Refine
Has Fulltext
- no (152)
Year of publication
- 2015 (152) (remove)
Document Type
- Article (152) (remove)
Is part of the Bibliography
- yes (152) (remove)
Keywords
- biomaterials (4)
- Arenes (3)
- Cross-coupling (3)
- Palladium (3)
- click chemistry (3)
- peptides (3)
- polymers (3)
- self-assembly (3)
- Anisotropy effect (2)
- FRET (2)
- H-1 NMR (2)
- Ring current effect (2)
- Theoretical calculations (2)
- block copolymers (2)
- dendrimers (2)
- density functional calculations (2)
- fluorescence (2)
- hydrogen bonds (2)
- molecular rods (2)
- 1,2-Dithiosquarate,1,2-Dithiosquaratonickelate (1)
- 1,3-Oxasilinanes (1)
- 2,2-Disubstituted adamantane derivatives (1)
- 2-Hydroxyethylammonium 1-R-indol-3-ylsulfanylacetates (1)
- 2-Substituted adamantane derivatives (1)
- 3-Silatetrahydropyrans (1)
- AFM (1)
- ATR-FTIR (1)
- Allylic compounds (1)
- Amides (1)
- Anisotropy (1)
- Antiplasmodial activity (1)
- Aptamer (1)
- Assignment of stereochemistry (1)
- Azadironolide (1)
- Azobenzene (1)
- B3LYP/6-31+G(d,p) calculations (1)
- Barrier to ring inversion (1)
- Beer mashing (1)
- Bentonite clay (1)
- Benzenoid structure (1)
- Biaryls (1)
- Biomaterials (1)
- Biomineralization (1)
- Bone repair material (1)
- Breakthrough curve (1)
- Brewster angle microscopy (1)
- C-13 NMR (1)
- C-C coupling (1)
- Cadmium (1)
- Calcium phosphates (1)
- Carbene ligands (1)
- Catalytic reaction (1)
- Cationic surfactants (1)
- Cavity ring-down spectroscopy (1)
- Chiral dopants (1)
- Classical MD (1)
- Click chemistry (1)
- Cobalt (1)
- Composite hydrogels (1)
- Confocal microscopy (1)
- Conformational analysis (1)
- Conformational equilibrium (1)
- Coordination polymers (1)
- Crystal and molecular structure (1)
- Crystal structures (1)
- Cytotoxicity (1)
- DNA copolymers (1)
- DNA nanotechnology (1)
- DOPA (1)
- Delta-Kohn Sham method (1)
- EPR spectroscopy (1)
- ESI (1)
- Ellipsometry (1)
- Energy-transfer probe (1)
- Enzymatic milk coagulation (1)
- Exciplex (1)
- F12 methods (1)
- Flexible linker (1)
- Fluorescence (1)
- Fluorescence imaging (1)
- Fluorescence spectroscopy (1)
- Fluorescent probes (1)
- Fluoroassay (1)
- Fourier-transform infrared (1)
- G-quadruplexes (1)
- GIAO calculations (1)
- Gas sorption (1)
- Gas-phase electron diffraction (1)
- Gate-effects (1)
- Gold (1)
- HPLC (1)
- Heavy metal ions (1)
- Heterocycles (1)
- Human donor blood (1)
- Hydrogel (1)
- Hydrogen-bonding (1)
- Hydrophobic (1)
- ICSS (1)
- IMS (1)
- Imidazole (1)
- Immunoactive properties (1)
- Interchain interactions (1)
- Kinetic model (1)
- L-selectin (1)
- LCST behavior (1)
- Langmuir monolayer (1)
- Lanthanide (1)
- Layer-by-layer (1)
- Light scattering (1)
- Limonoid (1)
- Lobelia tupa (1)
- Low temperature NMR spectroscopy (1)
- Luminescence spectroscopy (1)
- Michael addition (1)
- Microwave chemistry (1)
- Molecular dynamics simulations (1)
- Molecular orientation (1)
- N (1)
- NCA (1)
- NICE-2014 (1)
- Nanoparticles (1)
- Natural products (1)
- Nickel oxide (1)
- Oxygen heterocycles (1)
- P ligands (1)
- Pentylsedinine (1)
- Phenols (1)
- Photoinduced optical anisotropy (1)
- Photon Density Wave spectroscopy (1)
- Pi interactions (1)
- Piperidine alkaloid (1)
- Platinum group metals (1)
- Poly vinyl alcohol (1)
