(Deutsch) Professor Robert Schlögl erhält Ehrentitel der TU München

Thursday, 13th April 2017Preise und Auszeichnungen

Sorry, this entry is only available in German.


(Deutsch) Maschinelles Lernen erobert die klassischen Naturwissenschaften

Wednesday, 25th January 2017Publication highlights

Sorry, this entry is only available in German.


Gerard Meijer decorated as a Knight of the Order of the Netherlands Lion

Monday, 16th January 2017Preise und Auszeichnungen

GM_Radoboud_Farewell2For his exceptional achievements as President of the Executive Board of Radboud University, Gerard Meijer was knighted on the occasion of his farewell ceremony.

The university states in a press release:

“Under the presidency of Gerard Meijer, Radboud University has celebrated many successes. Researchers at the University received no less than five Spinoza Prizes—the highest scientific distinction in the Netherlands. Three Gravitation Programmes with Nijmegen consortium leadership were awarded. With the Radboud Excellence Initiative, an idea of Gerard Meijer, international scientific talent from all over the world was attracted to Nijmegen.

Throughout his tenure, the University was annually named the Best Comprehensive University in the Netherlands, most recently receiving the honour for the sixth consecutive year. The campus was made even more beautiful with the new Faculty of Law building and the purchase of the Berchmanianum. He achieved success for the joint Dutch Universities in his dealings with publishers in the field of open access, which enabled free access to scientific articles for everyone.”

Read the full press release here.

 

 

 



Free-electron laser allows scientists to observe a molecular ball bearing

Tuesday, 3rd January 2017Miscellaneous
Graduate students Matias Fagiani (left) and Sreekanta Debnath (right) in front of the undulator of the free-electron laser at the Fritz Haber Institute.

Graduate students Matias Fagiani (left) and Sreekanta Debnath (right) in front of the undulator of the free-electron laser at the Fritz Haber Institute.

The free-electron laser (FEL) at the Fritz Haber Institute (FHI) generates intense pulses of infrared radiation of widely tunable wavelength. Unlike conventional lasers, where the radiation is produced in a gas, liquid, or solid, in an FEL it is generated by an electron beam propagating freely through a vacuum tube. In a device called undulator (Fig. 1),strong magnetic fields of alternating polarity force the electrons on a wiggling (undulating) motion, thereby causing the emission of radiation. The radiation wavelength can be tuned simply by varying the electron energy or the magnetic field strength. Before entering the undulator, however, the electrons need to be accelerated to almost the speed of light, requiring a complex electron accelerator. Since 2013 such an installation has been operational at the Fritz Haber Institute.

In collaboration with scientists from the Wilhelm Ostwald Institute for Physical und Theoretical Chemistry (Leipzig University) and from the Institute for Optics und Atomic Physics (Technical University Berlin) the FEL radiation has been applied to investigate a very special molecular system, the boron cluster B13+. It was known previously that 13 boron atoms can form a highly stable compound, referred to as a magic cluster. It is a planar system composed of two concentric rings; an inner B3-ring and an outer B10-ring (see Fig. 2). The key feature is that the system is very stable but not rigid. Previously, Thomas Heine (Theoretical Chemistry, Leipzig) and his coworkers predicted that it is possible for the rings to rotate like a ball bearing with no detrimental effect on the stability of the system. Pairs of electrons serve as the bearing’s balls, enabling the inner and outer rings to counter rotate effectively free of friction.titelbild_en_png

The group of Knut Asmis (Physical Chemistry, Leipzig), jointly with André Fielicke (TU Berlin), succeeded to prepare a single-isotope form of this very special boron system. And application of the FHI FEL radiation provided evidence for its concentric ring structure and also for the predicted rotational motion. The intense and tunable IR radiation from the FEL made it possible to measure the vibrational spectrum of B13+, revealing a fingerprint of the possible motions within the cluster. The spectrum exhibits clear evidence for the quasi rotation of the two rings.

Wieland Schöllkopf, who is heading the FHI FEL facility, points out that these results could not have been achieved with a conventional laser source. Hence, it represents another impressive example of possible applications of FEL radiation. Furthermore, demonstrating a molecular ball bearing consisting of just 13 atoms presents another example from the young and exciting research field of “Molecular Machines”, the development of which was just awarded by the 2016 Nobel Prize in Chemistry.

Publication:

Structure and Fluxionality of B13+ Probed by Infrared Photodissociation Spectroscopy
M.R. Fagiani, X. Song, P. Petkov, S. Debnath, S. Gewinner, W. Schöllkopf, T. Heine, A. Fielicke, K.R. Asmis
Angew. Chem. Int. Ed., 56, 501–504, (2017)


(Deutsch) EMIL am Synchrotron BESSY II eingeweiht

Tuesday, 8th November 2016Miscellaneous

Sorry, this entry is only available in German.


