Institute of Organic Chemistry

Kiev, Ukraine

Institute of Organic Chemistry

Kiev, Ukraine
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News Article | April 17, 2017
Site: phys.org

By applying 'green chemistry' techniques, Russian researchers say they can use plant biomass to produce industrial quantities of a basic ingredient, or 'platform chemical', for useful pharmaceutical compounds. The researchers have used the platform chemical to manufacture model products that include, for example, a stomach antacid. There is potential for far more. The chemical, 5-hydroxymethylfurfural (5-HMF), is under research in several fields of chemistry and appears poised to be a building block for a new generation of organic synthesis procedures. The new process is attractive because it neutralises carbon, which contributes to global climate change. The source material, plant biomass, draws in carbon through natural photosynthesis. The new process then converts this biomass to 5-HMF. Then the starter molecule is further processed to make other chemicals with uses in organic chemistry, materials science, biofuels and pharmaceutical drugs. Using environmentally sustainable processes to synthesize commercial molecules costs less and creates less waste than traditional chemical manufacturing methods. Synthesizing a kilogram of a drug using traditional chemical methods creates anywhere from 30 to 100 kilograms of waste byproducts, many of them toxic. Making 5-HMF using green chemistry creates only water as a byproduct. Researchers at the Zelinsky Institute of Organic Chemistry say that older, oil-based forms of 5-HMF decompose very quickly, a deal breaker for large-scale industrial use. Many platform chemicals are oils, but oilbased 5-HMF has an unusual problem. With as few as 1 to 3% impurities, it oxidizes and degrades badly in less than a month. The degraded feedstock reduces refining efficiency, increases waste and drastically cuts yields of the desired product. Repurifying it is not cost effective. The researchers developed a catalysed process to make a crystalline solid form of 5-HMF that is cleaner than the oil-based version—around 99.9% pure—and doesn't degrade. They did this by continually evaporating water from the surface of the biomass during the reaction. This caused the ionized liquid still in the system to form what the researchers call nanostructured water compartments. These aided efficient catalysis and prevented impurities, resulting in a stable form of the chemical that gives much higher yields in model reactions. The researchers are now working to develop further efficient green processes to produce pharmaceuticals and drug molecules directly from biomass. Explore further: Scientists harness solar power to produce clean hydrogen from biomass