- Polyaromatic fragments (1)
- Polyether ether ketone (1)
- Polyethyleneimine (1)
- Polyimides (1)
- Polypeptoid (1)
- Post-polymerization modification (1)
- Process analytical technology (1)
- Protic 2-hydroxyethylammonium ionic liquids (1)
- Quantum chemical calculations (1)
- Quasi-aromaticity (1)
- Quinonoid structure (1)
- Rearrangement (1)
- SANS (1)
- SAXS (1)
- Simulation of polymer XPS (1)
- Solid-phase extraction (1)
- Solvent effects (1)
- Solvothermal synthesis (1)
- Substituent chemical shifts (1)
- Sulphoxide (1)
- Supramolecular ball structure (1)
- Supramolecular chemistry (1)
- Surface enhanced Raman scattering (SERS) (1)
- Surface relief grating (1)
- Surfactant micelles (1)
- TG/DTA (1)
- TSNMRS (1)
- Thermal broadening effects (1)
- Thermoresponsive (1)
- Thiol-ene (1)
- ToF-SIMS (1)
- Toonacilin (1)
- Toonapubesins F (1)
- Total synthesis (1)
- Turraea nilotica (1)
- Turraea robusta (1)
- X-ray structure (1)
- XPS (1)
- ab initio (1)
- ab initio calculations (1)
- aldol reaction (1)
- alignments (1)
- amino acid N-carboxyanhydride (NCA) (1)
- amorphous polymers (1)
- anti-HIV (1)
- articulated rods (1)
- basis sets (1)
- benzofurans (1)
- biocompatibility (1)
- biodegradable polymers (1)
- biorecognition reactions (1)
- body temperature (1)
- broad melting temperature range (1)
- carbohydrates (1)
- catanionic surfactants (1)
- cell culture device (1)
- cell-material interaction (1)
- coating (1)
- collagen (1)
- column operation mode (1)
- conformational analysis (1)
- controlled release (1)
- copolymer networks (1)
- coupled-cluster (1)
- crystal structure (1)
- cyclic voltammetry (1)
- cycloaddition (1)
- degradable polyester (1)
- dendritic cells (1)
- di(ethylene glycol) methy ether methacrylate (1)
- dielectric spectroscopy (1)
- dispersion (1)
- electric fields (1)
- electrodes (1)
- electrostatic interactions (1)
- enzyme inhibitors (1)
- ephedrine/pseudoephedrine (1)
- fibers (1)
- fluorescent probes (1)
- galactosylceramide (1)
- gas sensing (1)
- gels (1)
- glycal (1)
- glycolipids (1)
- gold (1)
- hollow-core photonic bandgap fiber (1)
- hydrogels (1)
- hydrogen bonding (1)
- hydrogen-2 (1)
- hydrophilic-to-lipophilic balance (1)
- interfaces (1)
- intermolecular interactions (1)
- inverse micelles (1)
- isotope ecology (1)
- ketones (1)
- leaf wax (1)
- lipase release (1)
- liposomes (1)
- mAb (1)
- magnetic nanoparticles (1)
- maleimide (1)
- membranes (1)
- mesenchymal stem cells (1)
- metal coordination (1)
- metal-free crosslinking (1)
- microgels (1)
- microparticles (1)
- mixed quantum-classical methodology (1)
- molecular structure (1)
- multiblock copolymer (1)
- mussel byssus (1)
- n-alkanes (1)
- nAChR (1)
- nanocomposites (1)
- nanoparticle characterization (1)
- nanoparticles (1)
- nanoreactor (1)
- nanostructures (1)
- neuroleptics (1)
- nucleation polymerization (1)
- oak tree (1)
- oligo(ethylene glycol) methyl ether methacrylate (1)
- oligospiroketals (1)
- one-pot reaction (1)
- optical spectra (1)
- orientational memory (1)
- osteogenic differentiation (1)
- oxygen (1)
- oxygen heterocycles (1)
- oxygenation (1)
- palmitic acid (1)
- palmitoylation (1)
- para-Nitro-pyridine N-oxides (1)
- peroxides (1)
- pesticides (1)
- phosphate (1)
- photodynamic therapy (1)
