthesis cost. Thus, for bulk production of the MOFs, the proposed vapor-assisted, dry-gel method is efficient, simple, and inexpensive when compared to the conventional synthesis method.

  17. An Efficient Synthesis Strategy for Metal-Organic Frameworks: Dry-Gel Synthesis of MOF-74 Framework with High Yield and Improved Performance.

    Science.gov (United States)

    Das, Atanu Kumar; Vemuri, Rama Sesha; Kutnyakov, Igor; McGrail, B Peter; Motkuri, Radha Kishan

    2016-06-16

    Vapor-assisted dry-gel synthesis of the metal-organic framework-74 (MOF-74) structure, specifically Ni-MOF-74 produced from synthetic precursors using an organic-water hybrid solvent system, showed a very high yield (>90% with respect to 2,5-dihydroxyterepthalic acid) and enhanced performance. The Ni-MOF-74 obtained showed improved sorption characteristics towards CO2 and the refrigerant fluorocarbon dichlorodifluoromethane. Unlike conventional synthesis, which takes 72 hours using the tetrahydrofuran-water system, this kinetic study showed that Ni-MOF-74 forms within 12 hours under dry-gel conditions with similar performance characteristics, and exhibits its best performance characteristics even after 24 hours of heating. In the dry-gel conversion method, the physical separation of the solvent and precursor mixture allows for recycling of the solvent. We demonstrated efficient solvent recycling (up to three times) that resulted in significant cost benefits. The scaled-up manufacturing cost of Ni-MOF-74 synthesized via our dry-gel method is 45% of conventional synthesis cost. Thus, for bulk production of the MOFs, the proposed vapor-assisted, dry-gel method is efficient, simple, and inexpensive when compared to the conventional synthesis method.

  18. Synthesis of a Parkinson's Disease Treatment Drug, the "R,R"-Tartrate Salt "of R"-Rasagiline: A Three Week Introductory Organic Chemistry Lab Sequence

    Science.gov (United States)

    Aguilar, Noberto; Garcia, Billy; Cunningham, Mark; David, Samuel

    2016-01-01

    A synthesis of the "R,R"-tartrate salt of the popular anti-Parkinson's drug "R"-rasagiline (Azilect) was adapted to introduce the organic laboratory student to a medically relevant synthesis. It makes use of concepts found in the undergraduate organic chemistry curriculum, appropriately fits into three approximately 4 h lab…

  19. Synthesis of a Parkinson's Disease Treatment Drug, the "R,R"-Tartrate Salt "of R"-Rasagiline: A Three Week Introductory Organic Chemistry Lab Sequence

    Science.gov (United States)

    Aguilar, Noberto; Garcia, Billy; Cunningham, Mark; David, Samuel

    2016-01-01

    A synthesis of the "R,R"-tartrate salt of the popular anti-Parkinson's drug "R"-rasagiline (Azilect) was adapted to introduce the organic laboratory student to a medically relevant synthesis. It makes use of concepts found in the undergraduate organic chemistry curriculum, appropriately fits into three approximately 4 h lab…

  20. Toward Developing Made-to-Order Metal-Organic Frameworks: Design, Synthesis and Applications

    KAUST Repository

    Ashri, Lubna Y.

    2016-05-26

    Synthesis of materials with certain properties for targeted applications is an ongoing challenge in materials science. One of the most interesting classes of solid-state materials that have been recently introduced with the potential to address this is metal-organic frameworks (MOFs). MOFs chemistry offers a higher degree of control over materials to be synthesized utilizing various new design strategies, such as the molecular building blocks (MBBs) and the supermolecular building layers (SBLs) approaches. Depending on using predetermined building blocks, these strategies permit the synthesis of MOFs with targeted topologies and enable fine tuning of their properties. This study examines a number of aspects of the design and synthesis of MOFs while exploring their possible utilization in two diverse fields related to energy and pharmaceutical applications. Concerning MOFs design and synthesis, the work presented here explores the rational design of various MOFs with predicted topologies and tunable cavities constructed by pillaring pre-targeted 2-periodic SBLs using the ligand-to-axial and six-connected axial-to-axial pillaring strategies. The effect of expanding the confined spaces in prepared MOFs or modifying their functionalities, while preserving the underlying network topology, was investigated. Additionally, The MBBs approach was employed to discover new modular polynuclear rare earth (RE)-MBBs in the presence of different angular polytopic ligands containing carboxylate and nitrogen moieties with the aid of a modulator. The goal was to assess the diverse possible coordination modes and construct highly-connected nets for utility in the design of new MOFs and enhance the predictability of structural outcomes. The effect of adjusting ligands’ length-to-width ratio on the prepared MOFs was also evaluated. As a result, the reaction conditions amenable for reliable formation of the unprecedented octadecanuclear, octanuclear and double tetranuclear RE-MBBs were

  1. Site-specific immobilization of enzymes on magnetic nanoparticles and their use in organic synthesis.

    Science.gov (United States)

    Yu, Ching-Ching; Kuo, Yu-Ying; Liang, Chien-Fu; Chien, Wei-Ting; Wu, Huan-Ting; Chang, Tsung-Che; Jan, Fan-Dan; Lin, Chun-Cheng

    2012-04-18

    Magnetic nanoparticles (MNPs) are attractive materials that serve as a support for enzyme immobilization and facilitate separations by applying an external magnetic field; this could facilitate the recycling of enzymes and broaden their applications in organic synthesis. Herein, we report the methods for the immobilization of water-soluble and membrane-bound enzymes, and the activity difference between free and immobilized enzymes is discussed. Sialyltransferase (PmST1, from Pasteurella multocida ) and cytidine monophosphate (CMP)-sialic acid synthetase (CSS, from Neisseria meningitides ) were chosen as water-soluble enzymes and expressed using an intein expression system. The enzymes were site-specifically and covalently immobilized on PEGylated-N-terminal cysteine MNPs through native chemical ligation (NCL). Increasing the length of the PEG linker between the enzyme and the MNP surface increased the activity of the immobilized enzymes relative to the free parent enzymes. In addition, the use of a fluorescent acceptor tag for PmST1 affected enzyme kinetics. In contrast, sialyltransferase from Neisseria gonorrheae (NgST, a membrane-bound enzyme) was modified with a biotin-labeled cysteine at the C-terminus using NCL, and the enzyme was then assembled on streptavidin-functionalized MNPs. Using a streptavidin-biotin interaction, it was possible to immobilize NgST on a solid support under mild ligation conditions, which prevented the enzyme from high-temperature decomposition and provided an approximately 2-fold increase in activity compared to other immobilization methods on MNPs. Finally, the ganglioside GM3-derivative (sialyl-lactose derivative) was synthesized in a one-pot system by combining the use of immobilized PmST1 and CSS. The enzymes retained 50% activity after being reused ten times. Furthermore, the results obtained using the one-pot two-immobilized-enzyme system demonstrated that it can be applied to large-scale reactions with acceptable yields and

  2. Development of a Novel, Oxidatively Activated, Safety-Catch Linker for Solid-Phase Asymmetric Organic Synthesis (SPOS)

    Institute of Scientific and Technical Information of China (English)

    LIN,Jun; Hjalmar Skarphedinsson; Stepehen G.Davies

    2004-01-01

    @@ Solid-phase asymmetric organic synthesis has become a very important synthetic strategy within the organic chemistry community.[1] Critical to success in SPOS is a linking strategy which allows both the substrate to be loaded and the product released efficiently from the polymeric support. A safety catch linker[2] (SCL) is in principle a linking molecule orthogonal to the reaction conditions of the library synthesis, which can be easily activated by a simple chemical transformation to allow efficient cleavage of the products from the polymer under mild conditions. In order to introduce the SuperQuat chiral auxiliaries[3] for SOPS, we report herein design and synthesis of a novel safety catch linker for asymmetric conjugate addition reactions.

  3. Composite polymer/oxide hollow fiber contactors: versatile and scalable flow reactors for heterogeneous catalytic reactions in organic synthesis.

    Science.gov (United States)

    Moschetta, Eric G; Negretti, Solymar; Chepiga, Kathryn M; Brunelli, Nicholas A; Labreche, Ying; Feng, Yan; Rezaei, Fateme; Lively, Ryan P; Koros, William J; Davies, Huw M L; Jones, Christopher W

    2015-05-26

    Flexible composite polymer/oxide hollow fibers are used as flow reactors for heterogeneously catalyzed reactions in organic synthesis. The fiber synthesis allows for a variety of supported catalysts to be embedded in the walls of the fibers, thus leading to a diverse set of reactions that can be catalyzed in flow. Additionally, the fiber synthesis is scalable (e.g. several reactor beds containing many fibers in a module may be used) and thus they could potentially be used for the large-scale production of organic compounds. Incorporating heterogeneous catalysts in the walls of the fibers presents an alternative to a traditional packed-bed reactor and avoids large pressure drops, which is a crucial challenge when employing microreactors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Estimation of breast dose reduction potential for organ-based tube current modulated CT with wide dose reduction arc

    Science.gov (United States)

    Fu, Wanyi; Sturgeon, Gregory M.; Agasthya, Greeshma; Segars, W. Paul; Kapadia, Anuj J.; Samei, Ehsan

    2017-03-01

    This study aimed to estimate the organ dose reduction potential for organ-dose-based tube current modulated (ODM) thoracic CT with wide dose reduction arc. Twenty-one computational anthropomorphic phantoms (XCAT, age range: 27- 75 years, weight range: 52.0-105.8 kg) were used to create a virtual patient population with clinical anatomic variations. For each phantom, two breast tissue compositions were simulated: 50/50 and 20/80 (glandular-to-adipose ratio). A validated Monte Carlo program was used to estimate the organ dose for standard tube current modulation (TCM) (SmartmA, GE Healthcare) and ODM (GE Healthcare) for a commercial CT scanner (Revolution, GE Healthcare) with explicitly modeled tube current modulation profile, scanner geometry, bowtie filtration, and source spectrum. Organ dose was determined using a typical clinical thoracic CT protocol. Both organ dose and CTDIvol-to-organ dose conversion coefficients (h factors) were compared between TCM and ODM. ODM significantly reduced all radiosensitive organ doses (psaw an increase or no significant change. The organ-dose-based tube current modulation significantly reduced organ doses especially for radiosensitive superficial anterior organs such as the breasts.

