Template synthesis in the nickel(II)–thiocarbohydrazide–propanone triple system

The complexing process proceeding in the Ni^II–thiocarbohydrazide (H₂N–H–NC(=S)–NH–NH₂)–propanone triple system in EtOH solution and nickel(II)hexacyanoferrate(II) gelatin-immobilized matrix has been studied. It has been found that in the first case, template synthesis leading, as a minimum, to formation of three coordination compounds of Ni^II with (N,N,S,S)-donor tetradentate ligands having NiL¹, NiL² and NiL³compositions where L¹ is 4,6,6-trimethyl-2,3,7,8-tetraazanonen-3-di(thiohydrazide)-1,9, L² is 4,6,6,12-tetrametyl-1,9-dithio-2,3,7,8,10,11-hexaazatridekadien-3,11-hydrazide-1 and L³ is 2,8,10,10,16-pentamethyl-5,13-dithio-3,4,6,7,11,12,14,15-octaazaheptadekatrien-2,7,15 is observed, whereas in the gelatin-immobilized matrix, a complexing process in the system considered does not occur.     

Organoaluminum–cyclic ether-cyclic imide catalysts for the polymerization of epoxides

A catalyst for the polymerization of epoxides consisting of trialkylaluminums, cyclic ethers, and cyclic imides has been investigated. Various catalyst components were examined to reveal that the combination of triisobutylaluminum, dioxane, and succinimide gives the most active catalyst. The catalytic activity is greatly enhanced with aging in which the change in color from pale yellow to dark red takes place. The polymerization data show that the dioxane provides a pathway for the catalyst components to form an active species. The dioxane-containing catalyst is likely to be different in structure from that of the dioxane-free catalyst. It was shown that the catalyst solution is electrically conductive. A parallel correlation seems to exist between the electrical conductivity and the catalytic activity, suggesting that the catalytic species may be of an ionic character.     

Chemische Vitamin D<Subscript>3</Subscript>-Bestimmung in Lebertran

The different aspects of Vitamin D₃ determination and the data reported in the literature are discussed. The spectrophotometric determination of Vitamin D₃ in cod-liver oil is carried out after the alkaline saponification, extraction of unsaponified parts, precipitation of accompanying sterols and the column- and thin-layer chromatographic purification and separation of vitamin D₃ on 40 cm plates from other vitamins. The dyestuff α-naphtholbenzein is suited well as standard substance for the better location and identification of vitamin D₃ zone on the thin-layer plate. The results obtained from the chemical method were checked through the simultaneous biological determination.     

Proteomic LC-MS systems using nanoscale liquid chromatography with tandem mass spectrometry

Current nano-scale liquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) approaches in proteome research are reviewed from an analytical perspective. For comprehensive analysis of cellular proteins, analytical methods with higher resolution, sensitivity, and wider dynamic range are required. Miniaturized LC coupled with tandem mass spectrometry is currently one of the most versatile techniques. In this review, the current status of nanoLC-MS/MS systems as well as data management systems is addressed. In addition, the future prospects for complete proteomics are discussed.     

Light emission from chlorine atoms formed in the dissociative excitation of HCI in a flowing afterglow of discharged argon

Light emission from Cl(5p) atoms (near 440 nm) produced in the reaction of HCl in a discharged flow of argon was investigated with a flowing-afterglow apparatus. Ionic species, most probably argon ions in metastable states, Ar^+M, were found to be responsible for the Cl(5p) production in the dissociative excitation of HCl.     

Stereospecific polymerization of isobutyl vinyl ether. III. Polymerization with VCl3 • LiCl

The polymerization of isobutyl vinyl ether by vanadium trichloride in n-heptane was studied. VCl₃ ? LiCl was prepared by the reduction of VCl₄ with stoichiometric amounts of BuLi. This type of catalyst induces stereospecific polymerization of isobutyl vinyl ether without the action of trialkyl aluminum to an isotactic polymer when a rise in temperature during the polymerization was depressed by cooling. It is suggested that the cause of the stereospecific polymerization might be due to the catalyst structure in which LiCl coexists with VCl₃, namely, VCl₃ ? LiCl or VCl₂ ? 2LiCl as a solid solution in the crystalline lattice, since VCl₃ prepared by thermal decomposition of VCl₄ and a commercial VCl₃ did not produce the crystalline polymer and soluble catalysts such as VCl₄ in heptane and VCl₃ ? LiCl in ether solution did not yield the stereospecific polymer. It was found that some additives, such as tetrahydrofuran or ethylene glycol diphenyl ether, to the catalyst increased the stereospecific polymerization activity of the catalysts. Influence of the polymerization conditions such as temperature, time, monomer and catalyst concentrations, and the kind of solvent on the formed polymer was also examined.     

The passivation phenomenon of platinum in fused lithium chloride + potassium chloride eutectic: Part II. Chlorine overpotential and superpassivation of platinum

Platinum is known to have a very high chlorine overpotential, about 0.8 V, in fused lithium chloride + potassium chloride eutectic. The high overpotential can be ascribed to the formation of the thick passivation film of platinum chlorides. The high chlorine overpotential was decreased by the addition of alkali metal oxides and a reversible chlorine evolution was revealed in a similar manner as the graphite electrode. The reversible chlorine evolution was ascribed to the formation of the oxide passivation film. The chlorine overpotential at the oxide film was increased stepwise as the applied potential was made more positive. The stepped transitions of the chlorine overpotential was ascribed to the valence change of the oxide film. Platinum shows a typical N-shaped passivation at +0.65 V versus Ag/AgCl(0.1) which has been ascribed to the dissolution of platinum into Pt(II) ions and following formation of the passivation film of supersaturated Pt(II) chloride. Platinum was found to show another passivation phenomenon at high temperatures, above 450°C. The N-shaped current-potential curve was observed at +1.8 V which was far more positive than the potential of the standard chlorine electrode. The dissolution of platinum prior to the passivation was found to occur due to the formation of high valence platinum ions such as Pt⁶⁺ and Pt⁸⁺.     

Palladium salicylaldimine complexes containing boronate esters

Reactions of salicylaldehydes with boronate ester derivatives of aniline have been examined. Addition of these Schiff base ligands to palladium acetate or Na₂PdCl₄ afforded novel boron-containing trans-bis(N-arylsalicylaldiminato) palladium complexes.Condensation of salicylaldehyde (2-HOC₆H₄C(O)H) with H₂NC₆H₄Bpin (pin=1,2-O₂C₂Me₄) afforded the boron-containing Schiff bases, 2-HOC₆H₄C(H)=NC₆H₄Bpin (1–3a). Similar reactivity with 2-hydroxy-5-nitrobenzaldehyde and 2-hydroxy-1-naphthaldehyde gave the corresponding Schiff bases (1-3b) and (1-3c), respectively. Reaction of Schiff bases (2) and (3) with palladium acetate or Na₂PdCl₄ afforded complexes of the type PdL₂ (4,5), where L=deprotonated Schiff base. The molecular structure of the nitro-salicylaldehyde 4-Bpin palladium complex (5b) was characterized by an X-ray diffraction study. All new palladium compounds have been characterized fully and tested for their antifungal activity against Aspergillus niger and Aspergillus flavus.