- photonic crystals (1)
- photopolymerization (1)
- platinum (1)
- poly[(rac-lactide)-co-glycolide] (1)
- polydepsipeptide (1)
- polyesterurethanes (1)
- polymersomes (1)
- polypeptoid (1)
- polysaccharides (1)
- polystyrene-block-poly(4-vinylpyridine) (1)
- porphyrins (1)
- potassium (1)
- processing (1)
- programmable adhesion (1)
- propargyl (1)
- properties (1)
- protein-protein interactions (1)
- pyrene excimer (1)
- radical addition (1)
- rearrangement (1)
- reorientation (1)
- responsive materials (1)
- responsive polymers (1)
- reversible bidirectional shape-memory polymer (1)
- ring opening polymerization (1)
- ring-opening polymerization (1)
- selective syntheses (1)
- sensors (1)
- shape-memory effect (1)
- shape-memory polymer (1)
- silica nanoparticles (1)
- singlet oxygen (1)
- soft-templating (1)
- solid-phase extraction (1)
- solid-state NMR (1)
- solvent vapor annealing (1)
- spectroscopic ellipsometry (1)
- spray imaging (1)
- stimuli-sensitive polymers (1)
- sugar amino acids (1)
- supramolecular chemistry (1)
- surface functionalization (1)
- surface-initiated photopolymerization (1)
- surfactants (1)
- synthesis (1)
- tetrapyrroles (1)
- thermoresponsive (1)
- thermoresponsive polymers (1)
- thermoresponsive substrates (1)
- thiol (1)
- tin-rich ITO (1)
- two-photon (1)
- two-photon absorption (1)
- ultrasound (1)
- vesicles (1)
- water/decane contact angle (1)
- yolk@shell materials (1)
Institute
- Institut für Chemie (152) (remove)
Lobelia tupa, also called devil's tobacco, is a native plant from the center-south of Chile which has been used by the native people of Chile as a hallucinogenic and anesthetic plant. A new piperidine alkaloid, called pentylsedinine, which comprises five carbons in the side chain, was isolated from the aerial part of L. tupa, along with lobeline and lobelanidine. The structure was established on the basis of 1D and 2D NMR spectroscopy. While lobeline is a neutral antagonist at alpha 3 beta 2/alpha 3 beta 4 nAChR and alpha 7 nAChR, both lobelanidine and pentylsedinine act as partial agonists at nAChR
The complete H-1 and C-13 NMR chemical shifts assignment for various 2-substituted and 2,2-disubstituted adamantane derivatives 1-38 in CDCl3 solution was realized on the basis of NMR experiments combined with chemical structure information and DFT-GIAO (B3LYP/6-31+G(d,p)-GIAO) calculations of chemical shifts in solution. Substituent-induced C-13 NMR chemical shifts (SCS) are discussed. C-H-ax center dot center dot center dot Y-ax contacts are a textbook prototype of steric hindrance in organic chemistry. The nature of these contacts will be further investigated in this work on basis of new adamantane derivatives, which are substituted at C-2 to provide models for 1,4-C-H-ax center dot center dot center dot Y-ax and 1,5-C-H-ax center dot center dot center dot Y-ax contacts. The B3LYP/6-31+G(d,p) calculations predicted the presence of NBO hyperconjugative attractive interactions between C-H-ax and Y-ax groups along C-H-ax center dot center dot center dot Y-ax contacts. The H-1 NMR signal separation, Delta delta(gamma-CH2), reflects the strength of the H-bonded C-H-ax center dot center dot center dot Y-ax contact. (C) 2015 Elsevier Ltd. All rights reserved.
