On the empirical validity of koopmans’ theorem

The application of Koopmans' theorem is investigated within the context of the LCAO interpretation of a general SCF formalism. An empirical criterion for the validity of the assumption of identity of corresponding orbitals in the ion and parent system is discussed. Calculations on He, Li, Be and pyridine are reported.

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Zusammenfassung Die Gültigkeit von Koopmans' Theorem läßt sich mittels eines verallgemeinerten SCF-Formalismus prüfen. Ein Kriterium für das Zutreffen der Annahme, einander entsprechende Einteilchenzustände in Atom und Tochter-Ion seien identisch, wird in diesem Zusammenhang diskutiert. Die Rechnungen sind am Helium, Lithium, Beryllium und Pyridin durchgeführt worden.

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Résumé La validité du théorème de Koopmans dans un formalisme SCF général est étudiée au cadre d'une interprétation LCAO. Un critère empirique pour l'identité des orbitales de l'ion et du système père correspondant est discuté. Nous rapportons des calculs sur He, Li, Be et pyridine.

     

Aktivierungsanalytische Bestimmung von Verunreinigungen in Aluminium. I

Zusammenfassung In der vorliegenden Arbeit wird die aktivierungsanalytische Bestimmung des Mangans und des Galliums mit gammaspektrometrischer Messung beschrieben. Für Mangan wird eine rasche und selektive Extraktionsmethode angegeben, wobei das Permanganation mit Tetraphenylarsoniumion und Chloroform extrahiert wird. Gallium kann nach dem Abklingen der Manganaktivität zerstörungsfrei gammaspektrometrisch bestimmt werden.

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Summary This study deals with the activation analytical determination of manganese and gallium with gamma spectrometric measurement. A rapid and selective extraction method is given for manganese in which the permanganate ion is extracted with tetraphenylarsonium ion and chloroform. After the manganese activity has died away, the gallium can be determined gamma speotrometrically without interference.

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Résumé On décrit dans le présent travail la détermination analytique de l'activité du manganèse et du gallium au moyen d'une mesure par spectroscopie-. On donne pour le manganèse une méthode d'extraction rapide et sélective, grâce à laquelle l'ion permanganate est extrait par l'ion tétraphenylarsonium et par le chloroforme. On peut doser le gallium par spectrométrie gamma, et sans interférence, après disparation de l'activité du manganèse.

     

Gas chromatography/negative-ion chemical ionisation mass spectrometry for the quantitative analysis of morphine in human plasma using pentafluorobenzyl carbonate derivatives

A sensitive and specific method for the quantitative determination of morphine in human plasma is presented. Morphine was extracted from plasma by solid phase extraction on C18 and converted to its pentafluorobenzyl carbonate trimethylsilyl derivative. The derivatives were analysed without further purification. Using gas chromatography/negative ion chemical ionisation mass spectrometry, a useful diagnostic fragment ion at m/z 356 is obtained at high relative abundance. Deuterated morphine was used as internal standard. Calibration graphs were linear within the range 1.25 to 320 nmol/L. Intra-day precision was 3.82% (15 nmol/L), 2.85% (75 nmol/L) and 4.13% (225 nmol/L), inter-day variability was found to be 1.77% (15 nmol/L), 4.95% (75 nmol/L) and 9.88% (225 nmol/L). Inter-day accuracy showed deviations of 2.18% (15 nmol/L), -0.72% (75 nmol/L) and -0.13% (225 nmol/L). The method is rugged and robust and has been applied to the batch analysis of morphine during pharmacokinetic profiling of the drug.     

A convenient synthesis of cis and trans 4-tert-butoxycarbonyl-substituted cyclohexylglycine

A novel synthesis of cis and trans substituted 4-tert-butoxycarbonyl cyclohexylglycines via asymmetric aminohydroxylation of vinyl styrene followed by reduction of the aromatic ring and subsequent oxidation is reported.     

13C-NMR. Spectroscopy of Naturally Occuring Substances. XLII. Conformational analysis of quebrachamine-like indole alkaloids and related substances

The ¹³C shifts of 16α- and 16β-substituted derivatives of quebrachamine, 14,15-dehydroquebrachamine, cleavamine, 15,20α-dihydrocleavamine and 15,20β-dihydrocleavamine are determined and correlated with possible conformations of these tetracycles. The method of analysis of the C(16) configuration of these compounds, which emanated from this study, is used for the determination of the configuration of the site of coupling of vindoline and cleavamine β-chloroindolenine.     

