Refine
Has Fulltext
- yes (46)
Is part of the Bibliography
- yes (46)
Year of publication
- 2021 (46) (remove)
Document Type
- Journal article (33)
- Doctoral Thesis (13)
Language
- English (46) (remove)
Keywords
- Supramolekulare Chemie (6)
- Aggregation (4)
- RNA (4)
- Selbstorganisation (4)
- organic chemistry (4)
- water oxidation (4)
- Organische Chemie (3)
- Naphthylisochinolinalkaloide (2)
- Perylenderivate (2)
- SARS-CoV-2 (2)
- Self-assembly (2)
- Wasser (2)
- cage compounds (2)
- chirality (2)
- dynamic covalent chemistry (2)
- exciton coupling (2)
- homogenous catalysis (2)
- organic photodiodes (2)
- photocatalysis (2)
- ruthenium complexes (2)
- squaraine dyes (2)
- 5'-O-Methyldioncophylline D (1)
- Aggregat <Chemie> (1)
- Alkaloid (1)
- Alkaloide (1)
- Ancistrocladaceae (1)
- Ancistrocladus (1)
- Ancistrolikokine E3 (1)
- Anti-infectious activity (1)
- Antiausterity activity (1)
- Biochemistry (1)
- Biradikal (1)
- Chili RNA Aptamer (1)
- Chirality (1)
- Chirality Transfer (1)
- Chiralität <Chemie> (1)
- Chromophor (1)
- Co-Crystal Structures of Chili RNA (1)
- Congo (1)
- Corannulene (1)
- Cryoelectron Microscopy (1)
- Cryoelectron microscopy (1)
- DNA (1)
- DNS (1)
- Deoxyribozymes (1)
- Dimer (1)
- Dimere (1)
- Dioncophylline C (1)
- Dyade (1)
- EPR spectroscopy (1)
- Elektronenspinresonanzspektroskopie (1)
- Elektronentransfer (1)
- Epitranscriptomics (1)
- Farbstoff (1)
- Fluoreszenzspektrometer (1)
- Fluorogenic RNA Aptamers (1)
- Flüssigkristall (1)
- Fotokatalyse (1)
- G-quadruplexes (1)
- Gibbs activation energy (1)
- HIV (1)
- HRMS (1)
- Holothuria spinifera (1)
- Host-Guest-Chemistry (1)
- Iridium-Photosensibilisator (1)
- Isolation (1)
- Isolierung (1)
- Isolierung <Chemie> (1)
- J-Aggregates (1)
- J-aggregates (1)
- Jozimine A2 (1)
- Katalyse (1)
- Konglomerat (1)
- Kongo (1)
- Liquid Crystal (1)
- Lower Critical Solution Temperature (LCST) (1)
- Metallosupramolekulare Chemie (1)
- Molecular mechanism (1)
- Molnupiravir (1)
- Molnupiravir-Induced RNA Mutagenesis Mechanism (1)
- Naphthyl Isoquinolines (1)
- Naphthylisoquinolin (1)
- Naphthylisoquinoline (1)
- Natural Products (1)
- Non-linear optics (1)
- Nonlinear Optical Properties of Organic Materials (1)
- Nucleic acids (1)
- Nucleinsäuren (1)
- Optical Spectroscopy (1)
- Oxidation (1)
- Pancreatic cancer (1)
- Perylenbisdicarboximide (1)
- Perylenbisdicarboximide <Perylen-3,4:9,10-bis(dicarboximide)> (1)
- Perylenbisimid (1)
- Perylene Bisimide (1)
- Photoconductivity (1)
- Polycyclische Aromaten (1)
- Polymorphismus (1)
- Protonenreduktion (1)
- Quadruplex-DNS (1)
- RNA Modification (1)
- RNA modification (1)
- RNA-Dependent RNA Polymerase (1)
- RNA-dependent RNA polymerase (1)
- RNS (1)
- Reduction (1)
- Remdesivir (1)
- Ruthenium complexes (1)
- Ruthenium-Photosensibilisator (1)
- Rutheniumkomplexe (1)
- SARS-CoV-2 polymerase (1)
- SARS-CoV2 Replication Impairment (1)
- Self-Assembly (1)
- Self-Assembly in Water (1)
- Site-Specific RNA Cleavage (1)
- Spectroscopy (1)
- Spin labels (1)
- Spin-Sonde (1)
- Squaraine (1)
- Structural Biology (1)
- Structural elucidation (1)
- Strukturaufklärung (1)
- Supramolecular Chemistry (1)
- Suzuki coupling (1)
- Synthetic Functional RNAs (1)
- TERRA RNA (1)
- Thermodynamics (1)
- Total Synthesis (1)
- Totalsynthese (1)
- Two-photon absorption (1)
- UV/Vis spectroscopy (1)
- Wasseroxidation (1)
- Water (1)
- Wirt-Gast-Beziehung (1)
- X-ray Crystallography (1)
- X-ray crystallography (1)
- Zweiphotonenabsorption (1)
- [FeFe] hydrogenase mimic (1)
- [FeFe]-Hydrogenase Imitator (1)
- [n]helicenes (1)
- acid sphingomyelinase (1)
- adsorption (1)
- antidepressants (1)
- antimicrobials (1)
- artificial photosynthesis (1)
- bile salt (1)
- biological techniques (1)
- biomass (1)
- biradical (1)
- boronate esters (1)
- boronateesters (1)
- catalysis (1)
- catalytic (1)
- ceramides (1)
- cerebrosides (1)
- chirality transfer (1)
- circular polarized luminescence (1)
- click chemistry (1)
- colloid (1)
- columnar phases (1)
- configurational stability (1)
- cooperative (1)
- cooperative self-assembly (1)
- covalent organic frameworks (1)
- crystal engineering (1)
- cyclophanes (1)
- cytotoxicity (1)
