Strukturaufklärung gemischter Komplexe von Eisen(II), Kobalt(II) und Nickel

Iron(II), cobalt(II) and nickel form complexes of the formula [Me(TTA)₂B¹] with 1-(2′-thenoyl)-3,3,3-trifluoroacetone (HTTA) and 2-pyridinalphenylimines (B¹) or bis-(2-pyridinal-R-diimines) (B²) and — in dependence of the -R group in the B² compounds — complexes of the formula [Me₂(TTA)₄B₂] and [Me₂(TTA)₂B²]. The octahedral geometry of the complexes can be unequivocally proven by means of electron spectra, IR spectra and from magnetic measurements. The labelling of solid [Ni(TTA)₂B¹] complexes with the nickel isotopes⁵⁸Ni or⁶²Ni permits an allocation of the Me-O- and Me-N-valency oscillations in the FIR.     

Studies with model membranes

Summary Thermodynamic effective fixed charge densities of mercuric phosphate and carbonate parchment supported membranes were evaluated by a number of methods particularly those ofTeorell-Meyer-Sievers, Altug andHair andKobatake et al. The value of the permselectivity was obtained for the two membranes based onKobatake et al. procedure. Membrane transport number was calculated using a modified Nernst relation and compared with the values determined by the TMS method. The theoretical predictions for membrane potential usingKobatake et al. equation are borne out quite satisfactorily by our experimental results for both membrane.

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Zusammenfassung Es wurden die Dichte der fixierten Ladungen von Quecksilberphosphat und Quecksilberkarbonat-Niederschlagsmembranen nach den Methoden vonTorell-Meyer-Sievers, Altug undHair undKobatake bestimmt. Weiterhin wurden Durchlässigkeit und Transportzahlen ermittelt und mit Werten der TMS-Methode verglichen. Theoretische Voraussagen über das Membranpotential nach den Gleichungen vonKobatake stimmen mit den experimentellen Ergebnissen überein.

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With 8 figures and 3 tables     

Suggested calculations using transition density matrices

It is suggested that certain transition density matrices, N-representable in a limit, be used in a variational calculation. It is noted that such trial matrices should yield reasonable values for the ground state energies of small atoms or molecules provided a set of overlap integrals is maximised.

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Zusammenfassung Es wird vorgeschlagen, bestimmte Übergangsdichtematrizen, die im Limit N-darstellbar sind, in einer Variationsrechnung zu benutzen. Es wird festgestellt, daß solche Näherungsmatrizen gute Werte für die Energie des Grundzustandes kleiner Atome oder Moleküle geben sollten, falls im Satz von Überlappungsintegralen maximiert wird.

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Résumé On propose d'utiliser dans un calcul variationnel certaines matrices densité de transition, N représentables à la limite. Ces matrices d'essai devraient fournir des valeurs raissonnables pour l'énergie de l'état fondamental dans les petits atomes et les petites molécules à condition de maximiser un ensemble d'intégrales de recouvrement.

     

Use of thenoyltrifluoroacetone for the determination of manganese by activation analysis

A new procedure for the substoichiometric extraction of bivalent manganese by thenoyltrifluoroacetone into ethyl acetate has been developed and used in activation analysis. The value of the extraction constant has been found to be 3.1 x 10(-6); the pH range in which the extraction can be performed is 7.8-9.2. The influence of oxalate, citrate, tartrate, fluoride and cyanide ions has been studied. A selective substoichiometric extraction of manganese in the presence of Zr, Hf, Nb, Th, Fe and Sc is possible at pH 8-8.5, tartrate and fluoride being used as masking agents. Copper and cobalt can be screened by ammonia and cyanide respectively. The method has been used for the determination of manganese in biological materials, potassium fluoride and zirconium.     

Plasma chromatography of heroin and cocaine with mass-identified mobility spectra.

Plasma chromatography detects and identifies compounds in trace quantities at atmospheric pressure through characteristic positive and negative mobility spectra. To facilitate use of the technique to detect gas chromatographic effluents, a number of reference mobility spectra for different classes of compounds have been reported. Reference spectra for two more compounds, heroin and cocaine, are presented in this study. The primary ions found in these mobility spectra were determined to be M+, (M - H2)+, and (M - CH3CO2)+ for heroin and M+, (M - C6H5CO2)+ and (M - C6H5CO2 - CO2CH3)+ for cocaine using a directly interfaced plasma chromatograph-mass spectrometer. The identified ions agree closely with those predicted in the ion mobility spectra using mass-mobility correlation data coupled with chemical ionization mass spectrometry data. Also, an independent check demonstrating the reliability of reduced mobility values reported in earlier reference spectra was made.     

