Photochemistry with Chlorine Trifluoride: Syntheses and Characterization of Difluorooxychloronium(V) Hexafluorido(non)metallates(V), [ClOF2][MF6] (M=V,Nb, Ta,Ru, Os,Ir, P,Sb)

A photochemical route to salts consisting of difluorooxychloronium(V) cations, [ClOF₂]⁺, and hexafluorido(non)metallate(V) anions, [MF₆]⁻ (M=V, Nb, Ta, Ru, Os, Ir, P, Sb) is presented. As starting materials, either metals, oxygen and ClF₃ or oxides and ClF₃ are used. The prepared compounds were characterized by single-crystal X-ray diffraction and Raman spectroscopy. The crystal structures of [ClOF₂][MF₆] (M=V, Ru, Os, Ir, P, Sb) are layer structures that are isotypic with the previously reported compound [ClOF₂][AsF₆], whereas for M=Nb and Ta, similar crystal structures with a different stacking variant of the layers are observed. Additionally, partial or full O/F disorder within the [ClOF₂]⁺ cations of the Nb and Ta compounds occurs. In all compounds reported here, a trigonal pyramidal [ClOF₂]⁺ cation with three additional Cl⋅⋅⋅F contacts to neighboring [MF₆]⁻ anions is observed, resulting in a pseudo-octahedral coordination sphere around the Cl atom. The Cl−F and Cl−O bond lengths of the [ClOF₂]⁺ cations seem to correlate with the effective ionic radii of the M^V ions. Quantum-chemical, solid-state calculations well reproduce the experimental Raman spectra and show, as do quantum-chemical gas phase calculations, that the secondary Cl⋅⋅⋅F interactions are ionic in nature. However, both solid-state and gas-phase quantum-chemical calculations fail to reproduce the increases in the Cl−O bond lengths with increasing effective ionic radius of M in [MF₆]⁻ and the Cl−O Raman shifts also do not generally follow this trend.     

On Synge-type angle condition for <Emphasis Type="Italic">d</Emphasis>-simplices

The maximum angle condition of J. L. Synge was originally introduced in interpolation theory and further used in finite element analysis and applications for triangular and later also for tetrahedral finite element meshes. In this paper we present some of its generalizations to higher-dimensional simplicial elements. In particular, we prove optimal interpolation properties of linear simplicial elements in ? ^d that degenerate in some way.     

Fourier's law from closure equations

We sketch a rigorous derivation of Fourier's law from a system of closure equations for a nonequilibrium stationary state of a Hamiltonian system of coupled oscillators subjected to heat baths on the boundary. The local heat flux is proportional to the temperature gradient with a temperature dependent heat conductivity and the stationary temperature exhibits a nonlinear profile.     

Hybrid Supramolecular and Colloidal Hydrogels that Bridge Multiple Length Scales

Hybrid nanocomposites were constructed based on colloidal nanofibrillar hydrogels with interpenetrating supramolecular hydrogels, displaying enhanced rheological yield strain and a synergistic improvement in storage modulus. The supramolecular hydrogel consists of naphthyl‐functionalized hydroxyethyl cellulose and a cationic polystyrene derivative decorated with methylviologen moieties, physically cross‐linked with cucurbit[8]uril macrocyclic hosts. Fast exchange kinetics within the supramolecular system are enabled by reversible cross‐linking through the binding of the naphthyl and viologen guests. The colloidal hydrogel consists of nanofibrillated cellulose that combines a mechanically strong nanofiber skeleton with a lateral fibrillar diameter of a few nanometers. The two networks interact through hydroxyethyl cellulose adsorption to the nanofibrillated cellulose surfaces. This work shows methods to bridge the length scales of molecular and colloidal hybrid hydrogels, resulting in synergy between reinforcement and dynamics.     

Ultrasonically aided mineral processing technique for remediation of soil contaminated by heavy metals

In this study, power ultrasound was used as aiding method for the mineral processing technique, which have recently been developed for the remediation of soil contaminated by heavy metal containing bullets, their broken parts and alteration products. Power ultrasound was used to disperse the soil to remove metals and metal compounds from soil particle surfaces instead of attrition conditioning. The soil diluted with water was treated using 22 kHz ultrasound power of 100 W up to 500 W. The effect of different ultrasonic treatment time and pulsation of ultrasound were studied on the purity of sink and float fractions in heavy medium separation process, screen fractions, and mineral concentrates and tailings from flotation process. Ultrasound enhanced the remediation of soil fractions in all the studied cases. Optimisation of the ultrasonic power will be done in the continuation study.     