- density functional calculations (1)
- deoxyribozymes (1)
- deracemization (1)
- diketopyrrolopyrroles (1)
- dinuclear (1)
- dyad (1)
- dye chemistry (1)
- dyes/pigments (1)
- electronic collective variables (1)
- electronic wavefunction (1)
- enantiomerization (1)
- epitranscriptomics (1)
- ferroelectrics (1)
- fluorescence spectroscopy (1)
- flux (1)
- folding landscapes (1)
- functionalization (1)
- glycocalyx (1)
- glycosphingolipids (1)
- hMSC-TERT (1)
- heavy metals (1)
- helicenes (1)
- homochiral dimer (1)
- homogeneous catalysis (1)
- hybrid materials (1)
- hydrogen bonding (1)
- imaging (1)
- in vitro Selection (1)
- in vitro selection (1)
- iridium photosensitizer (1)
- iron oxide nanoparticles (1)
- kinetics (1)
- lectin (1)
- liquid crystal alignment (1)
- luminescence (1)
- macrocycles (1)
- major depression (1)
- measles (1)
- merocyanine dyes/pigments (1)
- metabolic glycoengineering (1)
- metadynamics (1)
- metallomacrocycles (1)
- metallosupramolecular chemistry (1)
- microbiology (1)
- microbiology techniques (1)
- microscopy (1)
- modified monosaccharides (1)
- molecular docking (1)
- nanorods and nanosheets (1)
- narrow bandwidth (1)
- near-infrared sensitivity (1)
- optical spectroscopy (1)
- organic semiconductors (1)
- oxidation (1)
- parallel polar dimers (1)
- perylenebisimide dyes (1)
- phenylboronate (1)
- photosenitizers (1)
- phthalocyanines (1)
- polymer drug interaction (1)
- polymers (1)
- polymorphism (1)
- polyoxazolines (1)
- porousmaterials (1)
- porphyrins (1)
- probes (1)
- proton reduction (1)
- pyrene (1)
- racemization (1)
- real-time NMR spectroscopy (1)
- regulatory T cells (1)
- renewable fuels (1)
- ruthenium (1)
- ruthenium catalysts (1)
- ruthenium photosensitizer (1)
- separation techniques (1)
- simulated intestinal fluid (1)
- site-specific RNA cleavage (1)
- social self‐sorting (1)
- solvent effects (1)
- spectroscopy (1)
- sphingolipids (1)
- sphingomyelinase (1)
- sphingosine 1-phosphate (1)
- structural biology (1)
- structure elucidation (1)
- structure–function relation (1)
- subphthalocyanine (1)
- superparamagnetism (1)
- superstructure (1)
- supramolecular assembly (1)
- supramolecular folding (1)
- supramolecular polymers (1)
- template catalysis (1)
- trinuclear (1)
- umbrella-shaped mesogens (1)
- viral epidemiology (1)
- viral infection (1)
- water (1)
Institute
- Institut für Organische Chemie (46) (remove)
Sonstige beteiligte Institutionen
- Department of Cellular Biochemistry, University Medical Center Göttingen (1)
- Georg August University School of Science (1)
- Helmholtz Institute for RNA-based Infection Biology (HIRI), Josef-Schneider-Straße 2/D15, DE-97080 Wuerzburg, Germany (1)
- Institute of Cancer Research (ICR) London (1)
- Max Planck Institute for Biophysical Chemistry (1)
- Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, DE-37077 Goetingen, Germany (1)
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Göttingen (1)
- Max Planck Institute for Biophysical Chemistry, Research Group Structure and Function of Molecular Machines, Göttingen (1)
- Max-Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Göttingen (1)
- Novartis Pharma AG, Lichtstrasse 35, CH-4056 Basel, Switzerland (1)
In this communication, we demonstrate a novel approach to prepare a discrete dimer of chiral phthalocyanine (Pc) by exploiting the flexible molecular geometry of helicenes, which enables structural interlocking and strong aggregation tendency of Pcs. Synthesized [7]helicene-Pc hybrid molecular structure, zinc-[7]helicenocyanine (Zn-7HPc), exclusively forms a stable dimeric pair consisting of two homochiral molecules. The dimerization constants were estimated to be as high as 8.96×10\(^6\) M\(^{−1}\) and 3.42×107 M\(^{−1}\) in THF and DMSO, respectively, indicating remarkable stability of dimer. In addition, Zn\(^{-7}\)HPc exhibited chiral self-sorting behavior, which resulted in preferential formation of a homochiral dimer also in the racemic sample. Two phthalocyanine subunits in the dimeric form strongly communicate with each other as revealed by a large comproportionation constant and observation of an IV-CT band for the thermodynamically stable mixed-valence state.
