Inst. Chemie

814 Items

Recent Submissions
Micro-Patterning of PEG-Based Hydrogels With Gold Nanoparticles Using a Reactive Micro-Contact-Printing Approach

Yesildag, Cigdem ; Ouyang, Zhaofei ; Zhang, Zhenfang ; Lensen, Marga C. (2019-01-17)

In this work a novel, relatively simple, and fast method for patterning of gold nanoparticles (Au NPs) on poly(ethylene glycol) (PEG)-based hydrogels is presented. In the hereby exploited reactive micro-contact printing (reactive-μ-CP) process, the surface of a micro-relief patterned PDMS-stamp is first functionalized with an amino-silane self-assembled monolayer (SAM), which is then inked with...

Alternative Biochemistries for Alien Life: Basic Concepts and Requirements for the Design of a Robust Biocontainment System in Genetic Isolation

Diwo, Christian ; Budisa, Nediljko (2018-12-28)

The universal genetic code, which is the foundation of cellular organization for almost all organisms, has fostered the exchange of genetic information from very different paths of evolution. The result of this communication network of potentially beneficial traits can be observed as modern biodiversity. Today, the genetic modification techniques of synthetic biology allow for the design of spe...

Chromophore binding to two cysteines increases quantum yield of near-infrared fluorescent proteins

Buhrke, David ; Tavraz, Neslihan N. ; Shcherbakova, Daria M. ; Sauthof, Luisa ; Moldenhauer, Marcus ; Vélazquez Escobar, Francisco ; Verkhusha, Vladislav V. ; Hildebrandt, Peter ; Friedrich, Thomas (2019-02-12)

Phytochromes are red/far-red light sensing photoreceptors employing linear tetrapyrroles as chromophores, which are covalently bound to a cysteine (Cys) residue in the chromophore-binding domain (CBD, composed of a PAS and a GAF domain). Recently, near-infrared (NIR) fluorescent proteins (FPs) engineered from bacterial phytochromes binding biliverdin IXα (BV), such as the iRFP series, have beco...

Dynamics of metal catalysts under reactive conditions studied by ESEM

Cao, Jing (2019)

Solid surfaces are extremely important in heterogeneous catalysis. They represent the boundary between lid catalyst and surrounding gaseous or liquid environment, and heavily influence chemisorption, surface diffusion, reaction and desorption processes involved in the catalytic cycle. All of these key steps critically depend on the surface composition, structure and morphology. In many cases, c...

In situ studies of Pt nanoparticles on different supports for corrosion stable PEM fuel cell cathodes

Schmies, Henrike (2019)

Wasserstoffbrennstoffzellen bieten als elektrochemische Energiewandler die Möglichkeit, Wasserstoff aus erneuerbaren Resourcen als saubere und emissionsarme Energiequelle für elektrische Verbraucher, wie Elektromotoren, zu nutzen. Um eine konkurrenzfähige Alternative zu heutigen Verbrennungsmotoren in der Automobilindustrie darstellen zu können, müssen aber noch verschiedenste Hindernisse überw...

A new inductive-annealing dual electrochemical cell for crystal alloy and thin-film electrode voltammetry

Özer, Ebru (2019)

Proton exchange membrane (PEM) electrolyzers are considered as the most promising candidates for the supply of high purity hydrogen through water electrolysis. As a non polluting technology these electrolyzers enable to store surplus electricity of intermittent renewable power sources. In the highly acidic corrosive media of PEM electrolyzers, noble metal materials and their oxides represent th...

Development and investigation of photoswitchable DTE(OMe)-fluorophore conjugates

Ziebart, Nandor (2019)

Photoswitchable modulation of fluorescence became a field of high interest for different applications, as optical devices. The detailed nature of energy and electron transfer in conjugates on semiconductor surfaces could lead to a better understanding and future applications in sensors or optoelectronics. Former work group projects showed efficient on off energy transfer in photoswitchable DTE...