News Article | December 21, 2016
Site: www.nanotech-now.com

Abstract: Nanotechnology offers many chances to benefit the environment and health. It can be applied to save raw materials and energy, develop enhanced solar cells and more efficient rechargeable batteries and replace harmful substances with eco-compatible solutions. "Nanotechnology is a seminal technology. The UMWELTnanoTECH project association has delivered excellent results. Even the smallest achievements can make a huge contribution to protecting the environment. We must treat the opportunities this future technology offers with responsibility; its eco-compatible use has top priority," said the Bavarian Minister of the Environment, Ulrike Scharf, in Erlangen on 23 November 2016 where the results were presented at the international congress "Next Generation Solar Energy Meets Nanotechnology". For three years, the Bavarian State Ministry for the Environment and Consumer Protection had financed the association consisting of ten individual projects with around three million euros. Three Würzburg projects Three of the ten projects were located in Würzburg. Professor Vladimir Dyakonov from the Department of Physics headed the project for environmentally compatible, highly efficient organic solar cells; he was also the spokesman of the "Organic Photovoltaics" section. Anke Krüger, Professor of Chemistry, was in charge of the project on ultra-fast electrical stores based on nano-diamond composites. Responsibility for the third project rested with Professor Gerhard Sextl, Head of the Fraunhofer Institute for Silicate Research titled "Hybrid capacitors for smart grids and regenerative energy technologies". Sextl, who holds the Chair for Chemical Technology of Material Synthesis at the Julius-Maximilians-Universität (JMU) Würzburg, was also the spokesman of the "Energy storage" section. Below are the three projects from Würzburg and their results. Eco-friendly inks for organic solar cells Organic solar cells have become quite efficient, converting about eleven percent of the solar energy received into electricity. What is more, they are relatively easy to manufacture using ink-jet printing processes where organic nanoparticles are deposited on non-elastic or flexible carrier materials with the help of solvents. This enables new applications in architecture, for example integrating solar cells in window façades or cladding concave surfaces. There is, however, a catch to it: So far, most ink-jet printing processes have been based on toxic solvents such as dichlorobenzene. These substances are harmful for humans and the environment and require extensive and costly standards of safety. The Professors Vladimir Dyakonov and Christoph Brabec (University of Erlangen-Nuremberg) have managed to use nanomaterials to develop ecologically compatible photovoltaic inks based on water or alcohol with equal efficiency. Moreover, the research team has developed new simulation processes: "They allow us to predict which combinations of solvents and materials are suitable for the eco-friendly production of organic solar cells," Dyakonov explains. Nanodiamonds for ultra-fast electrical storage In order to build highly efficient electric cars, more powerful energy stores are needed as the standard batteries still have some drawbacks, including low cycle stability and very limited power density. The first means that the battery capacity decreases following multiple charging and discharging cycles. The latter implies that only a fraction of the energy store is used during fast charging or discharging. Supercapacitors play an important role as highly efficient energy stores besides batteries, because they outperform rechargeable batteries in terms of cycle stability and power density. Their energy density, however, is much lower compared with lithium-ion batteries. This is why supercapacitors need to be much bigger in size than batteries in order to deliver comparable amounts of energy. Professor Anke Krüger has teamed up with Dr Gudrun Reichenauer from the Bavarian Center for Applied Energy Research (ZAE Bayern) to make progress in this regard. Their idea was to build the supercapacitors' electrodes not only of active charcoal, but to modify them using other carbon materials, namely nanodiamonds and carbon onions, which are small particles that have multiple layers like an onion. Their approach is promising: By combining nanomaterials with suitable electrolytes, the performance parameters of the supercapacitors can be boosted. "Based on these findings, it is now possible to build application-oriented energy stores and test their applicability," Krüger further. Increased storage capacity of hybrid capacitors More efficient and faster energy stores were also the research focus of Professor Gerhard Sextl's project. His research team at the University of Würzburg managed to develop so-called hybrid capacitors further into highly efficient energy stores that can be manufactured in an environmentally compatible process. Hybrid capacitors are a combination of supercapacitors based on electrochemical double-layer capacitors and charge storage in a battery. Firstly, they are capable of storing energy quickly by forming an electrochemical double layer as in a supercapacitor and also deliver the energy promptly when it is needed. Secondly, they hold more energy due to lithium ions embedded in an active battery material, analogously to lithium-ion batteries. By combining the two storage mechanisms, it is possible to implement systems with a high energy and power density at low costs. The electrodes are the heart of the hybrid capacitors. They are coated with modified active materials: lithium iron phosphate and lithium titanate. This allows achieving storage capacities which are twice as high as those relying on conventional supercapacitor electrode materials. "We have managed to develop a material that combines the advantages of both systems. This has brought us one step closer to implementing a new, fast and reliable storage concept," Sextl says. The activities at the university were supported by the Fraunhofer Institute for Silicate Research in Würzburg, one of the leading battery research centres in Germany. For more information, please click Contacts: Dr. Esther Knemeyer Pereira 49-931-318-6002 Eco-friendly inks for organic solar cells Prof. Dr. Vladimir Dyakonov Department of Physics University of Würzburg T +49 931 31-83111 Nanodiamonds for ultra-fast electrical storage Prof. Dr. Anke Krueger Institute of Organic Chemistry University of Würzburg T +49 931 31-85334 Increased storage capacity of hybrid capacitors Prof. Dr. Gerhard Sextl Department for Chemical Technology of Material Synthesis University of Würzburg and Fraunhofer Institute for Silicate Research ISC T +49 931 4100-100 If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