Our research group focusses on the isolation, structural elucidation, and synthesis of bioactive natural products, among others, the naphthylisoquinoline alkaloids from tropical lianas. This intriguing class of compounds comprises representatives with activities against, e.g. P. falciparum, the cause of Malaria tropica, against the neglected disease leishmaniasis, and, as discovered more recently, against different types of cancer cells. Based on the high potency of theses extraordinary secondary metabolites, this thesis was devoted to the total synthesis of bioactive natural products and closely related analogs.
To circumvent time-consuming clinical trials, testing whether existing drugs are effective inhibitors of SARS-CoV-2, has led to the discovery of Remdesivir. We decided to follow this path and screened approved medications "off-label" against SARS-CoV-2. Fluoxetine inhibited SARS-CoV-2 at a concentration of 0.8 mu g/ml significantly in these screenings, and the EC50 was determined with 387 ng/ml. Furthermore, Fluoxetine reduced viral infectivity in precision-cut human lung slices showing its activity in relevant human tissue targeted in severe infections. Fluoxetine treatment resulted in a decrease in viral protein expression. Fluoxetine is a racemate consisting of both stereoisomers, while the S-form is the dominant serotonin reuptake inhibitor. We found that both isomers show similar activity on the virus, indicating that the R-form might specifically be used for SARS-CoV-2 treatment. Fluoxetine inhibited neither Rabies virus, human respiratory syncytial virus replication nor the Human Herpesvirus 8 or Herpes simplex virus type 1 gene expression, indicating that it acts virus-specific. Moreover, since it is known that Fluoxetine inhibits cytokine release, we see the role of Fluoxetine in the treatment of SARS-CoV-2 infected patients of risk groups.
We investigated the folding kinetics of G‐quadruplex (G4) structures by comparing the K\(^{+}\)‐induced folding of an RNA G4 derived from the human telomeric repeat‐containing RNA (TERRA25) with a sequence homologous DNA G4 (wtTel25) using CD spectroscopy and real‐time NMR spectroscopy. While DNA G4 folding is biphasic, reveals kinetic partitioning and involves kinetically favoured off‐pathway intermediates, RNA G4 folding is faster and monophasic. The differences in kinetics are correlated to the differences in the folded conformations of RNA vs. DNA G4s, in particular with regard to the conformation around the glycosidic torsion angle χ that uniformly adopts anti conformations for RNA G4s and both, syn and anti conformation for DNA G4s. Modified DNA G4s with \(^{19}\)F bound to C2′ in arabino configuration adopt exclusively anti conformations for χ. These fluoro‐modified DNA (antiTel25) reveal faster folding kinetics and monomorphic conformations similar to RNA G4s, suggesting the correlation between folding kinetics and pathways with differences in χ angle preferences in DNA and RNA, respectively.
In the course of this work, a total of three photocatalytically active dyads for proton reduction could be synthesized together with the associated individual components. Two of them, D1 and D2, comprised a [Ru(bpy)3]2+ photosensitizer and D3 an [Ir(ppy)2bpy]+ photosensitizer. A Ppyr3-substituted propyldithiolate [FeFe] complex was used as catalyst in all systems. The absorption spectroscopic and electrochemical investigations showed that an inner-dyadic electronic coupling is effectively prevented in the dyads due to conjugation blockers within the bridging units used. The photocatalytic investigations exhibited that all dyad containing two-component systems (2CS) showed a significantly worse performance than the corresponding bimolecular three-component systems (3CS). Transient absorption spectroscopy showed that the 2CS behave very similarly to the associated multicomponent systems during photocatalysis. The electron that was intended for the intramolecular transfer from the photosensitizer unit to the catalyst unit within the dyads remains at the photosensitizer for a relatively long time, analogous to the 3CS and despite the covalently bound catalyst. It is therefore assumed that this intramolecular electron transfer is likely to be hindered as a result of the weak electronic coupling caused by the bridge units used. Instead, the system bypasses this through an intermolecular transfer to other dyad molecules in the immediate vicinity. In addition, with the help of emission quenching experiments and electrochemical investigations, it could be clearly concluded that all investigated systems proceed via the reductive quenching mechanism during photocatalysis.