Molecular Stew Analysis produces World´s First Description of Amyloid Intermediate Structures

Tuesday, 27th September 2016Publication highlights

Scientists of Freie Universität and Max Planck Society succeed in world´s first structural analysis of aggregates believed to be cause of Alzheimer´s disease

Prof. Dr. Kevin Pagel and Dr. Gert von Helden, © Sven Jungtow

Prof. Dr. Kevin Pagel and Dr. Gert von Helden, © Sven Jungtow

Scientists of Freie Universität Berlin und the Fritz Haber Institute of the Max Planck Society made a major step forward in analyzing the biochemical causes of Alzheimer´s and Parkinson´s disease. The results of Prof. Kevin Pagel and Dr. Gert von Helden´s work could enable the development of new medications fighting the causes of both diseases. Their research was published in the current issue of Nature Chemistry.

Alzheimer´s disease is the most common form of dementia, predominantly in the age group of 65-85 years. There are currently 48 million known patients with Alzheimer´s disease worldwide. This number is expected to double by 2050.

The causes of neurodegenerative diseases like Parkinson´s and Alzheimer´s disease are not fully understood to this day. In both cases, a biochemical disorder can be observed during the course of the disease, but the exact mechanism is unknown. Water-soluble proteins undergo a spontaneous transition into insoluble amyloid fibrils. In the case of Alzheimer´s disease, protein fragments that the body can normally easily dispose accumulate to abnormal species called amyloid plaques, which are deposited outside the neurons and slowly degenerate the brain.

Recent research showed that these plaques are an effect, but not the cause of Alzheimer´s disease. Instead, scientists focus more and more on the issue of what causes the deadly plaque accumulation and why exactly the harmless water-soluble Jekyll proteins turn into the dangerous, insoluble Hyde fibrils. There is  increasing evidence that the disease-causing factor is a toxic intermediate that occurs during the aggregation into fibrils, but analyzing the exact structure of these intermediates was an unresolvable problem, resembling the children´s birthday party game of blind man´s bluff. From the perspective of a researcher, the toxic intermediates are not nicely separated species, but present themselves as parts of a stew with unknown ingredients. The research on pharmaceutically active compounds was, therefore, often more or less trial and error up to now. This problem has now been solved by the research of the scientists of Freie Universität and the Fritz Haber Institute.
For the first time the research groups around assistant professor Dr. Kevin Pagel and Dr. Gert von Helden succeeded in developing a method to exactly analyze and describe the toxic intermediates believed to be triggering the disease on a molecular level. They succeeded in separately analyzing each individual ingredient of the stew and specifically describing their structure. Based on this basic research, other scientists can now start developing specific compounds to neutralize the intermediates causing Alzheimer´s disease.

Kevin Pagel and Gert van Helden achieved this using a trick: they combined two elaborate methods. Each method alone is incapable of solving a part of the problem, but combined they did the trick. The first method is ion-mobility spectrometry, which can best be described as a molecular wind tunnel, which separates the intermediates according to their drag coefficient. This method, however, only provides information about the size and shape, but not the molecular structure producing the drag. To shed light on this problem, however, the scientists additionally used gas-phase-infrared spectroscopy. Using this combination of methods, the researchers discovered specific intermediates that closely resemble the structure of the mature Hyde fibrils that are present in deadly amyloid plaques. With the newly developed method, other researchers can now test new medications to specifically tackle the emergence of Alzheimer´s disease.

Contact:

  • Dr. Kevin Pagel, Institut für Chemie und Biochemie der Freien Universität Berlin, Takustraße 3, 14195 Berlin und Fritz-Haber-Institut der Max-Planck-Gesellschaft, Abteilung Molekülphysik, Faradayweg 4–6, 14195 Berlin, Telefon: +49 (0)30 – 838 – 72703 (Freie Universität Berlin)/ +49 (0)30 – 8413 – 5646 (Fritz-Haber-Institut), E-Mail: kevin.pagel@fu-berlin.de, im Internet: www.bcp.fu-berlin.de/chemie/pagel
  • Gert von Helden, Fritz Haber-Institut der Max-Planck-Gesellschaft, Abteilung Molekülphysik, Faradayweg 4-6, 14195 Berlin, Telefon +49 (0)30-8413 – 5615, E-Mail: helden@fhi-berlin.mpg.de, im Internet: http://www.fhi-berlin.mpg.de/mp/helden/

Original publication:
Seo, J.; Hoffmann, W.; Warnke, S.; Huang, X.; Gewinner, S.; Schöllkopf, W.; Bowers, M.T.;von Helden, G.; and Pagel, K.
An Infrared Spectroscopy Approach to Follow β-Sheet Formation in Peptide Amyloid Assemblies
Nature Chemistry 2016, doi: 10.1038/NCHEM.2615


Julia Stähler gets Edith Flanigan Award 2016

Wednesday, 14th September 2016Preise und Auszeichnungen

The Humboldt University of Berlin announced: “We are pleased to announce that the winner of the Edith Flanigen Award 2016 is Dr. A. Julia Stähler, Fritz Haber Institute of the Max Planck Society, Berlin”.