Überprüfung der katalytischen Aktivität von keramischen Wabenkörpern an einem Modellgas und einem thermisch regenerativen Nachverbrennungsprozess

Knoll, Manuela (2019)

Durch Untersuchungen zum Abbauverhalten des Modellgases Propan an keramischen Wabenkörpern, die als katalytisch inaktiv vermarktet werden, konnten Aktivitätsunterschiede in einer Modell-Anlage festgestellt werden. Dabei wurden aus den 27 untersuchten Wabenkörpern die vier aktivsten ermittelt. Die Bewertung der Wabenkörper erfolgt unter anderem aus dem Vergleich der Umsatzgradkurven von Propan ü...

Application of a Rapid and Integrated Analysis System (RIAS) as a High-Throughput Processing Tool for In Vitro ADME Samples by Liquid Chromatography/Tandem Mass Spectrometry

Luippold, Andreas H. ; Arnhold, Thomas ; Jörg, Wolfgang ; Krüger, Beate ; Süßmuth, Roderich D. (2011)

Over the past decade, drug discovery programs have started to address the optimization of key ADME properties already at an early stage of the process. Hence, analytical chemists have been confronted with tremendously rising sample numbers and have had to develop methodologies accelerating quantitative liquid chromatography/tandem mass spectrometry (LC/MS/MS). This article focuses on the applic...

Polystyrene-grafted Carbon Fibers: Surface Properties and Adhesion to Polystyrene

Bismarck, Alexander ; Pfaffernoschke, Matthias ; Springer, Jürgen ; Schulz, Eckhard (2005)

It is highly desirable to improve attractive interactions between carbon fibers and unreactive thermoplastic matrices to the possible maximum. This could be achieved by a simple grafting process to create a covalently bonded interface or interlayer, which should result in cohesive interactions between the polymer-grafted fibers and the same matrix material, leading to a better adhesion strength...

Isolation of the Phytochrome Chromophore. The Cleavage Reaction with Hydrogen Bromide

Rüdiger, Wolfhart ; Brandlmeier, Thomas ; Blos, Inge ; Gossauer, Albert ; Weller, Jens-Peter (1980)

The cleavage of the bilin chromophore from C-phycocyanin with hydrogen bromide yields 3E-configurated phycocyanobilin (4) as the major and 3 Z-configurated phycocyanobilin (5) as the minor reaction product. The reaction of synthetic 3E-configurated phytochromobilin (2) with hydrogen bromide and methanol leads only to a methanol adduct at the C-18 side chain (7) whereas the same reaction with th...

Verteilung und Valenz der Kationen in Spinellsystemen mit Eisen und Vanadium, I Röntgenographische und Mößbauer-spektroskopische Untersuchung des Spinellsystems ZnV2O4-ZnFe2O4

Riedel, Erwin ; Dützmann, Till ; Pfeil, Norbert (1980)

The spinel system Zn[FexV2-x]O4 has been prepared by heating mixtures of ZnV2O4 and ZnFe2O4 at 1000 °C. The lattice constants increase linearly with x by 3.6 pm, the oxygen parameters are constant with a mean value u = 0.384s. The parameters of room temperature Mössbauer spectra show that in the whole series V(III) and Fe(III) are present.

Verteilung und Valenz der Kationen in Spinellsystemen mit Eisen und Vanadium, II Röntgenographische Untersuchung, Seebeck Koeffizienten, Mößbauer-und IR-Spektren der Mischkristallreihen Fe2VO4-ZnV2O4 und Fe2VO4-ZnFe2O4

Riedel, Erwin ; Pfeil, Norbert (1980)

The spinel series Fe2VO4-ZnV2O4 and Fe2VO4-ZnFe2O4 have been prepared and investigated. The lattice constants and Mössbauer spectra lead to a distribution of cations which proves that Fe2VO4 is a partially inverse spinel with Fe(II) and Fe(III) on the tetrahedral site. The Seebeck effect is interpreted with a model of both tetrahedral and octahedral conduction based on charge hopping.

