Volume 6, Issue 4

A colour change of doped YAB crystals and microcrystalline powders takes place upon illumination with different white light sources. This paper presents extensive experimental data on the new materials Ho,Nd:YAB; Ho,Cr:YAB, Nd,Cr:YAB and Ho,Nd,Cr:YAB, resulting in a chart providing the observed crystal colours and chromaticity differences of the materials under illumination with seven different types of white light sources. The microcrystalline powders could be used as coatings in order to produce a special colour changing effect. Furthermore, the colour table presented enables the observer to discriminate the investigated light sources at one glance.

Herein, the first example of a co-crystal system formed by an imidazolium nitrate, a carbene precursor, and copper (II) nitrate, {[Cu(NO3)2(H2O)2]L1(NO3)2} (1) (L1 = 1,1′-dibenzyl-3,3′-butyl-diimidazolium-2,2′-diylidene) is reported. These two building blocks are connected in the solid state through hydrogen bonds to generate a three-dimensional supramolecular network.

The interaction between bovine serum albumin and the mono azo reactive dye Orange ZT has been investigated using absorption difference spectroscopy. The influence of pH and ionic strength of the solution on the stability of the dye-protein complex has been determined. At 25°C, the complex dissociation constants were equal to 24.0, 28.0, 7.0, 11.0, 17.6 and 46.0 μM at pH 7.0, 6.5, 6.0, 5.5, 5.0 and 4.3, respectively. In the presence of 0.1, 0.2, 0.3 M KCl, at pH 6.0 and 25°C, the complex dissociation constants were 8.8, 20.0, 18.0 μM, respectively. The protein-dye complex dissociation constants show that Orange ZT could be used as an affinity ligand for protein purification.

Naproxen membrane electrodes based on different plasticizers and the quaternary ammonium salts (QASs) dimethyldidecylammonium bromide, methyltrioctylammonium chloride, or tetraoctylammonium chloride, were prepared. The following basic parameters were investigated for the optimal electrode: measurement range (10−4 − 10−1 mol L−1), slope of the linear range of the calibration curve (−58.3 mV decade−1), limit of detection (6.0 × 10−5 mol L−1), lifetime (2.5 months), dependence of the electrode potential on pH (5.5 − 9.0), reproducibility of potential (1.2 mV) and selectivity coefficients in relation to selected organic and inorganic anions. The electrode was utilized for determination of naproxen in tablets by the calibration curve method and the standard addition method.

Preliminary results of development of a direct and fast method of determination of antimony in samples of tap water using GFAAS are presented. The found levels of antimony were lower than permitted for human consumption. A mixture of Pd and Mg(NO3)2 (concentrations in the injected solution: 8.6 μg mL−1 and 5.8 μg mL−1 respectively) was used as the chemical modifier. The pyrolysis and atomization temperatures were 1000 and 1700°C, respectively and the mean analytical recovery 98.2%.

A clandestine two-step route to psychoactive racemic phenylalkylamines utilises the Henry reaction. In the first step an aromatic aldehyde reacts with a nitroalkane to give the nitrostyrene intermediate. In the second step the nitrostyrene is reduced to the phenylalkylamine. An impurity profile of both steps was evaluated through the synthesis and analysis of common street derivatives. The formation of nitrile impurities in the nitroaldol reaction and hydroxylamine impurities in the reduction step were shown by NMR spectroscopy and GC-MS. A selection of reducing agents has been used to give the phenylalkylamines, together with variable quantities of the partially reduced hydroxylamine product. GC-MS analysis of the hydroxylamines showed heat-induced disproportionation which led to the detection of the corresponding oximes.

In this paper we report a method to determine tensile strengths and Young’s modulus of cubic biaxial textured metal tapes used as substrate materials for coated conductors (CC). Simplicity, rapidity and reproducibility of the procedure are important for the evaluation of continuous in-house productions. Our approach is based on the EN 10002-1 B tensile test method. A key role for satisfactory results is the sample preparation of 100–250 μm thick tapes, which will be described in detail. Copper (E-Cu57) can be successfully transformed to cubic biaxial textured substrates. Best results were achieved by annealing between 750°C and 850°C in reducing atmosphere. Best FWHM values for the ψ scan are 5.51° and for the ϕ scan are 4.5°. Pole figure analysis verified the sharp {001} texture of the tape. Vickers hardness measurements (HV 0.1) for the cold worked material yielded values of 135 and for the annealed tape, values of 37. The ultimate tensile yield strength Rm of the textured substrate is 150 MPa and thus significantly lower than that for the cold worked material (413 MPa). Cubic biaxial substrates could be manufactured from Isotan CuNi44 (WM49) bars. Best results were achieved by annealing at 1200°C in reducing atmosphere. Pole figure analysis verified the {001} texture with other low intensity texture components. Vickers hardness measurements (HV 0.1) for the cold worked material yielded values of 236 and for the annealed tape values of 92. The ultimate tensile yield strength R m of the textured substrate is 300 MPa and thus significantly lower than that for the cold worked material (723 MPa).

