@article{BrietzkeDietzKellingetal.2017, author = {Brietzke, Thomas Martin and Dietz, Thomas and Kelling, Alexandra and Schilde, Uwe and Bois, Juliana and Kelm, Harald and Reh, Manuel and Schmitz, Markus and Koerzdoerfer, Thomas and Leimk{\"u}hler, Silke and Wollenberger, Ulla and Krueger, Hans-Joerg and Holdt, Hans-J{\"u}rgen}, title = {The 1,6,7,12-Tetraazaperylene Bridging Ligand as an Electron Reservoir and Its Disulfonato Derivative as Redox Mediator in an Enzyme-Electrode Process}, series = {Chemistry - a European journal}, volume = {23}, journal = {Chemistry - a European journal}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201703639}, pages = {15583 -- 15587}, year = {2017}, abstract = {The homodinuclear ruthenium(II) complex [{Ru(l-N4Me2)}(2)(-tape)](PF6)(4) {[1](PF6)(4)} (l-N4Me2=N,N-dimethyl-2,11-diaza[3.3](2,6)-pyridinophane, tape=1,6,7,12-tetraazaperylene) can store one or two electrons in the energetically low-lying * orbital of the bridging ligand tape. The corresponding singly and doubly reduced complexes [{Ru(l-N4Me2)}(2)(-tape(.-))](PF6)(3) {[2](PF6)(3)} and [{Ru(l-N4Me2)}(2)(-tape(2-))](PF6)(2) {[3](PF6)(2)}, respectively, were electrochemically generated, successfully isolated and fully characterized by single-crystal X-ray crystallography, spectroscopic methods and magnetic susceptibility measurements. The singly reduced complex [2](PF6)(3) contains the -radical tape(.-) and the doubly reduced [3](PF6)(2) the diamagnetic dianion tape(2-) as bridging ligand, respectively. Nucleophilic aromatic substitution at the bridging tape in [1](4+) by two sulfite units gave the complex [{Ru(l-N4Me2)}(2){-tape-(SO3)(2)}](2+) ([4](2+)). Complex dication [4](2+) was exploited as a redox mediator between an anaerobic homogenous reaction solution of an enzyme system (sulfite/sulfite oxidase) and the electrode via participation of the low-energy *-orbital of the disulfonato-substituted bridging ligand tape-(SO3)(2)(2-) (E-red1=-0.1V versus Ag/AgCl/1m KCl in water).}, language = {en} } @article{GrottKnollenbergHammetal.2019, author = {Grott, Matthias and Knollenberg, J. and Hamm, M. and Ogawa, K. and Jaumann, R. and Otto, Katharina Alexandra and Delbo, M. and Michel, Patrick and Biele, J. and Neumann, Wladimir and Knapmeyer, Martin and K{\"u}hrt, E. and Senshu, H. and Okada, T. and Helbert, Jorn and Maturilli, A. and M{\"u}ller, N. and Hagermann, A. and Sakatani, Naoya and Tanaka, S. and Arai, T. and Mottola, Stefano and Tachibana, Shogo and Pelivan, Ivanka and Drube, Line and Vincent, J-B and Yano, Hajime and Pilorget, C. and Matz, K. D. and Schmitz, N. and Koncz, A. and Schr{\"o}der, Stefan E. and Trauthan, F. and Schlotterer, Markus and Krause, C. and Ho, T-M and Moussi-Soffys, A.}, title = {Low thermal conductivity boulder with high porosity identified on C-type asteroid (162173) Ryugu}, series = {Nature astronomy}, volume = {3}, journal = {Nature astronomy}, number = {11}, publisher = {Nature Publishing Group}, address = {London}, issn = {2397-3366}, doi = {10.1038/s41550-019-0832-x}, pages = {971 -- 976}, year = {2019}, abstract = {C-type asteroids are among the most pristine objects in the Solar System, but little is known about their interior structure and surface properties. Telescopic thermal infrared observations have so far been interpreted in terms of a regolith-covered surface with low thermal conductivity and particle sizes in the centimetre range. This includes observations of C-type asteroid (162173) Ryugu1,2,3. However, on arrival of the Hayabusa2 spacecraft at Ryugu, a regolith cover of sand- to pebble-sized particles was found to be absent4,5 (R.J. et al., manuscript in preparation). Rather, the surface is largely covered by cobbles and boulders, seemingly incompatible with the remote-sensing infrared observations. Here we report on in situ thermal infrared observations of a boulder on the C-type asteroid Ryugu. We found that the boulder's thermal inertia was much lower than anticipated based on laboratory measurements of meteorites, and that a surface covered by such low-conductivity boulders would be consistent with remote-sensing observations. Our results furthermore indicate high boulder porosities as well as a low tensile strength in the few hundred kilopascal range. The predicted low tensile strength confirms the suspected observational bias6 in our meteorite collections, as such asteroidal material would be too frail to survive atmospheric entry7}, language = {en} }