  5. Graphic organizers and their effects on the reading comprehension of students with LD: a synthesis of research.

    Science.gov (United States)

    Kim, Ae-Hwa; Vaughn, Sharon; Wanzek, Jeanne; Wei, Shangjin

    2004-01-01

    Previous research studies examining the effects of graphic organizers on reading comprehension for students with learning disabilities (LD) are reviewed. An extensive search of the professional literature between 1963 and June 2001 yielded a total of 21 group design intervention studies that met the criteria for inclusion in the synthesis. Using graphic organizers (i.e., semantic organizers, framed outlines, cognitive maps with and without a mnemonic) was associated with improved reading comprehension overall for students with LD. Compared to standardized reading measures, researcher-developed comprehension measures were associated with higher effect sizes. Initial gains demonstrated when using graphic organizers were not revealed during later comprehension tasks or on new comprehension tasks.

  6. The Combined C—H Functionalization/Cope Rearrangement: Discovery and Applications in Organic Synthesis

    Science.gov (United States)

    Davies, Huw M. L.; Lian, Yajing

    2012-01-01

    Conspectus The development of methods for the stereoselective functionalization of sp3 C–H bonds is a challenging undertaking. This Account describes the scope of the combined C–H functionalization/Cope rearrangement (CHCR), a reaction that occurs between rhodium-stabilized vinylcarbenoids and substrates containing allylic C–H bonds. Computational studies have shown that the CHCR reaction is initiated by a hydride transfer to the carbenoid from an allyl site of the substrate, which is then rapidly followed by C–C bond formation between the developing rhodium-bound allyl anion and the allyl cation. In principle, the reaction can proceed through four distinct orientations of the vinylcarbenoid and the approaching substrate. The early examples of the CHCR reaction were all highly diastereoselective, consistent with a reaction proceeding via a chair transition state with the vinylcarbenoid adopting an s-cis conformation. Recent computational studies have revealed that other transition state orientations are energetically accessible, and these results have guided the development of highly stereoselective CHCR reactions that proceed through a boat transition state with the vinylcarbenoid in an s-cis configuration. The CHCR reaction has broad applications in organic synthesis. In some new protocols, the CHCR reaction acts as a surrogate to some of the classic synthetic strategies in organic chemistry. The CHCR reaction has served as a synthetic equivalent of the Michael reaction, the vinylogous Mukaiyama aldol reaction, the tandem Claisen rearrangement/Cope rearrangement, and the tandem aldol reaction/siloxy-Cope rearrangement. In all of these cases, the products are generated with very high diastereocontrol. With a chiral dirhodium tetracarboxylate catalyst such as Rh2(S-DOSP)4 or Rh2(S-PTAD)4, researchers can achieve very high levels of asymmetric induction. Applications of the CHCR reaction include the effective enantiodifferentiation of racemic

  7. Organically functionalized mesoporous silica as a support for synthesis and catalysis

    Science.gov (United States)

    McEleney, Kevin Andrew

    class of inorganic-organic hybrid materials. The majority of PMOs prepared utilize simple organic bridges such as ethyl, phenyl or biphenyl. The use of a chiral organic bridging group, such as BINAP, allows the synthesis of chiral PMOs with possible applications in catalysis and separation science. The synthesis of a triethoxysilyl functionalized BINAP as well as its incorporation into PMO materials with 4,4'-bistriethoxysilyl biphenyl or tetraethylorthosilicate as cosilica sources are described.

  8. Magnetite as Possible Template for the Synthesis of Chiral Organics in Carbonaceous Chondrites

    Science.gov (United States)

    Chan, Q. H. S.; Zolensky, M. E.

    2014-01-01

    The main goal of the Japanese Aerospace Ex-ploration Agency (JAXA) Hayabusa-2 mission is to visit and return to Earth samples of a C-type asteroid (162173) 1999 JU3 in order to understand the origin and nature of organic materials in the Solar System. Life on Earth shows preference towards the set of organics with particular spatial arrangements, this 'selectivity' is a crucial criterion for life. With only rare exceptions, life 'determines' to use the left- (L-) form over the right- (D-) form of amino acids, resulting in a L-enantiomeric excess (ee). Recent studies have shown that L-ee is found within the alpha-methyl amino acids in meteorites [1, 2], which are amino acids with rare terrestrial occurrence, and thus point towards a plausible abiotic origin for ee. One of the proposed origins of chiral asymmetry of amino acids in meteorites is their formation with the presence of asymmetric catalysts [3]. The catalytic mineral grains acted as a surface at which nebular gases (CO, H2 and NH3) were allowed to condense and react through Fisher Tropsch type (FTT) syntheses to form the organics observed in meteorites [4]. Magnetite is shown to be an effective catalyst of the synthesis of amino acids that are commonly found in meteorites [5]. It has also taken the form as spiral magnetites (a.k.a. 'plaquettes'), which were found in various carbonaceous chondrites (CCs), including C2s Tagish Lake and Esseibi, CI Orgueil, and CR chondrites [e.g., 6, 7, 8]. In addition, L-ee for amino acids are common in the aqueously altered CCs, as opposed to the unaltered CCs [1]. It seems possible that the synthesis of amino acids with chiral preferences is correlated to the alteration process experienced by the asteroid parent body, and related to the configuration of spiral magnetite catalysts. Since C-type asteroids are considered to be enriched in organic matter, and the spectral data of 1999 JU3 indicates a certain de-gree of aqueous alteration [9], the Hayabusa-2 mission serves as

  9. Facile synthesis of one-dimensional organometallic-organic hybrid polymers based on a diphosphorus complex and flexible bipyridyl linkers.

    Science.gov (United States)

    Elsayed Moussa, M; Attenberger, B; Peresypkina, E V; Fleischmann, M; Balázs, G; Scheer, M

    2016-08-21

    The selective synthesis of a series of new "ladderlike" one-dimensional organometallic-organic hybrid polymers is shown. The polymers are obtained from the reaction of the diphosphorus ligand complex [Cp2Mo2(CO)4(η(2)-P2)] with the copper salt [Cu(CH3CN)4]BF4 in the presence of flexible organic bipyridyl linkers in high selectivity. This unique behaviour is supported by DFT calculations.

  10. Microwave-Enhanced Organic Syntheses for the Undergraduate Laboratory: Diels-Alder Cycloaddition, Wittig Reaction, and Williamson Ether Synthesis

    Science.gov (United States)

    Baar, Marsha R.; Falcone, Danielle; Gordon, Christopher

    2010-01-01

    Microwave heating enhanced the rate of three reactions typically performed in our undergraduate organic chemistry laboratory: a Diels-Alder cycloaddition, a Wittig salt formation, and a Williamson ether synthesis. Ninety-minute refluxes were shortened to 10 min using a laboratory-grade microwave oven. In addition, yields improved for the Wittig…

  11. Low Band Gap Polymers for Roll-to-Roll Coated Organic Photovoltaics – Design, Synthesis and Characterization

    DEFF Research Database (Denmark)

    Bundgaard, Eva; Hagemann, Ole; Jørgensen, Mikkel

    2011-01-01

    In this paper we present the design and synthesis of 25 new low band gap polymers. The polymers were characterized by UV-vis spectroscopy which showed optical band gaps of 2.0–0.9 eV. The polymers which were soluble enough were applied in organic photovoltaics, both small area devices with a spin...

  12. The Cyclohexanol Cycle and Synthesis of Nylon 6,6: Green Chemistry in the Undergraduate Organic Laboratory

    Science.gov (United States)

    Dintzner, Matthew R.; Kinzie, Charles R.; Pulkrabek, Kimberly; Arena, Anthony F.

    2012-01-01

    A one-term synthesis project that incorporates many of the principles of green chemistry is presented for the undergraduate organic laboratory. In this multistep scheme of reactions, students react, recycle, and ultimately convert cyclohexanol to nylon 6,6. The individual reactions in the project employ environmentally friendly methodologies, and…

  13. A one pot organic/CdSe nanoparticle hybrid material synthesis with in situ π-conjugated ligand functionalization.

    Science.gov (United States)

    Mazzio, Katherine A; Okamoto, Ken; Li, Zhi; Gutmann, Sebastian; Strein, Elisabeth; Ginger, David S; Schlaf, Rudy; Luscombe, Christine K

    2013-02-14

    A one pot method for organic/colloidal CdSe nanoparticle hybrid material synthesis is presented. Relative to traditional ligand exchange processes, these materials require smaller amounts of the desired capping ligand, shorter syntheses and fewer processing steps, while maintaining nanoparticle morphology.

