Structural and Physicochemical Characteristics of Tetrabutylammonium Tetrahalogenoferrates(III), [(C4H9)4N][FeBr4−nCln]

A series of tetrahalogenoferrates(III), [FeBr_4?nCl_n]^? (n=0‐4) stabilized with the tetrabutylammonium cation, of general formula [(C₄H₉)₄N][FeBr_4?nCl_n], has been synthesized. The crystal and molecular structure of [(C₄H₉)₄N][FeCl₄] was determined. The iron cation adopts slightly distorted tetrahedral coordination with two opposite angles smaller than tetrahedral one, two equal to tetrahedral and two larger than tetrahedral. The bond valences were computed. The total valence of iron atom is equal to 3.08. In the structure can be found only one hydrogen bond C(1)–H···Cl. Except mentioned there are no unusually intermolecular short contacts between ions existing in the structure. All [(C₄H₉)₄N][FeBr_4?nCl_n] (n=0‐4) compounds are isostructural in solid state. On the basis of conductometric measurements, relative stabilities of the anions have been estimated in methanol (MeOH), dimethyl sulfoxide (DMSO), acetone (AC), acetonitrile (AN) and dichloromethane (CH₂Cl₂) representing both polar (including amphiprotic and aprotic) as well as non‐polar solvents. Further, the dissociation constants of the compounds were calculated from the expanded Pitt's conductivity equation. The results of the conductometric measurements were supported by electronic spectra.     

Crystal and molecular structure of 2-(p-tolyl)-2-dehydrosparteine

The formula of the title compound is C₂₂H₃₀N₂,M _T =322.5; monoclinic:P2₁,a=7.569(3),b=9.381(1),c=13.684(4) Å,=105.81(2)°,Z=2,V _c =933.7 ų,D _x =1.15 g cm^–3,(CuK)=5.1 cm^–1. The sparteine skeleton (bis-quinolizidine system) has atrans-trans configuration. RingA has an intermediate form between the sofa and half-chair conformations, ringsB andD-chair, and ringC-boat conformations, respectively. The double bond C(2)=C(3) is equal to 1.343(9) Å. The phenyl ring is planar and makes an angle with a plane through N(1), C(2), C(3), and C(4) atoms equal to 43.9°.     

Studies on the Use of Commercial Capillary Gas Chromatographic Columns as Diffusion Denuders

The possibility of using a piece of gas chromatographic capillary column as a tubular denuder for isolation and enrichment of organic pollutants present in air was studied. The partition coefficients (K_fs) of typical organic pollutants (benzene, chlorobenzene, toluene) between the gaseous phase and the denuder sorption layer were determined and effects of analyte concentration in the gaseous phase and gas flow rate on partitioning were studied. The partition coefficients were found to be constant in the studied range of concentration and gaseous mixture flow rate. A piece of a capillary column coated with polydimethylosiloxane can be used as a tubular denuder.     

Thermal analysis of bis(tetraethylammonium) tetrachloroferrate(II)

Thermal decomposition of bis(tetraethylammonium) tetrachloroferrate(II) has been studied using the TG-FTIR, TG–MS and DTA techniques. The measurements were carried out in an inert atmosphere over the temperature range of 293–1073 K. The solid products of the thermal decomposition were identified by the FT-FIR, Mössbauer spectroscopy as well as the X-ray powder diffractometry. The influence of the oxidation state and the nature of a metal on thermal transformation profiles of analogous complexes have been discussed.     

Molecular and crystal structure of bis-quinolizidine immonium salts,II: Δ1(6)-dehydrosparteinium monoperchlorate

₁₍₆₎-Dehydrosparteinium monoperchlorate, [C₁₅H₂₅N₂]⁺·ClO ₄ ^– , is orthorhombicP2₁2₁2₁,a=12.473(2),b=24.292(3),c=10.835(1) Å,V _c =3353.7(9) ų,Z=8,D _x =1.32,D _m =1.32 g cm^–3, (CuK)=20.7 cm^–1. The finalR was 0.097 for 2091 observed counter reflections. A partial disorder of the crystal structure has been observed. The two independent perchlorate anions are orientationally disordered, and the peripheral atoms in the cation skeletons have large temperature factors due both to conformational disorder of ringsA and to disordered orientations of the whole cations alike. In ringsA, atoms C(3) and C(4), trans-annular to the immonium bond, are disordered to a different extent in each of the two independent cations. RingsB,C, andD have sofa (distorted towards half-chair), chair, and chair conformations, respectively. The quinolizidinium and quinolizidine moieties have planar and cis configurations, respectively. The title compound was obtained from ⁵-dehydrosparteine, the product of mercuric acetate dehydrogenation of sparteine at room temperature. From¹³C NMR measurements in²H₂O and in DMSO-²H₆ it is evident that, in solution, the molecular geometry with chair/chair cis-ring fusion within the quinolizidine moiety is present, as was found in the crystalline state by X-ray analysis.     

The influence of ultrasonics on liquid-liquid extraction

The effect of ultrasonics on the extraction of acetic acid from a methyl isobutyl ketone-acetic acid mixture, with the use of water in an extraction column, was investigated. The location of the transducer and input power were varied. Results indicate that at a frequency of 21 kHz ultrasonic irradiation increases with the extraction rate and that the extraction rate also increases with input power.     

