Inst. Chemie

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Untersuchungen zur Biosynthese von Omphalotin

Ramm, Sascha (2019)

Originally discovered in 1987, Omphalotin is an undodecapeptide (which is) synthesized by the basidiomycete Omphalotus olearius. The fungal secondary metabolite shows a strong nematicide and selective activity against the plant parasite Meloidogyne incognita. Structurally, it bears various remarkable characteristics, as for example nine methylations of the α-nitrogen atoms in the peptide backbo...

Commensurate Nb2Zr5O15: Accessible Within the Field Nb2ZrxO2x+5 After All

Wiedemann, Dennis ; Orthmann, Steven ; Mühlbauer, Martin J. ; Lerch, Martin (2019-04-04)

Doped niobium zirconium oxides are applied in field-effect transistors and as special-purpose coatings. Whereas their material properties are sufficiently known, their crystal structures remain widely uncharacterized. Herein, we report on the comparably mild sol–gel synthesis of Nb2Zr5O15 and the elucidation of its commensurately modulated structure via neutron diffraction. We describe the stru...

Structure–Thermodynamic‐Property Relationships in Cyanovinyl‐Based Microporous Polymer Networks for the Future Design of Advanced Carbon Capture Materials

Yassin, Ali ; Trunk, Matthias Georg ; Czerny, Frank ; Fayon, Pierre ; Trewin, Abbie ; Schmidt, Johannes ; Thomas, Arne (2017)

Nitrogen‐rich solid absorbents, which have been immensely tested for carbon dioxide capture, seem until this date to be without decisive molecular engineering or design rules. Here, a family of cyanovinylene‐based microporous polymers synthesized under metal‐catalyzed conditions is reported as a promising candidate for advanced carbon capture materials. These networks reveal that isosteric heat...

Room-Temperature Activation of Hydrogen by Semi-immobilized Frustrated Lewis Pairs in Microporous Polymer Networks

Trunk, Matthias Georg ; Teichert, Johannes F. ; Thomas, Arne (2017)

Porous polymer networks based on sterically encumbered triphenylphosphine motifs, mimicking the basic sites employed in frustrated Lewis pair (FLP) chemistry, were synthesized via Yamamoto polymerization and their interactions with the strong Lewis acid B(C6F5)3 probed. The combinations yield semi-immobilized FLPs, which are able to cleave dihydrogen heterolytically at ambient temperature and l...

Electric fields at biomimetic interfaces

Staffa, Jana Katharina (2019)

Electric fields and electrostatic interactions can essentially influence biological processes. This is particularly true for membrane proteins since their activities may be controlled by changes of the transmembrane potential. To elucidate such processes requires appropriate biomimetic membranes, preferentially on electrodes to allow variations of the potential across a bilayer. Particular conv...

Surface functionalised and nanostructured transparent conductive oxides

Harris, Tomos Gwilym Ab Alun (2019)

Storage of (renewable) energy in the form of chemical bonds in electrofuels, their later conversion back to electricity, or the generation of renewable chemical feedstocks from CO2, N2 etc. all require the use of stable and efficient catalysts. In particular, there is urgent need for the development of efficient, precious-metal free catalysts. Enzymes and inorganic (e.g. biomimetic) molecular c...

Nanostructured porous carbon synthesized from metal-organic precursors as efficient electrochemical catalysts

Li, Shuang (2019)

The development of electrocatalysts for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) is of crucial importance to address the global demand for sustainable energy conversion devices with high efficiency, such as fuel cells and metal–air batteries, and the production of hydrogen by electrolysis of water. Nanostructured carbons are pro...

Copper‐Free Sonogashira Coupling for High‐Surface‐Area Conjugated Microporous Poly(aryleneethynylene) Networks

Trunk, Matthias Georg ; Herrmann, Anna ; Bildirir, Hakan ; Yassin, Ali ; Schmidt, Johannes ; Thomas, Arne (2016)

A modified one‐pot Sonogashira cross‐coupling reaction based on a copper‐free methodology has been applied for the synthesis of conjugated microporous poly(aryleneethynylene) networks (CMPs) from readily available iodoarylenes and 1,3,5‐triethynylbenzene. The polymerization reactions were carried out by using equimolar amounts of halogen and terminal alkyne moieties with extremely small loading...

Controlling the formation of vesicle structures and their fixation by polymerization

Yalcinkaya, Hacer (2019)

In recent years, nanostructures have drawn much interest due to their potential applications in biomedicine, energy conversion, detergency or electronics. Controlling their formation and stability is one of the key issues to obtain such versatile structures with enhanced morphological properties. Especially vesicles are interesting nanostructures with their hollow spherical geometry, allowing e...

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...