2,4-dinitrophenylhydrazine hydrochloride hydrate (I) was determined by X-ray crystallography, and the intermolecular interaction energies were calculated in terms of Natural Bond Orbital analysis. The asymmetric unit of (I) consists of a dinitrophenylhydrazinium cation, a chloride anion and a water molecule. The interatomic distances and angles in (I) show no unusual values. In the structure there are intermolecular N—H⊎⊎⊎O, N—H⊎⊎⊎Cl, O—H⊎⊎⊎Cl, C—H⊎⊎⊎O hydrogen bonds with bonding energy ranging form 16.03 to 0.76 kcal mol−1. These hydrogen bonds create the following N1 motifs: 6D, S(5), S(6), C(6), C(9). N1D motifs become infinite at the third level and are 2C 32(6), C 32(7).

Using a modified Augustine’s method variously substituted Rh complexes were anchored on Al2O3 support. The prepared catalysts were characterized by spectroscopic methods and were applied in the hydrogenation of several acetophenone derivatives (p-CF3-acetophenone, acetophenone, p-NH2-acetophenone). Enantioselective C=O hydrogenations were observed with reasonable activity and selectivity on all heterogenized complexes, e.e. up to 80%. At the same time the immobilized samples showed the advantages of the heterogeneous systems: easy handling and recyclability.

Molecular dynamics NVE simulations have been performed for five thermodynamic states of water including ambient, sub-and supercritical conditions. Clustering of molecules via hydrogen bonding interaction has been studied with respect to the increasing temperature and decreasing density to examine the relationship between the extent of hydrogen bonding and macroscopic properties. Calculations confirmed decrease of the average number of H-bonds per molecule and of cluster-size with increasing temperature and decreasing density. In the sub-and supercritical region studied, linear correlations between several physical quantities (density, viscosity, static dielectric constant) and the total engagement of molecules in clusters of size k > 4, Pk>4, have been found. In that region there was a linear relationship between Pk>4 and the average number of H-bonds per water molecule. The structural heterogeneity resulting from hydrogen bonding interactions in low-density supercritical water has been also discussed.

The addition of formylphenylboronic acid derivatives to thiourea and ethyl acetoacetate proceeds in the presence of an additional Lewis acid catalyst to give the corresponding 3,4-dihydropyrimidin-2(1H)-(thio)ones (Biginelli products) in moderate yield. Compounds were tested for antifungal activity against pure cultures of Aspergillus niger, Aspergillus flavus, Candida albicans and Saccharomyces cerevisiae but, unfortunately, none showed any appreciable activity.

Formamide colloidal suspensions of layered double hydroxides (LDHs) with anionic dye, meso-tetrakis(4-sulfonatophenyl)porphine (TPPS) were prepared. Optical properties of these suspensions were investigated by means of absorption and fluorescence spectroscopies in the visible region. For more detailed characterization, second derivative curves of the spectra were calculated. The adsorption of the dye on LDH nanosheets led to partial molecular aggregation, reflected in significant changes of the dye optical properties. The Soret band in the absorption spectra was split into two peaks and decreased in intensity. Changes were observed also for the Q-bands. The molecular aggregation significantly quenched the emission of the dye. The low intensity emission from dye H-aggregates was identified at slightly longer wavelengths. The molecular aggregation increased with the dye/LDH ratio. At low dye loadings, the optical properties were very similar to the dye solution. The yields of the dye molecular aggregation increased with LDH surface charge.

