for curious readers:
Our research is focused on molecular switches and machines in the field of molecular nanosciences. About 100 scientists from chemistry, physics, materials sciences, and pharmacy collaborate in an interdisciplinary way. On these pages we provide scientists, corporations, media, teachers and students with information on our research as well as our progress.
Most technical functional units are built bit by bit according to a well-designed construction plan. The components are sequentially put in place by humans or machines. Life, however, is based on a different principle. It starts bottom-up with molecular self-assembly. The crystallization of sugar or salt are simple examples of self-assembly processes, where almost perfect crystals form from molecules that randomly move in a solution. To better understand the growth of macroscopic structures from molecules, a research team of physicists and chemists of Kiel University has mimicked such processes with custom-made molecules. As recently reported in the journal Angewandte Chemie they fabricated a variety of patterns over a wide range of sizes including the largest structures reported so far.
Today, there is a great effort to scale down magnetic memory towards nanometer-sized bits in order to ultimately store information in a single magnetic atom. This makes it necessary to image magnetic properties on the atomic scale. At the heart of magnetism is the exchange interaction – proposed by Werner Heisenberg in 1926 based on quantum mechanics – which aligns the “bar magnets” of single atoms. Utilizing a novel type of microscope allowing to measure forces and currents on magnetic surfaces and first-principles quantum mechanical calculations, scientists from Nijmegen and Kiel have now reported on ultra-high magnetic resolution of a magnetic spiral structure and quantification of exchange interactions at the atomic scale. Their joint work is published in the renowned journal Nature Communications..
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. To do so, they have to be placed on surfaces, which is challenging without damaging their ability to save the information. A research team from Kiel University has now not only managed to successfully place a new class of spin-crossover molecules onto a surface, but they have also used interactions which were previously regarded as obstructive to improve the molecule’s storage capacity.
Plenty of publications report on the conductance of molecular wires between electrodes. Characterization of the junction geometry, however, is usually missing. We synthesized a molecule for low-temperature STM experiments that stands vertically on a substrate. Despite this reductionist approach, its conductance data turned out to be complex. Calculations show that geometrical changes, orbital symmetries, and bond formation control the conductance. This joint work within SFB677 by Torben Jasper-Tönnies, Aran Garcia-Lekue, Thomas Frederiksen, Sandra Ulrich, Rainer Herges, and Richard Berndt has recently been published in Physical Review Letters and highlighted as Editors' Selection.
At the meeting of the condensed matter division of the German Physical Society Dr. Guillaume Schull will be awarded the Gaede Preis 2017 for the work performed in the Berndt group. Dr. Guillaume Schull will receive the award for his groundbreaking experimental studies on electrical cantacts to single molecules as well as light emission from such contacts.
Although Yong-Feng Wang left Kiel University five years ago the cooperation with the colleagues from the SFB 677 and the group of Professor Richard Berndt at the Institute of Experimental and Applied Physics still continues. Most recently a joint paper about the vacuum synthesis was published as a cover story of the journal Chemical Communications. Since 2006 Wang worked as a postdoc in the group of Professor Berndt and was involved in numerous publications. 2012 Wang went to Peking University, by now he leads a group at the Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics himself.
This video deals with the synthesis of functional or “smart”polymers at the WG Staubitz. These interesting polymers respond to an external stimulus by changing their properties reversibly. Stimuli can be for example light or mechanical force. Such polymers can be used for interesting applications, which are investigated within the Collaborative Research Center 677, which is called “Function by switching”, at Kiel University.
This applied research is part of the second movie "Nanoscale switches for memorizing polymers" of the WG Adelung. The obtained "smart" polymers are used to indicate mechanical stress. In this way the failure of composite materials can be predicted.
During the recent meeting of the condensed matter division of the German Physical Society Dr. Manuel Gruber successfully competed for the PhD thesis prize of the magnetism division (ThyssenKrupp Electrical Steel PhD prize).
