Searching for Monomeric Nickel Tetrafluoride: Unravelling Infrared Matrix Isolation Spectra of Higher Nickel Fluorides.

Binary transition metal fluorides are textbook examples combining complex electronic features with most fundamental molecular structures. High-valent nickel fluorides are among the strongest known fluorinating and oxidizing agents, but there is a lack of experimental structural and spectroscopic investigations on molecular NiF or NiF . Apart from their demanding synthesis, also their quantum-chemical description is difficult due to their open shell nature and low-lying excited electronic states.

Toxicity and Toxicokinetic Study of Subcutaneously Administered RPh201 in Minipigs.

Mastic gum extracts are widely used as herbal remedies and are being tested for several clinical indications. Nevertheless, information on their safety is limited. RPh201 is an extract of the mastic gum, formulated and stabilized in a proprietary method, which is being developed as a novel drug candidate for neurological indications.

Real-time binding kinetic analyses of the interaction of the dietary stain orange II with dentin matrix.

Objectives: Dietary stains can be adsorbed into the dentin of teeth. Using Orange II as a model dietary stain, this study investigated the strength of its interaction with the mineral and protein components of dentin matrix and how hydrogen peroxide (HO) treatment influences this interaction.

Methods: Dentin slices were prepared from human teeth and were either deproteinized (5.

How Inert, Perturbing, or Interacting Are Cryogenic Matrices? A Combined Spectroscopic (Infrared, Electronic, and X-ray Absorption) and DFT Investigation of Matrix-Isolated Iron, Cobalt, Nickel, and Zinc Dibromides.

The interactions of FeBr, CoBr, NiBr, and ZnBr with Ne, Ar, Kr, Xe, CH, and N matrices have been investigated using IR, electronic absorption, and X-ray absorption spectroscopies as well as DFT calculations. ZnBr is linear in all of the matrices. NiBr is linear in all but N matrices, where it is severely bent.

Structure and Electronic Properties of the Quasi-One-Dimensional BaCoZnS Series.

This work focuses on the structure and physical properties of the solid solution BaCoZnS (0 ≤ x ≤ 1), a family of quasi-one-dimensional sulfides with end members BaCoS and BaZnS. The structure of selected compounds with increasing Zn content has been analyzed using neutron diffraction, transmission electron microscopy, and extended X-ray absorption fine structure, and the physical properties have been analyzed via magnetic susceptibility and resistivity measurements. The progressive substitution of the nonmagnetic Zn cation for Co rapidly destroys the antiferromagnetic transition present at 46 K in the quasi-one-dimensional BaCoS, leading to paramagnetic behavior down to the lowest investigated temperature (5 K) for compounds with x > 0.

A Matrix Isolation and Computational Study of Molecular Palladium Fluorides: Does PdF6 Exist?

Palladium atoms generated by thermal evaporation and laser ablation were reacted with and trapped in F2/Ar, F2/Ne, and neat F2 matrices. The products were characterized by electronic absorption and infrared spectroscopy, together with relativistic density functional theory calculations as well as coupled cluster calculations. Vibrational modes at 540 and 617 cm(-1) in argon matrices were assigned to molecular PdF and PdF2, and a band at 692 cm(-1) was assigned to molecular PdF4.

Spectroscopic and computational insight into the activation of O2 by the mononuclear Cu center in polysaccharide monooxygenases.

Strategies for O2 activation by copper enzymes were recently expanded to include mononuclear Cu sites, with the discovery of the copper-dependent polysaccharide monooxygenases, also classified as auxiliary-activity enzymes 9-11 (AA9-11). These enzymes are finding considerable use in industrial biofuel production. Crystal structures of polysaccharide monooxygenases have emerged, but experimental studies are yet to determine the solution structure of the Cu site and how this relates to reactivity.

How does iron interact with sporopollenin exine capsules? An X-ray absorption study including microfocus XANES and XRF imaging.

Sporopollenin exine capsules (SECs) derived from plant spores and pollen grains have been proposed as adsorption, remediation and drug delivery agents. Despite many studies there is scant structural data available. This X-ray absorption investigation represents the first direct structural data on the interaction of metals with SECs and allows elucidation of their structure-property relationships.

A study of hydrogen peroxide chemistry and photochemistry in tea stain solution with relevance to clinical tooth whitening.

