Photoelectron spectral intensities of some first transition series elements in metal cyanides containing inequivalent atoms

Photoelectron spectral intensities of some first transition series elements were studied for metal cyanides containing inequivalent atoms. The spectra of low-spin ions coordinated via carbon to the cyanide ion, and of high-spin ions coordinated through nitrogen were separately obtained from manganese, iron, and cobalt cyanides. Metal 2p spectra obtained as sums of the appropriate spectra of low- and high-spin ions were nearly coincident with the spectra of the compounds containing inequivalent atoms. These results show that the intensity of the 2p electron for each atom must include the main peak and perhaps multiplet splitting effects, shake-up effects, and the inelastic scattering tail, and verify the non-interaction nature of the inequivalent atoms in these compounds.     

Increase in aminobutyrate aminotransferase and cholineacetyltransferase in cerebrum of aged rats

We previously reported an increase in aminobutyrate aminotransferase (GABA-T) activity in the cerebrum of Alzheimer patients. In the present study, we investigated whether such findings are common in the usual aging process as well. We examined the activity of various enzymes, which were examined in the previous study, in the cerebrum of Wistar-Kyoto rats and spontaneously hypertensive rats. In the two strains, we compared the enzyme activities between the two groups of animals, 5 weeks and 13 weeks of age. In both strains, the older animals had significantly higher activities of GABA-T and choline acetyltransferase (ChAc-T). In spite of other enzymatic changes coexisting, the above two enzymes were suggested by discriminant function analysis to be playing a major role in the multiple enzymatic changes in the cerebrum of the animals.     

Determination of the oxidation states of bismuth and copper in superconductor Bi-Ca-Sr-Cu-O by oxidation-reduction titration

Summary The oxidation state of the superconductor Bi-Ca-Sr-Cu-O was determined by two procedures. One was ferrous-chromate titration after dissolution of the sample in manganous nitrate solution. The other was the titration after dissolution in ferrous ion solution. The former procedure gives the concentration of a state like pentavalent bismuth and the latter gives the sum of concentrations of a state like pentavalent bismuth and a state like trivalent copper or peroxide. The result of the titration shows that the superconductor oxide has the state like pentavalent bismuth but not like that of trivalent copper. This is a striking contrast to YBa₂Cu₃O_7–y having a high concentration of the latter state. Although the result was compared with X-ray photoelectron spectra, a clear relationship between them was not obtained.

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Bestimmung der Oxidationsstufen von Bismut und Kupfer im Supraleiter Bi-Ca-Sr-Cu-O durch Redoxtitration

     

Ion chromatography for determination of nitrite and nitrate in seawater using monolithic ODS columns

A fast and highly sensitive ion chromatographic method using monolithic ODS columns was developed for the determination of nitrite (NO2-) and nitrate (NO3-) in seawater. Two monolithic ODS columns (50 mm x 4.6 mm i.d. + 100 mm x 4.6 mm i.d.) connected in series were coated and equilibrated with 5 mM cetyltrimethylammonium chloride (CTAC) aqueous solution. The column efficiency with 0.5 M NaCl as the mobile phase did not decrease in spite of the increase in flow rate of the mobile phase. Thus, good chromatograms were obtained within 3 minutes for NO2- and NO3 in artificial seawater without interferences by coexisting ions. The detection limit (S/N = 3) with UV detection at 225 nm was 0.8 and 1.6 microg/L for NO2- and NO3-, respectively. The characteristics of the monolithic CTA(+)-coated ODS columns were discussed. The present method was successfully applied to the fast and sensitive determination of NO2- and NO3- in real seawater samples.     

Effect of backing metals in the X-ray fluorescence spectral analysis of metal films and its application

Summary The enhancement effect of the backing metal on the x-ray intensity of an element in a film has been studied. This effect is dependent on the wave length of the x-ray absorption edge of the element in the film. In the case of nickel film, the infinite thickness at which this effect is lost is about 20, and the infinite thickness is independent on the kind of backing metals. It has also been recognized that this enhancement effect is convenient for increasing the x-ray intensity of small amounts of an element. The application of this effect has been demonstrated for the determination of small amounts of nickel and cobalt, which were concentrated in an organic precipitate.

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Zusammenfassung Die verstärkende Wirkung des Grundmetalls auf die Röntgenstrahlenintensität eines Elementes in einem Überzugsfilm wurde untersucht. Diese Wirkung ist abhängig von der Wellenlänge der Röntgenabsorptions-kante des Elementes im Überzug. Im Falle eines Nickelüberzugs beträgt die Dicke, bei der diese Wirkung aufhört, etwa 20. Diese Dicke ist unabhängig von der Art des Grundmetalls. Die Erscheinung kann zur Erhöhung der Röntgenfluorescenzintensität kleiner Mengen eines Elementes benutzt werden. Als Anwendungsbeispiel wird die Bestimmung kleiner Mengen Nickel und Kobalt beschrieben, die in einem organischen Niederschlag konzentriert wurden.