Photochemically driven molecular switches are extremely fast: Typically, the switching movement is finished in just 1 picosecond (10‑12 s). To understand molecular switching mechanisms, it is therefore necessary to observe them on a time scale of femtoseconds (10‑15 s). Experimentally, this can be done with modern methods of ultrafast spectroscopy, as applied in the working group of Professor Friedrich Temps. In a complementary approach, the molecular switching dynamics is simulated theoretically in the working group of Professor Bernd Hartke.
On September 19, Dr. Mehdi Keshavarz Hedayati was presented with the Young Scientist Award of the the DGM (Deutsche Gesellschaft für Materialkunde). Dr. Hedayati has successfully worked on project C01 for several years.
Interpreting electron transport through molecular junctions lies in the broad interest of understanding nanoscale junctions, which are sensitive to both physical and chemical parameters. In a Letter recently published in Physical Review, Sujoy Karan, and colleagues from the group of Professor Richard Berndt, the Max-Planck-Institut für Mikrostrukturphysik and the Universities of Hamburg and Würzburg report how the electrostatic potential is distributed across a junction comprising single molecules coupled to macroscopic electrodes. Contacting a porphyrin molecule on gold in a low-temperature scanning tunneling microscope, they showed a way to utilize a sharp spectral feature to obtain information on the local potential of the molecule. The paper is featured in APS Physics.
Great excitement at Kiel University: As the DFG (German Research Foundation) announced on May 21, it will continue to support the research on molecules which function like machines with another 8.9 million EUR. The scientists in Germany's northernmost state develop new engineering techniques to build tiny machine-like molecules over the next four years. This ultimate miniaturisation of engineering functions should improve the efficiency of energy conversion systems, medicines, diagnostic methods and materials. Moreover, completely new areas of applications will open up along this line. The Collaborative Research Center 677 (SFB 677) "Function by Switching" now starts into the third and final funding period. Collaborative Research Centers are supported for a maximum of twelve years. They are highly competitive and prestigious flagship institutions at German universities. In total, around 100 scientists from the fields of chemistry, physics, material sciences and medicine collaborate in this Kiel research network.
The shootings in the working groups of the Collaborative Research Center 677 were worthwile: The first three videos of the six part series, which is created in collaboration with the “Beilstein-Institut zur Förderung der Chemischen Wissenschaften”, can now be watched online. They give insights into the fascinating research on antifreeze proteins, molecular data storage and anticancer drugs.
“Fixation of spin crossover complexes on surfaces” is the title of the video from the working group of Professor Felix Tuczek. Building smaller storage devices is a big challenge in industry and calls for innovation. In the podcast, Tuczek and his team show an approach from the design, synthesis of novel transition metal complexes to the fixation of these molecular switches on gold surfaces.
The film „Switchable Antifreeze Proteins“ from the working group of Professor Frank Sönnichsen is about a mechanism, which lets plants, insects, bacteria and fish survive in extreme cold. The proteins responsible for that are the area of interest of the Sönnichsen group. The film shows how they try to decode the relation between the structure and the functions of AFP, a protein that can be found in Arctic Flounders. Moreover, the project wants to make AFP switchable.
Along with the third funding period of SFB677 comes a new research project: the third video “Photoswitchable protein kinase Inhibitors for novel anti-cancer applications“ covers Professor Christian Pfeifer and his team’s plan to create photoswitchable protein kinase inhibitors, which will be designed to be employed in novel cancer drugs.
Collaborative Research Center (SFB) 677 “Function by Switching” and Kiel Nano, Surface and Interface Science (KiNSIS) take the interested public on a fascinating journey through time in Kiel University’s 350th birthday year. Their multimedia exposition shows the scientific and technical highlights in research from the past, the present and dares to look ahead to the future. “-100 / today / +100” is a concept of the Leibniz Institute for Science and Mathematics Education (IPN).
Antifreeze proteins, mechanophoric dyes, molecular data storage: These were the main actors in the second part of the video podcast shooting beside the staff of Collaborative Research Center 677’s working groups. Overall, six short films were shot in collaboration with the “Beilstein-Institut zur Förderung der Chemischen Wissenschaften”.
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