  14. A Model of Problem Solving: Its Operation, Validity, and Usefulness in the Case of Organic-Synthesis Problems.

    Science.gov (United States)

    Tsaparlis, Georgios; Angelopoulous, Vasileios

    2000-01-01

    Presents a test of the limits of the Johnstone--El-Banna model of problem solving as related to students' responses to organic-synthesis problems. Finds that the predicted pattern was observed in both samples, although the model was more useful for students without previous problem-solving training and for field-independent and field-intermediate…

  15. Facile synthesis of multiple enzyme-containing metal-organic frameworks in a biomolecule-friendly environment.

    Science.gov (United States)

    Wu, Xiaoling; Ge, Jun; Yang, Cheng; Hou, Miao; Liu, Zheng

    2015-09-07

    The one-step and facile synthesis of multi-enzyme-containing metal-organic framework (MOF) nanocrystals in aqueous solution at 25 °C was reported in this study. The GOx&HRP/ZIF-8 nanocomposite displayed high catalytic efficiency, high selectivity and enhanced stability due to the protecting effect of the framework.

  16. The Cyclohexanol Cycle and Synthesis of Nylon 6,6: Green Chemistry in the Undergraduate Organic Laboratory

    Science.gov (United States)

    Dintzner, Matthew R.; Kinzie, Charles R.; Pulkrabek, Kimberly; Arena, Anthony F.

    2012-01-01

    A one-term synthesis project that incorporates many of the principles of green chemistry is presented for the undergraduate organic laboratory. In this multistep scheme of reactions, students react, recycle, and ultimately convert cyclohexanol to nylon 6,6. The individual reactions in the project employ environmentally friendly methodologies, and…

  17. Flow through reactors for organic chemistry: directly electrically heated tubular mini reactors as an enabling technology for organic synthesis

    Directory of Open Access Journals (Sweden)

    Ulrich Kunz

    2009-11-01

    Full Text Available Until recently traditional heating in organic chemistry has been done with oil heating baths or using electric heat exchangers. With the advent of microwave equipment, heating by microwaves was rapidly introduced as standard method in organic chemistry laboratories, mainly because of the convenient possibility to operate at high temperature accompanied by accelerated reaction rates. In the present contribution we discuss the method of heating small, continuously operated reactors by passing electric current directly through the reactor wall as an enabling technology in organic chemistry. The benefit of this method is that the heat is generated directly inside the reactor wall. By this means high heating rates comparable to microwave ovens can be reached but at much lower cost for the equipment. A tool for the comparison of microwave heating and traditional heating is provided. As an example kinetic data for the acid catalyzed hydrolysis of methyl formate were measured using this heating concept. The reaction is not only a suitable model but also one of industrial importance since this is the main production process for formic acid.

  18. Flow through reactors for organic chemistry: directly electrically heated tubular mini reactors as an enabling technology for organic synthesis.

    Science.gov (United States)

    Kunz, Ulrich; Turek, Thomas

    2009-11-30

    Until recently traditional heating in organic chemistry has been done with oil heating baths or using electric heat exchangers. With the advent of microwave equipment, heating by microwaves was rapidly introduced as standard method in organic chemistry laboratories, mainly because of the convenient possibility to operate at high temperature accompanied by accelerated reaction rates. In the present contribution we discuss the method of heating small, continuously operated reactors by passing electric current directly through the reactor wall as an enabling technology in organic chemistry. The benefit of this method is that the heat is generated directly inside the reactor wall. By this means high heating rates comparable to microwave ovens can be reached but at much lower cost for the equipment. A tool for the comparison of microwave heating and traditional heating is provided. As an example kinetic data for the acid catalyzed hydrolysis of methyl formate were measured using this heating concept. The reaction is not only a suitable model but also one of industrial importance since this is the main production process for formic acid.

  19. Flow through reactors for organic chemistry: directly electrically heated tubular mini reactors as an enabling technology for organic synthesis

    Science.gov (United States)

    Turek, Thomas

    2009-01-01

    Summary Until recently traditional heating in organic chemistry has been done with oil heating baths or using electric heat exchangers. With the advent of microwave equipment, heating by microwaves was rapidly introduced as standard method in organic chemistry laboratories, mainly because of the convenient possibility to operate at high temperature accompanied by accelerated reaction rates. In the present contribution we discuss the method of heating small, continuously operated reactors by passing electric current directly through the reactor wall as an enabling technology in organic chemistry. The benefit of this method is that the heat is generated directly inside the reactor wall. By this means high heating rates comparable to microwave ovens can be reached but at much lower cost for the equipment. A tool for the comparison of microwave heating and traditional heating is provided. As an example kinetic data for the acid catalyzed hydrolysis of methyl formate were measured using this heating concept. The reaction is not only a suitable model but also one of industrial importance since this is the main production process for formic acid. PMID:20300506

  20. Current Problems of Food Safety in Terms of Russia Membership in World Trade Organization

    Directory of Open Access Journals (Sweden)

    Andrey A. Schetkin

    2013-09-01

    Full Text Available Food industry stirs close interest of researches due to the extension and deepening of the problems of ecologic, microbiologic, epidemiologic safety of food industry and intake, determined by many social, anthropogenic and natural factors: change of human food ration; world economy globalization and, in particular, food market due to the penetration of pathogens, toxins into the new territories; adaptation of pathogenic agents to food storage conditions and new factors of transmission and other reasons. As a result, food-borne diseases significantly determine the increase of infectious and non-infectious pathologies in the world, including economically developed countries. The paper presents the data on the existing systems of catering risk control, current data on the role of some food pathogens in alimentary outbreaks, offers measures to increase food safety in the Russian Federation on both national and federal levels in terms of its membership in World Trade Organization.

  1. Lean management in the current context of evolution of an organization

    Directory of Open Access Journals (Sweden)

    AMALIA VENERA TODORUŢ

    2011-06-01

    Full Text Available In this paper I have approached issues concerning the importance of Lean Management method in the current context of evolution of an organization. With roots in the just in time method, Lean Management model focuses on the process of changes evolving and adapting to them and regards issues such as: the dimensioning of life cycle, the dimensioning of processes, the dimensioning of ranges of products. I have also presented the relationship between Lean Management method and the human factor as a determinant in forming an organizational culture which leads to the formation and development of Lean thinking. Relevant factors which determine the change and interact with the Lean Management method are: training, motivation, teamwork spirit, communication methods, training and motivation. An important aspect of this paper is to integrate Lean Management with Six Sigma, and with other managerial techniques leading to getting quality products at low costs

  2. Elucidating the interplay between dark current coupling and open circuit voltage in organic photovoltaics

    KAUST Repository

    Erwin, Patrick

    2011-01-01

    A short series of alkyl substituted perylenediimides (PDIs) with varying steric bulk are used to demonstrate the relationship between molecular structure, materials properties, and performance characteristics in organic photovoltaics. Devices were made with the structure indium tin oxide/copper phthalocyanine (200 Å)/PDI (200 Å)/bathocuproine (100 Å)/aluminum (1000 Å). We found that PDIs with larger substituents produced higher open circuit voltages (VOC\\'s) despite the donor acceptor interface gap (Δ EDA) remaining unchanged. Additionally, series resistance was increased simultaneously with VOC the effect of reducing short circuit current, making the addition of steric bulk a tradeoff that needs to be balanced to optimize power conversion efficiency. © 2011 American Institute of Physics.

  3. Current attitudes toward organ donation after cardiac death in northwest China

    Institute of Scientific and Technical Information of China (English)

    Pan Xiaoming; Liu Linjuan; Xiang Heli; Ding Chenguang; Ren Li; Xue Wujun

    2014-01-01

    Background People's attitude toward organ donation after cardiac death (DCD) has not come to an agreement in different countries and regions.Influenced by the local culture in China for thousands of years,the general public has different ideas about this issue.The purpose of this study was to investigate the current attitudes trend and characteristics of transplantation with organs donated after cardiac death in northwest China.Methods This largest single-center cohort study was performed by an interview or by telephone using a questionnaire.The family members of potential DCD donors were recruited from the First Affiliated Hospital,medical college of Xi'an Jiaotong University located in a metropolitan area of northwest China.The 12-item attitude questionnaire was specifically developed from the literature review with coordinator,physician,and donor's family feedback.The participants were asked to rate the queries on a 5-point Likert intensity scale.Results The 174 participants included 56 (32.2%) women and 118 (67.8%) men.Most people were aged between 41 and 50 years (n=63,36.2%),31 and 40 years (n=59,33.9%),and less than 30 years (n=36,20.7%).The top five attitudes of participants were the best person to suggest organ donation to a family was ranked as the DCD coordinator of Red Cross Organization (RCO,n=160,92%),donor is a hero (n=143,82.2%),honor to be a donor's family member (n=136,78.2%),improved relationship with colleagues (n=124,71.3%),and with recipient after donation (n=123,70.7%).The best person to suggest organ donation to a family was ranked as the coordinator of RCO (n=160,92%),doctor unrelated to transplantation (n=104,59.8%),social worker (n=36,20.7%),and doctor related to transplantation (n=25,14.4%).The top two reasons for non-consent to donation were that the family insisted on intact body after patient death and did not want to have surgery again (n=51,41.5%),and feared that they would be misunderstood by neighbors

  4. A short designed semi-aromatic organic nanotube--synthesis, chiroptical characterization, and host properties.

    Science.gov (United States)

    Wixe, Torbjörn; Christensen, Niels Johan; Lidin, Sven; Fristrup, Peter; Wärnmark, Kenneth

    2014-11-28

    The first generation of an organic nanotube based on the enantiomerically pure bicyclo[3.3.1]nonane framework is presented. The helical tube synthesised is the longest to date having its aromatic systems oriented parallel to the axis of propagation (length ∼26 Å and inner diameter ∼11 Å according to molecular dynamics simulations in chloroform). The synthesis of the tube, a heptamer, is based on a series of Friedländer condensations and the use of pyrido[3,2-d]pyrimidine units as masked 2-amino aldehydes, as a general means to propagate organic tubular structures and the introduction of a methoxy group for modification toward solubility and functionalization are described. The electronic CD spectra of the tube and molecular intermediates are correlated with theoretical spectra calculated with time-dependent density functional theory to characterize the chirality of the tube. Both experimental (NMR-titrations) and theoretical (molecular dynamics simulations) techniques are used to investigate the use of the tube as a receptor for the acetylcholine and guanidinium cations, respectively.