Home > Press > How copper makes organic light-emitting diodes more efficient: KIT researchers measure intersystem crossing directly in a thermally activated delayed fluorescence copper complex -- publication in Science Advances Abstract: Use of copper as a fluorescent material allows for the manufacture of inexpensive and environmentally compatible organic light-emitting diodes (OLEDs). Thermally activated delayed fuorescence (TADF) ensures high light yield. Scientists of Karlsruhe Institute of Technology (KIT), CYNORA, and the University of St Andrews have now measured the underlying quantum mechanics phenomenon of intersystem crossing in a copper complex. The results of this fundamental work are reported in the Science Advances journal and contribute to enhancing the energy efficiency of OLEDs. Organic light-emitting diodes are deemed tomorrow's source of light. They homogeneously emit light in all observation directions and produce brilliant colors and high contrasts. As it is also possible to manufacture transparent and flexible OLEDs, new application and design options result, such as flat light sources on window panes or displays that can be rolled up. OLEDs consist of ultra-thin layers of organic materials, which serve as emitter and are located between two electrodes. When voltage is applied, electrons from the cathode and holes (positive charges) from the anode are injected into the emitter, where they form electron-hole pairs. These so-called excitons are quasiparticles in the excited state. When they decay into their initial state again, they release energy. Excitons may assume two different states: Singlet excitons decay immediately and emit light, whereas triplet excitons release their energy in the form of heat. Usually, 25 percent singlets and 75 percent triplets are encountered in OLEDs. To enhance energy efficiency of an OLED, also triplet excitons have to be used to generate light. In conventional light-emitting diodes heavy metals, such as iridium and platinum, are added for this purpose. But these materials are expensive, have a limited availability, and require complex OLED production methods. It is cheaper and environmentally more compatible to use copper complexes as emitter materials. Thermally activated delayed fluorescence (TADF) ensures high light yields and, hence, high efficiency: Triplet excitons are transformed into singlet excitons which then emit photons. TADF is based on the quantum mechanics phenomenon of intersystem crossing (ISC), a transition from one electronic excitation state to another one of changed multiplicity, i.e. from singlet to triplet or vice versa. In organic molecules, this process is determined by spin-orbit coupling. This is the interaction of the orbital angular momentum of an electron in an atom with the spin of the electron. In this way, all excitons, triplets and singlets, can be used for the generation of light. With TADF, copper luminescent material reaches an efficiency of 100 percent. Stefan Bräse and Larissa Bergmann of KIT's Institute of Organic Chemistry (IOC), in cooperation with researchers of the OLED technology company CYNORA and the University of St Andrews, United Kingdom, for the first time measured the speed of intersystem crossing in a highly luminescent, thermally activated delayed fluorescence copper(I) complex in the solid state. The results are reported in the Science Advances journal. The scientists determined a time constant of intersystem crossing from singlet to triplet of 27 picoseconds (27 trillionths of a second). The reverse process - reverse intersystem crossing - from triplet to singlet is slower and leads to a TADF lasting for an average of 11.5 microseconds. These measurements improve the understanding of mechanisms leading to TADF and facilitate the specific development of TADF materials for energy-efficient OLEDs. About Karlsruhe Institute of Technology (KIT) Karlsruhe Institute of Technology (KIT) pools its three core tasks of research, higher education, and innovation in a mission. With about 9,400 employees and 24,500 students, KIT is one of the big institutions of research and higher education in natural sciences and engineering in Europe. KIT - The Research University in the Helmholtz Association Since 2010, the KIT has been certified as a family-friendly university. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | January 8, 2016
Site: phys.org

