Fluordiazadiphosphetidine, 24. Mitt.: Reaktion monosubstituierter Fluordiazadiphosphetidine mit Kaliumfluorid/Kronenether

Summary The reactivity of some monosubstituted fluorodiazadiphosphetidines towards potassium fluoride utilizing 18-crown-6-ether as a phase transfer catalyst has been studied. The following compounds were investigated: 2,2,2,4,4-pentafluoro-4-methoxy-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine, 2,2,2,4,4-pentafluoro-4-methylamino-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine, 2,2,2,4,4-pentafluoro-4-methylthio-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine, and a 1:1 mixture of 2,2,2,4,4-pentafluoro-4-(N²,N²-dimentyl-hydrazino)-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine and 2,2,2,4,4-pentafluoro-4-methylamino-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine. All reactions proceeded in a similar way and led to the disubstituted derivates of the starting materials and the potassium salt K₂(CH₃NPF₄)₂. In this way 2,2,4,4-tetrafluoro-2-methylamino-4-(N²,N²-dimethylhydrazino)-1,3-dimethyl-1,3,2⁵,4⁵-diazadiphosphetidine has been synthesized for the first time and a new way has been found for the synthesis of several compounds reported in literature.

Verstorben     

Simultaneous determination of yohimbine and boldine by first-derivative synchronous spectrofluorimetry

A method for the simultaneous determination of yohimbine and boldine in mixtures by first-derivative synchronous spectrofluorimetry has been developed. The method is based on their native fluorescence in 0.1N sulphuric acid medium. The constant wavelength difference chosen to optimize the determination was =_em -_em=82 nm. Yohimbine was measured at _ex//_em= 285/367 nm, and boldine at _ex/_em=272/354 nm. The range of application is 10–500 g/l for yohimbine and 1–50 g/l for boldine. The method was applied to the determination of yohimbine and boldine in synthetic mixtures and pharmaceuticals, with errors generally 2%. Relative standard deviations were about 2%.Dedicated to Professor Fermin Capitán on his 72th birthday     

Poly(3,4-ethylenedioxythiophene) Heterogeneity: A Differential Cyclic Voltabsorptometry Study

A voltabsorptometry study of the redox behavior of poly(3,4-ethylenedioxythiophene) films in tetrabutylammonium tetrafluoroborate solutions in acetonitrile shows the polymer to exhibit heterogeneous properties when both reduced and oxidized. The measurements are taken at characteristic wavelengths selected on the basis of stationary absorption spectra. The reduced polymer's heterogeneity is explained under the assumption that the polymer contains simultaneously linear ( = 530 nm) and spiral ( = 660 nm) structures. The formation of two oxidized polymer states is proved experimentally. Both states presumably result from strong ( = 880 nm) and weak ( = 1050 nm) interactions between the anion and the positively charged polymer chain. The oxidized 880-nm state is shown to arise from the 660-nm state, whereas the 1050-nm state forms of the 530-nm state.     

Unicyclic Graphs with Minimal Energy

If G is a graph and ₁,₂,..., _n are its eigenvalues, then the energy of G is defined as E(G)=|₁|+|₂|++| _n |. Let S _n ³ be the graph obtained from the star graph with n vertices by adding an edge. In this paper we prove that S _n ³ is the unique minimal energy graph among all unicyclic graphs with n vertices (n6).     

Four spectrophotometric methods for determination of nitrofurazone in pharmaceutical formulations

Four simple and sensitive visible spectrophotometric methods (A-D) for the determination of nitrofurazone in bulk samples and pharmaceutical formulations are described. They are based on the formation of colored species by treating either its reduction product with 3-methylbenzothiazolin-2-one hydrazone in the presence of ferric chloride (method A: _max 600 nm) or its hydrolysis product with thiobarbituric acid (method B: _max 520 nm, 440 nm) or barbituric acid (method C: _max 400 nm) or by oxidizing it with excess N-bromosuccinimide and determining the consumed NBS using metol-isonicotinic acid hydrazide (method D: _max 620 nm).     