  5. Enhanced Enzymatic Synthesis of a Cephalosporin, Cefadroclor, in the Presence of Organic Co-solvents.

    Science.gov (United States)

    Liu, Kun; Li, Sha; Pang, Xiao; Xu, Zheng; Li, Dengchao; Xu, Hong

    2017-05-01

    In this study, we investigated the enzymatic synthesis of a semi-synthetic cephalosporin, cefadroclor, from 7-aminodesacetoxymethyl-3-chlorocephalosporanic acid (7-ACCA) and p-OH-phenylglycine methyl ester (D-HPGM) using immobilized penicillin G acylase (IPA) in organic co-solvents. Ethylene glycol (EG) was employed as a component of the reaction mixture to improve the yield of cefadroclor. EG was found to increase the yield of cefadroclor by 15-45%. An investigation of altered reaction parameters including type and concentration of organic solvents, pH of reaction media, reaction temperature, molar ratio of substrates, enzyme loading, and IPA recycling was carried out in the buffer mixture. The best result was a 76.5% conversion of 7-ACCA, which was obtained from the reaction containing 20% EG (v/v), D-HPGM to 7-ACCA molar ratio of 4:1 and pH 6.2, catalyzed by 16 IU mL(-1) IPA at 20 °C for 10 h. Under the optimum conditions, no significant loss of IPA activity was found after seven repeated reaction cycles. In addition, cefadroclor exhibited strong inhibitory activity against yeast, Bacillus subtilis NX-2, and Escherichia coli and weaker activity against Staphylococcus aureus and Pseudomonas aeruginosa. Cefadroclor is a potential antibiotic with activity against common pathogenic microorganisms.

  6. Nanoscaled palladium catalysts on activated carbon support "Sibunit" for fine organic synthesis

    Science.gov (United States)

    Simakova, I.; Koskin, A.; Deliy, I.; Simakov, A.

    2005-08-01

    The application of nanosized palladium catalysts has gained growing importance over the last few years. Palladiumbased catalytic methods for fine organic synthesis permits the replacement of traditional labor-consuming techniques in multi-step organic syntheses and provides an improvement from the standpoint of cost and environmental impact. The use of activated carbon "Sibunit" as a substrate for catalysts has been fostered by the substrate's high surface area, chemical inertness both in acidic and basic media, and at the same time by the absence of very strong acidic centers on its surface which could promote undesirable side reactions during the catalytic run. A conversion of alpha-pinene derivatives to commercial biologically active compounds and fragrances as well as sun screens with ultra violet filtering properties, involves a catalytic hydrogenation as a key intermediate step. The aim of the present work is to clarify the factors favoring the dispersion of Pd metal on carbon. The effect of reduction temperature and pretreatment of the carbon surface on metal size during preparation of Pd on "Sibunit" catalysts for selective verbenol conversion was studied. The electron microscopy method (TEM) was used to show the influence on Pd metal dispersion of carbon surface oxidation by the oxidant H2O2, HNO3. The catalytic activity of Pd/C catalyst samples in verbenol hydrogenation reaction was determined. Kinetic peculiarities of verbenol hydrogenation over the most active catalyst sample were obtained.

  7. Microwave Assisted Organic Synthesis of Heterocycles in Aqueous Media: Recent Advances in Medicinal Chemistry.

    Science.gov (United States)

    Frecentese, Francesco; Saccone, Irene; Caliendo, Giuseppe; Corvino, Angela; Fiorino, Ferdinando; Magli, Elisa; Perissutti, Elisa; Severino, Beatrice; Santagada, Vincenzo

    2016-01-01

    Green chemistry is a discipline of great interest in medicinal chemistry. It involves all fields of chemistry and it is based on the principle to conduct chemical reactions protecting the environment at the same time, through the use of chemical procedures able to avoid pollution. In this context, water as solvent is a good choice because it is abundant, nontoxic, non-caustic, and non-combustible. Even if microwave assisted organic reactions in conventional solvents have quickly progressed, in the recent years medicinal chemists have focused their attention to processes deemed not dangerous for the environment, using nanotechnology and greener solvents as water. Several reports of reaction optimizations and selectivities, demonstrating the capability of microwave to allow the obtaining of increased yields have been recently published using water as solvent. In this review, we selected the available knowledge related to microwave assisted organic synthesis in aqueous medium, furnishing examples of the newest strategies to obtain useful scaffolds and novel derivatives for medicinal chemistry purposes. The intention of this review is to demonstrate the exclusive ability of MAOS in water as solvent or as co-solvent. For this purpose we report here the most representative applications of MAOS using water as solvent, focusing on medicinal chemistry processes leading to interesting nitrogen containing heterocycles with potential pharmaceutical applications.

  8. A New Energy Source for Organic Synthesis in Europa's Surface Ice

    Science.gov (United States)

    Borucki, Jerome G.; Khare, Bishun; Cruikshank, Dale P.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    Colored regions on Jupiter's satellite Europa and other icy bodies in the outer Solar System may be contaminated by organic macromolecular solid material that is produced when surface ices are exposed to electrical energy. Hypervelocity meteorite impacts and fracture release tidal and tectonic stresses in icy crusts in the form of electrical discharges, which provide the energy for in situ synthesis of the organic solids. We report measurements of electrical discharge, light emission, and magnetic phenomena in hypervelocity impacts into ice with projectiles with V approx. 5 km/s. Part of the projectile's kinetic energy is converted into electrical potential, while the mechanical disruption of the impact also releases stress energy as light, heat, electrical, and magnetic fields as secondary emissions. These newly recognized energy sources suggest that the dark material in the area of impact craters are tholins generated from the energy of the impacts and that well up from the fracture zone. Large pools of liquid water would persist under the meteorite crater for thousands of years, with the potential for prebiotic chemistry to take place at an accelerated rate due to energy pumped in from the secondary emissions.

  9. Lipase catalyzed synthesis of organic acid esters of lactic acid in non-aqueous media.

    Science.gov (United States)

    Kiran, K R; Divakar, S

    2001-05-04

    Lipases from Rhizomucor miehei (Lipozyme IM20) and porcine pancreas (PPL) were employed as catalysts for the esterification reaction between the hydroxyl group of lactic acid and the carboxyl group of organic acids. Reactions were carried out at both shake-flask and bench-scale levels. Various parameters, such as solvent, temperature, substrate and enzyme concentrations, effect of buffer volume, buffer pH and water volume, were investigated for optimization of yields. While ethylmethyl ketone (EMK) was found to be the best solvent for shake-flask reactions, chloroform gave higher yields at bench-scale level. Detailed studies were carried out with respect to the synthesis of palmitoyl and stearoyl lactic acids. At shake-flask level, maximum yields of 37.5 and 40% were observed in case of palmitoyl and stearoyl lactic acids, respectively, with Lipozyme IM20; at bench-scale level, the maximum yields were 85.1 and 99% respectively, when PPL was employed. Of all the organic acids employed (C(2)--C(18)), only lauric, palmitic and stearic acids gave yields above 50%. At bench-scale level, PPL could be reused for up to three cycles with yields above 40%. Esters prepared were found to conform to Food Chemical Codex (FCC) specifications in terms of acid value, ester value, sodium and lactic acid contents.

  10. Organic luminescent materials. First results on synthesis and characterization of Alq{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Baldacchini, G.; Gagliardi, S.; Montereali, R.M.; Pace, A. [ENEA, Centro Ricerche Frascati, Frascati, RM (Italy). Div. Fisica Applicata; Balaji Pode, R. [Nagpur University, Nagpur (India). Dept. of Physics

    2000-07-01

    Inorganic semiconductor diodes brought a technological revolution in the field of efficient light and laser sources in the last 20 years. New development in this field are expected from organic compounds, thanks to their low cost of synthesis and the relative easiness of growth as thin films. In particular, electrically pumped luminescent devices based on organic thin layers are among the most promising systems for next generation flat panel displays and semiconductor lasers. The tris - (8-hydroxy quinoline)-aluminium complex-Alq{sub 3} - is one of the most studied electro luminescent materials. In this paper, after a short introduction regarding historical development in the field, are reported preliminary results on the growth of Alq{sub 3} films and on their optical and spectroscopic characterization. [Italian] Negli ultimi 20 anni i diodi semiconduttori hanno portato una rivoluzione tecnologica nel campo delle sorgenti luminose e laser. Un nuovo sviluppo possibile in questo campo sono i composti organici, grazie al basso costo di sintesi e la relativa facilita' di crescerli in forma di film sottile. In particolare, dispositivi luminescenti pompati elettricamente basati su film sottili di materiali organici sono promettenti per una nuova generazione di display per schermi piatti e laser a Alq{sub 3} e' uno dei materiali elettroluminescenti piu' studiati. In questo rapporto, dopo una breve introduzione sullo sviluppo storico in questo campo, presentiamo i nostri primi risultati sulla crescita e caratterizzazione ottica di film di Alq{sub 3}.