Thanks to knowledge of their quantum mechanics, dyes can be customized for use in organic light-emitting diodes. Use of copper as a fluorescent material allows for the manufacture of inexpensive and environmentally compatible organic light-emitting diodes (OLEDs). Thermally activated delayed fuorescence (TADF) ensures high light yield. Scientists of Karlsruhe Institute of Technology (KIT), CYNORA, and the University of St Andrews have now measured the underlying quantum mechanics phenomenon of intersystem crossing in a copper complex. The results of this fundamental work are reported in the Science Advances journal and contribute to enhancing the energy efficiency of OLEDs. Organic light-emitting diodes are deemed tomorrow's source of light. They homogeneously emit light in all observation directions and produce brilliant colors and high contrasts. As it is also possible to manufacture transparent and flexible OLEDs, new application and design options result, such as flat light sources on window panes or displays that can be rolled up. OLEDs consist of ultra-thin layers of organic materials, which serve as emitter and are located between two electrodes. When voltage is applied, electrons from the cathode and holes (positive charges) from the anode are injected into the emitter, where they form electron-hole pairs. These so-called excitons are quasiparticles in the excited state. When they decay into their initial state again, they release energy. Excitons may assume two different states: Singlet excitons decay immediately and emit light, whereas triplet excitons release their energy in the form of heat. Usually, 25 percent singlets and 75 percent triplets are encountered in OLEDs. To enhance energy efficiency of an OLED, also triplet excitons have to be used to generate light. In conventional light-emitting diodes heavy metals, such as iridium and platinum, are added for this purpose. But these materials are expensive, have a limited availability, and require complex OLED production methods. It is cheaper and environmentally more compatible to use copper complexes as emitter materials. Thermally activated delayed fluorescence (TADF) ensures high light yields and, hence, high efficiency: Triplet excitons are transformed into singlet excitons which then emit photons. TADF is based on the quantum mechanics phenomenon of intersystem crossing (ISC), a transition from one electronic excitation state to another one of changed multiplicity, i.e. from singlet to triplet or vice versa. In organic molecules, this process is determined by spin-orbit coupling. This is the interaction of the orbital angular momentum of an electron in an atom with the spin of the electron. In this way, all excitons, triplets and singlets, can be used for the generation of light. With TADF, copper luminescent material reaches an efficiency of 100 percent. Stefan Bräse and Larissa Bergmann of KIT's Institute of Organic Chemistry (IOC), in cooperation with researchers of the OLED technology company CYNORA and the University of St Andrews, United Kingdom, for the first time measured the speed of intersystem crossing in a highly luminescent, thermally activated delayed fluorescence copper(I) complex in the solid state. The results are reported in the Science Advances journal. The scientists determined a time constant of intersystem crossing from singlet to triplet of 27 picoseconds (27 trillionths of a second). The reverse process – reverse intersystem crossing – from triplet to singlet is slower and leads to a TADF lasting for an average of 11.5 microseconds. These measurements improve the understanding of mechanisms leading to TADF and facilitate the specific development of TADF materials for energy-efficient OLEDs. Explore further: Color of OLEDs can now at last be predicted thanks to new modeling technique More information: L. Bergmann et al. Direct observation of intersystem crossing in a thermally activated delayed fluorescence copper complex in the solid state, Science Advances (2016). DOI: 10.1126/sciadv.1500889


