Mixed ternary ion associate formation between xanthene dye, cinchona-alkaloid and quaternary ammonium ion and its application to the determination of trace amounts of quaternary ammonium salts in pharmaceuticals

Xanthene dyes such as eosin and tetraiodofluorescein form 1:2 ion associates with quaternary ammonium ions at pH 7-9; however, the development of color in the organic solvent is poor. When a quaternary ammonium salt is added in the extractable 1:2 associate formed between a xanthene dye and a cinchona-alkaloid in the neutral media, a mixed ternary ion associate (xanthene dye:cinchona-alkaloid:quaternary ammonium ion=1:1:1) is formed. Its extractability is enhanced due to the more bulky associate formation. The ion association caused by addition of cinchona-alkaloids is unique. Of the cinchona-alkaloids, quinidine and cinchonidine with tetraiodofluorescein show excellent effects on sensitivity and extractability. Eosin and tetraiodofluorescein are useful as ion association reagents in the ion associate formation. The apparent molar absorptivities are about 1×10⁵ l mol⁻¹ cm⁻¹ and the calibration range for quaternary ammonium salt is from 2.5×10⁻⁷ to 1.5×10⁻⁶ M. The proposed method is applicable to the selective and sensitive determination of cetylpyridinium chloride, berberine chloride and benzethonium chloride in pharmaceuticals.     

Radiation-induced polymerization of isoprene in aqueous solution of silver nitrate

The rate of radiation-induced polymerization of isoprene in aqueous solution of silver nitrate is 20–50 times as fast as the rate of radiation-induced polymerization of pure isoprene. The formation of a 1:2 complex of isoprene and silver nitrate was confirmed spectrometrically, and this complex seems to polymerize by attack of an active species. The equilibrium constant K_f and the extinction coefficient E of the complex were estimated to be 0.18 and 1.4, respectively. The polymerization mechanism was concluded to be a radical one, based on the effects of inhibitors. The polyisoprene obtained had a crosslinked structure, was insoluble, and did not give a distinct melting point. The 1,2 structure was the predominant polyisoprene configuration. This was interpreted on the basis of the frontier electron density of isoprene.     

Vinyl polymerization. Part 268. Polymerization of acrylonitrile initiated by the system of tetramethyl tetrazene and bromoacetic acid

The polymerization of acrylonitrile (AN) initiated by the system of tetramethyl tetrazene (TMT) and bromoacetic acid (BA) in dimethylformamide (DMF) was studied. The TMT–BA system could initiate the polymerization of AN more easily than TMT alone. The polymerization was confirmed to proceed through a radical mechanism. The initial rate of polymerization R_p was expressed by the equation: R_p = [TMT]^0.62-[BA]^0.5[AN]^1.5. The overall activation energy for the polymerization was estimated as 9.4 kcal/mole. In the absence of monomer, the reaction of TMT with BA in DMF was also studied kinetically by measuring the evolution of nitrogen gas. The reaction was first-order in TMT and first-order in BA; the rate data at 49°C were k₂ = 9.1 × 10^?2l./mole-sec., ΔH? = 17.0 kcal/mole, and ΔS? = ? 6.6 eu. In addition, the treatment of TMT with BA in benzene led to the formation of tetramethylhydrazine radical cation, which was identified by its ESR spectrum. On the other hand, the relatively strong interaction between TMT and DMF was observed by absorption spectrophotometry.     

Synthesis of uniform anatase TiO2 nanoparticles by gel-sol method. 3. Formation process and size control

Uniform anatase-type TiO(2) nanoparticles were prepared by the gel-sol process from a condensed Ti(OH)(4) gel preformed by the hydrolysis of a Ti-triethanolamine (TEOA) complex. The particle size of the anatase TiO(2) was increased from ca. 5 to 30 nm with pH increasing from 0.6 to 12 by aging the Ti(OH)(4) gel at 140 degrees C for 72 h, while the yield of the anatase TiO(2), 100% below pH 9.6, started to decrease from pH 10, to 67% at pH 11.5 and only 9% at pH 12.2. These results reveal a significant reduction of the nucleation rate of the anatase TiO(2) with increasing pH, as is explained by the reduction of the concentration of a precursor complex, Ti(OH)(3)(+), and the adsorption of hydroxide ion onto the embryos of TiO(2). Triethanolamine appeared to enhance the pH effect on the nucleation rate of anatase TiO(2) particles by adsorption onto their embryos, leading to the wide range of the size control. Triethanolamine was also found to act as a shape controller of the anatase TiO(2) particles for yielding ellipsoidal particles from Ti(OH)(4) gel at a relatively high pH above 11. The particle size was also controlled by seeding of anatase TiO(2). Moreover, the seeding experiment suggested that the rate-determining step of the gel-sol process was not the dissolution of the hydroxide gel, but the deposition of the monomeric precursor from the solution phase.     