  11. A New Energy Source for Organic Synthesis in Europa's Surface Ice

    Science.gov (United States)

    Borucki, Jerome G.; Khare, Bishun; Cruikshank, Dale P.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    Colored regions on Jupiter's satellite Europa and other icy bodies in the outer Solar System may be contaminated by organic macromolecular solid material that is produced when surface ices are exposed to electrical energy. Hypervelocity meteorite impacts and fracture release tidal and tectonic stresses in icy crusts in the form of electrical discharges, which provide the energy for in situ synthesis of the organic solids. We report measurements of electrical discharge, light emission, and magnetic phenomena in hypervelocity impacts into ice with projectiles with V approx. 5 km/s. Part of the projectile's kinetic energy is converted into electrical potential, while the mechanical disruption of the impact also releases stress energy as light, heat, electrical, and magnetic fields as secondary emissions. These newly recognized energy sources suggest that the dark material in the area of impact craters are tholins generated from the energy of the impacts and that well up from the fracture zone. Large pools of liquid water would persist under the meteorite crater for thousands of years, with the potential for prebiotic chemistry to take place at an accelerated rate due to energy pumped in from the secondary emissions.

  12. Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups

    Science.gov (United States)

    Gillett-Kunnath, Miriam M.; Sevov, Slavi C.

    2012-01-01

    Although the first studies of Zintl ions date between the late 1890's and early 1930's they were not structurally characterized until many years later.1,2 Their redox chemistry is even younger, just about ten years old, but despite this short history these deltahedral clusters ions E9n- (E = Si, Ge, Sn, Pb; n = 2, 3, 4) have already shown interesting and diverse reactivity and have been at the forefront of rapidly developing and exciting new chemistry.3-6 Notable milestones are the oxidative coupling of Ge94- clusters to oligomers and infinite chains,7-19 their metallation,14-16,20-25 capping by transition-metal organometallic fragments,26-34 insertion of a transition-metal atom at the center of the cluster which is sometimes combined with capping and oligomerization,35-47 addition of main-group organometallic fragments as exo-bonded substituents,48-50 and functionalization with various organic residues by reactions with organic halides and alkynes.51-58 This latter development of attaching organic fragments directly to the clusters has opened up a new field, namely organo-Zintl chemistry, that is potentially fertile for further synthetic explorations, and it is the step-by-step procedure for the synthesis of germanium-divinyl clusters described herein. The initial steps outline the synthesis of an intermetallic precursor of K4Ge9 from which the Ge94- clusters are extracted later in solution. This involves fused-silica glass blowing, arc-welding of niobium containers, and handling of highly air-sensitive materials in a glove box. The air-sensitive K4Ge9 is then dissolved in ethylenediamine in the box and then alkenylated by a reaction with Me3SiC≡CSiMe3. The reaction is followed by electrospray mass spectrometry while the resulting solution is used for obtaining single crystals containing the functionalized clusters [H2C=CH-Ge9-CH=CH2]2-. For this purpose the solution is centrifuged, filtered, and carefully layered with a toluene solution of 18-crown-6. Left

  13. Individual and family consent to organ and tissue donation: is the current position coherent?

    Science.gov (United States)

    Wilkinson, T M

    2005-10-01

    The current position on the deceased's consent and the family's consent to organ and tissue donation from the dead is a double veto-each has the power to withhold and override the other's desire to donate. This paper raises, and to some extent answers, questions about the coherence of the double veto. It can be coherently defended in two ways: if it has the best effects and if the deceased has only negative rights of veto. Whether the double veto has better effects than other policies requires empirical investigation, which is not undertaken here. As for rights, the paper shows that it is entirely possible that individuals have a negative right of veto but no positive right to compel acceptance of their offers. Thus if intensivists and transplant teams turn down the deceased's offer, they do not thereby violate the deceased's right. This leaves it open whether non-rights based reasons-such as avoiding bad publicity or distress -require intensivists and transplant teams to turn down or accept the deceased's offer. This, however, is beyond the scope of this paper. The current position may or may not be wrong, but it is at least coherent.

  14. Can Public Managers Make Their Welfare Organizations Adapt to the New Performance Landscape Shaped by the Current Austerity?

    DEFF Research Database (Denmark)

    Pedersen, John Storm; Aagaard, Peter

    2014-01-01

    How managers try to adapt their organizations to the new performance landscape shaped by the current austerity by new forms of change management in Denmark, in the public sector of citizens with disabilities and socially disadvantaged people.......How managers try to adapt their organizations to the new performance landscape shaped by the current austerity by new forms of change management in Denmark, in the public sector of citizens with disabilities and socially disadvantaged people....

  15. Does disease-irrelevant intrathecal synthesis in multiple sclerosis make sense in the light of tertiary lymphoid organs?

    Directory of Open Access Journals (Sweden)

    Mickael eBonnan

    2014-03-01

    Full Text Available Although partly disease-irrelevant, intrathecal Ig synthesis is a typical feature of multiple sclerosis (MS and is driven by the tertiary lymphoid organs (TLO. A long-known hallmark of this non-specific intrathecal synthesis is the MRZ pattern, an intrathecal synthesis of Ig against measles, rubella and zoster viruses, which could also be involved in a wide range of pathogens. However, this non-specific synthesis is highly problematic since brain TLO should not be able to drive the clonal expansion of lymphocytes against alien antigens that are thought to be absent in MS brain.We propose to explain the paradox of non-specific intrathecal synthesis by discussing the natural properties of TLO. In fact, besides local antigen-driven clonal expansion, circulating plasmablasts and plasma cells (PC are non-specifically recruited from blood and gain access to survival niches in the inflammatory CNS. This mechanism, which has been described in other inflammatory disorders, takes place in the TLO. As a consequence, PCs recruited in brain mirror the individual’s history of immunization and intrathecal synthesis of IgG in MS may target a broad range of common infectious agents, a hypothesis in line with epidemiological data. Moreover, the immunization schedule and its timing may interfere with PC recruitment. If this hypothesis is correct, the reaction against EBV appears paradoxical: although early infection of MS patients is systematic, intrathecal synthesis is far lower than expected, suggesting a crucial interaction between MS onset and timing of EBV infection. A growing body of evidence suggests that the non-specific intrathecal synthesis observed in MS is also common in many chronic CNS inflammatory disorders. Assuming that cortical TLO in MS are associated with typical sub-pial lesions, we have coined the concept of ‘TLO-pathy’ to describe these lesions and take examples of them from non-MS disorders.

  16. Black (pyrogenic) carbon: a synthesis of current knowledge and uncertainties with special consideration of boreal regions

    Science.gov (United States)

    Preston, C. M.; Schmidt, M. W. I.

    2006-09-01

    The carbon (C) cycle in boreal regions is strongly influenced by fire, which converts biomass and detrital C mainly to gaseous forms (CO2 and smaller proportions of CO and CH4), and some 1-3% of mass to pyrogenic C (PyC). PyC is mainly produced as solid charred residues, including visually-defined charcoal, and a black carbon (BC) fraction chemically defined by its resistance to laboratory oxidation, plus much lower proportions of volatile soot and polycyclic aromatic hydrocarbons (PAHs). All PyC is characterized by fused aromatic rings, but varying in cluster sizes, and presence of other elements (N, O) and functional groups. The range of PyC structures is often described as a continuum from partially charred plant materials, to charcoal, soot and ultimately graphite which is formed by the combination of heat and pressure. There are several reasons for current interest in defining more precisely the role of PyC in the C cycle of boreal regions. First, PyC is largely resistant to decomposition, and therefore contributes to very stable C pools in soils and sediments. Second, it influences soil processes, mainly through its sorption properties and cation exchange capacity, and third, soot aerosols absorb solar radiation and may contribute to global warming. However, there are large gaps in the basic information needed to address these topics. While charcoal is commonly defined by visual criteria, analytical methods for BC are mainly based on various measures of oxidation resistance, or on yield of benzenepolycarboxylic acids. These methods are still being developed, and capture different fractions of the PyC structural continuum. There are few quantitative reports of PyC production and stocks in boreal forests (essentially none for boreal peatlands), and results are difficult to compare due to varying experimental goals and methods, as well as inconsistent terminology. There are almost no direct field measurements of BC aerosol production from boreal wildfires, and

  17. Black (pyrogenic carbon: a synthesis of current knowledge and uncertainties with special consideration of boreal regions

    Directory of Open Access Journals (Sweden)

    C. M. Preston

    2006-01-01

    Full Text Available The carbon (C cycle in boreal regions is strongly influenced by fire, which converts biomass and detrital C mainly to gaseous forms (CO2 and smaller proportions of CO and CH4, and some 1–3% of mass to pyrogenic C (PyC. PyC is mainly produced as solid charred residues, including visually-defined charcoal, and a black carbon (BC fraction chemically defined by its resistance to laboratory oxidation, plus much lower proportions of volatile soot and polycyclic aromatic hydrocarbons (PAHs. All PyC is characterized by fused aromatic rings, but varying in cluster sizes, and presence of other elements (N, O and functional groups. The range of PyC structures is often described as a continuum from partially charred plant materials, to charcoal, soot and ultimately graphite which is formed by the combination of heat and pressure. There are several reasons for current interest in defining more precisely the role of PyC in the C cycle of boreal regions. First, PyC is largely resistant to decomposition, and therefore contributes to very stable C pools in soils and sediments. Second, it influences soil processes, mainly through its sorption properties and cation exchange capacity, and third, soot aerosols absorb solar radiation and may contribute to global warming. However, there are large gaps in the basic information needed to address these topics. While charcoal is commonly defined by visual criteria, analytical methods for BC are mainly based on various measures of oxidation resistance, or on yield of benzenepolycarboxylic acids. These methods are still being developed, and capture different fractions of the PyC structural continuum. There are few quantitative reports of PyC production and stocks in boreal forests (essentially none for boreal peatlands, and results are difficult to compare due to varying experimental goals and methods, as well as inconsistent terminology. There are almost no direct field measurements of BC aerosol production from boreal