Potential for coal calorific value corrections,dependent on the carbonate mineral type present

In addition to calcite, other carbonate minerals in coal all undergo endothermic reactions on heating, i.e. dolomite, ankerite, siderite, aragonite, magnesite, rhodochrosite, witherite and strontianite. Of these, when determined in air, siderite and rhodochrosite give small exothermic resultants, while the amount of Fe in ankerites affects the actual endothermic values obtained. The magnitude of these carbonate decomposition reactions can be shown by DTA to be different and will need to be allowed for individually in calorific value corrections of coals containing them.

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Zusammenfassung Nicht nur Kalkspat, sondern auch andere in Kohle vorkommende Karbonatmineralien wie z. B. Dolomit, Ankerit, Spateisenstein, Aragonit, Magnesit, roter Braunstein, Witherit und Strontionit gehen bei Erhitzen endothermische Reaktionen ein. Von diesen zeigen Spateisenstein und roter Braunstein exotherme Ergebnisse kleinen Wertes, während der Betrag an Eisengehalt in Ankeriten den jeweils gemessenen endothermischen Wert beeinflußt. Das Ausmaß dieser Karbonatzersetzungsreaktionen kann durch DTA-Messungen als unterschiedlich nachgewiesen werden und muß bei den Kaloriewertkorrektionen für Kohlen, die diese Mineralien enthalten, berücksichtigt werden.

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, , , , , , , , . , , . , , .

     

Activity in CO oxidation of manganese dioxide for batteries

The low temperature oxidation of CO over MnO₂ containing samples for batteries has been investigated. It is found that the samples contain compositional and hydrate water and Mn⁴⁺, Mn³⁺, Mn²⁺ ions. The high efficiency is due to Mn⁴⁺ content.

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CO MnO₂, . , Mn⁴⁺, Mn³⁺, Mn²⁺. Mn⁴⁺.

     

Sedimentation equilibrium of suspensions of colloidal particles at finite concentrations

Equilibrium concentration profiles of non-dilute colloidal suspensions are calculated by means of the Carnahan-Starling expression for the osmotic compressibility of hard sphere liquids. The profiles depend on the average volume fraction of the suspension, , and on the field interaction parameter, ₀ (reciprocal of the Péclet number at infinite dilution). Profiles are computed for values of and ₀ typical of those encountered in sedimentation field-flow fractionation experiments. It is found that, in most cases, the volume fraction at the depletion wall is negligibly small and that the volume fraction at the accumulation wall ₀, depends on the ratio <>₀/₀ only. An inflexion point is found in the concentration profile if ₀ is larger than 0.13 whatever the value of ₀.     

Fluordiazadiphosphetidine, 23. Mitt.: Die Herstellung neuer unsymmetrisch substituierter Fluordiazadiphosphetidine

Summary Using 1-chloromethyl-2,2,2,4,4,4-hexafluoro-3-methyl-1,3,2⁵,4⁵-diazadiphosphetidine as starting material for nucleophilic reactions, the following new compounds were prepared: 2,2,2,4,4-pentafluoro-4-methoxy-1-propyl-3-methyl-1,3,2⁵,4⁵-diazadiphosphetidine, 1-benzyl-2,2,2,4,4-pentafluoro-4-methoxy-3-methyl-1,3,2⁵,4⁵-diazadiphosphetidine, and 1-benzyl-2,2,2,4,4-pentafluoro-4-methylamino-3-methyl-1,3,2⁵,4⁵-diazadiphosphetidine

     

Beitrag zur mathematischen Beschreibung des Spannungs-Dehnungs-Verhaltens von Elastomeren