     

Stereochemistry in cationic polymerization of alkenyl ethers. I. 1H- and 13C-NMR spectra of poly(propenyl ethers)

Benzyl, ethyl, and deuterated ethyl propenyl ethers (BzPE, EPE, and EPE-d₅, respectively) with different cis/trans isomer ratios were polymerized by BF₃O(C₂H₅)₂ at ?78°C in toluene, methylene chloride, and nitroethane solvents. Poly(propenyl alcohol) [poly(PA)] was also prepared by treating poly(BzPE) with HBr gas. The steric structure of these polymers was studied by ¹H- and ¹³C-NMR spectroscopy. The poly(EPE-d₅) obtained from a trans-rich monomer mixture was crystalline, while one from a cis-rich monomer mixture was amorphous. Poly(BzPE) was always amorphous. Poly(BzPE), poly(PA), and poly(EPE-d₅) gave ¹H-NMR spectra with two β-methine peaks, relative intensities of which depended on the geometric structure of the monomers. Their spectra of β-methyl protons decoupled from β-methine proton were also split into two peaks, relative intensities of which corresponded to those of the two α-methine peaks. ¹³C-NMR spectra of α-OCH₂ and β-CH₃ of poly(EPE), respectively, consisted of two peaks. These observations show that the poly(propenyl ethers) examined, whether crystalline or amorphous, have only two dyad structures (probably threo or erythro-meso and racemic), and that their α- and β-carbons have the same dyad structure, irrespective of the kind of the alkoxyl groups.     

Stereoelective cationic polymerization of propenyl ether by asymmetric catalysts

In order to elucidate the possibility of stereoelective cationic polymerization (asymmetric selective polymerization) of olefinic monomers, racemic cis- and trans-1-methylpropyl propenyl ether and racemic 1-methylpropyl vinyl ether were polymerized by asymmetric alkoxyaluminum dichlorides. In the polymerization of racemic cis-1-methylpropyl propenyl ether with (?)-menthoxyaluminum dichloride in toluene at ?78°C, the polymer obtained showed a positive optical activity, and the residual monomers were converted by BF₃OEt₂ into a polymer having a negative optical activity. Thus, the stereoelective polymerization of racemic cis-1-methylpropyl propenyl ether was beyond any doubt attained in homogeneous cationic polymerization. In the polymerization of the trans isomer by the same catalyst, an optically active polymer was hardly formed. In the polymerization of racemic 1-methylpropyl vinyl ether which has no β-methyl group, stereoelectivity was not observed at all. The cis-1-methylpropyl propenyl ether did not produce an optical active polymer in the polymerization catalyzed by (S)-1-methylpropoxyaluminum dichloride or (S)-2-methylbutoxyaluminum dichloride under the same polymerization conditions.     

Isolation of the intermetallic compounds Al2Cu, Al12Mg17 Al3Fe, Al9Co2 and Al3Ni in binary aluminium alloys by application of an organic solvent

Summary For the isolation of the intermetallic compounds Al₂Cu, Al₁₂Mg₁₇, Al₃Fe, Al₉Co₂ and Al₃Ni in their binary alloys a new method is proposed: Sample alloy particles are placed in a flask with a methanolic solution of benzoic acid (20% wt.), oxine (5% wt.), chloroform (20% vol.) and sodium hydroxide (0.02% wt.). After sufficient time of agitation, the intermetallic compounds remain quantitatively in the solution.

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Isolierung der intermetallischen Verbindungen Al₂Cu, Al₁₂Mg₁₇, Al₃Fe, Al₉Co₂ und Al₃Ni aus binären Aluminiumlegierungen mit Hilfe eines organischen Lösungsmittels

Zusammenfassung Zur Isolierung der intermetallischen Verbindungen aus den entsprechenden binären Legierungen wird die Probe mehrere Stunden bis Tage unter Rühren mit einer methanolischen Lösung von Benzoesäure (20%), Oxin (5%), Chloroform (20%) und Natriumhydroxid (0,02%) behandelt. Hierbei wird die Matrix aufgelöst und die intermetallischen Verbindungen bleiben zurück.

     

Ion chromatographic separation of alkali metal and ammonium cations on a C18 reversed-phase column

The separation of alkali metal (Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺) and ammonium cations on a C₁₈ reversed-phase column using three anionic surfactants [sodium 1-eicosyl sulphate, sodium dodecyl benzenesulphonate and sodium dodecyl sulphate (SDS)] is described. Two methods were examined: (a) “permanent” coating, with the use of a C₁₈ reversed-phase column previously coated with the surfactants; and (b) dynamic coating, with addition of the surfactants to the mobile phase. With method (a) the separation of the six cations was achieved with SDS. However, the retention times gradually decreased owing to dissolution of the SDS coating. Good separation was obtained with method (b), where 10 mM HNO₃ containing 0.1 mM SDS was used as the mobile phase with conductivity detection, and it was applied satisfactorily to real samples. The effect of system peaks on determination is also discussed.