  18. Black (pyrogenic carbon in boreal forests: a synthesis of current knowledge and uncertainties

    Directory of Open Access Journals (Sweden)

    C. M. Preston

    2006-02-01

    Full Text Available The carbon (C cycle in boreal regions is strongly influenced by fire, which converts biomass and detrital C mainly to gaseous forms (CO2 and smaller proportions of CO and CH4, and some 1–7% of mass to pyrogenic C (PyC. PyC is mainly produced as solid charred residues, including visually-defined charcoal, and a black carbon (BC fraction chemically defined by its resistance to laboratory oxidation, plus much lower proportions of volatile soot and polycyclic aromatic hydrocarbons (PAHs. All PyC is characterized by fused aromatic rings, but varying in cluster sizes, and presence of other elements (N, O and functional groups. There are several reasons for current interest in defining more precisely the role of PyC in the C cycle of boreal regions. First, PyC is resistant to decomposition, and therefore contributes to very stable C pools in soils and sediments. Second, it influences soil processes, mainly through its sorption properties and cation exchange capacity, and third, soot aerosols absorb solar radiation and may contribute to global warming. However, there are large gaps in the basic information needed to address these topics. While charcoal is commonly defined by visual criteria, analytical methods for BC are mainly based on various measures of oxidation resistance, or on yield of benzenepolycarboxylic acids. These methods are still being developed, and capture different fractions of the PyC "continuum". There are few quantitative reports of PyC production and stocks in boreal forests (essentially none for boreal peatlands, and results are difficult to compare due to varying experimental goals and methods, as well as inconsistent terminology. There are almost no direct field measurements of BC aerosol production from boreal wildfires, and little direct information on rates and mechanisms for PyC loss. Structural characterization of charred biomass and forest floor from wildfires generally indicates a low level of

  19. Miller-Urey and Beyond: What Have We Learned About Prebiotic Organic Synthesis Reactions in the Past 60 Years?

    Science.gov (United States)

    McCollom, Thomas M.

    2013-05-01

    The synthesis of amino acids in the Miller-Urey spark-discharge experiments in the early 1950s inspired a strong interest in experimental studies of prebiotic organic chemistry that continues today. Over the years, many of the basic building blocks of life as we know it have been synthesized in the laboratory from simple ingredients, including amino acids, sugars, nucleobases, and membrane-forming lipids. Questions remain, however, concerning whether the conditions that allow synthesis of these compounds in the laboratory accurately simulate those that might have been present on the early Earth, and a closer convergence between plausible prebiotic conditions and laboratory simulations remains a challenge for experimentalists.

  20. Synthesis and Electrospraying of Nanoscale MOF (Metal Organic Framework) for High-Performance CO2 Adsorption Membrane

    OpenAIRE

    Wahiduzzaman,; Allmond, Kelsey; Stone, John; Harp, Spencer; Mujibur, Khan

    2017-01-01

    We report the sonochemical synthesis of MOF (metal organic framework) nanoparticles of 30–200 nm in size and electrospraying of those particles on electrospun nanofibers to process a MOF-attached nanofibrous membrane. This membrane displayed significant selectivity towards CO2 and capacity of adsorbing with 4000–5000 ppm difference from a mixed gas flow of 1% CO2 and 99% N2. Applying ultrasonic waves during the MOF synthesis offered rapid dispersion and formation of crystalline MOF nanopartic...

  1. Greening the Processes of Metal-Organic Framework Synthesis and their Use in Sustainable Catalysis.

    Science.gov (United States)

    Chen, Junying; Shen, Kui; Li, Yingwei

    2017-08-24

    Given the shortage of sustainable resources and the increasingly serious environmental issues in recent decades, the demand for clean technologies and sustainable feedstocks is of great interest to researchers worldwide. With regard to the fields of energy saving and environmental remediation, the key point is the development of efficient catalysts, not only in terms of facile synthesis methods, but also the benign utilization of such catalysts. This work reviews the use of metal-organic frameworks (MOFs) and MOF-based materials in these fields. The definition of MOFs and MOF-based materials will be primarily introduced followed by a brief description of the characterization and stability of MOF-related materials under the applied conditions. The greening of MOF synthesis processes will then be discussed and catalogued by benign solvents and conditions and green precursors of MOFs. Furthermore, their suitable application in sustainable catalysis will be summarized, focusing on several typical atom-economic reactions, such as the direct introduction of H2 or O2 and C-C bond formation. Approaches towards reducing CO2 emission by MOF-based catalysts will be described with special emphasis on CO2 fixation and CO2 reduction. In addition, driven by the explosive growth of energy consumption in the last century, much research has gone into biomass, which represents a renewable alternative to fossil fuels and a sustainable carbon feedstock for chemical production. The advanced progress of biomass-related transformations is also illustrated herein. Fundamental insights into the nature of MOF-based materials as constitutionally easily recoverable heterogeneous catalysts and as supports for various active sites is thoroughly discussed. Finally, challenges facing the development of this field and the outlook for future research are presented. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Optimized synthesis and crystalline stability of γ-cyclodextrin metal-organic frameworks for drug adsorption.

    Science.gov (United States)

    Liu, Botao; Li, Haiyan; Xu, Xiaonan; Li, Xue; Lv, Nana; Singh, Vikramjeet; Stoddart, J Fraser; York, Peter; Xu, Xu; Gref, Ruxandra; Zhang, Jiwen

    2016-11-30

    The biocompatible and renewable cyclodextrin metal-organic frameworks (CD-MOFs) have addressed a range of opportunities in molecular storage and separation sciences. The reported protocols for their synthesis, however, were carried out at room temperature over long time periods of time (24h), producing crystals of relatively poor uniformity. In this investigation, micron sized γ-CD-MOFs were synthesized by an optimized vapor diffusion method at elevated temperature (50°C) within 6h, after which the size control, crystalline stability and drug adsorption behavior were investigated in detail. In this manner, uniform cubic γ-CD-MOF crystals were obtained when the reaction temperature was raised to 50°C with pre-addition of the reaction solvent. The size of γ-CD-MOFs was adjusted efficiently by changing the reactant concentrations, temperatures, time, γ-CD ratios to KOH and surfactant concentrations, without influencing the porosity and crystallinity of the material markedly. Varing degrees of reduction in crystallinity and change in morphology were observed when the γ-CD-MOF crystals are treated under conditions of high temperature (100°C), high humidity (92.5%) and polar solvents (e.g., MeOH and DMF). In relation to drug adsorption by γ-CD-MOFs, most of the drug molecules containing carboxyl groups showed relatively high adsorption (>5%), while low adsorption (synthesis and size control of γ-CD-MOFs, the crystalline stability and drug adsorption characteristics of γ-CD-MOF crystals have been evaluated as a fundamental requirement of a potential vehicle for drug delivery.

  3. Synthesis of Thin Film Composite Metal-Organic Frameworks Membranes on Polymer Supports

    KAUST Repository

    Barankova, Eva

    2017-06-01

    Since the discovery of size-selective metal-organic frameworks (MOF) researchers have tried to manufacture them into gas separation membranes. ZIF-8 became the most studied MOF for membrane applications mainly because of its simple synthesis, good chemical and thermal stability, recent commercial availability and attractive pore size. The aim of this work is to develop convenient methods for growing ZIF thin layers on polymer supports to obtain defect-free ZIF membranes with good gas separation properties. We present new approaches for ZIF membranes preparation on polymers. We introduce zinc oxide nanoparticles in the support as a secondary metal source for ZIF-8 growth. Initially the ZnO particles were incorporated into the polymer matrix and later on the surface of the polymer by magnetron sputtering. In both cases, the ZnO facilitated to create more nucleation opportunities and improved the ZIF-8 growth compared to the synthesis without using ZnO. By employing the secondary seeded growth method, we were able to obtain thin (900 nm) ZIF-8 layer with good gas separation performance. Next, we propose a metal-chelating polymer as a suitable support for growing ZIF layers. Defect-free ZIF-8 films with a thickness of 600 nm could be obtained by a contra-diffusion method. ZIF-8 membranes were tested for permeation of hydrogen and hydrocarbons, and one of the highest selectivities reported so far for hydrogen/propane, and propylene/propane was obtained. Another promising method to facilitate the growth of MOFs on polymeric supports is the chemical functionalization of the support surface with functional groups, which can complex metal ions and which can covalently bond the MOF crystals. We functionalized the surface of a common porous polymeric membrane with amine groups, which took part in the reaction to form ZIF-8 nanocrystals. We observed an enhancement in adhesion between the ZIF layer and the support. The effect of parameters of the contra-diffusion experiment

  4. Activity of α-Chymotrypsin Enhanced in the Presence of Iron Oxide Nanoparticles in Organic Solvent: Application to Peptide Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheolwoo; Kim, Mahnjoo [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of)

    2013-03-15

    We have demonstrated that α-CT displays a significantly enhanced activity in the presence of IONs relative to its IONs-free counterparts in organic solvent. IONs-activated α-CT catalyzed efficiently the synthesis of peptides without the formation of hydrolyzed byproducts. Enzymes are a useful class of catalysts for the preparation of enantiomeric compounds. The applications of enzymes in synthetic transformations, however, are limited by their reduced activities in organic solvent. Particularly, proteases such as subtilisin and α-chymotrypsin display several orders of magnitude lower activities in organic solvent than their aqueous counterparts.

