Additions- und SubstitutionsReaktionen an Tetrafluor- und Tetrachlordiboran(4)

Addition and Substitution Reactions at Tetrafluoro- and Tetrachlorodiborane(4) From equimolar mixtures of B₂F₄ and Me_nN(SiMe₃)_3-n (n = 0–3) the mono-addition products 1–4 are formed at low temperatures. By elimination of Me₃SiF the adduct 2 gives the dimeric monosubstituted diborane 8 , which slowly decomposes at room temperature to the aminoborane 6 and (BF)_n. The course of the reactions was studied by means of ¹¹B and ¹⁹F NMR spectroscopy and by measuring the vapor pressures. According to the ¹¹B and ³¹P NMR spectra the reaction of B₂Cl₄ with PCl₅ or [Me₄N]Cl in liquid hydrogen chloride at 0°C does not yield [PCl₄]₂⁺[B₂Cl₆]^2? or [Me₄N]₂⁺[B₂Cl₆]^2? but gives [PCl₄]⁺[BCl₄]^?, PCl₃ and BCl₃ or [Me₄N]⁺[BCl₄]^? and BCl₃ besides (BCl)_n.     

Bestimmung des hei?wasserl?slichen Borgehalts in B?den mit der induktionsgekoppelten Plasma-Atom-Emissionsspektrometrie

Summary The purpose of this study is to find out whether the previously applied procedures for determining hot water soluble boron trace contents in soils using dianthrimide or azomethin-H can be substituted by ICP-AES. Research was made into chemical and spectral interferences which can arise in all three methods. The 249.678 nm boron emission line is not affected by the sample matrix indicated. The boron content from more than 60 extracts was determined using the three methods mentioned and the results were compared by means of regression calculations. It was found that ICP-AES and the dianthrimide procedure do not differ significantly, whereas the azomethin-H technique leads to somewhat higher values. The accuracy of the results achieved by means of ICP-AES was confirmed by a collaborative study. In order to determine the concentration of boron in soils in the range of 0–2 mg/kg the ICP-AES can be applied following the hot water extraction without further pretreatment of samples. This method is superior in particular when additional elements are to be considered in the soil.     

Synthesis of halogenated polyhedral phosphaboranes. Crystal structure of closo-1,7-P2B10Cl10

The 12-vertex closo-phosphaborane 1,7-P2B10Cl10 (1) has been prepared in low yield from the pyrolysis reaction of B2Cl4 with PCl3 at temperatures above 400 degrees C. A single-crystal X-ray structure determination of 1 (monoclinic space group P2(1)/n with a = 9.239(2) A, b = 16.786(3) A, c = 15.739(3) a, beta = 93.25(3) degrees, and Z = 4) confirmed that, consistent with its 26 skeletal electron count, the phosphaborane adopts a distorted icosahedral structure with the phosphorus atoms in the 1,7-positions. Crystals of 1 contain toluene in a 1:1 molar ratio embedded between each P atom of neighboring cluster molecules. Alteration of the pyrolytic conditions resulted in the formation of the phosphaboranes P4B8Cl6 (2) and P2B8Cl8 (3), which were characterized spectroscopically. Copyrolysis of B2Cl4 with a mixture of PCl3 and AsCl3 at 450 degrees C generated the six-vertex arsaphosphaborane AsPB4Cl4 (4) and traces of the icosahedral arsaphosphaborane AsPB10Cl10. These compounds are examples of heteroboranes which contain two different group-15 atoms within a single molecule.     

Über Phosphorstickstoffverbindungen. XXIX. Reaktionen von Diphenyltrichlorphosphoran mit Stickstoff enthaltenden Verbindungen

The reaction of diphenyltrichlorophosphorane with amides leads to (C₆H₅)₂P(Cl)?N-acyl compounds, whereas with amines salt-like compounds, [(C₆H₅)₂P(Cl)? NHR]Cl, are formed.     

Darstellung,Kristall- und Molekülstruktur von Triphenylphosphinoxidhydrochlorid (C6H5)3PO · HCl

On Phosphazo Compounds from Nitriles. IV. The Reaction of Tri, Di, and Monochloroacetonitrile with [Cl₃P?N? PCl₃]Cl. Improved Preparation of [Cl₃P?N? PCl₃]Cl Trichloroacetonitrile reacts with P₂NCl₇ to give Cl₃C? CCl₂? N?PCl₂? N?PCl₃ I , dichloroacetonitrile to give Cl₂C?CCl? N?PCl₂? N?PCl₃ II , and chloroacetonitrile to give the ring compound III . Preparation, n.m.r. and mass spectra of the new compounds are described. The mechanism of formation is discussed. An improved procedure for the preparation of P₂NCl₇ is given.     

Thermolyse von Phosphor(V)-Schwefel(VI)-nitridhalogeniden

Thermolysis of Phosphorus(V) Sulfur(VI) Nitride Halides Thermolysis of compounds of the type R₂PCl = N–SO₂X (R = Cl, CH₃, C₆H₅; X = F, Cl) results in the formation of the compounds R₂P(O)Cl and [NS(O)X]_n. Pyrolysis of the title compounds with longer chains yields, among others, the cyclic compounds III and IX. IX is also one of the decomposition products of a sulfamide derivative (XXI). Finally the thermal behaviour of carbon containing phosphorus(V) sulfur(VI) nitride chlorides has been investigated.     

On generalized entropy measures and pathways

Product probability property, known in the literature as statistical independence, is examined first. Then generalized entropies are introduced, all of which give generalizations to Shannon entropy. It is shown that the nature of the recursivity postulate automatically determines the logarithmic functional form for Shannon entropy. Due to the logarithmic nature, Shannon entropy naturally gives rise to additivity, when applied to situations having product probability property. It is argued that the natural process is non-additivity, important, for example, in statistical mechanics [C. Tsallis, Possible generalization of Boltzmann-Gibbs statistics, J. Stat. Phys. 52 (1988) 479-487; E.G.D. Cohen, Boltzmann and Einstein: statistics and dynamics—an unsolved problem, Pramana 64 (2005) 635-643.], even in product probability property situations and additivity can hold due to the involvement of a recursivity postulate leading to a logarithmic function. Generalized entropies are introduced and some of their properties are examined. Situations are examined where a generalized entropy of order α leads to pathway models, exponential and power law behavior and related differential equations. Connection of this entropy to Kerridge's measure of “inaccuracy” is also explored.     

Auf die mannigfache Verwendbarkeit der Centrifugalmaschine zu analytischen Zwecken

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