Optimisation of ultrasonic-assisted extraction of bioactive compounds from chokeberry pomace using response surface methodology.

Background: Chokeberry pomace is a valuable by-product of fruit processing because of its high levels    of phenolic compounds and anthocyanins. The study was aimed to optimise chokeberry pomace extraction of total phenolic content, total anthocyanin content and antioxidant activity using response surface methodology.

Methods: Response surface methodology was used to evaluate the effect of the concentration of ethanol (in the range of 60–96%) and sonication time (from 10 to 30 min) as independent variables on total phenolic content, antioxidant capacity and total anthocyanin content as the response functions.

Molecular weaving via surface-templated epitaxy of crystalline coordination networks.

One of the dream reactions in polymer chemistry is the bottom-up, self-assembled synthesis of polymer fabrics, with interwoven, one-dimensional fibres of monomolecular thickness forming planar pieces of textiles. We have made a major step towards realizing this goal by assembling sophisticated, quadritopic linkers into surface-mounted metal-organic frameworks. By sandwiching these quadritopic linkers between sacrificial metal-organic framework thin films, we obtained multi-heteroepitaxial, crystalline systems.

Identification of saponins from sugar beet (Beta vulgaris) by low and high-resolution HPLC-MS/MS.

We profiled triterpene saponins from the roots of sugar beet Beta vulgaris L. cultivars Huzar and Boryna using reversed-phase liquid chromatography combined with negative-ion electrospray ionization quadrupole mass spectrometry. We tentatively identified 26 triterpene saponins, including 17 that had not been detected previously in this plant species and 7 saponins that were tentatively identified as new compounds.

Characterisation and identification of triterpene saponins in the roots of red beets (Beta vulgaris L.) using two HPLC-MS systems.

Triterpene saponins are important bioactive constituents with an enormous variety in structure widely distributed in many plants. Here, we profiled triterpene saponins from the skin and flesh of red beetroot Beta vulgaris L. cultivars Nochowski from 2012 and 2013 season using reversed-phase liquid chromatography combined with negative-ion electrospray ionisation quadrupole mass spectrometry.

Redox-switching in a viologen-type adlayer: an electrochemical shell-isolated nanoparticle enhanced Raman spectroscopy study on Au(111)-(1×1) single crystal electrodes.

We reported the first application of in situ shell-isolated nanoparticle enhanced Raman spectroscopy (SHINERS) to an interfacial redox reaction under electrochemical conditions. We construct gap-mode sandwich structures composed of a thiol-terminated HS-6V6H viologen adlayer immobilized on a single crystal Au(111)-(1×1) electrode and covered by Au(60 nm)@SiO(2) core-shell nanoparticles acting as plasmonic antennas. We observed high-quality, potential-dependent Raman spectra of the three viologen species V(2+), V(+●), and V(0) on a well-defined Au(111) substrate surface and could map their potential-dependent evolution.

Electroluminescence from a single nanotube-molecule-nanotube junction.

The positioning of single molecules between nanoscale electrodes has allowed their use as functional units in electronic devices. Although the electrical transport in such devices has been widely explored, optical measurements have been restricted to the observation of electroluminescence from nanocrystals and nanoclusters and from molecules in a scanning tunnelling microscope setup. In this Letter, we report the observation of electroluminescence from the core of a rod-like molecule between two metallic single-walled carbon nanotube electrodes forming a rigid solid-state device.

Variation of the ultrafast fluorescence quenching in 2,6-sulfanyl-core-substituted naphthalenediimides by electron transfer.

The ultrafast fluorescence quenching of 2,6-sulfanyl-core-substituted naphthalenediimides was investigated by transient spectroscopy. We find a strong dependence of the relaxation on the chemical structure of the substituent. Direct linking of an aryl rest to the sulfur atom leads to a strong red shift of the fluorescence in 1 ps and the disappearance of the emission in 5-7 ps depending on the polarity and viscosity of the solvent.

High aspect ratio constructive nanolithography with a photo-dimerizable molecule.

A major challenge in constructive nanolithography is the preservation of the lateral resolution of a monolayer-thick template pattern while amplifying it to a structure with a thickness above 10 nm. So far, the most successful approach to achieve this is surface-initiated polymerization (SIP) from e-beam structured monolayer templates in a multistep process. However, spreading of the polymer on the substrate leads to a rapid line-widening.

Self-assembled monolayers from biphenyldithiol derivatives: optimization of the deprotection procedure and effect of the molecular conformation.

A series of biphenyl-derived dithiol (BDDT) compounds with terminal acetyl-protected sulfur groups and different structural arrangements of both phenyl rings have been synthesized and fully characterized. The different arrangements were achieved by introducing hydrocarbon substituents in the 2 and 2' positions of the biphenyl backbone. The presented model compounds enable the investigation of the correlation between the intramolecular conformation and other physical properties of interest, like, e.

Bromine catalyzed conversion of S-tert-butyl groups into versatile and, for self-assembly processes accessible, acetyl-protected thiols.

The facile and efficient conversion of a tert-butyl protecting group to an acetyl protecting group for thiols by catalytic amounts of bromine in acetyl chloride and the presence of acetic acid has been developed. The fairly mild reaction conditions are of particular interest for new protecting group strategies for sulfur functionalised target structures.