Femtosecond UV excitation in imidazolium-based ionic liquids.

Femtosecond pump-probe absorption spectroscopy was employed to investigate ultrafast dynamics in various room temperature ionic liquids (RTILs) based on imidazolium cations, i.e., 1,3-dimethylimidazolium iodide ([DMIM]I), 1-butyl-3-methylimidazolium iodide ([BMIM]I), 1-hexyl-3-methylimidazolium iodide ([HMIM]I), 1-hexyl-3-methylimidazolium chloride ([HMIM]Cl), and 1-methyl-3-octylimidazolium chloride ([MOIM]Cl).

Suppression of the kinase activity of receptor tyrosine kinases by anthocyanin-rich mixtures extracted from bilberries and grapes.

Two standardized anthocyanin-rich mixtures were investigated for their ability to inhibit the receptor tyrosine kinases (RTKs) EGFR, ErbB2, ErbB3, VEGFR-2, and VEGFR-3. Both mixtures reduced the kinase activity of recombinant kinase domains of each RTK at concentrations View Article and Find Full Text PDF

Family of heterometallic semicircular Mn(III)2Ln(III)3 strands.

A series of heterometallic complexes of formula [Mn(III)(2)Ln(III)(3)(bdeaH)(3)(bdea)(2)(piv)(8)] x MeCN, where bdeaH(2) = N-butyldiethanolamine, piv = pivalate, and Ln = Y (1), Tb (2), Dy (3), Ho (4), and Er (5), has been prepared. 1-5 are isostructural, with the metal centers forming a novel semicircular Ln(III)-Mn(III)-Ln(III)-Mn(III)-Ln(III) strand. Only 2 and 3 exhibit slow relaxation of the magnetization, suggesting that the highly anisotropic Ln(III) ions (Tb(III) and Dy(III)) are essential for an energy barrier to spin reversal.

Functionalization of hexakis methanofullerene malonate crown-ethers: promising octahedral building blocks for molecular networks.

Hexaazido and hexaiodo macrocyclic methanofullerenes undergo high-yielding sixfold click reactions or sixfold Heck, Sonogashira and Suzuki cross-coupling reactions, respectively, to yield all organic building blocks for higher molecular architectures.

Sn3I8 x 2 (18-crown-6): a mixed-valent tin-crown-ether complex.

By reaction of SnI(2), SnI(4), and crown ether (18-crown-6) in the ionic liquid [NMe(n-Bu)(3)][N(Tf)(2)], Sn(3)I(8) x 2 (18-crown-6) is obtained in the form of black, plate-shaped crystals and crystallizes with a monoclinic lattice symmetry. In detail, Sn(3)I(8) x 2 (18-crown-6) is constituted of trigonal-bipyramidal [SnI(5)](-)-anions and [Sn(2)I(3)(18-crown-6)(2)](+)-cations. The cation exhibits an endocyclical coordination of Sn(2+) by the crown ether.

Ray-based simulation of the propagation of light with different degrees of coherence through complex optical systems.

We show the functional extension of a standard ray tracer to be capable of tracing light fields of different degrees of coherence through complex optical systems. The light fields are represented by spherical waves. An approximate reconstruction of the optical field is possible at arbitrary positions in an optical system under investigation.

Method to determine the speckle characteristics of front projection screens.

We present a method to determine the speckle properties of front projection screens. Seven different screens are investigated in a backscattering geometry for 808 nm light. The speckle contrast reduction that results from polarization scrambling and reduced temporal coherence is modeled for the case of volume scattering in the screens.

Syntheses, structures and electronic properties of zwitterionic iron(II) and cobalt(II) complexes featuring ambidentate tris(pyrazolyl)methanide ligands.

By deprotonation of the corresponding tris(pyrazolyl)methane ((Me)Tpm) precursor complexes [M((Me)Tpm)(2)][(OTf)(2)] (1 and 2), the zwitterionic tris(pyrazolyl)methanide iron(II) (3) and cobalt(II) (4) "sandwich" complexes of the general formula [M((Me)Tpmd)(2)] are easily accessible. The structurally characterised complexes 3 and 4 are the first such homoleptic 3d transition metal species to feature two "naked", outward pointing pyramidal carbanions. Density functional theory calculations show metal-centred HOMOs and LUMOs with the destabilised carbanion orbitals in the energy region of the filled transition-metal-centred frontier orbitals.

Design of a microwave applicator for nanoparticle synthesis.

This paper presents the design and realization of a microwave applicator at 2.45 GHz for the synthesis of gold nanoparticles. The particles are dissolved in N,N-dimethylformamide (DMF).

Ultrafast click conjugation of macromolecular building blocks at ambient temperature.

Block copolymers in seconds: Catalyst-free, ambient-temperature click conjugation of individual polymer strands becomes possible using novel ATRP-derived cyclopentadienyl-capped polymers in an extremely rapid hetero-Diels-Alder cycloaddition with macromolecules equipped with electron-deficient dithioester end groups prepared by the RAFT process.

Pyrenylmethyldeoxyadenosine: a 3'-cap for universal DNA hybridization probes.

A ligand that stabilizes a three-dimensional structure can be expected to have a positive effect on the specificity with which this structure is formed. Here we report on a ligand covalently linked to an oligonucleotide that increases duplex stability, but decreases base-pairing selectivity at the terminus. The ligand consists of a dangling 2'-deoxyadenosine residue with a pyrenylmethyl substituent at the N6-position, that is, a deoxynucleoside with a covalently linked polycyclic aromatic hydrocarbon (PAH).

Nanostructuring of organic-inorganic hybrid materials for distributed feedback laser resonators by two-photon polymerization.