Zusammenfassung Ausgehend von der Hypothese vonValanis undLandel, nach der die DehnungsenergieW( _x , _y , _z ) als Summe dreier identischer Funktionenw( _i ) der Dehnungsverhältnisse _i (i=x,y,z) dargestellt werden kann, wird fürw( _i ) ein Ausdruck vorgeschlagen, der sich durch seine relative Einfachheit auszeichnet. Es wird gezeigt, daß die mit Hilfe dieses Ausdruckes abgeleiteten Formeln für das Spannungs-Dehnungs-Verhalten von Elastomeren in der Lage sind, Meßdaten anderer Autoren mit guter Genauigkeit wiederzugeben. Untersucht wurden die Beanspruchungsarten einaxialer Zug, biaxialer Zug und reine Scherung mit Dehnungen bis zu ca. 700%.

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Summary Based on the hypothesis ofValanis andLandel that the strain-energy functionW( _x , _y , _z ) could be represented as the sum of three identical functionsw( _i ) of the principal extension ratios _i (i=x,y,z), an expression forw( _i ) is suggested which is distinguished by its relative simplicity. The stress-strain relations developed from this expression are tested successfully by applying them to experimental results of other authors. The types of strain which were examined were simple extension, biaxial extension and pure shear; the elongations were to about 700%.

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Mit 4 Abbildungen     

A method for preliminary estimation of solid oxidation kinetics and mechanism

The possibility of preliminary estimation of the oxidation kinetics and mechanism using the quantity t_o from the exponential kinetic rate equation is discussed.

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, t_o .

     

Calixcrown Binding to Caesium – X-Ray Structural Determination of a 1,3-Alternate Calix[4]arenebiscrown-7 Ligand

The crystal structure of calix[4]biscrown-7, 1, (C₅₂H₆₈O₁₄), (triclinic,space group P1, Z = 2, a = 11.115 (5), b = 11.710 (5), c = 18.990 (7)Å, = 85.12 (4), = 93.11 (5), = 91.01 (5)4°,V = 2458.9 ų, Rw = 0.0737 for 4170 observed, I 3 (I),reflections) has been determined. It is suggested that the polyether loopswith a radius of ca. 2.1 Å are too shallow to efficiently complex theCs⁺ cation (radius = 1.69 Å).     

Catalytic performance in hydrodesulfurization of thiophene and ir investigation of Co and no adsorption over Co?Mo/Al2O3 and Ru?Co?Mo/Al2O3 catalysts

A new Ru–Co–Mo/Al₂O₃ catalyst has been prepared by impregnation of Ru salt as a secondary promoter onto Co–Mo/Al₂O₃ catalyst, and it was found that the Ru–Co–Mo/Al₂O₃ exhibited higher activity than Co–Mo/Al₂O₃ in hydrodesulfurization of thiophene to hydrocarbons. Ir studies on Ru–Co–Mo/Al₂O₃ revealed that the Co and NO adspecies increased significantly in intesnities and displayed a bathochromic shift in frequencies, as compared with Co–Mo/Al₂O₃.

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Ru–Co–Mo/Al₂O₃ Ru, , Co–Mo/Al₂O₃. Co–Mo/Al₂O₃. CO NO, Co Mo, Co–Mo/Al₂O₃. , Mo , Mo³⁺ Mo³⁺ Co Ru–Co–Mo/Al₂O₃.

     

Principal vectors of crystallographic groups and applications

For a crystallographic group acting on ann-dimensional Euclidean space we consider the -invariant linear elliptic differential operatorP with constant coefficients and to it the -automorphic eigenvalue problemP [] + = 0. N() is the number of all eigenvalues smaller than or equal to the frequency bound ^q (q: order ofP). Earlier we found the asymptotic estimationN() c₀ · ⁿ + c₁ · ^n–1 (c ₀,c ₁: certain volumina). Furthermore,N() was interpreted as the number of so-called principal classes of principal lattice vectors within a convex domain. In this paper we demonstrate these results for the casen = 2 for two representative crystallographic groups and the assigned lattices. Above all we demonstrate a counting method for an exact estimation ofN() if a is not too big. In an analogous way we can treat all the 230 space groups of crystallography. It will be seen that these applications are brought about by the so-called principal vectors of these lattices.     