Laser-Induced Fluorescence Molecular Beam Investigation of New Singlet and Triplet Electronic States of Yttrium Monohydride

The yttrium monohydride spectrum in the range 12 500-25 000 cm⁻¹ has been studied by various laser-induced fluorescence (LIF) techniques. YH (YD) molecules have been produced in a free jet molecular beam apparatus by a laser vaporizing yttrium metal in the presence of He doped with H₂ (D₂) or NH₃ (ND₃). Low-resolution (∼0.04 cm⁻¹) excitation spectra have been recorded in the entire studied range. Four green bands (19 300-19 900 cm⁻¹) of the YH isotopomer have been studied in more detail: (1) high-resolution (∼120 MHz, ∼0.004 cm⁻¹) excitation spectra have been recorded, (2) dispersed fluorescence spectra have been obtained, and (3) lifetimes of the selected rotational levels of the upper states have been measured. Our observations have confirmed that the ground state of yttrium monohydride has ¹Σ⁺ symmetry and have provided a link between the singlet and triplet manifolds. The upper states of the observed transitions have been tentatively assigned to five electronic states, d0⁺, f³Π, f′1, D¹Π, E0⁺, and Fl. The low-energy excited electronic state observed in the dispersed fluorescence experiment has been assigned as the a³Δ state.     

Study on the Horizontal Transport of Some Radionuclides in the Wieprz River Valley

A horizontal transport of radionuclides was studied by the analysis of the radioactivity of the surface soil samples from valleys of Wieprz river and its bottom sediments. Natural gamma-isotopes (⁴⁰K, ²³⁸U and ²³²Th series) antropogenic (¹³⁴Cs and ¹³⁷Cs) and alpha-isotopes ²³⁸Pu and ^239,240Pu were measured. The different kind of bed rock and terrain configuration, influenced the radionuclide transportation from the soil to river bottom sediments. Radioactivity of the sediment samples is definitely lower than the soils. Very strong adsorption of isotopes in soil hinders their horizontal migration. Calculated ²³⁸Pu/^239,240Pu ratio is characteristic for global fallout and about 90% of the ¹³⁷Cs comes from Chernobyl.     

Noncovalent functionalization of boron nitride nanotubes using poly(2,7-carbazole)s

To fully actualize the potential of boron nitride nanotubes (BNNTs), it is necessary to overcome the inherent insolubility of this nanomaterial. Drawing on the successes realized in the analogous carbon nanotube field, noncovalent functionalization with conjugated polymers offers a simple, scalable route toward the production of stable dispersions of BNNTs. 2,7-carbazoles were chosen as our core monomer based on density functional theory (DFT) predictions, which suggest superior interactions with BNNTs when compared to fluorene-BNNT interactions. Homo poly(2,7-carbazole)s and copolymers with fluorenes were synthesized and used successfully to disperse BNNTs into organic solvents. Thermogravimetric analysis and atomic force microscopy results confirm the proficiency of these polymers to disperse large amounts (> 80% by weight) of individualized BNNTs. Analysis of absorbance data shows that the choice of solvent is critical, with stability enhanced in THF compared to CHCl₃ due to the more efficient planarization of polymer chains on the surface of BNNTs, particularly for the homopolymers. The utility of these highly-soluble poly(2,7-carbazole)-BNNT complexes for printed electronics and transparent composites was demonstrated by the fabrication of simple capacitors and incorporation into poly(methyl methacrylate) composites, respectively.     

Depth‐integrated,non‐hydrostatic model with grid nesting for tsunami generation,propagation, and run‐up

Tsunamis generated by earthquakes involve physical processes of different temporal and spatial scales that extend across the ocean to the shore. This paper presents a shock‐capturing dispersive wave model in the spherical coordinate system for basin‐wide evolution and coastal run‐up of tsunamis and discusses the implementation of a two‐way grid‐nesting scheme to describe the wave dynamics at resolution compatible to the physical processes. The depth‐integrated model describes dispersive waves through the non‐hydrostatic pressure and vertical velocity, which also account for tsunami generation from dynamic seafloor deformation. The semi‐implicit, finite difference model captures flow discontinuities associated with bores or hydraulic jumps through the momentum‐conserved advection scheme with an upwind flux approximation. The two‐way grid‐nesting scheme utilizes the Dirichlet condition of the non‐hydrostatic pressure and both the horizontal velocity and surface elevation at the inter‐grid boundary to ensure propagation of dispersive waves and discontinuities across computational grids of different resolution. The inter‐grid boundary can adapt to bathymetric features to model nearshore wave transformation processes at optimal resolution and computational efficiency. A coordinate transformation enables application of the model to small geographic regions or laboratory experiments with a Cartesian grid. A depth‐dependent Gaussian function smoothes localized bottom features in relation to the water depth while retaining the bathymetry important for modeling of tsunami transformation and run‐up. Numerical experiments of solitary wave propagation and N‐wave run‐up verify the implementation of the grid‐nesting scheme. The 2009 Samoa Tsunami provides a case study to confirm the validity and effectiveness of the modeling approach for tsunami research and impact assessment. Copyright © 2010 John Wiley & Sons, Ltd.