The Edith Flanigen Award is conferred annually by the CRC 1109 to an exceptional female scientist at an early stage of her career (postdoctoral fellow, junior researcher) for outstanding results on metal oxide water systems. It is associated with a financial support of 15.000 Euro, one third of which represents a personal award, while the other two thirds are meant to enable research stays within the surroundings of the CRC thus establishing collaborative links.

This years award ceremony is taking place at the 6th of October.

Go to the HU page.



Pushing a single-molecule switch

Monday, 11th July 2016Publication highlights
(Top) Single porphycene molecule imaged at 5 K with a scanning tunneling microscope. The white star in the left indicates the position where the force-induced switching can occur by bringing the tip to the molecule. (Bottom) Chemical structure of porphycene. The molecule switches between two states through intramolecular hydrogen-atom transfer as indicated by the curved arrows.

(Top) Single porphycene molecule imaged at 5 K with a scanning tunneling microscope. The white star in the left indicates the position where the force-induced switching can occur by bringing the tip to the molecule.
(Bottom) Chemical structure of porphycene. The molecule switches between two states through intramolecular hydrogen-atom transfer as indicated by the curved arrows.

One finds switches everywhere in our modern life, and everyone knows the force that is needed to push them, for example, to turn on a room light from a wall switch—the force from one’s finger is enough. But, how does one push and how much force does one need to apply if the switch were dramatically scaled down to the “Nano-world”, for example, to push a “single-molecule switch” at nano-meter (10-9 m) scale. This “extremely small” question is related not only to basic science but also to potential future technological application of molecular devices. Researchers at Fritz-Haber Institute of the Max-Planck Society, Berlin, together with colleagues in Poland (Warsaw), Spain (San Sebastian) and the UK (Liverpool), have succeeded in operating a single-molecule switch and measuring the force needed to activate it by using a state-of-the-art scanning probe microscope. They found that only a very tiny force, fraction of a nano-Newton (10-9 Newton), was required to switch a single molecule.

The researchers discovered that about 1 nm-size organic molecule (porphycene) attached on a metal surface can be switched with an atomically-sharp metallic tip of a scanning probe microscope (whose very apex has a single atom and sometimes called an “atomic-scale finger”). The molecule changes between two states through an intramolecular hydrogen atom transfer, a so-called tautomerization that is important in nature, which can be triggered by “pushing” the molecule with the sharp tip. The experiments could not only quantify the forces but also revealed that switching can be induced at a very specific position within a single molecule, with a spatial resolution of about 0.02 nm which is less than a typical chemical bond length (about 0.1 nm). Furthermore, the researchers found that the switching mechanism cannot be rationalized by a pure “mechanical” force because switching could not be induced even if a sufficient force was applied, when the tip apex was decorated by a single xenon atom—a chemically inert rare gas that lacks a chemical reactivity. This result indicates that the chemical force (interaction) between the tip apex atom and molecule plays a crucial role in the reaction.

(Top) Artwork of the experiment. (Bottom) Measured force curve during tip approach and retraction.

(Top) Artwork of the experiment.
(Bottom) Measured force curve during tip approach and retraction.

The research team in Spain and UK carried out extensive first principle calculations by using a supercomputer to elucidate the force-induced tautomerization mechanism. From the simulation the researchers found that the force-induced reaction resembles an activation step in a catalytic reaction rather than pure mechanical activation. The researchers believe that the results may also provide a microscopic insight into complex catalytic processes with a fresh perspective, leading to a new method to control chemistry at the atomic level.

Nanoscale molecular devices are a fascinating future application, in which individual functionalized molecules behave as an independent element based on their physical/chemical properties. The research team demonstrated a novel way to operate a molecular switch which should play a central role in such devices. The researcher at Fritz-Haber Institute, who conceived the experiment, believes that our approach will make it possible not only to operate various types of molecular switches, but also to construct “Rube Goldberg machine” from single molecules since the “atomic-scale finger” of a scanning tunneling microscope also allows us to manipulate single atoms and molecules one by one.

Contact address

Dr. Takashi Kumagai
Research group leader
Fritz-Haber Institute of the Max-Planck Society
Department of Physical Chemistry
Email: kuma@fhi-berlin.mpg.de
Web: http://www.fhi-berlin.mpg.de/pc/kumagai/
Tel.: +49 (0)30 8413 5110

Publication

Force-induced tautomerization in a single molecule
Ladenthin et al. Nature Chemistry (http://dx.doi.org/10.1038/nchem.2552)

Please read the Japanese version here.