The world of chemistry has witnessed another step forward: researchers at the University of Würzburg in Germany have succeeded in twisting molecules so much that their double bonds have been completely destroyed. The result: unusually stable biradicals.
Boron has a range of uses throughout everyday life, from laundry bleaches to heat-proof glass and ceramics. Chemists at Julius-Maximilians-Universität Würzburg (JMU) in Bavaria, Germany, have a particular interest in the chemistry this element, and have been researching the fundamental properties of boron for years. These researchers have now succeeded in twisting molecules with multiple bonds between boron atoms, leading to unusually stable biradicals.
Biradicals are usually highly reactive molecules. They are generated in energetic processes such as combustion and are normally so short-lived that they are unable to be isolated or studied by traditional methods of chemical analysis.
The new biradicals prepared at the JMU are dramatically different, however: they are solid compounds and were found to be stable for weeks. "We now have model compounds in hand that we can study without having to rush", explains Prof. Holger Braunschweig from the Institute for Inorganic Chemistry. The results have been presented in the journal Nature Communications.
Twisting of boron-boron double bonds
For a long time, chemists have attempted to twist, distort and rupture double bonds between atoms – with only limited success. The JMU team has now made the dream of twisting a double bond by a full 90 degrees a reality.
The Würzburg researchers had originally expected to obtain diborenes from their reactions: the products should have had double bonds between their boron atoms, as would normally be the case. Instead, they obtained molecules where the double bond between the atoms was twisted by 90 degrees and thereby completely broken.
Biradicals in their electronic ground state
The result of the experiments was the synthesis of unusually stable biradicals. This is highly unusual: "When a molecule is twisted against its will, it usually becomes less stable, and also more reactive", explains Julian Böhnke, doctoral student at the JMU and first author of the publication in Nature Communications. "The stability of the molecules is due to them being biradicals in their electronic ground state, despite their two unpaired electrons", says Braunschweig. "This structure was completely unexpected."
Applications of the molecules are still far away, according to Prof. Braunschweig. If they could be installed into a polymeric material, their use in organic electronics could become a possibility. However, Braunschweig emphasises that "this is still a long way off". The next step for the JMU chemists is to test whether similarly stable biradicals can be prepared with double bonds between boron and carbon.
A success story of Research Training Group 2112
The study of the biradicals was particularly extensive and complex, involving sixteen researchers and three years of research. The main part of Julian Böhnke's doctoral thesis will be based on the topic. Böhnke is part of the Research Training Group (Graduiertenkolleg) 2112 (Molecular Biradicals: Structure, Properties and Reactivity), a research consortium headed by Prof. Ingo Fischer. The Research Training Group allows doctoral students to investigate the physical and chemical properties of biradicals in an interdisciplinary team.
Critical to the success of the study was the efficient collaboration with expert theoretical chemistry groups. Work by the teams of Profs. Bernd Engels and Roland Mitrić was essential in obtaining a thorough understanding of the bonding situations in the newly-prepared biradicals. Two other German research groups from Göttingen and Mülheim an der Ruhr were also integral parts of the team.
The work was financially supported as part of the Research Training Group 2112 funded by the German Research Foundation (DFG). Further support came from Prof. Braunschweig's Advanced Grant from the European Research Council.
Isolation of diborenes and their 90°-twisted diradical congeners, Nature Communications, 22 March 2018, DOI: 10.1038/s41467-018-02998-3
Prof. Dr. Holger Braunschweig, Institute for Inorganic Chemistry/Institute for Sustainable Chemistry & Catalysis with Boron, JMU, Tel +49 931 31-85260, firstname.lastname@example.org
Robert Emmerich | Julius-Maximilians-Universität Würzburg
Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View
22.06.2018 | University of Sussex
New cellular pathway helps explain how inflammation leads to artery disease
22.06.2018 | Cedars-Sinai Medical Center
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
22.06.2018 | Materials Sciences
22.06.2018 | Earth Sciences
22.06.2018 | Life Sciences