Reaction of ferrocenylmethyl derivatives of silicon and germanium with methanol: Solvolysis of the metal-carbon bond in the presence of ferric ions

Nine ferrocenylmethyl derivatives of silicon and germanium were prepared and found to undergo methanolysis of their C---M (M = Si or Ge) bonds in the presence of ferric ions to give ferrocenylmethyl methyl ether. For this reaction, relative rate studies and polarographic studies of the pertinent ferrocene derivatives were carried out to obtain some insight into the reaction mechanism. The substituted ferricenium ion intermediate which is formed by oxidation with ferric ions can readily undergo nucleophilic attack by methanol on the metal (Si or Ge) atom. The observed higher reactivity of the germanium derivative relative to the silicon congener in this reaction is not that expected for the usual base-catalyzed attack at the metal atom, and may be reasonably interpreted in terms of a possible change in the transition state depending on the nature of the leaving group, viz. on the acidity of the corresponding hydrocarbon acid, in the solvolysis of the C---M bond.     

ESR and NMR study of the γ-ray-induced postpolymerization of vinyl monomers adsorbed on zeolite

The γ-ray-induced postpolymerization of acrylonitrile and methyl methacrylate adsorbed on Linde zeolite 13X irradiated at 77°K has been studied between 303 and 343°K as a function of the amount of adsorbed monomer and of the irradiation dose. The change in the nature and the concentration of free radical with temperature and duration of the postpolymerization was followed by the ESR method, whereas the formation of polymer was monitored continuously by the decay of the ¹H-NMR absorption line of the monomer under high-resolution conditions. It was found that the overall postpolymerization kinetics may be accounted for by assuming an exponential decay of radical propagation and recombination reactions with chain length. The tacticity of the polymer recovered by destroying the matrix in hydrofluoric acid was determined by ¹³C-NMR. The probability of isotactic addition of AN and MMA is larger than in the radical polymerization in solution owing likely to the association of adsorbed monomer molecules in pairs preforming an isotactic diad.     

Effect of metal oxide additives on the thermal decomposition of perchlorates, oxalates and hydroxides

The effects of -Fe₂O₃ and -Al₂O₃ additives on the thermal decomposition of perchlorates, oxalates and hydroxides were investigated by means of DTA, TG and X-ray techniques. It was found that the oxide additives catalytically promoted the decomposition of perchlorates (NaClO₄, KClO₄ and Mg(ClO₄)₂) and resulted in a lowering of the initial decomposition temperature (T_i). On the other hand, the oxides showed no significant effect on the decomposition of oxalates (FeC₂O₄ and CuC₂O₄) and hydroxides (Mg(OH)₂ and Al(OH)₃).

The thermal decomposition of KClO₄ was chosen to compare the catalytic effect of twelve metal oxides. The results indicated that the transition metal oxides such as Cr₂O₃, -Fe₂O₃ and CuO markedly accelerated the decomposition; these oxides resulted in a solid-phase decomposition before fusion of KClO₄, and the initial decomposition temperature (T_i) of KClO₄ with oxides was about 100–200°C lower than that without catalyst. The oxides such as -Al₂O₃ and MgO resulted in a slight lowering of the temperature of the fusion and promoted the molten-phase decomposition of KClO₄, but their effects were not so remarkable as those of the transition metal oxides. The modified catalytic mechanisms of transition metal oxides were proposed by considering the electron transfer and the oxygen-abstraction models.     

Structure of cinerarin, a tetra-acylated anthocyanin isolated from the blue garden cineraria,

Structure of cinerarin is determined to be 3-0-(6-0-malonyl-β-D-glucopyranosyl)-7-0-(6-0-(4-0-(6-0-caffeyl-β-D-glucopyranosyl)caffeyl)-β-D-glucopyranosyl)-3′-0-(6-0-caffeyl-β-D-glucopyranosyl)delphinidin.     

The corrected structure of depressoside,an antioxidative iridoid glucoside extracted from the flowers of Gentiana urnula Harry Sm.

Three known iridoid glucosides (gentiournoside A, gentiournoside E and depressoside) were isolated from the flowers of Gentiana urnula Harry Sm. through activity-guided fractionations with a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. All three compounds exhibited excellent DPPH radical scavenging activities (IC₅₀: 10–20 μmol L^?1) comparable to that of ascorbic acid and Trolox. However, examination of the NMR data revealed that the reported chemical structure of depressoside, previously isolated from the leaves of G. depressa, needed correcting due to incorrect elucidation around C-7 of the iridane skeleton, and was corrected to 6-β-(2,3-dihydroxyphenyl)-d-glucosyl 7-O-(2,3-dihydroxybenzoyl)-loganate. Depressoside exhibited a much higher scavenging activity against superoxide radicals (IC₅₀: 45.5 μmol L^?1) than the other two extracted compounds (IC₅₀: more than 900 μmol L^?1) due to the crucial presence of a pyrogallyl unit.     

Measurement Theory in Deutsch’s Algorithm Based on the Truth Values

We propose a new measurement theory, in qubits handling, based on the truth values, i.e., the truth T (1) for true and the falsity F (0) for false. The results of measurement are either 0 or 1. To implement Deutsch’s algorithm, we need both observability and controllability of a quantum state. The new measurement theory can satisfy these two. Especially, we systematically describe our assertion based on more mathematical analysis using raw data in a thoughtful experiment.