X-ray photoelectron spectroscopy (XPS) is a powerful tool for probing the local chemical environment of atoms near surfaces. When applied to soft matter, such as polymers, XPS spectra are frequently shifted and broadened due to thermal atom motion and by interchain interactions. We present a combined quantum mechanical QM/molecular dynamics (MD) simulation of X-ray photoelectron spectra of polyvinyl alcohol (PVA) using oligomer models in order to account for and quantify these effects on the XPS (C1s) signal. In our study, molecular dynamics at finite temperature were performed with a classical forcefield and by ab initio MD (AIMD) using the Car-Parrinello method. Snapshots along, the trajectories represent possible conformers and/or neighbouring environments, with different C1s ionization potentials for individual C atoms leading to broadened XPS peaks. The latter are determined by Delta-Kohn Sham calculations. We also examine the experimental practice of gauging XPS (C1s) signals of alkylic C-atoms in C-containing polymers to the C1s signal of polyethylene.
We find that (i) the experimental XPS (C1s) spectra of PVA (position and width) can be roughly represented by single-strand models, (ii) interchain interactions lead to red-shifts of the XPS peaks by about 0.6 eV, and (iii) AIMD simulations match the findings from classical MD semi-quantitatively. Further, (iv) the gauging procedure of XPS (C1s) signals to the values of PE, introduces errors of about 0.5 eV. (C) 2014 Elsevier B.V. All rights reserved.
A highly K+-selective two-photon fluorescent probe for the in vitro monitoring of physiological K+ levels in the range of 1-100 mM is reported. The two-photon excited fluorescence (TPEF) probe shows a fluorescence enhancement (FE) by a factor of about three in the presence of 160 mM K+, independently of one-photon (OP, 430 nm) or two-photon (TP, 860 nm) excitation and comparable K+-induced FEs in the presence of competitive Na+ ions. The estimated dissociation constant (K-d) values in Na+-free solutions (K-d(OP)=(28 +/- 5) mM and K-d(TP)=(36 +/- 6) mM) and in combined K+/Na+ solutions (K-d(OP)=(38 +/- 8) mM and K-d(TP)=(46 +/- 25) mM) reflecting the high K+/Na+ selectivity of the fluorescent probe. The TP absorption cross-section (sigma(2PA)) of the TPEF probe+160 mMK(+) is 26 GM at 860 nm. Therefore, the TPEF probe is a suitable tool for the in vitro determination of K+.
A multi-reference study of the byproduct formation for a ring-closed dithienylethene photoswitch
(2015)
Photodriven molecular switches are sometimes hindered in their performance by forming byproducts which act as dead ends in sequences of switching cycles, leading to rapid fatigue effects. Understanding the reaction pathways to unwanted byproducts is a prerequisite for preventing them. This article presents a study of the photochemical reaction pathways for byproduct formation in the photochromic switch 1,2-bis-(3-thienyl)-ethene. Specifically, using single-and multi-reference methods the post-deexcitation reaction towards the byproduct in the electronic ground state S-0 when starting from the S-1-S-0 conical intersection (CoIn), is considered in detail. We find an unusual low-energy pathway, which offers the possibility for the formation of a dyotropic byproduct. Several high-energy pathways can be excluded with high probability.
A multi-reference study of the byproduct formation for a ring-closed dithienylethene photoswitch
(2015)
Photodriven molecular switches are sometimes hindered in their performance by forming byproducts which act as dead ends in sequences of switching cycles, leading to rapid fatigue effects. Understanding the reaction pathways to unwanted byproducts is a prerequisite for preventing them. This article presents a study of the photochemical reaction pathways for byproduct formation in the photochromic switch 1,2-bis-(3-thienyl)-ethene. Specifically, using single- and multi-reference methods the post-deexcitation reaction towards the byproduct in the electronic ground state S0 when starting from the S1–S0 conical intersection (CoIn), is considered in detail. We find an unusual low-energy pathway, which offers the possibility for the formation of a dyotropic byproduct. Several high-energy pathways can be excluded with high probability.
