TY  - JOUR
A1  - Brietzke, Thomas Martin
A1  - Dietz, Thomas
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
A1  - Bois, Juliana
A1  - Kelm, Harald
A1  - Reh, Manuel
A1  - Schmitz, Markus
A1  - Koerzdoerfer, Thomas
A1  - Leimkühler, Silke
A1  - Wollenberger, Ulla
A1  - Krueger, Hans-Joerg
A1  - Holdt, Hans-Jürgen
T1  - The 1,6,7,12-Tetraazaperylene Bridging Ligand as an Electron Reservoir and Its Disulfonato Derivative as Redox Mediator in an Enzyme-Electrode Process
JF  - Chemistry - a European journal
N2  - 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).
KW  - electrochemistry
KW  - enzyme catalysis
KW  - N-ligands
KW  - redox-active ligands
KW  - ruthenium
Y1  - 2017
U6  - https://doi.org/10.1002/chem.201703639
SN  - 0947-6539
SN  - 1521-3765
VL  - 23
SP  - 15583
EP  - 15587
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Postberg, Frank
A1  - Grün, Eberhard
A1  - Horanyi, Mihaly
A1  - Kempf, Sascha
A1  - Krueger, Harald
A1  - Schmidt, Jürgen
A1  - Spahn, Frank
A1  - Srama, Ralf
A1  - Sternovsky, Zoltan
A1  - Trieloff, Mario
T1  - Compositional mapping of planetary moons by mass spectrometry of dust ejecta
JF  - Planetary and space science
N2  - Classical methods to analyze the surface composition of atmosphereless planetary objects from an orbiter are IR and gamma ray spectroscopy and neutron backscatter measurements. The idea to analyze surface properties with an in-situ instrument has been proposed by Johnson et al. (1998). There, it was suggested to analyze Europa's thin atmosphere with an ion and neutral gas spectrometer. Since the atmospheric components are released by sputtering of the moon's surface, they provide a link to surface composition. Here we present an improved, complementary method to analyze rocky or icy dust particles as samples of planetary objects from which they were ejected. Such particles, generated by the ambient meteoroid bombardment that erodes the surface, are naturally present on all atmosphereless moons and planets. The planetary bodies are enshrouded in clouds of ballistic dust particles, which are characteristic samples of their surfaces. In situ mass spectroscopic analysis of these dust particles impacting onto a detector of an orbiting spacecraft reveals their composition. Recent instrumental developments and tests allow the chemical characterization of ice and dust particles encountered at speeds as low as 1 km/s and an accurate reconstruction of their trajectories. Depending on the sampling altitude, a dust trajectory sensor can trace back the origin of each analyzed grain with about 10 km accuracy at the surface. Since the detection rates are of the order of thousand per orbit, a spatially resolved mapping of the surface composition can be achieved. Certain bodies (e.g., Europa) with particularly dense dust clouds, could provide impact statistics that allow for compositional mapping even on single flybys. Dust impact velocities are in general sufficiently high at orbiters about planetary objects with a radius > 1000 km and with only a thin or no atmosphere. In this work we focus on the scientific benefit of a dust spectrometer on a spacecraft orbiting Earth's Moon as well as Jupiter's Galilean satellites. This 'dust spectrometer' approach provides key chemical and isotopic constraints for varying provinces or geological formations on the surfaces, leading to better understanding of the body's geological evolution.
KW  - Moon
KW  - Europa
KW  - Ganymede
KW  - Dust
KW  - Surface composition
KW  - Spectrometry
Y1  - 2011
U6  - https://doi.org/10.1016/j.pss.2011.05.001
SN  - 0032-0633
VL  - 59
IS  - 14
SP  - 1815
EP  - 1825
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Thiessenhusen, Kai-Uwe
A1  - Krueger, Harald
A1  - Spahn, Frank
A1  - Grün, Eberhard
T1  - Large dust grains around Jupiter : the observations of the Galileo dust detector
Y1  - 2000
ER  -