  5. Aquatic organism passage at road-stream crossings—synthesis and guidelines for effectiveness monitoring

    Science.gov (United States)

    Hoffman, Robert L.; Dunham, Jason B.; Hansen, Bruce P.

    2012-01-01

    Restoration and maintenance of passage for aquatic organisms at road-stream crossings represents a major management priority, involving an investment of hundreds of millions of dollars (for example, U.S. Government Accounting Office, 2001). In recent years, passage at hundreds of crossings has been restored, primarily by replacing barrier road culverts with bridges or stream simulation culverts designed to pass all species and all life stages of aquatic life and simulate natural hydro-geomorphic processes (U.S. Forest Service, 2008). The current situation has motivated two general questions: 1. Are current design standards for stream simulation culverts adequately re-establishing passage for aquatic biota? and 2. How do we monitor and evaluate effectiveness of passage restoration? To address the latter question, a national workshop was held in March 2010, in Portland, Oregon. The workshop included experts on aquatic organism passage from across the nation (see table of participants, APPENDIX) who addressed four classes of methods for monitoring effectiveness of aquatic organism passage—individual movement, occupancy, demography, and genetics. This report has been written, in part, for field biologists who will be undertaking and evaluating the effectiveness of aquatic organism passage restoration projects at road-stream crossings. The report outlines basic methods for evaluating road-stream crossing passage impairment and restoration and discusses under what circumstances and conditions each method will be useful; what questions each method can potentially answer; how to design and implement an evaluation study; and points out the fundamental reality that most evaluation projects will require special funding and partnerships among researchers and resource managers. The report is organized into the following sections, which can be read independently: 1. Historical context: In this section, we provide a brief history of events leading up to the present situation

  6. Evaluation of ink-jet printed current collecting grids and bushbars for ITO-free organic solar cells

    NARCIS (Netherlands)

    Galagan, Y.O.; Coenen, E,W.C.; Sabik, S.; Gorter, H.H.; Barink, M.; Veenstra, S.C.; Kroon, J.M.; Andriessen, H.A.J.M.; Blom, P.W.M.

    2012-01-01

    ITO-free organic solar cells with ink-jet printed current collecting grids and high conducting PEDOT:PSS as composite anode are demonstrated. Inkjet printed current collecting grids with different cross-sectional are as have been investigated. The effect of the width and height of the gridlines and

  7. Evaluation of ink-jet printed current collecting grids and bushbars for ITO-free organic solar cells

    NARCIS (Netherlands)

    Galagan, Y.O.; Coenen, E,W.C.; Sabik, S.; Gorter, H.H.; Barink, M.; Veenstra, S.C.; Kroon, J.M.; Andriessen, H.A.J.M.; Blom, P.W.M.

    2012-01-01

    ITO-free organic solar cells with ink-jet printed current collecting grids and high conducting PEDOT:PSS as composite anode are demonstrated. Inkjet printed current collecting grids with different cross-sectional are as have been investigated. The effect of the width and height of the gridlines and

  8. Anchoring of Cu(II) onto surface of porous metal-organic framework through post-synthesis modification for the synthesis of benzimidazoles and benzothiazoles

    Energy Technology Data Exchange (ETDEWEB)

    Kardanpour, Reihaneh; Tangestaninejad, Shahram, E-mail: stanges@sci.ui.ac.ir; Mirkhani, Valiollah, E-mail: mirkhani@sci.ui.ac.ir; Moghadam, Majid, E-mail: moghadamm@sci.ui.ac.ir; Mohammadpoor-Baltork, Iraj; Zadehahmadi, Farnaz

    2016-03-15

    Efficient synthesis of various benzimidazoles and benzothiazoles under mild conditions catalyzed by Cu(II) anchored onto UiO-66–NH{sub 2} metal organic framework is reported. In this manner, first, the aminated UiO-66 was modified with thiophene-2-carbaldehyde and then the prepared Schiff base was reacted with CuCl{sub 2}. The prepared catalyst was characterized by FT-IR, UV–vis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N{sub 2} adsorption, inductively coupled plasma atomic emission spectroscopy (ICP-AES) and field emission scanning electron microscopy (FE-SEM). The UiO-66–NH{sub 2}–TC–Cu was applied as a highly efficient catalyst for synthesis of benzimidazole and benzothiazole derivatives by the reaction of aldehydes with 1,2-diaminobenzene or 2-aminothiophenol. The Cu(II)-containing MOF was reused several times without any appreciable loss of its efficiency. - Graphical abstract: Efficient synthesis of benzimidazoles and benzothiazoles catalyzed by Cu(II) anchored onto UiO-66–NH{sub 2} metal organic framework is reported. - Highlights: • A copper Schiff base was immobilized on UiO-66 via postsynthetic modification. • The modified MOFs were fully characterized by a variety of methods. • The catalyst was used for the preparation of benzimidazoles and benzothiazoles. • In comparison of other catalysts, our catalyst was more efficient and forceful.

  9. Synthesis of Frontalin, the Aggregation Pheromone of the Southern Pine Beetle: A Multistep Organic Synthesis for Undergraduate Students.

    Science.gov (United States)

    Bartlett, Paul A.; And Others

    1984-01-01

    Background information and experimental procedures are provided for the multistep synthesis of frontalin. The experiment exposes students to a range of practical laboratory problems and important synthetic reactions and provides experiences in working on a medium-size, as well as a relatively small-size scale. (JN)

  10. Current EU-27 technical potential of organic waste streams for biogas and energy production.

    Science.gov (United States)

    Lorenz, Helge; Fischer, Peter; Schumacher, Britt; Adler, Philipp

    2013-11-01

    Anaerobic digestion of organic waste generated by households, businesses, agriculture, and industry is an important approach as method of waste treatment - especially with regard to its potential as an alternative energy source and its cost-effectiveness. Separate collection of biowaste from households or vegetal waste from public green spaces is already established in some EU-27 countries. The material recovery in composting plants is common for biowaste and vegetal waste. Brewery waste fractions generated by beer production are often used for animal feeding after a suitable preparation. Waste streams from paper industry generated by pulp and paper production such as black liquor or paper sludge are often highly contaminated with toxic substances. Recovery of chemicals and the use in thermal processes like incineration, pyrolysis, and gasification are typical utilization paths. The current utilization of organic waste from households and institutions (without agricultural waste) was investigated for EU-27 countries with Germany as an in-depth example. Besides of biowaste little is known about the suitability of waste streams from brewery and paper industry for anaerobic digestion. Therefore, an evaluation of the most important biogas process parameters for different substrates was carried out, in order to calculate the biogas utilization potential of these waste quantities. Furthermore, a calculation of biogas energy potentials was carried out for defined waste fractions which are most suitable for anaerobic digestion. Up to 1% of the primary energy demand can be covered by the calculated total biogas energy potential. By using a "best-practice-scenario" for separately collected biowaste, the coverage of primary energy demand may be increased above 2% for several countries. By using sector-specific waste streams, for example the German paper industry could cover up to 4.7% and the German brewery industry up to 71.2% of its total energy demand.

  11. Baylis-Hillman acetates in organic synthesis: convenient one-pot synthesis of α-carboline framework--a concise synthesis of neocryptolepine.

    Science.gov (United States)

    Basavaiah, Deevi; Mallikarjuna Reddy, Daggula

    2012-11-28

    A convenient, facile, and one-pot methodology for the synthesis of α-carbolines from Baylis-Hillman (BH) acetates, involving three steps (reactions), (1) mono alkylation of 2-nitroarylacetonitriles with BH-acetates, (2) reduction of nitro group into amino group using Fe/AcOH and (3) formation of two (five and six membered) rings, is presented. This methodology is successfully applied to the synthesis of bioactive alkaloid neocryptolepine.

  12. The first one-pot synthesis of metal-organic frameworks functionalised with two transition-metal complexes.

    Science.gov (United States)

    Platero-Prats, Ana E; Bermejo Gómez, Antonio; Samain, Louise; Zou, Xiaodong; Martín-Matute, Belén

    2015-01-07

    The synthesis of a metal-organic framework (UiO-67) functionalised simultaneously with two different transition metal complexes (Ir and Pd or Rh) through a one-pot procedure is reported for the first time. This has been achieved by an iterative modification of the synthesis parameters combined with characterisation of the resulting materials using different techniques, including X-ray absorption spectroscopy (XAS). The method also allows the first synthesis of UiO-67 with a very wide range of loadings (from 4 to 43 mol %) of an iridium complex ([IrCp*(bpydc)(Cl)Cl](2-) ; bpydc=2,2'-bipyridine-5,5'-dicarboxylate, Cp*=pentamethylcyclopentadienyl) through a pre-functionalisation methodology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Anchoring of Cu(II) onto surface of porous metal-organic framework through post-synthesis modification for the synthesis of benzimidazoles and benzothiazoles

    Science.gov (United States)

    Kardanpour, Reihaneh; Tangestaninejad, Shahram; Mirkhani, Valiollah; Moghadam, Majid; Mohammadpoor-Baltork, Iraj; Zadehahmadi, Farnaz

    2016-03-01

    Efficient synthesis of various benzimidazoles and benzothiazoles under mild conditions catalyzed by Cu(II) anchored onto UiO-66-NH2 metal organic framework is reported. In this manner, first, the aminated UiO-66 was modified with thiophene-2-carbaldehyde and then the prepared Schiff base was reacted with CuCl2. The prepared catalyst was characterized by FT-IR, UV-vis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption, inductively coupled plasma atomic emission spectroscopy (ICP-AES) and field emission scanning electron microscopy (FE-SEM). The UiO-66-NH2-TC-Cu was applied as a highly efficient catalyst for synthesis of benzimidazole and benzothiazole derivatives by the reaction of aldehydes with 1,2-diaminobenzene or 2-aminothiophenol. The Cu(II)-containing MOF was reused several times without any appreciable loss of its efficiency.