Thermoanalytische und Kalorimetrische Untersuchung von CoOOH und CoOOD

Zusammenfassung CoOOH und CoOOD wurden definiert hydrothermal synthetisiert, chemischanalytisch und röntgenographisch charakterisiert sowie thermoanalytisch untersucht.Nach den Ergebnissen verläuft der thermische Abbau zu CO₃O₄, H₂O_(g) bzw. D₂O_(g) und O₂ in einer für Hydroxide typischen Einstufenreaktion. Ihre Temperaturlage ist vom Partialdruck der Reaktionsgase abhängig.Die hochtemperaturkalorimetrische Untersuchung erbrachte Werte für die Standardbildungsenthalpien _B H ₂₉₈ (CoOOH: –456±3; CoOOD: –455±3 kJ mol^–1) sowie die Standardreaktionsenthalpien ihrer Zersetzungsreaktionen.

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Hydrothermally synthesized CoOOH and CoOOD were characterized by chemical, X-ray and thermal analysis. The thermal decomposition leads to CO₃O₄, H₂O_(g) or D₂O_(g) and O₂ in a one-step reaction typical for hydroxides. The decomposition temperature depends on the partial pressure of the gaseous reaction products. High-temperature calorimetric studies allowed determination of the standard enthalpy of formation _B H ₂₉₈ (CoOOH: – 456±3; CoOOD: –455±3 kJ mol^–1) and the standard enthalpy of the decomposition reactions.

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CoOOD , . , , Co₃O₄, ₂ D₂ O₂. . . _BH ₂₉₈ (: –456±3; CoOOD: – 455±3 kJ ml^{– 1}.

     

Effect of acid treatment on the properties of an activated carbon

The enhancement of the activity of a carbon treated with HF is due to the drastic diminution of its inorganic impurities, which produces an increase of the surface area of the carbon, a stronger Pt-C interaction and a higher Pt dispersity.

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, HF, , , Pt-C Pt.

     

The thermal decomposition reactions of bis-(pyridine-2-aldoxime)-copper(II) complexes

The thermal properties of some complexes of copper(II) with pyridine-2-aldoxime (HPAO), where the ligand appears either as the ion (PAO^–) or as a neutral molecule, were determined in vacuo and in dynamic nitrogen and oxygen gas atmospheres. The study was carried out by thermoanalytical (TG, DTG. DTA), spectroscopic and spectrometric (UV-visible, IR, diffuse reflectance, mass) techniques.The initial decomposition temperature is influenced by the number of acid hydrogens in the complex; the thermal stability sequence in vacuo is: [Cu(PAO)₂H]Cl > [Cu(PAO)₂H₂]Cl₂ > [Cu(PAO)₂]The thermal decomposition reactions occur in several separate steps, the first of which gives rise to partial ligand decomposition, the reduction of copper(II) to copper(I), and the conversion of the residual pyridine-2-aldoxime into acid amide.

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Zusammenfassung Die thermischen Eigenschaften einiger Komplexe von Kupfer(II) mit Pyridin-2-aldoxim (HPAO), in denen der Ligand entweder als Ion (PAO^–) oder als neutrales Molekül vorliegt, wurden im Vakuum und in dynamischer N₂- und O₂-Atmosphäre ermittelt. Zur Untersuchung wurden thermoanalytische (TG, DTG, DTA) und spektrometrische (UV-sichtbar, IR, diffuse Reflektionsspektrophotometrie, Massenspektrometrie) Techniken herangezogen. Die Temperatur, bei der die Zersetzung beginnt, wird durch die Zahl der sauren Wasserstoffatome im Komplex beeinflußt; für die thermische Stabilität im Vakuum gilt die Reihenfolge [Cu(PAO)₂H]Cl > [Cu(PAO)₂H₂]Cl₂ > [Cu(PAO)₂]. Die thermischen Zersetzurigsreaktionen verlaufen in mehreren diskreten Schritten, wobei der erste von diesen eine partielle Zersetzung des Liganden, die Reduktion von Kupfer(II) zu Kupfer(I) und die Konversion des verbleibenden Pyridin-2-aldoxims in das Säureamid in sich einschließt.