Effect of van der Waals interactions on H<Subscript>2</Subscript> dissociation on clean and defected Ru(0001) surface

Ab initio computational methods are used to study the relevance of van der Waals interactions in the case of a hydrogen molecule adsorption on the Ru(0001) surface. In addition to the clean surface, the effects of ruthenium adatom and vacancy on the process are studied. The adsorption characteristics are analyzed in terms of two dimensional cuts of the potential energy surface (PES). Based on the earlier studies for such systems, we mostly concentrate on the trajectories where the hydrogen molecule approaches the surface in parallel orientation. The results indicate that for a clean Ru(0001) the calculations applying the non-local van der Waals potentials yield higher barriers for the dissociation of the H₂ molecule. Of the high symmetry sites on Ru(0001), the top site is found to be the most reactive one. The vacancy and ruthenium adatom sites exhibit high dissociation barriers compared with the clean surface.     

Stable carbon isotopic composition of peat columns,subsoil and vegetation on natural and forestry-drained boreal peatlands

ABSTRACT

We studied natural and forestry-drained peatlands to examine the effect of over 34 years lowered water table on the δ¹³C values of vegetation, bulk peat and subsoil. In the seven studied sites, δ¹³C in the basal peat layer was 1.1 and 1.2?‰ lower than that of the middle-layer and surface layer, respectively. Furthermore, there was a positive correlation between the δ¹³C values of the basal and surface peat layers, possibly due to carbon (C) recycling within the peat column. In the same mire complex, natural fen peat δ¹³C values were lower than those of the nearby bog, possibly due to the dominance of vascular plants on fen and the generally larger share of recycled C in the fens than in the bogs. Furthermore, natural and 51 years previously drained fen and bog, on the opposite sides of a ditch on the same mire complex, showed no significant differences in δ¹³C values. Plant δ¹³C values were lower, while δ¹³C values of subsoil were higher in the drained than in the natural site of the fen.     

Antibody-free lanthanide-based fluorescent probe for determination of protein tyrosine kinase and phosphatase activities

A single-labeled peptide probe for measuring peptide phosphorylation status was developed by using a phosphate sensitive terbium chelate. The activity of Abl protein tyrosine kinase and T-cell protein Tyrosine phosphatase (TC PTP) was monitored in real time. To study the probe design in detail, variable substrate peptide sequences, where the enzyme target site was located from two to five amino acids apart from the nearest tyrosine residue, were synthesized. The maximum change observed in fluorescence intensity after phosphorylation was up to 320%, when the phosphorylated tyrosine was located two amino acids from the lysine coupled to the phosphate sensitive terbium chelate, demonstrating an excellent performance for a homogeneous assay. Also the longer distance of five amino acids between the phosphorylated tyrosine residue and terbium chelate resulted up to 260% change in fluorescence intensity.

Octanuclear gold(I) alkynyl-diphosphine clusters showing thermochromic luminescence

The unprecedented, purely gold(I) alkynyl-diphosphine clusters 1-3 demonstrate intense room-temperature phosphorescence with maximum quantum efficiency of 92% in solution (3) and 86% in solid (2) and thermally dependent emission in the crystalline form, attributed to the crystal lattice arrangement.     

Structural Characteristics of Graphane‐Type C and BN Nanostructures by Periodic Local MP2 Approach

The structural characteristics of fully‐hydrogenated carbon and boron nitride mono‐ and multilayer slabs, together with nanotubes derived from the slabs, are investigated mainly by means of periodic local second‐order Møller–Plesset perturbation (LMP2) calculations and the results are compared with Hartree–Fock (HF), density functional theory (DFT), and dispersion function‐augmented DFT (DFT‐D) obtained ones. The investigated systems are structurally analogous to (111) and (110) slabs of diamond, where the hydrogenated (111) slab of diamond corresponds to the experimentally known graphane. Multilayering of monolayers and nanotubes is energetically favorable at the LMP2 level for both C and BN, while HF and DFT are not able to reproduce this behavior for CH systems. The work highlights the importance of utilizing methods capable of properly describing weak interactions in the investigation of dispersively‐bound systems such as the multilayered graphanes and the corresponding nanotubes.