  14. One-pot green synthesis of zinc oxide nano rice and its application as sonocatalyst for degradation of organic dye and synthesis of 2-benzimidazole derivatives

    Science.gov (United States)

    Paul, Bappi; Vadivel, Sethumathavan; Dhar, Siddhartha Sankar; Debbarma, Shyama; Kumaravel, M.

    2017-05-01

    In this paper, we report novel and green approach for one-pot biosynthesis of zinc oxide (ZnO) nanoparticles (NPs). Highly stable and hexagonal phase ZnO nanoparticles were synthesized using seeds extract from the tender pods of Parkia roxburghii and characterized by XRD, FT-IR, EDX, TEM, and N2 adsorption-desorption (BET) studies. The present method of synthesis of ZnO NPs is very efficient and cost effective. The powder XRD pattern furnished evidence for the formation of hexagonal close packing structure of ZnO NPs having average crystallite size 25.6 nm. The TEM image reveals rice shapes ZnO NPs are with an average diameter of 40-60 nm. The as-synthesized ZnO NPs has proved to be an excellent sonocatalysts for degradation of organic dye and synthesis of 2-benzimidazole derivatives.

  15. Forum for Arctic Modeling and Observational Synthesis (FAMOS): Past, current, and future activities

    Science.gov (United States)

    Proshutinsky, A.; Steele, M.; Timmermans, M.-L.

    2016-06-01

    The overall goal of the Forum for Arctic Modeling and Observational Synthesis (FAMOS) community activities reported in this special issue is to enhance understanding of processes and mechanisms driving Arctic Ocean marine and sea ice changes, and the consequences of those changes especially in biogeochemical and ecosystem studies. Major 2013-2015 FAMOS accomplishments to date are: identification of consistent errors across Arctic regional models; approaches to reduce these errors, and recommendations for the most effective coupled sea ice-ocean models for use in fully coupled regional and global climate models. 2013-2015 FAMOS coordinated analyses include many process studies, using models together with observations to investigate: dynamics and mechanisms responsible for drift, deformation and thermodynamics of sea ice; pathways and mechanisms driving variability of the Atlantic, Pacific and river waters in the Arctic Ocean; processes of freshwater accumulation and release in the Beaufort Gyre; the fate of melt water from Greenland; characteristics of ocean eddies; biogeochemistry and ecosystem processes and change, climate variability, and predictability. Future FAMOS collaborations will focus on employing models and conducting observations at high and very high spatial and temporal resolution to investigate the role of subgrid-scale processes in regional Arctic Ocean and coupled ice-ocean and atmosphere-ice-ocean models.

  16. Highly efficient synthesis of endomorphin-2 under thermodynamic control catalyzed by organic solvent stable proteases with in situ product removal.

    Science.gov (United States)

    Xu, Jiaxing; Sun, Honglin; He, Xuejun; Bai, Zhongzhong; He, Bingfang

    2013-02-01

    An efficient enzymatic synthesis of endomorphin-2 (EM-2) was achieved using organic solvent stable proteases in nonaqeous media, based on thermodynamic control and an in situ product removal methodology. The high stability of biocatalysts in organic solvents enabled the aleatoric modulation of the nonaqueous reaction media to shift thermodynamic equilibrium toward synthesis. Peptide Boc-Phe-Phe-NH2 was synthesized with a high yield of 96% by the solvent stable protease WQ9-2 in monophase medium with an economical molar ratio of the substrate of 1:1. The tetrapeptide Boc-Tyr-Pro-Phe-Phe-NH2 was synthesized with a yield of 88% by another organic solvent tolerant protease PT121 from Boc-Tyr-Pro-OH and Phe-Phe-NH2 in an organic-aqueous biphasic system. The reaction-separation coupling in both enzymatic processes provides "driving forces" for the synthetic reactions and gives a high yield and high productivity without purification of the intermediate, thereby making the synthesis more amenable to scale-up. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Specimen banking of marine organisms in the United States: current status and long-term prospective.

    Science.gov (United States)

    Becker, P R; Wise, S A; Thorsteinson, L; Koster, B J; Rowles, T

    1997-05-01

    A major part of the activities conducted over the last decade by the National Biomonitoring Specimen Bank (NBSB) has involved the archival of marine specimens collected by ongoing environmental monitoring programs. These archived specimens include bivalves, marine sediments, and fish tissues collected by the National Status and Trends and the Exxon Valdez Oil Spill Damage Assessment programs, and marine mammal tissues collected by the Marine Mammal Health and Stranding, Response Program and the Alaska Marine Mammal Tissue Archival Project. In addition to supporting these programs, the specimens have been used to investigate circumpolar patterns of chlorinated hydrocarbon concentrations, genetic separation of marine animal stocks, baseline levels of essential and nonessential elements in marine mammals, and the potential risk to human consumers in the Arctic from anthropogenic contaminants found in local subsistence foods. The NBSB specimens represent a resource that has the potential for addressing future issues of marine environmental quality and ecosystem changes through retrospective analysis; however, an ecosystem-based food web approach would maximize this potential. The current status of the NBSB activities related to the banking of marine organisms is presented and discussed, the long-term prospective of these activities is presented, and the importance of an ecosystem-based food web monitoring approach to the value of specimen banking is discussed.

  18. Current Status and Regulatory Aspects of Pesticides Considered to be Persistent Organic Pollutants (POPs) in Taiwan

    Science.gov (United States)

    Tsai, Wen-Tien

    2010-01-01

    Organochlorine pesticides (OCPs) are capable of persisting in the environment, transporting between phase media and accumulating to high levels, implying that they could pose a risk of causing adverse effects to human health and the environment. Consequently, most OCPs are designated as persistent organic pollutants (POPs) and even as endocrine disrupting chemicals (EDCs). The objective of this paper was to review the current status of pesticide POPs in Taiwan, including aldrin, chlordane, chlordecone, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene, α/β-hexachlorocyclohexanes, lindane, mirex, pentachloro-benzene, and toxaphene. The information about their environmental properties, banned use, carcinogenic toxicity and environmental levels, can be connected with the regulatory infrastructure, which has been established by the joint-venture of the central competent authorities (i.e., Environmental Protection Administration, Department of Health, Council of Agriculture, and Council of Labor Affairs). The significant progress to be reported is that the residual levels of these pesticide-POPs, ranging from trace amounts to a few ppb, have declined notably in recent years. PMID:21139852

  19. Current Status and Regulatory Aspects of Pesticides Considered to be Persistent Organic Pollutants (POPs in Taiwan

    Directory of Open Access Journals (Sweden)

    Wen-Tien Tsai

    2010-10-01

    Full Text Available Organochlorine pesticides (OCPs are capable of persisting in the environment, transporting between phase media and accumulating to high levels, implying that they could pose a risk of causing adverse effects to human health and the environment. Consequently, most OCPs are designated as persistent organic pollutants (POPs and even as endocrine disrupting chemicals (EDCs. The objective of this paper was to review the current status of pesticide POPs in Taiwan, including aldrin, chlordane, chlordecone, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene, α/β-hexachlorocyclohexanes, lindane, mirex, pentachloro-benzene, and toxaphene. The information about their environmental properties, banned use, carcinogenic toxicity and environmental levels, can be connected with the regulatory infrastructure, which has been established by the joint-venture of the central competent authorities (i.e., Environmental Protection Administration, Department of Health, Council of Agriculture, and Council of Labor Affairs. The significant progress to be reported is that the residual levels of these pesticide-POPs, ranging from trace amounts to a few ppb, have declined notably in recent years.

  20. Specimen banking of marine organisms in the United States: Current status and long-term prospective

    Science.gov (United States)

    Becker, P.R.; Wise, S.A.; Thorsteinson, L.; Koster, B.J.; Rowles, T.

    1997-01-01

    A major part of the activities conducted over the last decade by the National Biomonitoring Specimen Bank (NBSB) has involved the archival of marine specimens collected by ongoing environmental monitoring programs. These archived specimens include bivalves, marine sediments, and fish tissues collected by the National Status and Trends and the Exxon Valdez Oil Spill Damage Assessment programs, and marine mammal tissues collected by the Marine Mammal Health and Stranding Response Program and the Alaska Marine Mammal Tissue Archival Project. In addition to supporting these programs, the specimens have been used to investigate circumpolar patterns of chlorinated hydrocarbon concentrations, genetic separation of marine animal stocks, baseline levels of essential and nonessential elements in marine mammals, and the potential risk to human consumers in the Arctic from anthropogenic contaminants found in local subsistence foods. The NBSB specimens represent a resource that has the potential for addressing future issues of marine environmental quality and ecosystem changes through retrospective analysis; however, an ecosystem-based food web approach would maximize this potential. The current status of the NBSB activities related to the banking of marine organisms is presented and discussed, the long-term prospective of these activities is presented, and the importance of an ecosystem-based food web monitoring approach to the value of specimen banking is discussed.