With two-photon absorption induced polymerization arbitrary three dimensional nano- and microstructures can be patterned directly into photoresists. We report on the fabrication of a low threshold organic semiconductor distributed feedback laser using the technique of two-photon absorption induced polymerization. A surface grating with 400 nm periodicity and 40 nm height modulation was fabricated by two-photon absorption induced polymerization in the organic-inorganic hybrid material ORMOCER.

Low-speckle laser projection with a broad-area vertical-cavity surface-emitting laser in the nonmodal emission regime.

We demonstrate low-speckle laser projection using a broad-area vertical-cavity surface-emitting laser (VCSEL) emitting at 840 nm wavelength as the illumination source. By driving the source in a nonmodal emission regime, we were able to achieve speckle contrast values as low as 3.5% in a realistic projection setup.

Delphinidin modulates the DNA-damaging properties of topoisomerase II poisons.

The anthocyanidin delphinidin (DEL) has recently been shown to inhibit human topoisomerase I and II, without stabilizing the covalent DNA/topoisomerase intermediate [Habermeyer, M., Fritz, J., Barthelmes, H.

Comparison of the electrophysiologically based optimization methods with different pacing parameters in patient undergoing resynchronization treatment.

Many studies conducted on patients suffering from congestive heart failure have shown the efficacy of cardiac resynchronization therapy (CRT). The presented research investigates an off-line optimization algorithm based on different electrode positioning and timing delays. A computer model of the heart was used to simulate left bundle branch block (LBBB), myocardial infarction (MI) and reduction of intraventricular conduction velocity in order to customize the patient symptom.

Dependencies of micro-pillar cavity quality factors calculated with finite element methods.

We present simulation results for optical modes in micro-pillar cavities that were computed with the finite element method and that show good agreement with experimental data. By means of this viable tool various influences on the quality factor of the fundamental mode were calculated: Firstly, the light confinement depends strongly on the absorption of the semiconductor cavity material. Here we were able to determine absolute maximum quality factors achievable in a GaAs/AlAs Bragg micro-pillar cavity.

[(OtBu)(2)C(6)H(3)](3)Ge(+) a free germyl cation with aryl ligands.

The reaction of Ar(3)GeBr (Ar = 2,6-(OtBu)(2)C(6)H(3)), which is the side product of the synthesis of the metalloid germanium cluster compound Ge(8)Ar(6), with the silver salt of the weakly coordinating anion (WCA) [Al(OR(f))(4)](-) (R(f) = C(CF(3))(3)) gives the free germyl cation Ar(3)Ge(+). Quantum chemical calculations open an insight into the bonding situation of this first free cation exhibiting aryl ligands and a first reaction leading to Ar(3)GeOH is presented.

Pentagerma[1.1.1]propellane: a combined experimental and quantum chemical study on the nature of the interactions between the bridgehead atoms.

Ge, whiz! A detailed study of the synthesis, structure, redox chemistry, and bonding properties of pentagerma[1.1.1]propellane (1, see picture) examines fundamental aspects of the interactions between the bridgehead germanium atoms.

Negative-index bianisotropic photonic metamaterial fabricated by direct laser writing and silver shadow evaporation.

We present the blueprint for a novel negative-index metamaterial. This structure is fabricated via three-dimensional two-photon direct laser writing and silver shadow evaporation. The comparison of measured linear optical spectra with theory shows good agreement and reveals a negative real part of the refractive index at around 3.

Reconsidering the quantitative analysis of organic carbon concentrations in size exclusion chromatography.

The evaluation of the molecular size distribution of natural organic matter (NOM) in aquatic environments via size exclusion chromatography (SEC) is important for the understanding of environmental processes such as nutrient cycling and pollutant transport as well as of technical water treatment processes. The use of organic carbon (OC) detectors has become popular in recent studies due to improved availability and quantification possibilities, which supposedly are superior to those of ultraviolet (UV) detectors. A set of 12 NOM samples was used to demonstrate the limitations of online OC detection (OCD) when analyzing complex aquatic organic matter.

Multidentate ligand systems featuring dual functionality.

Multifunctional ligands with podand topology provide intrinsically well-defined coordination geometries. Several subgroups of multidentate ligand systems comprising dual functionality have been developed so far. Recent advances made in this research area reflect its topicality.

Diaryl ether and diaryl thioether syntheses on solid supports via copper (I)-mediated coupling.

An efficient method to synthesize diaryl ethers and thioethers on solid supports is described. Starting from immobilized phenols or arylhalides, coupling with an access of aryliodides/arylbromides or phenolic/thiophenolic substrates in solution was successful in the presence of CuCl and Cs(2)CO(3) as base. Coupling conditions known from solution-phase syntheses of diaryl ethers have been effectively modified and adapted to solid-phase synthesis.

Heat of formation of the HOSO2 radical from accurate quantum chemical calculations.

The reaction HOSO(2)+O(2)-->HO(2)+SO(3) (2) is of crucial importance for sulfuric acid formation in the atmosphere, and reliable thermochemical data are required for an adequate modeling. The currently least well known thermochemical quantity of reaction (2) is the enthalpy of formation of the hydroxysulfonyl radical (HOSO(2)). We report on high-level quantum chemical calculations to predict the binding energy of the HO-SO(2) bond and deduce a value for the enthalpy of formation of HOSO(2) using the most reliable thermodynamic data of OH and SO(2).

Low energy hydrogenation products of extended pi systems CnH2x: a density functional theory search strategy, benchmarked against CCSD(T), and applied to C60.

An approach for the systematic determination of particularly stable hydride compositions C(n)H(2x) of a fullerene C(n) is presented. The study is divided into three parts. First, a CCSD(T) benchmark study on benzene and naphthalene hydrogenation is carried out.