Interactions modes and physical properties in transition metal chalcogenolene-based molecular materials

Molecule-based materials are extremely versatile materials as they can be built from specifically designed building blocks with the desired size, shape, charge and electronic properties which determine their intermolecular interactions and, thus, their organization in the solid. The intermolecular interactions, therefore, in particular van der Waals interactions, π–π and π–d interactions, H-bonding, etc., play a crucial role in self-assembling these pre-designed molecular units and may provide a powerful way to afford layered mono- and multifunctional molecular materials with new or unknown physical properties. In this review the relationship between interaction modes and physical properties of organic/inorganic hybrids based on transition metal complexes with chalcogenolene ligands will be examined and an outlook will be proposed. With this goal, magnetic materials, highly conducting and metallic single-component materials containing dithiolene complex building blocks, multifunctional materials where the dithiolene complex is the magnetic or conducting component in addition to more complex systems involving other types of building block such as the metal oxalate complexes, will be discussed.     

MSFIA-LOV system for Ra isolation and pre-concentration from water samples previous radiometric detection

An automatic system based on multisyringe flow injection analysis (MSFIA) and lab-on-valve (LOV) flow techniques for separation and pre-concentration of ²²⁶Ra from drinking and natural water samples has been developed. The analytical protocol combines two different procedures: the Ra adsorption on MnO₂ and the BaSO₄ co-precipitation, achieving more selectivity especially in water samples with low radium levels.     

Technical electrodes catalyzed with PtRu on mesoporous ordered carbons for liquid direct methanol fuel cells

This paper presents the behavior of ordered mesoporous carbon (OMC)-supported catalysts as anodes for direct methanol fuel cells (DMFC), fed with an aqueous methanol solution. OMC samples were prepared by the nanocasting method from a polymerized furan resin using mesoporous silica as a template. Pt and PtRu nanoparticles were supported on OMC with high dispersion, the particle size being 2.4 nm at PtRu loading of 15 wt.%. The resulting catalysts were analyzed using carbon monoxide stripping voltammetry, cyclic voltammetry, and chronoamperometry in three-electrode experiments and recording cell voltage vs. current density curves in practical DMFC. It was found that PtRu-catalyzed technical electrodes exhibited good activity towards methanol electrooxidation in half-cell experiments under fuel-cell-relevant conditions. Specifically, Pt₈₅Ru₁₅/OMC catalyst showed the highest catalytic enhancement compared to Pt/OMC for the steady-state electrooxidation of methanol at 60 °C and 0.5 V, by a factor of 22 in 2-M MeOH solution. DMFC single cells yielded an open-circuit voltage of 0.625 V at 60 °C. Polarization curves indicate that DMFC with OMC-supported Pt₈₅Ru₁₅ catalyst at the anode exhibited the best performance.     

Sulfoxides in the allylation of aldehydes in the presence of silicon tetrachloride and allyltributylstannane

SiCl₄ can be conveniently activated by catalytic amounts of dimethyl sulfoxide or other readily-available sulfoxides for the allylation of aromatic, hetero-aromatic and unsaturated aldehydes in the presence of allyltributyl stannane. Chiral aryl methyl sulfoxides have been used to develop asymmetric allylation methods, as well as probe the aldehyde substrate scope.     

Enhanced Anion Binding from Unusual Coordination Modes of Bis(thiourea) Ligands in Platinum Group Metal Complexes

Treatment of a range of bis(thiourea) ligands with inert organometallic transition‐metal ions gives a number of novel complexes that exhibit unusual ligand binding modes and significantly enhanced anion binding ability. The ruthenium(II) complex [Ru(η⁶‐p‐cymene)(κS,S′,N‐ L³ ?H)]⁺ ( 2 b ) possesses juxtaposed four‐ and seven‐membered chelate rings and binds anions as both 1:1 and 2:1 host guest complexes. The pyridyl bis(thiourea) complex [Ru(η⁶‐p‐cymeme)(κS,S′,N_py‐ L⁴ )]²⁺ ( 4 ) binds anions in both 1:1 and 1:2 species, whereas the free ligand is ineffective because of intramolecular NH???N hydrogen bonding. Novel palladium(II) complexes with nine‐ and ten‐membered chelate rings are also reported.     

Investigation of drift gas selectivity in high resolution ion mobility spectrometry with mass spectrometry detection

Recent studies in electrospray ionization (ESI)/ion mobility spectrometry (IMS) have focussed on employing different drift gases to alter separation efficiency for some molecules. This study investigates four structurally similar classes of molecules (cocaine and metabolites, amphetamines, benzodiazepines, and small peptides) to determine the effect of structure on relative mobility changes in four drift gases (helium, nitrogen, argon, carbon dioxide). Collision cross sections were plotted against drift gas polarizability and a linear relationship was found for the nineteen compounds evaluated in the study. Based on the reduced mobility database, all nineteen compounds could be separated in one of the four drift gases, however, the drift gas that provided optimal separation was specific for the two compounds.     

Capillary sodium dodecyl sulfate-DALT electrophoresis with laser-induced fluorescence detection for size-based analysis of proteins in human colon cancer cells

Capillary sodium dodecyl sulfate (SDS)-DALT electrophoresis (SDS-DALT-CE) refers to CE separation of proteins based on their size; DALT is the abbreviation for Dalton, the unit used to describe molecular weight. In this work, seven proteins from 18 to 116 kDa were denatured by SDS, labeled by 3-(2-furoyl) quinoline-2-carboxaldehyde, separated by SDS-DALT-CE in polyethylene oxide sieving matrix, and detected by laser-induced fluorescence (LIF) in a sheath flow cuvette. This method was combined with detergent differential fractionation, which is a protein fractionation method using a series of detergent-containing buffers to sequentially extract protein fractions from cells, to analyze the proteins in HT29 human colon adenocarcinoma cells. In addition, on-column labeling was demonstrated for protein analysis by SDS-DALT-CE with LIF, and applied to analysis of proteins in a single HT29 cancer cell. Most proteins had molecular masses from 10 to 120 kDa. Similar protein profiles were obtained for single cells and protein extract of a large cell population.     

A Mononuclear Uranium(IV) Single‐Molecule Magnet with an Azobenzene Radical Ligand

A tetravalent uranium compound with a radical azobenzene ligand, namely, [{(SiMe₂NPh)₃‐tacn}U^IV(η²‐N₂Ph₂^.)] ( 2 ), was obtained by one‐electron reduction of azobenzene by the trivalent uranium compound [U^III{(SiMe₂NPh)₃‐tacn}] ( 1 ). Compound 2 was characterized by single‐crystal X‐ray diffraction and ¹H NMR, IR, and UV/Vis/NIR spectroscopy. The magnetic properties of 2 and precursor 1 were studied by static magnetization and ac susceptibility measurements, which for the former revealed single‐molecule magnet behaviour for the first time in a mononuclear U^IV compound, whereas trivalent uranium compound 1 does not exhibit slow relaxation of the magnetization at low temperatures. A first approximation to the magnetic behaviour of these compounds was attempted by combining an effective electrostatic model with a phenomenological approach using the full single‐ion Hamiltonian.