Fluid force microscopy combines the positional accuracy and force sensitivity of an atomic
force microscope (AFM) with nanofluidics via a microchanneled cantilever. However, adequate
loading and cleaning procedures for such AFM micropipettes are required for various
application situations. Here, a new frontloading procedure is described for an AFM micropipette
functioning as a force- and pressure-controlled microscale liquid dispenser. This frontloading
procedure seems especially attractive when using target substances featuring high
costs or low available amounts. Here, the AFM micropipette could be filled from the tip side
with liquid from a previously applied droplet with a volume of only a few μL using a short
low-pressure pulse. The liquid-loaded AFM micropipettes could be then applied for experiments
in air or liquid environments. AFM micropipette frontloading was evaluated with the
well-known organic fluorescent dye rhodamine 6G and the AlexaFluor647-labeled antibody
goat anti-rat IgG as an example of a larger biological compound. After micropipette usage,
specific cleaning procedures were tested. Furthermore, a storage method is described, at
which the AFM micropipettes could be stored for a few hours up to several days without drying
out or clogging of the microchannel. In summary, the rapid, versatile and cost-efficient
frontloading and cleaning procedure for the repeated usage of a single AFM micropipette is
beneficial for various application situations from specific surface modifications through to
local manipulation of living cells, and provides a simplified and faster handling for already
known experiments with fluid force microscopy.
Fluid force microscopy combines the positional accuracy and force sensitivity of an atomic force microscope (AFM) with nanofluidics via a microchanneled cantilever. However, adequate loading and cleaning procedures for such AFM micropipettes are required for various application situations. Here, a new frontloading procedure is described for an AFM micropipette functioning as a force-and pressure-controlled microscale liquid dispenser. This frontloading procedure seems especially attractive when using target substances featuring high costs or low available amounts. Here, the AFM micropipette could be filled from the tip side with liquid from a previously applied droplet with a volume of only a few mu L using a short low-pressure pulse. The liquid-loaded AFM micropipettes could be then applied for experiments in air or liquid environments. AFM micropipette frontloading was evaluated with the well-known organic fluorescent dye rhodamine 6G and the AlexaFluor647-labeled antibody goat anti-rat IgG as an example of a larger biological compound. After micropipette usage, specific cleaning procedures were tested. Furthermore, a storage method is described, at which the AFM micropipettes could be stored for a few hours up to several days without drying out or clogging of the microchannel. In summary, the rapid, versatile and cost-efficient frontloading and cleaning procedure for the repeated usage of a single AFM micropipette is beneficial for various application situations from specific surface modifications through to local manipulation of living cells, and provides a simplified and faster handling for already known experiments with fluid force microscopy.
L-selectin is a protein with potential importance for numerous diseases and clinical disorders. In this paper, we present a new aptamer-based luminescent assay developed to detect L-selectin. The sensing system working principle is based on Forster Resonance Energy Transfer (FRET) from a donor terbium complex (TbC) to an acceptor cyanine dye (Cy5). In the present approach, the biotinylated aptamer is combined with Cy5-labelled streptavidin (Cy5-Strep) to yield an aptamer-based acceptor construct (Apta-Cy5-Strep), while L-selectin is conjugated using luminescent TbC. Upon aptamer binding to the TbC-labelled L-selectin (L-selectin-TbC), permanent donor-acceptor proximity is established which allows for radiationless energy transfer to occur. However, when unlabelled L-selectin is added, it competes with the L-selectin-TbC and the FRET signal decreases as the L-selectin concentration increases. FRET from the TbC to Cy5 was observed with time-gated time-resolved luminescence spectroscopy. A significant change in the corrected luminescence signal was observed in the dynamic range of 10 -500 ng/mL L-selectin, the concentration range relevant for accelerated cognitive decline of Alzheimer's disease, with a limit of detection (LOD) equal to 10 ng/mL. The aptasensor-based assay is homogeneous and can be realized within one hour. Therefore, this method has the potential to become an alternative to tedious heterogeneous analytical methods, e.g. based on enzyme-linked immunosorbent assay (ELISA). (C) 2015 Elsevier B.V. All rights reserved.