44 research outputs found
MeO-Biphep and Binap ligands as six-electron donors to ruthenium(II). X-ray and NMR studies on Cp-, pyrrole-, and indole-derived complexes
No full textRu(II) complexes of the chiral ligands Binap and MeO-Biphep containing six-electron hydrocarbon donors, such as Cp, a deprotonated pyrrole, or the benzene ring of indole, attain the 18-electron configuration by complexing a proximate biaryl double bond. The solid-state structures for two of these, [RuCp(2)]BF4 and [Ru(indole)(2)](BF4)(2) (2 = (6,6'-dimethoxybiphenyl-2,2'-diyl)bis(bis(3,5-di-tert-butylphenyl)phosphine)), have been determined by X-ray diffraction. They reveal that a biaryl double bond, immediately adjacent to one P-donor, coordinates to the ruthenium, thus making the chelating ligand a six-electron donor. The double bonds remain coordinated in solution as shown by HMBC C-13,H-1 long-range correlation spectroscopy. However, 2-D NMR exchange spectroscopy suggests that the biaryl double bond is weakly coordinated since the two halves of the C-2-symmetric Binap (or MeO-Biphep) Ligands are in slow exchange at ambient temperature
New chiral complexes of palladium(0) containing P,S- and P,P-bidentate ligands
No full textNew chiral complexes of Pd(O) containing either the bis(phosphine) (6,6'-dimethoxybiphenyl-2,2'-diyl)bis(3,5-di-tert -butylphenylphosphine) (MeO-BIPHEP, 1) or the phosphine-sulfur chelate (2,3,4,6-tetra-O-acetyl-1-{(2-diphenylphosphino)benzyl)thio) -beta-D-glucopyranose ((2-Ph2PC6H4CH2) -S-CHCH(OAc)CH(OAc)CH(OAc)CH(CH2OAc)O,2) have been prepared, and the solid-state structure of one of these, Pd(benzoquinone)(2), has been determined. These Pd(O) complexes reveal interesting solution dynamics, as shown by 2-dimensional exchange spectroscopy. For the MeO-BIPHEP derivatives, one can obtain useful structural insights based on the observed restricted rotation around the aryl(3,5-di-tert-butylphenl)P-C bonds
Anisotrope dynamische Dauerfestigkeitsberechnung einer geschmiedeten Kurbelwelle – Vorstellung neuer Berechnungsmöglichkeiten durch Berücksichtigung von Materialeffekten aus der Herstellung
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ChemInform Abstract: A Bimetallic Palladium Catalyst for Asymmetric Allylic Substitution Reactions.
No full text
Performance-Enhancing Asymmetric Separator for Lithium–Sulfur Batteries
No full textAsymmetric
separators with polysulfide barrier properties consisting of porous
polypropylene grafted with styrenesulfonate (PP-g-PLiSS) were characterized in lithium–sulfur cells
to assess their practical applicability. Galvanostatic cycling at
different C-rates with and without an electrolyte additive and cyclic
voltammetry were used to probe the electrochemical performance of
the cells with the PP-g-PLiSS separators
and to compare it with the performance of the cells utilizing state-of-the-art
separator, Celgard 2400. Overall, it was found that regardless of
the applied cycling rate, the use of the grafted separators greatly
enhances the Coulombic efficiency of the cell. An appropriate Li-exchange-site
(−SO3–) concentration at and near
the surface of the separator was found to be essential to effectively
suppress the polysulfide shuttle without sacrificing the Li-ion mobility
through the separator and to improve the practical specific charge
of the cell
ChemInform Abstract: An Unexpectedly Stable Chiral Hydrido-Solvent Complex of Ru(II): A Mechanistic Link in the Enantioselective Hydrogenation of Pyrones.
No full textPhotocatalytic discoloration of organic compounds on outdoor building cement panels modified by photoactive coatings
No full textCement based Eternit plates modified by TiO2/SiO2 surface layers acquired self-cleaning properties. The TiO2/SiO2 coating was transparent indicating that the small TiO2 (rutile) crystals cause no significant scattering. The parameters related to the composition of the TiO2/SiO2 coating were investigated in relation to concentration and ratio of the components and the time and temperature necessary for the colloid networking to produce the self-cleaning effect. The repetitive discoloration of natural pigments on the TiO2/SiO2/Eternit plates was observed showing the stable performance of the TiO2/SiO2 coating. FTIR spectroscopy shows the stability of the acrylic and cellulose components on the TiO2/SiO2/Eternit plates after repetitive self-cleaning cycles. A self-cleaning mechanism is suggested in agreement with the experimental findings. The SiO2 layers seem to avoid the radical attack on the acrylic topmost layers of the Eternit plates due to the TiO2 (h(vb)(+)) generated under solar simulated radiation. The profile and thickness of the coating was estimated by confocal microscopy. X-ray diffraction showed that the Eternit plates had a structure forming function on the TiO2/SiO2 layers leading to the formation of rutile from the Ti-colloids at temperatures as low as similar to 80 degrees C. (C) 2007 Elsevier B.V. All rights reserved.1884170033434
Photocatalytic Discoloration of Organic Compounds on Outdoor Building Cement Panels Modified by Photoactive Coatings
No full textCement based Eternit plates modified by TiO2/SiO2 surface layers acquired self-cleaning properties. The TiO2/SiO2 coating was transparent indicating that the small TiO2 (rutile) crystals cause no significant scattering. The parameters related to the composition of the TiO2/SiO2 coating were investigated in relation to concentration and ratio of the components and the time and temperature necessary for the colloid networking to produce the self-cleaning effect. The repetitive discoloration of natural pigments on the TiO2/SiO2/Eternit plates was observed showing the stable performance of the TiO2/SiO2 coating. FTIR spectroscopy shows the stability of the acrylic and cellulose components on the TiO2/SiO2/Eternit plates after repetitive self-cleaning cycles. A self-cleaning mechanism is suggested in agreement with the experimental findings. The SiO2 layers seem to avoid the radical attack on the acrylic topmost layers of the Eternit plates due to the TiO2 (h(vb)(+)) generated under solar simulated radiation. The profile and thickness of the coating was estimated by confocal microscopy. X-ray diffraction showed that the Eternit plates had a structure forming function on the TiO2/SiO2 layers leading to the formation of rutile from the Ti-colloids at temperatures as low as similar to 80 degrees C. (C) 2007 Elsevier B.V. All rights reserved.GPA