The aim of the first part of this thesis was to investigate (R,R)-PBI as a model system for polymorphism at its origin by a supramolecular approach. The pathway complexity of (R,R)-PBI was fine-tuned by experimental parameters such as solvent, temperature and concentration to make several supramolecular polymorphs accessible. Mechanistic and quantum chemical studies on the kinetics and thermodynamics of the supramolecular polymerization of (R,R)-PBI were conducted to shed light on the initial stages of polymorphism. The second part of this work deals with mechanistic investigations on the supramolecular polymerization of the racemic mixture of (R,R)- and (S,S)-PBI with regard to homochiral and heterochiral aggregation leading to conglomerates and a racemic supramolecular polymer, respectively.
Two di- and tetranuclear Ru(bda) (bda: 2,2′-bipyridine-6,6′-dicarboxylate) macrocyclic complexes were synthesized and their catalytic activities in chemical and photochemical water oxidation investigated in a comparative manner to our previously reported trinuclear congener. Our studies have shown that the catalytic activities of this homologous series of multinuclear Ru(bda) macrocycles in homogeneous water oxidation are dependent on their size, exhibiting highest efficiencies for the largest tetranuclear catalyst. The turnover frequencies (TOFs) have increased from di- to tetranuclear macrocycles not only per catalyst molecule but more importantly also per Ru unit with TOF of 6 \(^{-1}\) to 8.7 \(^{-1}\) and 10.5 s\(^{-1}\) in chemical and 0.6 s\(^{-1}\) to 3.3 \(^{-1}\) and 5.8 \(^{-1}\) in photochemical water oxidation per Ru unit, respectively. Thus, for the first time, a clear structure–activity relationship could be established for this novel class of macrocyclic water oxidation catalysts.
As viruses are obligatory intracellular parasites, any step during their life cycle strictly depends on successful interaction with their particular host cells. In particular, their interaction with cellular membranes is of crucial importance for most steps in the viral replication cycle. Such interactions are initiated by uptake of viral particles and subsequent trafficking to intracellular compartments to access their replication compartments which provide a spatially confined environment concentrating viral and cellular components, and subsequently, employ cellular membranes for assembly and exit of viral progeny. The ability of viruses to actively modulate lipid composition such as sphingolipids (SLs) is essential for successful completion of the viral life cycle. In addition to their structural and biophysical properties of cellular membranes, some sphingolipid (SL) species are bioactive and as such, take part in cellular signaling processes involved in regulating viral replication. It is especially due to the progress made in tools to study accumulation and dynamics of SLs, which visualize their compartmentalization and identify interaction partners at a cellular level, as well as the availability of genetic knockout systems, that the role of particular SL species in the viral replication process can be analyzed and, most importantly, be explored as targets for therapeutic intervention.
A protecting group strategy was employed to synthesise a series of indolenine squaraine dye oligomers up to the nonamer. The longer oligomers show a distinct solvent dependence of the absorption spectra, that is, either a strong blue shift or a strong red shift of the lowest energy bands in the near infrared spectral region. This behaviour is explained by exciton coupling theory as being due to H- or J-type coupling of transition moments. The H-type coupling is a consequence of a helix folding in solvents with a small Hansen dispersity index. DOSY NMR, small angle neutron scattering (SANS), quantum chemical and force field calculations agree upon a helix structure with an unusually large pitch and open voids that are filled with solvent molecules, thereby forming a kind of clathrate. The thermodynamic parameters of the folding process were determined by temperature dependent optical absorption spectra.
Two dipolar merocyanines consisting of the same π‐conjugated chromophore but different alkyl substituents adopt very different packing arrangements in their respective solid state with either H‐ or J‐type exciton coupling, leading to ultranarrow absorption bands at 477 and 750 nm, respectively, due to exchange narrowing. The social self‐sorting behavior of these push‐pull chromophores in their mixed thin films is evaluated and the impact on morphology as well as opto‐electronical properties is determined. The implementation of this well‐tuned two‐component material with tailored optical features allows to optimize planar heterojunction organic photodiodes with fullerene (C\(_{60}\)) with either dual or single wavelength selectivity in the blue and NIR spectral range with ultranarrow bandwidths of only 11 nm (200 cm\(^{-1}\)) and an external quantum efficiency of up to 18% at 754 nm under 0 V bias. The application of these photodiodes as low‐power consuming heart rate monitors is demonstrated by a reflectance‐mode photoplethysmography (PPG) sensor.