Röntgenstrukturanalyse und Schwingungsspektren von Trischwefeldistickstoffdioxid, S3N2O2 [1]

Steudel, Ralf ; Steidel, Jürgen ; Rautenberg, Norbert (1980)

A redetermination of the crystal and molecular structure of the chain-like molecule S(NSO)2 resulted in the following molecular parameters: d(SO) = 146.5(2), d(S = N) = 153.4(2), d(S-N) = 165.7(2) pm, bond angles OSN = 117.5(1)°, SNS = 123.6(2)°, and NSN = 97.2(1)°, torsion angles OSNS = -0.3(2)°, and SNSN = -177.7(2)° (molecular symmetry C2). Infrared and Raman spectra of S(NSO)2 are reported ...

Competition of Pyridoxal 5'-Phosphate with Ribulose 1,5-Bisphosphate and Effector Sugar Phosphates at the Reaction Centers of the Spinach Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase

Vater, Joachim ; Gaudszun, Thomas ; Scharnow, Harald ; Salnikow, Johann (1980)

The Stimulation of the carboxylase reaction by effectors of ribulose 1,5-bisphosphate carboxyl­ ase/oxygenase displays higher sensitivity towards pyridoxal 5'-phosphate inhibition than the catalytical process itself. Pyridoxal 5'-phosphate binding to the enzyme is not affected by the modulators 6-phospho-gluconate and fructose 1,6-bisphosphate at low concentrations at which these agents stimula...

Di-μ-iodo-bis [dicarbonyl(di-tert-butylphosphin)ruthenium(I)] (Ru-Ru) und Bis(tri-tert-butylphosphonium)-di-μ-iodo-bis[carbonyl-diiodo- (di-tert-butylphosphin)ruthenium(II)]

Schumann, Herbert ; Opitz, Joachim (1980)

[(t-C4H9)3PH]2[{Ru(μI)I2(CO)[P(t-C4H9)2H]}2] is prepared by the reaction of RUC13 · (H2O)x with CO, NaI, and P(t-C4H9)3 in 2-methoxyethanol. Its IR, Raman, and NMR spectra are reported and discussed. [Ru(μ-I)(CO)2P(t-C4H9)2H)2 is obtained by the reaction of [Ru(μ-I)I(CO)3]2 with P(t-C4H9)3 in 2-methoxyethanol. The X18MAA′M′X′18 spin system of its 1H NMR spectrum is analysed.

Frontorbitale und 1.2-Hydridwanderungen in Carbeniumionen

Frenking, Gernot ; Schwarz, Helmut (1981)

For various carbenium ions it is shown that the energy value and the degree of localization of the LUMO have a significant influence on the energy barriers of 1,2-hydrogen shifts. The structures of the transition states are in line with the Hammond-Postulate.

Verteilung und Valenz der Kationen in Spinellsystemen mit Eisen und Vanadium, III Röntgenographische und Mößbauer-spektroskopische Untersuchung des Spinellsystems ZnFeVO4-Fe3O4

Riedel, Erwin ; Anik, Hümeyra ; Dützmann, Till (1981)

The spinel system Zni_zFe2:[Fei+2;Vi_I]04 has been prepared by heating mixtures of ZnFeV(>4 and Fe3Ü4 at 1000 °C. The lattice constants, the oxygen parameters and the Mössbauer parameters show that a transition from a nearly normal to an inverse distribu-tion of Fe(II) and Fe(III) exists.

Zur McLafferty-Umlagerung bei Radikalkationen von Phenylpyridylalkanonen

Richter, Bernd ; Schwarz, Helmut (1981)

A detailed investigation concerning the genesis of McLafferty rearrangement products from molecular ions of phenyl pyridyl alkanones reveals the following features: 1) The various products are not formed by competitive dissociations of the molecular ion. Most of the relevant fragment ions are generated from the primary McLafferty product of a hydrogen transfer to the ionized carbonyl group (M+·...

Nachweis von Se6, Se7 und Se8 in Lösungen yon Selen mittels Hochdruckflüssigkeitschromatographie

Steudel, Ralf ; Strauss, Eva-Maria (1981)

Dissolution of crystalline Se8 or extraction of glassy or red amorphous selenium, prepared from aqueous SeO2 by reduction, by organic solvents yields solutions containing Se6, Se7 and Se8 in equilibrium as shown by HPLC. The equilibrium explains the concentration dependence of the molar absorbance of such solutions observed earlier. Since the Raman spectrum of red amorphous selenium does not sh...