Positron annihilation lifetime spectroscopy (PALS) has been used to determine the free volume in multiblock polyamide-6/poly-(isoprene) copolymers (PA-6/PI), synthesized via activated anionic bulk copolymerization. The diisocyanate functionalized telechelic PI, blocked with caprolactam (CL) has been used as a commoner and an activator at the same time. The elastic PI block incorporated into the main chain of PA-6 affects the amorphous and crystal phase of the copolymer leading to changing in degree of crystallinity. The positron annihilation lifetime spectroscopy (PAL) and Doppler broadening of annihilation line (DBAL) technique in a set of pure PA-6 and PA-6/PI copolymers with two different compositions have been applied and evaluation of the size of free-volume holes (pores), localized mainly in the disordered regions of the PA-6/PI copolymer by measuring the o-Ps lifetime (τ3) and o-Ps intensity (I3) has been performed.

The present work investigates the adsorptive interactions of Hg(II) ions in aqueous medium with hydroxylated silica, aminopropylsilica and silica chemically modified by β-cyclodextrin. Batch adsorption studies were carried out with various agitation times and mercury(II) concentrations. The maximum adsorption was observed within 15–30 min of agitation. The kinetics of the interactions, tested with the model of Lagergren for pseudo-first and pseudo-second order equations, showed better agreement with first order kinetics (k1 = 3.4 ± 0.2 to 5.9 ± 0.3 min−1). The adsorption data gave good fits with Langmuir isotherms. The results have shown that β-cyclodextrin-containing adsorbent has the largest adsorption specificity to Hg(II): K L = 4125 ± 205 mmol−1. “β-cyclodextrin-NO3-” inclusion complexes with ratio 1: 1 and super molecules with composition C42H70O35 ⊎ 3 Hg(NO3)2 are formed on the surface of β-cyclodextrin-containing silica.

Novel dicyanoisophorone derivative, (E)-2-(3-(4-aminostyryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile, is synthesized and its structure elucidated by means of conventional and linear polarized IR-spectroscopy of oriented colloids in nematic host, 1H, 13C, 1H, 1H-COSY NMR, HPLC tandem ESI MS-MS spectrometry, UV-VIS and thermal methods. Ab initio and DFT level of theory are used to theoretically obtain the electronic structure and optical properties, both in ground and exited state, of the compound.

Impact of silicon tripodand-type electrolyte additives and graphite pre-treatment agents on the electrochemical intercalation of lithium cations into graphite was investigated. Addition of Si-tripodand-type silanes to propylene carbonate-based electrolytes was found to suppress detrimental solvent co-intercalation and graphite exfoliation. Similar effects were observed for graphite pre-treated with the reported silane agents. It was observed that the presented supramolecular additives allow for the formation of effective passive layers on graphite during first charging, and thus can be considered as novel low-cost film-forming components for rechargeable lithium batteries.

A new all plastic sensor for Co2+ ions based on 2-amino-5 (hydroxynaphtyloazo-1′)-1,3,4 thiadiazole (ATIDAN) as ionophore was prepared. The electrode exhibits a low detection limit of 1.5 × 10−6 mol L−1 and almost theoretical Nernstian slope in the activity range 4.0 × 10−6–1 × 10−1 mol L−1 of cobalt ions. The response time of the sensor is less than 10 s and it can be used over a period of 6 months without any measurable divergence in potential. The proposed sensor shows a fairly good selectivity for Co(II) over other metal ions. The electrode was successfully applied for determination of Co2+ in real samples and as an indicator electrode in potentiometric titration of Co2+ ions with EDTA.

A novel triply bridged dinuclear copper(I) complex: Cu2(μ-paa)(μ-dcpm)2(BF4)2·2CH2Cl2 [ paa = pyridine-2-carbaldehyde azine (C12H10N4) and dcpm = bis(dicyclohexylphosphino)methane(C25H46P2) ] has been synthesized and structurally characterized. Crystallographic studies of the complex showed that two copper(I) ions were bridged by one paa ligand and two dcpm ligands. The paa ligand adopted the Z configuration at the partially double N-N bond and the two copper ions have distorted tetrahedral coordination geometry. Because of the steric effect of dcpm, the pyridine rings of the paa ligand are obviously not on the same plane (the dihedral angle is 43.610). The interaction between neighboring ligands results in a N-N bond length (1.374(7) Å) contraction. The UV-vis spectra of the complex exhibited intense high-energy absorptions at λmax

A rapid, simple and reliable capillary electrophoresis method for the separation and quantitation of inorganic cations with indirect UV detection at 214 nm was developed. The electrolyte was: 12 mM imidazole as background absorbance provider; 5 mM malic acid and 1.0 mM 18-crown-6 ether as complexing agents; and 20% D2O (v/v) to improve ion mobility. The pH was 4.25. The applied voltage was 22 kV at 22°C. Nine ions were completely separated and determined with correlation coefficients of 0.9979-0.9992. The relative standard deviations (RSD) were less than 0.5% for migration time and less than 5.2% for peak area (n=8). The detection limits (S/N=3) were from 0.08 mg L−1 (for Na+) to 0.51 mg L−1 (for Cu2+). To assess the reliability atomic absorption (AA) was also used to determine the same samples. Satisfactory results were obtained for real samples of jasmine tea drink and coconut milk.