Objective: Tooth whitening using hydrogen peroxide is a complex process, and there is still some controversy about the roles of pH, temperature, chemical activators, and the use of light irradiation. In this work the basic interactions between whitening agents and stain molecules are studied in simple solutions, thus avoiding the physics of diffusion and light penetration in the tooth to give clarity on the basic chemistry which is occurring.

Method: The absorbance of tea stain solution at 450 nm was measured over a period of 40 min, with various compositions of whitening agent added (including hydrogen peroxide, ferrous gluconate and potassium hydroxide) and at the same time the samples were subjected to blue light (465 nm) or infra-red light (850 nm) irradiation, or alternatively they were heated to 37°C.

A mechanistic study of the low pressure pyrolysis of linear siloxanes.

Matrix isolation IR spectroscopy has been used to study the vacuum pyrolysis of 1,1,3,3-tetramethyldisiloxane (L1), 1,1,3,3,5,5-hexamethyltrisiloxane (L2) and 3H,5H-octamethyltetrasiloxane (L3) at ca. 1000 K in a flow reactor at low pressures. The hydrocarbons CH3, CH4, C2H2, C2H4, and C2H6 were observed as prominent pyrolysis products in all three systems, and amongst the weaker features are bands arising from the methylsilanes Me2SiH2 (for L1 and L2) and Me3SiH (for L3).

Mercury-fluorine interactions: a matrix isolation investigation of Hg...F2, HgF2 and HgF4 in argon matrices.

HgF(2) and Hg have been trapped in dilute F(2)/Ar and neat F(2) matrices, subjected to UV-Vis and vac-UV photolysis and annealing, with the products identified by FTIR, UV-Vis-NIR and Hg L(3)-edge XAFS spectroscopic techniques. Whilst there was no convincing evidence for the formation of HgF(4) under our argon matrix isolation conditions, a new Hg..

Probing key coordination interactions: configurationally restricted metal activated CXCR4 antagonists.

The syntheses of configurationally restricted mono- and bis-macrocyclic copper(II) perchlorate complexes (copper(II) 5-benzyl-1,5,8,12-tetraazabicyclo[10.2.2]hexadecane and dicopper(II) 5,5'-[1,4-phenylenebis(methylene)]-bis(1,5,8,12-tetraazabicyclo[10.

Microscopy and spectroscopy of interactions between metallopolymers and carbon nanotubes.

The interaction between redox polymers, based on Ru- or Os-bis(2,2'-bipyridyl)-poly(4-vinylpyridine), and carbon nanotubes was investigated by spectroscopic and microscopic techniques. These metallopolymers were found to be excellent dispersants for nanotubes, as a result of a good wetting interaction between polymer and nanotubes. The results obtained show that well-coated individual nanotubes can be obtained.

General method of preparation of mesoporous M/Si3N4 nano-composites via a non-aqueous sol-gel route.

We report a general method for the preparation of transition-metal silicon nitride nanocomposites; for example, mesoporous Pd-Si3N4 nanocomposite materials with high surface area were prepared by pyrolysis of a silicon palladium imide-chloride complex which was synthesized by reaction of silicon diimide gel with palladium chloride. These porous nanocomposites catalyse organic reactions.

Structural study of the thermal and photochemical spin states in the spin crossover complex [Fe(phen)2(NCSe)2].

The first structural data for [Fe(phen)(2)(NCSe)(2)] (obtained using the extraction method of sample preparation) in its high-spin, low-spin and LIESST induced metastable high-spin states have been recorded using synchrotron radiation single crystal diffraction. The space group for all of the spin states was found to be Pbcn. On cooling from the high-spin state (HS-1) at 292 K through the spin crossover at about 235 K to the low-spin state at 100 K (LS-1) the iron coordination environment changed to a more regular octahedral geometry and the Fe-N bond lengths decreased by 0.

Use of released pigs as sentinels for Mycobacterium bovis.

Identifying the presence of bovine tuberculosis (TB; Mycobacterium bovis) in wildlife is crucial in guiding management aimed at eradicating the disease from New Zealand. Unfortunately, surveys of the principal wildlife host, the introduced brushtail possum (Trichosurus vulpecula), require large samples (> 95% of the population) before they can provide reasonable confidence that the disease is absent. In this study, we tested the feasibility of using a more wide-ranging species, feral pig (Sus scrofa), as an alternative sentinel capable of indicating TB presence.