Quality of Emulsions Based on Modified Watermelon Seed Oil,Stabilized with Orange Fibres

The aim of the study was to evaluate emulsion systems prepared on the basis of blended fat in different ratios (watermelon seed oil and mutton tallow) stabilised by orange fibres and xanthan gum. Emulsions were subjected to stability testing by Turbiscan and were assessed in terms of mean droplet size, colour, viscosity, texture, skin hydration and sensory properties. The most stable systems were found to be the ones containing a predominance of mutton tallow in a fat phase. For these emulsions the lowest increase in mean particle size during storage was observed. The study also confirmed the synergistic effect of the thickeners used. The presented emulsions despite favourable physicochemical parameters, did not gain acceptance in sensory evaluation.     

Solvent‐free alkali and alkaline earth metal complexes of di‐imine ligands

Compound [(dph‐BIAN)Mg(THF)]₂ ( 2 ) was prepared by reacting magnesium metal with 1,2‐bis[(2‐biphenyl)imino]acenaphthene (dph‐BIAN) in THF, followed by crystallization from toluene. Reaction of CaI₂ with (dpp‐BIAN)Li₂ in toluene afforded [(dpp‐BIAN)Li]₂Ca ( 3 ) (dpp‐BIAN = 1,2‐bis[(2,6‐diisopropylphenyl)imino]acenaphthene). Both complexes 2 and 3 were characterized by single crystal X‐ray diffraction. The ¹H NMR spectroscopic data obtained for complex 3 in toluene solution indicated an agostic interaction between the methyl groups of the ligand and lithium atoms. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:663–670, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20168     

Preparation and evaluation of 2-azinyl-2H-benzotriazoles as bidentate ligands: Synthesis and characterization of [2-(2-pyridynyl)-2H-benzotriazole](bpy)2Ru

Five 2-azinyl-2H-benzotriazoles (azinyl = 2-pyridinyl, 2-pyrazinyl, 2-pyrimidinyl, 6-methoxy-3-pyridazinyl, 5-methyl-2-pyridinyl were prepared and characterized as bidentate ligands. The electronic structure of these and related heterocycles was investigated spectroscopically and computationally (TD-DFT). They were tested at the B3LYP/6-31++G(d, p)//B3LYP/6-31G(d, p) level of theory as ligands for MgH₂, which permitted the elucidation of trends in complex formation, its geometry as a function of the ring structure, and the number and position of the nitrogen atoms in the azine ring. A Ru²⁺ complex 7a-Ru with 2-pyridinyl-2H-benzotriazole (7a) and two bpy ligands was prepared and characterized structurally, spectroscopically and electrochemically. The results were compared to those for similar complexes and discussed in the context of computational results for MgH₂ complexes.     

Determination of gallium in bayer process sodium aluminate solution by inductively coupled plasma atomic emission spectrometry

The determination of gallium in sodium aluminium solutions by inductively coupled plasma atomic emission spectrometry is reported. The spectral line profiles of three Ga lines are recorded over a short wavelength region in the presence of interfering ions, by varying the observation height from 8 to 20 mm and the RF power from 1.0 to 1.75 kW. Under fixed ICP conditions, matrix interferences are observed. The results indicate a complex matrix effect on gallium in the presence of different concentrations of sodium. The proposed method is applied successfully to the determination of gallium (110–120 μg ml^?) in Bayer process aluminate solution.     

Solvent influence on the rotational isomerism in terephthalaldehyde

Experimental and theoretical studies were carried out in order to investigate the rotational isomerism of terephthalaldehyde. The dipole moment measurements and infrared spectroscopy in Ar matrix and using various solvents were performed experimentally. In order to supplement the experimental study, both static and dynamical theoretical calculations were performed. IR spectra and potential energy distribution (PED) were calculated for both cis and trans isomers of terephthalaldehyde in gas phase using B3LYP/6-31G(d,p) level of theory. Further calculations consisted of conformational analysis were performed in order to estimate the rotational barrier and relative stabilities of isomers. The DFT theory with B3LYP functional and four double-zeta and triple-zeta basis sets served as framework for this part of calculations. Semiempirical AM1 and PM3 methods were also used for gas-phase modeling. Molecular dynamics using MM3 force field was applied to study the preferences of solvent molecules’ orientation around the studied molecule. Additionally, the effect of solvent polarity on the Gibbs energy of the trans ⇌ cis equilibrium was analyzed in terms of the continuum dielectric medium models.     

Medium Effect on the Rotational Isomerism in 1,3,5-Triacetylbenzene

Summary. The optimal geometries, energies, polarities, infrared frequencies, and intensities of the non-polar and polar conformers of 1,3,5-triacetylbenzene were calculated using DFT/B3LYP/6-311G** and semi-empirical (AM1 and PM3) methods. All the methods revealed that the non-polar conformer prevails in vacuum. The infrared spectra in the solid state, in Ar matrix, and in liquid solutions as well as the dipole moments of 1,3,5-triacetylbenzene in many solvents show the distinct influence of the environment on the non-polar conformer ⇌ polar conformer equilibrium. The effect of solvent polarity on the standard Gibbs energy of this conformational equilibrium is quantitatively discussed in terms of the continuum-homogenous dielectric model.     

Electron impact mass spectra of some enamines

The mass spectra of α,β-diarylaminocrotonic acid anilides have been determined and the fragmentation pathways are now discussed. The proposed pathways have been confirmed by deuterium labelling, the spectrum of the model compound, or the appropriate metastables. The detailed electron impact data are given.     

'Self-organization' processes in proton and deuteron mixtures in open-chain hydrogen bond systems: polarization IR spectra of 4-mercaptopyridine crystals.

This paper is devoted to IR spectroscopic studies in polarized light of 4-mercaptopyridine (4-MPD) hydrogen-bonded crystals. These studies were preceded by determination of the 4-mercaptopyridine X-ray structure. Polarization spectra of 4-mercaptopyridine crystals were measured in the frequency ranges of V(N-H) and V(N-D) bands at room temperature, and also at the temperature of liquid nitrogen, for the two different crystalline faces: 'bc' and 'ac'. When investigating 'residual' v(N-H) band shapes for crystals that were diluted by deuterium, strong dichroic effects in the spectra were still observed, providing evidence for the existence in the hydrogen bond chains of domains containing exclusively protons or deuterons. This phenomenon proves the existence of a new kind of H/D isotopic effects in open chain hydrogen bond systems, namely 'self-organization' effects. Such effects, however, were not observed for other open chain hydrogen bond systems, e.g. alcohol crystals. Solid-state spectra of 4-mercaptopyridine were quantitatively interpreted, along with the strong polarization and the isotopic effects, when based on the 'strong-coupling' theory for linearly arranged hydrogen bond dimers.     

Total synthesis of the tricyclic skeleton of the natural Celastraceae sesquiterpenoids and related synthetic analogs

A concise and efficient synthesis of the C₁₃ tricyclic core of the dihydro-β-agarofuran skeleton common to the natural Celastraceae sesquiterpenoids is described. The strategy entails a Mukaiyama aldol reaction of a tetrahydronaphthalene enol silane with acetone, epoxidation, ketone reduction, and acid-catalyzed cyclization. This key scaffold was converted into diverse polyhydroxylated derivatives, which were tested for insecticidal activity.