Anion-exchange behaviour of various metals on DEAE-cellulose in mixed acetic acid-nitric acid media

A number of nitrato complexes of metals have been found to be adsorbed on DEAE-cellulose from mixed acetic acid-nitric acid media, although none can be adsorbed from aqueous nitric acid solutions. The distribution coefficients of Sc, Mo, La, Sm, W, Re, Bi, Th and U are given as functions of acetic acid and nitric acid concentrations (sometimes in the presence of hydrogen peroxide to prevent hydrolytic precipitation). For 25 other metals column adsorption behaviour is described for a 90% acetic acid-10% 7.6M nitric acid mixture. Favourable differences in the distribution coefficients allow useful separations such as FeMoW and USmMoBiTh, to be achieved.     

Encapsulating bis(beta-ketoiminato) polyethers. Volatile, fluorine-free barium precursors for metal-organic chemical vapor deposition

The synthesis, characterization, and incorporation in volatile metal-organic chemical vapor deposition (MOCVD) precursors of a new class of linked beta-ketoiminate-polyether-beta-ketoiminate ligands is presented. These ligands are designed to encapsulate alkaline-earth cations having low charges and large ionic radii. Barium complexes having the general formula Ba[(RCOCHC(R')N)2(R")] (R = tert-butyl or CF3; R' = tert-butyl, methyl, or CF3; R" = -(CH2CH2O)4CH2CH2- or -(CH2CH2O)5CH2CH2)-) were prepared and characterized by 1H and 13C NMR spectroscopy, elemental analysis, and mass spectrometry. Single-crystal X-ray diffraction analysis of 2,2,5,25,28,28-hexamethyl-9,12,15,18,21-pentaoxa-4,25-diene-6,24- diimino-3,27-pentacosadionatobarium(II) reveals a monomeric, nine-coordinate, tricapped trigonal prismatic coordination geometry. Single-crystal X-ray structural analysis of 1,1,1,24,24,24-hexafluoro-4,21-ditrifluoromethyl-8,11,14,17- tetraoxa-3,21-diene-5,20-diimino-2,23-tetracosadionatobarium(II).2DMSO reveals a monomeric, ten-coordinate, distorted tetracapped trigonal prismatic coordination geometry. Volatility data are presented for these barium complexes, demonstrating viability as MOCVD precursors. In addition, it is demonstrated that thin epitaxial films of BaTiO3 can be grown on (001) MgO by low-pressure MOCVD techniques using one of these barium complexes and Ti(dipivaloylmethanate)2(isopropoxide)2 as precursors.     

Revaluation of the correlation of isomer shift with Np-O bond length in various neptunyl(V and VI) compounds

Summary The correlations of isomer shifts in various neptunyl(V and VI) compounds with crystallographic structures were revaluated. A linear correlation between the isomer shifts of neptunyl(VI) compounds and Np-O bond lengths of neptunyl group has been demonstrated. On the other hand, it has been evidenced that the isomer shifts of neptunyl(V) compounds are correlated much stronger with the mean Np-O distances in the crystals than the lengths in neptunyl(V) group.     

2,6-di-tert-butyl-4-perimidylphenols and their oxidation

1,8-Naphthylenediamine was reacted with 2,6-di-tert-butyl-4-formyl-phenol to produce 2,6-di-tert-butyl-4-(1,3-dihydro-perimidyl) phenol (I). The latter was coverted into 2,6-di-tert-butyl-4-(1H-perimidyl)phenol (II) by oxidizing I with sodium pyrosulfate. When phenol II was oxidized by lead dioxide in toluene and THF, the EPR spectra revealed a 12-component multiplet with perimidyl splitting constants a¹ _N=a³ _N=a_H ^NH=0.2 mT; a_H ^6.7=0.6 mT.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 1, pp. 64–67, January, 1992.     

Organophosphorus reagents as extractants-part 3. Synergic effect of triphenyl phosphine oxide and bis(diphenyl phosphinyl) alkanes on extraction of iron(III) from thiocyanate medium with 2,4-pentdione

The extraction of iron(III) from thiocyanate medium was carried out with a synergic combination of 2,4-pentdione (Hacac) and either triphenyl phosphine oxide (Ph(3) PO) or bis (diphenylphosphinyl) alkanes, Ph(2)P(O)(CH(2))(n).P(O)PH(2) [ligand abbreviation, n: dpeO(2), 2; dpbO(2), 4]. Iron(III) was quantitatively separated from its binary mixture with chromium(III), manganese(III), cobalt(II), nickel(II), zinc(II), cadmium(II), mercury(II), lead(II), magnesium(II) and from steel samples. Copper(II) and silver(I) however, interfered. The percentage extraction was 99.0%. The respective extraction constants, K(HA), K(L) or K(syn), for the extracted species, [Fe(NCS)(acac)(2)(H(2)O)] (HA Hacac), Fe(NCS)(3)L(2) [L b Ph(3)PO, dpeO(2) or dpbO(2)], or Fe(NCS)(acac)(2)L were found to be: K(HA), 1.48 x 10(3), K(L), 1.80 x 10(2) (L Ph(3)PO), 2.02 x 10(2) (L dpeO(2) or dpbO(2)) and K(syn), 1.87 x 10(6) (L Ph(3)PO), 2.56 x 10(6) [L dpeO(2) or dpbO(2)].     