1-benzyl-3-methyl imidazolium hydrogen sulphate [bnmim][HSO4] was found to be an effective catalyst for the condensation reaction of indoles and derivatives with benzaldehydes in microwave irradiation with lower reaction time and higher yields to give bis(indolyl) methanes.

In this study, a novel and effective suspension polymerization has been employed to prepare functional magnetic porous SrFe12O19/P(St-DVB-MAA) microspheres in the presence of bilayer surfactants (sodium dodecyl benzene sulfonate (SDBS) and oleic acid (OA)) coated on micro-size magnetic SrFe12O19. This was achieved by pre-polymerizing the organic phase, which contained co-monomers, porogens and treated magnetic particles, at 65°C for 0.5 h under ultrasound conditions. Aqueous solutions containing a dispersion agent were then added to effect suspension polymerization. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and magnetic property measurement system (MPMS) were used to characterize the functional magnetic porous microspheres. The results show that the microparticles are well shaped with a uniform size distribution of about 0.5 ∼ 0.7 mm and the surfaces of the microspheres have many micro-pores with an average diameter of 0.533 µm. There are carboxyl groups (−COOH) on the surface of the microspheres to the extent of 0.65 mmol g−1, as determined by conductometric titration. According to the XRD spectra, iron oxide consists mainly of SrFe12O19 which reveals hexahedral structure. The content of magnetic SrFe12O19 reaches 17.81% (by mass), and the microspheres have good heat resistance. The magnetic porous microspheres are ferromagnetic with high residual magnetization and coercivity, 21.59 emu g−1 and 4.13 kOe, respectively. The saturation magnetisation is around 42.85 emu g−1.

Poly(vinylalcohol)/poly(ethyleneglycol)/poly(ethyleneimine) blend membranes were prepared by solution casting followed by solvent evaporation. The chemical structure of the prepared membranes was analyzed by FTIR and DSC. The sorption behavior as well as the permeabilities of the membranes for pure CO2 and N2 were investigated. The results show that the PVA/PEI/PEG membranes possess a higher permeability of CO2 and a lower permeability of N2. The membrane displays a CO2 permeability of 27 Barrer, and a N2 permeability of 3 Barrer at 25°C and 1 bar. CO2 sorption behavior of the composite membrane, which can be classified as a dual-mode sorption model, and N2 sorption behavior of the copolymeric membrane is in agreement with the Fickian diffusion model.

In this work, 5-Methylresorcin (MR) bonded to untreated polyurethane foam (PUF) was successfully employed as a sorbent (MR-PUF) for the selective separation and determination of mercury in natural water samples. Mercury can be quantitatively recovered in the pH range of 5-7. The system presented a minicolumn packed with the new sorbent, where the sample solution was passed through it for a period of time and an eluent solution stripped out the retained mercury, which was further determined with dithizone. The new matrix was characterized by using different tools (IR spectra, stability and density). The kinetics of mercury uptake by the new matrix was found to be fast, reaching equilibrium in 20 minutes. A preconcentration factor of 350 was achieved. The proposed preconcentration procedure was applied successfully to the selective separation and determination of trace mercury in natural water samples.

A simple sol-gel process is proposed for synthesizing SnO2 nanopowders utilizing normal propanol and isopropanol mixture instead of just using normal alcohols such as ethanol, propanol or butanol for Sol preparation. No surfactant was used in this Sol preparation process. The structure of sol is studied by FT-IR-ATR technique. On altering propanol to isopropanol ratio, three different nanopowders were obtained. X-ray powder diffraction, high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction pattern (SAED) and BET techniques were used to characterize prepared powders. Results show that smaller grain size was obtained via altering alcohols ratio. In addition, Merck commercial SnO2 powder was also used as a reference material for comparing purposes; because it has nanometer scale (ca. 60 nm). HRTEM images show that obtained nanopowders were polycrystalline and their average diameters fall into the range of 6–80 nm. Finally, the effect of alkoxide ligand size through sol-gel synthesis on product particle size is discussed.