Crosslinking,filler, or transition constraint of polymer networks. I

The basic theory of modulus/swelling is developed to allow for limited extensibility, filler reinforcement or transition effects, and steric hindrance of aligned segments by extended chains or filler particles. Filler forms an effective hard fraction C_h per cubic centimeter of compound with v_c a new (compound) index of swelling. For 1/M_c + σ fix points having ratio φ to gum values 1/F₀(v_r) and with F(v_c) replacing the Flory function F(v_r): where σ denotes entanglement. Linkage reinforcement φ does not vary with sulfur crosslinking of SBR. Vacuoles invalidate φ from mass-increment F₀(v_r)/F(v_r) for inert fillers. Then, or for Graphon, with negligible φ ≈ 1: The effective C_h includes rubber stretched hard on Graphon by swelling or trapped inside hard aggregates. Only the right-hand equation fits normal blacks. In theory, C_h can always be obtained from swollen moduli G by linear slopes (1 + 1.4C_h) relating F(v_c) and (1 ? C)ρRT/G. For filler fractions C ≥ 0 cm^?3 and low strains α = 1.5?2.0 below prestretch the modulus G is given a new basic definition: Here C₂* ≈ 0.7 corresponds to Mooney-Rivlin C₂ and the effective crosslinking 1/[M_c] = (ρRT)^?1G is equal to (1 ? C)(1/M_c + σ) for unswollen prestretched rubber (v_r = 1). For higher strains a hypothesis of strain hardening is proposed. This is distinct and opposite in character to the initial prestretch softening (Mullins effect). Nonlinear effects of crosslinks are expressed by a fractional stress-upturn Ω (1/M_c + σ), effective mesh wieght (1/M_c + σ)^?1 ? Ω, and hard fraction Ω(1/M_c + σ). For μ_h characterizing strain hardening up to the prestretch (α_h ? 1) their contribution is: The sixth-power refinement has J = j(α_b ? 1)^1/2 with j ≈ 0.4. The hard phase is augmented by filler and grows with increasing strain up to the prestretch.     

Effect of radial distribution functions and poisson reparatition of reactants on the analysis of reactions involving long distance energy transfer

Starting from a uniform distribution and knowing the space dependent rate constant, it is possible to express the fluorescence quenching effect. In the case of long distance energy transfer (Forster), we show that the introduction of radial distribution functions and of non-uniform repartition of quenchers has only small effects on the kinetics of such reactions.

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. (Forster) , .

     

New catalytic method for the synthesis of vitamins K

A new catalytic method for the synthesis of vitamins of the K family is suggested. In this method 2-methyl-1-naphthol is oxidized by dioxygen in the presence of Mo-V-P heteropoly acids or their salts in a two-phase system (organic solvent + water) to 2-methyl-1,4-naphthoquinone or vitamin K3, which is the precursor of all K family vitamins.     

Quantitative determination of nitroglycerin in human plasma by capillary gas chromatography with electron-capture detection

A sensitive method for the selective determination of nitroglycerin at concentrations down to 50 pg/ml in human plasma is described. After the addition to plasma of a known amount of butane-1,2,4-triol trinitrate as internal standard, both compounds are extracted into hexane. Nitroglycerin is then quantitated by capillary gas chromatography with electron-capture detection.     

A method for experimental determination of effective resonance energies related to (n, γ) reactions

When making use of some single comparator or absolute standardization methods in reactor neutron and in epicadmium neutron activation analysis, the knowledge of the effective resonance energy ( ) is essential to correct for the effect of the nonideal epithermal flux distribution on the analysis result. can be calculated from neutron resonance data, but when these are incomplete, not accurate or even not known at all, experimental determination should be considered. Such a method, providing both and the resonance integral to 2200 ms^–1 cross-section ratio (Q_O), is described in this paper. Results are given for 11 isotopes.