News Article | January 14, 2016
Site: www.rdmag.com

Use of copper as a fluorescent material allows for the manufacture of inexpensive and environmentally compatible organic light-emitting diodes (OLEDs). Thermally activated delayed fuorescence (TADF) ensures high light yield. Scientists of Karlsruhe Institute of Technology (KIT), CYNORA, and the University of St Andrews have now measured the underlying quantum mechanics phenomenon of intersystem crossing in a copper complex. The results of this fundamental work are reported in the Science Advances journal and contribute to enhancing the energy efficiency of OLEDs. Organic light-emitting diodes are deemed tomorrow's source of light. They homogeneously emit light in all observation directions and produce brilliant colors and high contrasts. As it is also possible to manufacture transparent and flexible OLEDs, new application and design options result, such as flat light sources on window panes or displays that can be rolled up. OLEDs consist of ultra-thin layers of organic materials, which serve as emitter and are located between two electrodes. When voltage is applied, electrons from the cathode and holes (positive charges) from the anode are injected into the emitter, where they form electron-hole pairs. These so-called excitons are quasiparticles in the excited state. When they decay into their initial state again, they release energy. Excitons may assume two different states: Singlet excitons decay immediately and emit light, whereas triplet excitons release their energy in the form of heat. Usually, 25 percent singlets and 75 percent triplets are encountered in OLEDs. To enhance energy efficiency of an OLED, also triplet excitons have to be used to generate light. In conventional light-emitting diodes heavy metals, such as iridium and platinum, are added for this purpose. But these materials are expensive, have a limited availability, and require complex OLED production methods. It is cheaper and environmentally more compatible to use copper complexes as emitter materials. Thermally activated delayed fluorescence (TADF) ensures high light yields and, hence, high efficiency: Triplet excitons are transformed into singlet excitons which then emit photons. TADF is based on the quantum mechanics phenomenon of intersystem crossing (ISC), a transition from one electronic excitation state to another one of changed multiplicity, i.e. from singlet to triplet or vice versa. In organic molecules, this process is determined by spin-orbit coupling. This is the interaction of the orbital angular momentum of an electron in an atom with the spin of the electron. In this way, all excitons, triplets and singlets, can be used for the generation of light. With TADF, copper luminescent material reaches an efficiency of 100 percent. Stefan Bräse and Larissa Bergmann of KIT's Institute of Organic Chemistry (IOC), in cooperation with researchers of the OLED technology company CYNORA and the University of St Andrews, United Kingdom, for the first time measured the speed of intersystem crossing in a highly luminescent, thermally activated delayed fluorescence copper(I) complex in the solid state. The results are reported in the Science Advances journal. The scientists determined a time constant of intersystem crossing from singlet to triplet of 27 picoseconds (27 trillionths of a second). The reverse process - reverse intersystem crossing - from triplet to singlet is slower and leads to a TADF lasting for an average of 11.5 microseconds. These measurements improve the understanding of mechanisms leading to TADF and facilitate the specific development of TADF materials for energy-efficient OLEDs.


News Article | December 28, 2016
Site: www.cemag.us

Researchers of Karlsruhe Institute of Technology (KIT) and Universität Hannover developed novel membranes, whose selectivity can be switched dynamically with the help of light. For this purpose, azobenzene molecules were integrated into membranes made of metal-organic frameworks (MOFs). Depending on the irradiation wavelength, these azobenzene units in the MOFs adopt a stretched or angular form. In this way, it is possible to dynamically adjust the permeability of the membrane and the separation factor of gases or liquids. The results are reported in Nature Communications. Metal-organic frameworks, MOFs for short, are highly porous crystalline materials, consisting of metallic nodes and organic linkers. They can be tailored to many different applications. Among others, they have an enormous potential as membranes for efficient separation of molecules according to various parameters. By modifying pore sizes and chemical properties of the pore walls, static selectivity of the membranes can be adapted to the respective requirements. In Nature Communications the scientists for the first time present membranes, whose selectivities can be tuned dynamically. This is done remotely with the help of light. Researchers of KIT’s Institute of Functional Interfaces (IFG) and Institute of Organic Chemistry (IOC), in cooperation with scientists of Leibniz Universität Hannover, equipped MOF-based membranes with photoswitches. “In this way, the membranes are provided with minute windows that open and close depending on light irradiation,“ the Head of the Institute of Functional Interfaces, Professor Christof Wöll, explains. Azobenzene molecules are used as remote-controlled photoswitches. They consist of two phenyl rings each, which are linked by a nitrogen double bond. Two different configurations exist: A stretched trans-configuration and an angular cis-configuration. Irradiation with light causes the molecule to reposition. Under visible light the molecule stretches, under UV light it bends. Repositioning is reversible, can be repeated as often as desired, and does not affect the crystalline structure of the MOFs. Precise control of the ratio between cis- and trans-azobenzene by e.g. a precisely adjusted irradiation time or simultaneous irradiation with UV light and visible light enables dynamic tuning of membrane permeability and of separation efficiency of gaseous or liquid substance mixtures. “Control of these important properties by external stimuli, i.e. without having direct contact with the membrane, is a real breakthrough in membrane technology “, says Dr. Lars Heinke, Head of the IFG Group ”Dynamic Processes in Porous Systems.“ Functioning of the novel smart membranes was demonstrated by the separation of a hydrogen-carbon dioxide gas mixture. The scientists succeeded in dynamically tuning the separation factor between three and eight. The concept is also suited for separating other gas mixtures, such as nitrogen-carbon dioxide mixtures. It might also be feasible to use MOF membranes with photoswitches to control accessibility of catalyst or sensor surfaces or release of encapsulated medical substances.