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-2- ( ), (-), . (, , ) , - , , - . , [Cu(PAO)₂H]CI > [Cu(PAO)₂H₂]Cl₂ > [Cu(PAO)₂] , , -2- .

     

Synthesis of [SCo3(CO)7(S2COMe)] and the structure of its PPh3 derivative

Summary The title compound has been prepared in reasonable yield by reaction of a methanolic solution of CoCl₂ and MeOCS₂K with CO. I.r. spectra have been analyzed both in the C-O stretching region and in the region of the main vibrations of the xanthate ligand: an explanation of the appearance of only 4 out of 7 i.r.-active (CO) modes is proposed. The structure of the triphenylphosphine derivative has been solved by x-ray diffraction analysis: [SCo₃(CO)₆(PPh₃)(S₂COMe)] crystallizes in the triclinic space group P¯1, witha = 10.710(3),b = 10.199(3) andc = 16.208(4) Å, = 113.57(2)°, = 98.14(2)°, = 104.32(2)°, Z = 2, (MoK) = 0.7107 Å. The final R value is 0.045 [4461 reflections with F > 6 (F)]. The molecule is formed by an SCo₃ cluster, in which each Co atom coordinates two CO groups. The chelating xanthate ligand is equatorially bonded to two cobalt atoms forming a nonplanar pentaatomic ring; the phosphine is equatorially bonded to the other cobalt atom.     

Ein Ger?t zur h?chstempfindlichen Differentialspektrophotometrie mit dem Rapidspektroskop

Zusammenfassung Eine Methode zur Differentialspektrophotometrie durch Modulation eines Monochromators wird beschrieben. Der Monochromator oscilliert mit variabler Bandbreite zwischen ₁ und ( ₁+). Wenn ( ₁+) die Wellenlänge des Absorptionsmaximums ist, erscheint am Photo multiplierausgang einer Sinuswelle, deren Amplitude der Extinktions differenz zwischen ¹ und ( ₁+) proportional ist. Die Schaltung zur ultralinearen Messung dieser Amplitude ist angegeben und ihre Anwendung mit dem Zweistrahlphotometer Rapidspektroskop gezeigt. Die Empfindlichkeit wird durch die Kombination um den Faktor 10 bis 100 gesteigert. Der Rauschpegel ist bei der Monochromator-Modulationstechnik etwa 10^–4 E.Das Differentialspektrum stellt die erste Ableitung eines Spektrums dar und gestattet die genauere Lokalisation von Schultern in steilen Flanken eines Spektrums. Die Kombination der beschriebenen Methode mit der Technik des Rapidspektroskops erlaubt es, dasselbe mit gleichem Erfolg wie ein Dual-Wavelength-Gerät einzusetzen.

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Summary A method for differential spectrophotometry by modulation of a single monochromator is described. A single monochromator oscillates with variable bandwidth between ₁ and ( ₁+ ). If ( ₁ + ) is the wavelength at maximal optical density, the photomultiplier output gives a sinus-wave, the amplitude of which is proportional to the optical density difference between ₁ and ( ₁+). The circuit for ultralinear measurement of this amplitude is described and details of its application with the split-beam spectrophotometer Rapidspektroskop are given. The sensitivity of the entire assembly is increased by a factor of between ten and one hundred. The noise level of the monochromator-modulated technique is about 10^–4 optical density units. The differential spectrum represents the first derivative of a spectrum and allows one to determine more exactly the location of shoulders in the slope of a spectrum.The combination of the described method with the techniques of the Rapid spektroskop thus provides facilities which equal those of a dual-wavelength apparatus.