Effect of modified fibre glass on the structure and thermophysical properties of pentaplast(pentane)

The results of experimental investigations of the effects of ground fibre glass on the structural parameters and thermophysical characteristics of pentaplast(pentane) were assessed.The degree of crystallinity, thermal conductivity, specific heat and density of pentaplast containing various amounts of modified fibre glass were determined experimentally.The results obtained are discussed in terms of modern theories of the effects of fillers on the properties and structures of polymers.

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Zusammenfassung Es werden die Ergebnisse der experimentellen Untersuchungen des Einfl usses von gemahlenem Fiberglas auf die Strukturparameter und thermophysikalischen Eigenschaften von Pentaplast (Pentan) gewertet.Der Kristallinitätsgrad, das Wärmeleitvermögen, die spezifische Wärme und die Dichte von Pentaplast mit verschiedenem Gehalt an modifiziertem Fiberglas wurde experimentell ermittelt.Die erhaltenen Ergebnisse wurden hinsichtlich moderner Theorien über den Einfluß von Streckmitteln auf die Eigenschaften und die Struktur von Polymeren diskutiert.

     

Enzymatic sulfation of polyphenols related to tannins by arylsulfotransferase.

This report discusses a novel type of arylsulfotransferase (AST) which was derived from human intestinal bacterium sulfated polyphenolic compounds when p-nitrophenyl sulfate (PNS) was taken as a donor substrate. (+)-Catechin, (+/-)-catechin, (-)-epicatechin and (-)-epicatechin gallate were better substrates than tyramine. (-)-Epigallocatechin and (-)-epigallocatechin gallate were slightly worse substrates than tyramine. Although gallic acid was a bad substrate, alkyl gallate esters were better substrates than tyramine. The degree of acceptor specificity increased in proportion to the length of the alkyl group up to the carbon number of five. Pedunculagin, geraniin and corilagin were less effective than tyramine. Rosmarinic acid and penta-O-galloyl-beta-D-glucose were similarly well sulfated. Two products, 4'-monosulfate and 4',5-disulfate of (+)-catechin, were detected at a two-fold molar excess of PNS over (+)-catechin. When (+)-catechin-4'-monosulfate as an acceptor was enzymatically sulfated with PNS as a donor, only the 4',5-disulfate was produced. Thus, arylsulfotransferase was useful for the convenient preparation of sulfate esters of polyphenols at their specific hydroxyl groups.     

Simultaneous separation and determination (in serum) of phenytoin and carbamazepine and their deuterated analogues by high-performance liquid chromatography--ultraviolet detection for tracer studies

The use of stable isotope-labeled tracer compounds is the safest and most effective method to perform many steady state pharmacokinetic and drug interaction studies. We describe a method by which the heavily deuterated 2H10 analogues of carbamazepine (2H10 CBZ) and phenytoin (2H10 PHT) can be chromatographically separated by high-performance liquid chromatography from unlabeled CBZ and PHT. All compounds are quantitated against an internal standard (IS) (10,11-dihydrocarbamazepine) and measured using conventional UV detection rather than mass spectrometry. Baseline resolution of extracted serum containing 2H10 CBZ, CBZ, 2H10 PHT, PHT and IS is achieved on a heated (55 degrees C) 25 cm x 4.6 mm BioAnalytical Systems Phase II 5 microns ODS column with an isocratic mobile phase consisting of water-acetonitrile-tetrahydrofuran (80:16:4, v/v/v) at 1.2 ml/min. Eluting compounds were monitored at a UV wavelength of 214 nm. Calculated resolution of 2H10 CBZ from CBZ and of 2H10 PHT from PHT were 1.3. Serum standard curves were linear (R greater than or equal to 0.999) over a range of 0.5-14 micrograms/ml for 2H10 CBZ, 0.5-20 micrograms/ml for CBZ, 0.5-20 micrograms/ml for 2H10 PHT, and 0.5-30 micrograms/ml for PHT. Within-day percent relative standard deviations (precision) were less than 6% in all cases.     

Correlation of the position of the bond functions in H-X with electronegativity

S type Gaussian bond functions are optimized for HF, H₂O, NH₃, and CH₄. The optimization is carried out with respect to the exponent and position in the H-X bond. The position is found to correlate well with the electronegativity of Pauling and Allred-Rochow.