News Article | April 25, 2016
Site: cen.acs.org

They are also set to benefit from a new policy that liberalizes the transfer of technology from universities and institutes to companies and shifts from basic research to practical applications. The new technology transfer policy could have a greater impact on chemistry in China than the expected funding increase, observers say. The changes come after the conclusion in March of China’s annual parliament, the National People’s Congress (NPC), in Beijing. This is a transitional year for China as it moves from the 12th to the 13th five-year plan, which covers 2016–20. In these five-year plans, the Chinese government maps out how it will develop the country socially and economically, an approach China adopted from the Soviet Union in the 1950s. The newest plan includes a push for major breakthroughs in basic research, applied research, big data, and what the government calls “exploring frontiers,” which involves disciplines such as marine science. Speaking at NPC, Wang Yuanhong, senior economist from the State Information Center, explained how the government is increasing the ratio of deficit to gross domestic product to provide an additional $72 billion to spend on pro-growth measures. This includes setting up national-level efforts to boost research and innovation as China looks to science to fuel its slowing economy. The government estimates that scientific research will account for 60% of economic growth by 2020. During a news conference at NPC, Minister for Science & Technology Wan Gang confirmed that China will continue to increase research funding. Spending on R&D has increased by an annual average of 11.4% from 2012 to 2015 and will reach 2.5% of gross domestic product by 2020, up from 2.1% in 2015. Wan said overall R&D expenditure in China in 2015 amounted to $215 billion, 77% of which came from companies. Of that figure, $10.3 billion went to basic science, according to a summary from China’s National Bureau of Statistics that was released in advance of the full figures, which have not yet been made public. Yu Biao, vice director of Shanghai Institute of Organic Chemistry and director of State Key Laboratory of Bioorganic & Natural Products Chemistry, tells C&EN that work to address issues of health, energy, and climate change are important and reflect the Chinese government’s support of applied chemistry research. But he predicts that “it will be difficult to secure support for pure chemistry [research] and publishing papers.” Jay Siegel, dean of Tianjin University’s School of Pharmaceutical Science & Technology, agrees. “China is not a country that at this moment places a heavy importance on very basic research,” he says. “It wants to move toward basic science, but it’s a country that sees technology as a way to drive its economy in the next five years.” Yu foresees a strengthening of the relationship between basic and applied research in China. “The inherent mode of research is going to undergo a transformation,” he says. “Interdisciplinary and practical research will receive encouragement and vigorous support.” Chemists will need to consider focusing on problems in these areas of science. China’s government wants to make research outcomes more easily available to small businesses as well as big enterprises as part of its “Made in China 2025” policies aimed at boosting the economy. National research institutes and universities will be able to sell their intellectual property to businesses without needing national-level approval, which has previously involved lengthy waits. All profits earned on the sales will now be kept by the institutes where the research was conducted. New incentives aimed at researchers themselves may further speed up the commercialization of scientific research in China. At least 50% of the proceeds from the sale of findings will go to the researchers themselves. They will be able to work for the companies that buy their research for up to three years while maintaining their positions at the institute where they did the research. It is hoped that this will encourage greater productivity. Gao Xudong, deputy director of the Research Center for Technological Innovation at Tsinghua University, told People’s Daily, the official newspaper of the Chinese Communist Party, that this change should also resolve a fundamental issue: “Some enterprises who bought scientific research findings could not fully use them due to a lack of understanding of the findings.” In light of the increasing push to transfer technology to industry, Tianjin University in 2013 opened China’s first national center for patent and intellectual property. The Tianjin University Technology Transfer Center now has 18 full-time patent brokers who work on moving technology from the university to industry. “Passing greater autonomy to universities and cutting the red tape on the reporting for grants involving science and technology is a very big thing because, in general, funds have been very controlled. So if we see policies that allow for more entrepreneurial ventures within the university—your degree programs, new directions for research—that the university can control, then we get bottom-up control. This will have a big impact on research in general, and chemistry is poised to benefit enormously,” Siegel says.