Reaction of γ-picoline N-oxide with ketenimines in the presence of organic acids: Preparation of α-acyloxyamides

A synthesis of a-acyloxyamides is described which utilizes the reaction of 7-picoline N-oxide and various organic acids with diphenylketene N-p-tolylimine.     

SEASONAL VARIATION OF SOLAR UV-RADIATION AT A HIGH MOUNTAIN STATION

Abstract— At the high mountain station Jungfraujoch (3576 m), the maximum daily totals for erythemal dose (G_ER), UV-A radiation (G_UVA) and global radiation (G) are 29 Sunburn Units d⁻¹, l.7 MJ m⁻²d⁻¹ and 37 MJ m⁻² d⁻¹. The maximum instantaneous values at solar noon in midsummer are 4.2 Sunburn Unit h⁻¹, 53 W m⁻² and 1110 W m⁻². A significantly nonlinear relation between G_ER and G results from the influence of the irradiated ozone mass on the UV-B erythemal dose. In contrast, G_UVA and G are linearly proportional, which can be seen from the diurnal and seasonal courses of the ratios G_ER/G and G_UVA/G AND from their dependence on the optical air mass. UV-A radiation flux is less attenuated by cloudiness than is global radiation. This effect is masked for the erythemal dose by variations in the ozone concentration. Due to seasonal ozone layer thickness and effective pathlength variations, the ratio G_ER/G shows a significant asymmetry. At the autumn equinox it is about 16% higher than at the spring equinox.     

Gas chromatographic analysis of bifunctional amines after derivatization with methyldichlorophosphine and sulfur

Summary A derivatization procedure for the gas chromatographic analysis of bifunctional amines likeβ-adrenergic blocking drugs is described. The method consists of a two-step reaction with methyldichlorophosphine and sulfur in presence of triethylamine to form cyclic methylphosphonothioic derivatives. The properties of these compounds are discussed and the application of the method to the quantitation of ephedrine in human body fluids is presented. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

Ein Dreikomponenten-Zweiphasensystem für die schnelle Flüssigkeits-Chromatographie

Zusammenfassung Für die Hochdruck-Flüssigkeits-Chromatographie wird ein Dreikomponenten-Zweiphasensystem beschrieben. Die Mischungslücke besteht zwischen dem wenig polaren Methylenchlorid und dem stark polaren Wasser und kann durch Zugabe von Äthanol als Lösungsvermittler geschlossen werden. Durch den Anteil der stark polaren Komponente in den jeweils koexistenten Phasen ist die Polarität von stationärer und mobiler Phase als stationäre gebunden und aus der mobilen immer wieder regeneriert. Durch Verteilungs-Chromatographie in der Mischungslücke ist eine Vielzahl von Stoffklassen der Trennung zugänglich, so z.B. Corticosteroide, Östrogene, Phenole, Phenolcarbonsäuren usw.

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A three-component two-phase system for high speed liquid chromatography

Summary High pressure liquid chromatography with a three-component two-phase system is described. For the less polar methylenechloride and the highly polar water a wide range of incomplete miscibility exists which can be decreased with ethanol. The water content of the coexistent phases determines the polarity of the stationary and the mobile phases. The more polar phase is adsorbed on silicagel as the column support material and serves as the stationary phase. Numerous compounds can be separated by partition chromatography between the coexistent phases, for instance; corticosteroids, estrogens, phenols, phenol-carboxylic acids and so on

     

Über die adrenale Steroid-Biosynthese in vitro. III. Selektive Hemmung der Nebennierenrinden-Funktion

The possibility is discussed of inhibiting the adrenocortical functions either selectively or preferentially by blocking the hydroxylations in positions 11β, 17α, 18 and 19 of the steroid nucleus or in 20α, 21 and 22 of the side chain, which are necessary for the formation of the individual corticosteroids from cholesterol. Many compounds with or without other biological activities, such as o,p′-DDD, Amphenone B, various blockers of cholesterol biosynthesis, heparinoids and various heterocyclic compounds, are shown to be devoid of a specific blocking activity on the adrenal cortex in vitro. However, amongst a large group of glutaric imides a few compounds proved to be active, mainly by blocking the 20α-hydroxylation of cholesterol, the most active being a cyclic hydrazide; the secretion in vivo of corticosteroids greatly decreased in response to 3–20 mg/kg. A new class of compounds active in vitro was found among simple imidazole derivatives, which block 17α, 18 and 19-hydroxylation.