Interfacing Glycosylated Carbon‐Nanotube‐Network Devices with Living Cells to Detect Dynamic Secretion of Biomolecules

A sense of cell‐being : Single‐walled carbon nanotubes (SWNTs) are functionalized with bioactive monosaccharides to enable their use as biosensors. The glycosylated nanotube network is biocompatible and can interface with living cells (see scheme) to electronically detect biomolecular release with high temporal resolution and high sensitivity.

     

Formaldehyde Formation on Vanadium Oxide Surfaces V2O3(0001) and V2O5(001): How does the Stable Methoxy Intermediate Form?

Hydroxy‐mediated methoxy formation or stabilization is probably an important process in many methanol adsorption systems. Hydrogen atoms originating from the scission of the methanol O? H bond react with the substrate and form water. This process may result 1) in the production of additional surface defects as reactive centers for methoxy formation and 2) in the stabilization of methoxy groups by suppression of methanol formation.

     

Expressing Forest Origins in the Chemical Composition of Cooperage Oak Woods and Corresponding Wines by Using FTICR‐MS

A non‐targeted, ultra‐high‐resolution mass spectrometric, direct analysis of oak‐wood extracts from two species (Quercus robur L. and Quercus petraea Liebl.) from three French forests, and of a wine aged in barrels derived therefrom has been performed to identify families of metabolites that could discriminate both the species and the geographical origin of woods. From 12 T ultra‐high‐resolution Fourier transform ion cyclotron resonance mass spectra of wood extracts, hundreds of mass signals were identified as possible significant biomarkers of the two species, with phenolic and carbohydrate moieties leading the differentiation between Q. robur and Q. petraea, respectively, as corroborated by both FTMS and NMR data. For the first time, it is shown that oak woods can also be discriminated on the basis of hundreds of forest‐related compounds, and particular emphasis is put on sessile oaks from the Tronçais forest, for which sugars are significantly discriminant. Despite the higher complexity and diversity of wine metabolites, forest‐related compounds can also be detected in wines aged in related barrels. It is only by using these non‐targeted analyses that such innovative results, which reveal specific chemodiversities of natural materials, can be obtained.     

Phosphinoborane and Sulfidoborohydride as Chelating Ligands in Polyhydride Ruthenium Complexes: Agostic σ‐Borane versus Dihydroborate Coordination

A question of coordination mode : Two new borane compounds are prepared. They act as bifunctional ligands as illustrated by their reaction with ruthenium polyhydrides which leads to the formation of two complexes (see scheme) displaying either a δ‐agostic interaction of a η²‐B? H bond involving a trivalent boron atom or a dihydroborate ligation.

     

Hydrogen Bonding in Protic Ionic Liquids: Reminiscent of Water

Similarities and differences : Far‐infrared spectra of protic ionic liquids could be assigned to intermolecular bending and stretching modes of hydrogen bonds. The characteristics of the low‐frequency spectra resemble those of water. Both liquids form three‐dimensional network structures, but only water is capable of building tetrahedral configurations. EAN: ethylammonium nitrate, PAN: propylammonium nitrate, DMAN: dimethylammonium nitrate.

     

Mechanistic Insight into Formation of Oxo‐Iron(IV) Porphyrin π‐Cation Radicals from Enzyme Mimics of Cytochrome P450 in Organic Solvents

Two new models for cytochrome P450 in which the thiolate axial ligand is replaced by an RSO₃^? group, form oxo‐iron(IV) porphyrin π‐cation radicals as sole oxidation products in “peroxo shunt” reactions (see scheme) independent of the nature of the employed solvent (polar or non‐polar) and electronic nature of the porphyrin rings.

     

Discrimination of G‐Quadruplexes from Duplex and Single‐Stranded DNAs with Fluorescence and Energy‐Transfer Fluorescence Spectra of Crystal Violet

G‐rich nucleic acid sequences with the potential to form G‐quadruplex structures are common in biologically important regions. Most of these sequences are present with their complementary strands, so the development of a sensitive biosensor to distinguish G‐quadruplex and duplex structures and to determine the competitive ability of quadruplex to duplex structures has received a great deal of attention. In this work, the interactions between two triphenylmethane dyes (malachite green (MG) and crystal violet (CV)) and G‐quadruplex, duplex, or single‐stranded DNAs were studied by fluorescence spectroscopy and energy‐transfer fluorescence spectroscopy. Good discrimination between quadruplexes and duplex or single‐stranded DNAs can be achieved by using the fluorescence spectrum of CV or the energy‐transfer fluorescence spectra of CV and MG. In addition, by using energy‐transfer fluorescence titrations of CV with G‐quadruplexes, the binding‐stoichiometry ratios of CV to G‐quadruplexes can be determined. By using the fluorescence titrations of G‐quadruplex–CV complexes with C‐rich complementary strands, the fraction of G‐rich oligonucleotide that engages in G‐quadruplex structures in the presence of the complementary sequence can be measured. This study may provide a simple method for discrimination between quadruplexes and duplex or single‐stranded DNAs and for measuring G‐quadruplex percentages in the presence of the complementary C‐rich sequences.     

Chemical Infiltration during Atomic Layer Deposition: Metalation of Porphyrins as Model Substrates

New uses for ALD : By applying standard metal oxide atomic layer deposition (ALD) to two types of porphyrins, site‐specific chemical infiltration of substrate molecules is achieved: Diethylzinc can diffuse into the interior of porphyrin supramolecular structures and induce metalation of the porphyrin molecules from the vapor phase. A=Ph, p‐HO₃SC₆H₄.

     

Ferrocenyl‐Ended Thieno–Vinylene Oligomers: Donor–Acceptor Polarization and Mixed‐Valence Properties with Emphasis on the Raman Mapping of Localized‐to‐Delocalized Transitions

What's your role? New oligothiophene–vinylene compounds have been synthesized to study the role of the conjugated chain in two different cases (see scheme; MV=mixed valence). The electronic and molecular structures were analyzed by means of electronic, X‐ray photoelectron, and Raman spectroscopy, together with thermo spectroscopy, electrochemistry, and DFT calculations.