News Article | December 20, 2016
Site: phys.org

Irradiation with green light from below induces a vibration of the signalling molecules (RGD). This mechanical stimulus causes the cells to adhere to the surface. Credit: Rainer Herges Everyone is made up of approximately 100 trillion cells – if they were laid end to end, they would circle the globe 60 times. Most of these cells arise from mitosis and differentiation of a single egg cell. To orientate themselves, they constantly explore their environment and communicate with their neighbours while they adhere to other cells or surfaces. Two working groups from the fields of chemistry and biophysics at Kiel University have discovered a new method for stimulating cells, thereby increasing their adhesion. The results now appear in the renowned journal Angewandte Chemie. Cells are permanently under attack by bacteria that are attempting to infiltrate them. By contrast, useful bacteria aid digestion or live peacefully on human skin. Cells must communicate continuously and probe their environment to identify friend or foe, or to differentiate themselves from their neighbouring cells. This is why they seek out direct contact with other cells or to their environment. 'If individual cells are floating in a solution and encounter a surface, they first probe the area to determine whether it is a suitable location to settle. If this is the case, they extend protein sensors to attach themselves. Other cells follow suit, which creates cellular tissue,' explains Rainer Herges, professor at the Institute of Organic Chemistry. Cells adhere faster if they are stimulated Research has long shown that cells respond selectively to certain surface structures and their chemical composition. There are indications that, in addition to static stimuli, dynamic processes such as movements and mechanical forces also have an attracting effect on cells. If, for example, a fine needle is used to tug at cells, this stimulates them to increase their adhesion. 'However, this is not a very subtle, controlled method, since a large number of different cellular processes are affected,' reports Christine Selhuber-Unkel, professor for biocompatible nanomaterials at the Institute for Materials Science at Kiel University. The method that Selhuber-Unkel and Herges now have discovered for stimulating cells is much more sophisticated. They bind chemical recognition structures (so-called RGDs), which are recognised by cells, to surfaces. However, these signalling molecules do not stand stiff on the surface; instead, they can be moved with light. Tiny molecular switches are incorporated into the tether that binds the RGDs to the surfaces. These molecules bend back and forth approximately 1,000 times per second when they are irradiated with green light. 'This vibration is transferred to the RGDs, which in turn "pluck" at the cells. The cells appear to perceive this type of stimulation: they adhere faster and more strongly to the surface,' explains Selhuber-Unkel. This adhesion strength is measured using an atomic force microscope. The fact that there is increased production of adhesion proteins also indicates that the cells react to this stimulus. The discovery by the researchers in Kiel could trigger a multitude of potential applications. The molecular vibrators can be directly incorporated into cell membranes, which would allow cells to be controlled with light. 'Use of light as a type of "nanoscalpel" is also conceivable in the long-term; light could be employed to perform extremely precise, microscopic, surgical interventions', Herges continues. Research on how to use light to indirectly stimulate cells via molecular switches has been a topic at the Collaborative Research Centre 677 'Function by Switching' since several years. 'Using light for stimulation has a number of advantages. Firstly, it can be switched on and off in a controlled way,' explains Herges, the head of the SFB. 'Moreover, using a laser cells can be irradiated with a resolution of 300 nanometres to detect which areas on the cell are responsible for adhesion. Thereby, we can elucidate the mechanisms of cellular adhesion.' Interdisciplinary cooperation was initiated by the framework of the CRC 677. Michelle Holz and Grace Suana from Rainer Herges' working group in the organic chemistry institute synthesised the switching molecules and surfaces. Laith F. Kadem from Christine Selhuber-Unkel's working group conducted the cell experiments. More information: Laith F. Kadem et al. High-Frequency Mechanostimulation of Cell Adhesion, Angewandte Chemie International Edition (2016). DOI: 10.1002/anie.201609483


Ramos L.,Institute of Organic Chemistry
Journal of Chromatography A | Year: 2012

Sample preparation procedures in use in many application areas are still tedious and manually intensive protocols. These characteristics mean that sample treatment is considered the most time-consuming and error-prone part of the analytical scheme. The increasing demand for faster, more cost-effective and environmental friendly analytical methods is a major incentive to improve these conventional procedures and has spurred research in this field during the last decades. This review provides an overview of the most relevant developments and successful approaches proposed in recent years concerning sample preparation. The current state-of-the-art is discussed on the basis of examples selected from representative application areas and involving conventional instrumental techniques for the final determination of the target compounds. Emphasis will be on those techniques and approaches that have already demonstrated their practicality by the analysis of real-life samples, and in particular on those dealing with the determination of minor organic components. The potential of the latest developments in this field for sample treatment simplification and complete hyphenation and integration of analytical process is discussed and the most pressing remaining limitations evaluated. © 2011 Elsevier B.V.


News Article | October 26, 2016
Site: www.newscientist.com

FIZZZZZZZ…smoulder…BANG!!! If there’s only one thing you remember from chemistry lessons, it’s probably watching the violent, spectacular reaction that occurs when you drop a chunk of sodium or potassium in water. Now, chemists have found a way to slow down this reaction, but the show is even more spectacular: the ball of metal whizzes around and vividly changes colour as it moves through half a dozen stages before the final explosion. Pavel Jungwirth of the Institute of Organic Chemistry and Biochemistry in Prague, the Czech Republic, and his colleagues were inspired to investigate after noticing a momentary blue flash in the conventional reaction. They suspected it was an intermediate stage of the reaction in which clusters of electrons from the metal are surrounded by water molecules. “We wanted to take a spectral reading of the ‘blue flash’ we noticed during the explosions to prove it came from solvated electrons, and also to see them with the naked eye, and for this we needed to slow it down,” he says. Jungwirth and his colleagues made an alloy containing sodium and potassium, which is liquid at room temperature, and lowered this gently onto the water surface instead of the usual practice of dropping it in. The liquid alloy is easier to handle than the traditional pure metal solid, says Jungwirth. The video above shows what happens. At first, the blob of alloy gently circulates on the water surface. Then the blob turns blue as the electrons interact with water – exactly what the team wanted to see. Next the bluish-turquoise colour becomes more intense as the increasing heat of the reaction makes some metal evaporate. From blue, the blob turns bright red, marking the formation of sodium and potassium hydroxide, glowing red hot at 600 °C, and discharging smoke that contains the hydrogen gas formed during the reaction. Then, to the amazement of the chemists, the blob becomes completely transparent. It turns out to be liquid hydroxide, buoyed up at the surface instead of sinking thanks to a film of water vapour directly beneath. Finally, the drop of hydroxide cools down, goes black, loses its cushion of vapour and explodes through direct contact with the water. “The whole thing typically takes a few seconds, maybe three or four,” says Jungwirth. It’s also safer than the classic experiment because the entire reaction takes place under inert argon gas rather than air, preventing any hydrogen bubbling off from exploding or catching fire. The argon also serves to clear out any smoke that would otherwise obscure the view, although it should be possible to perform the updated experiment without resorting to the gas. This extra safety precaution  means there’s a chance pupils might see it at school in future, says Jungwirth. “What we’re showing is that high-school experiments can be done more safely and elegantly, and with the right explanation,” he says.

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