Alkylation of β-diketones through their co(II), co(III) and zn(II) complexes. 1-Bromoadamantane as alkylating agent.

α-(1-adamantyl)-β-diketones are now accessible by the alkylation of Co(II) complexes of β-diketones with 1-bromoadamantane. The intermediacy of adamantyl cation is proposed. Co(II), Co(III) and Zn(II) complexes of pentane-2,4-dione react with alkyl halides precursors of stabilized carbenium ions, to give 3-alkylpentane-2,4-diones.     

Use of the magnetic suspension balance for the study of polymersolutions

The method involves the isothermal gravimetric determination of the absorption of an organic vapour into a thin film of liquid polymer spread upon an inert particulate support. Results are presented for the absorption of benzene and cyclohexane at 25°C in poly (dimethylsiloxane), and the concentration variation of the interaction parameter determined is compared with that found by other workers.The determination of the partial molar enthalpy of mixing was also examined by studying the absorption of hexane in poly (dimethylsiloxane) over the temperature range of 25 to 35°C, and comparing the value obtained with published values.     

Formation of columns of anomalous water by condensation in quartz capillaries

It is shown that these columns are formed in the kinetic mode from unsaturated water vapor. The condensation coefficient for an anomalous column is much less than for ordinary water. The growth rate is dependent on the equilibration time for the concentration of the anomalous component in the column. The diffusion coefficient for the anomalous component in water is less than the self-diffusion coefficient of water by nearly an order of magnitude; this and the low volatility are to be ascribed to large molecular size. It is supposed that the molecules of the anomalous component are strong groups of H₂O molecules that are only slowly converted to monomers.     

Partial synthesis of evonoloside

Conclusions The synthesis of evonoloside has been effected from cannogenol and L-rhamnose with a yield of 35%. It has been shown that when a primary alcohol group (at C₁₉) and a secondary axial hydroxy group (at C₃) are present in the aglycone, to introduce the sugar component at C₃ it is desirable first to protect the primary OH group by the partial acetylation of the aglycone.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 1, pp. 20–22, 1969     

Highly Selective Ion-Sensitive Electrodes Based on Dibenzo-Crown Ethers Containing Functional Groups for the Determination of Potassium in Biological Fluids

The electrochemical properties of membranes based on dibenzo-crown ethers bearing hydroxyl and chloromethyl groups in polyether rings were studied. These substances were tested as membrane ionophores for ion-selective electrodes (ISEs) reversible to potassium ion. The developed ISEs were used for determining potassium in blood plasma samples. The generalized results of determining potassium in the blood of different patients with cardiovascular diseases revealed quantitative regularities that allowed the diseases to be diagnosed early.     

Growth dynamics and intracluster reactions in Ni+(CO2)n complexes via infrared spectroscopy

Ni(+)(CO(2))(n), Ni(+)(CO(2))(n)Ar, Ni(+)(CO(2))(n)Ne, and Ni(+)(O(2))(CO(2))(n) complexes are generated by laser vaporization in a pulsed supersonic expansion. The complexes are mass-selected in a reflectron time-of-flight mass spectrometer and studied by infrared resonance-enhanced photodissociation (IR-REPD) spectroscopy. Photofragmentation proceeds exclusively through the loss of intact CO(2) molecules from Ni(+)(CO(2))(n) and Ni(+)(O(2))(CO(2))(n) complexes, and by elimination of the noble gas atom from Ni(+)(CO(2))(n)Ar and Ni(+)(CO(2))(n)Ne. Vibrational resonances are identified and assigned in the region of the asymmetric stretch of CO(2). Small complexes have resonances that are blueshifted from the asymmetric stretch of free CO(2), consistent with structures having linear Ni(+)-O=C=O configurations. Fragmentation of larger Ni(+)(CO(2))(n) clusters terminates at the size of n=4, and new vibrational bands assigned to external ligands are observed for n> or =5. These combined observations indicate that the coordination number for CO(2) molecules around Ni(+) is exactly four. Trends in the loss channels and spectra of Ni(+)(O(2))(CO(2))(n) clusters suggest that each oxygen atom occupies a different coordination site around a four-coordinate metal ion in these complexes. The spectra of larger Ni(+)(CO(2))(n) clusters provide evidence for an intracluster insertion reaction assisted by solvation, producing a metal oxide-carbonyl species as the reaction product.     

A data-acquisition system for the combination gas chromatograph-mass spectrometer

Summary A method for fast digital recording of low-resolution mass spectra has been developed. The method has been used for combination gas chromatography — mass spectrometry and allows, inter alia, on-line inspection of the data being recorded. Since the central unit of the acquisition system consists only of a multi-channel analyser, the system costs less than computer-based alternatives.The data recorded and processed can be displayed in a number of ways, usually after semi-automatic back-ground subtraction and normalisation. Interpretable data are then presented as tables or plotted diagrams, and are in computer-compatible form to allow later comparison with library-stored mass spectra.

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Ein Datenverarbeitungssystem zur Kombination Gas-Chromatograph-Massenspektrometer

Zusammenfassung Es wurde eine Methode zum schnellen digitalen Aufzeichnen von Massenspektren niedriger Auflösung entwickelt. Die Methode wurde für die Kombination Gas-Chromatographie — Massenspektrometrie verwendet. Sie erlaubt unter anderem eine on-line-Beobachtung der erfaßten Daten. Da die Zentraleinheit des Datenverarbeitungssystems nur aus einem Viel-Kanal-Analysator besteht, kostet das System weniger als andere, die auf einem Prozeßrechner basieren.Die erfaßten und verarbeiteten Daten können auf verschiedene Weise — gewöhnlich aber nach halbautomatischer Untergrundkorrektur und Normierung — dargestellt werden. Interpretierbare Daten werden dann in Form von Tabellen oder von Diagrammen dargestellt; sie sind in einer Form, die den Daten aus einem Prozeßrechner entspricht, so daß ein späterer Vergleich mit gespeicherten Massenspektren möglich ist.

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Un système de traitement de donnèes pour la combinaison chromatographe en phase gazeuse — spectromètre de masse

Sommaire On a mis au point une méthode pour l'enregistrement digital rapide de spectres de masse à faible résolution. La méthode a été employée pour la combinaison chromatographie en phase gazeuse — spectrométrie de masse. Entre autres, elle permet l'observation «on-line» des données enregistrées. Puisque l'unité centrale du système de traitement de données consiste seulement d'un analyseur multi-canal, le système est moins coûteux que d'autres basés sur l'emploid d'un ordinateur de procédé.Les données enregistrées et traitées peuvent être présentées de façon différente — mais généralement après correction semi-automatique du bruit de fond et standardisation subséquente. Les données qui se prêtent à l'interprétation sont alors présentées sous forme de tables ou de diagrammes; elles ont une forme qui correspond à celle des données fournies par un ordinateur de procédé, de sorte qu'une comparaison avec des spectres de masse déjà existants est rendue possible.

     

Tetragonal paramagnetic complex in Gd3+ doped Nd2(SO4)3·(NH4)2SO4·8H2O au]V.M. Malhotra

EPR studies of Gd³⁺ doped in single crystals of Nd₂(SO₄)₃·(NH₄)₂SO₄·8H₂O (hereafter referred to as NASO) at room (RT) and liquid nitrogen (LNT) temperatures exhibit that (1) the metal aquo complex has a tetragonal symmetry with abnormally low magnitudes of crystalline field parameters at RT and (2) NASO undergoes a possible phase transition between RT and LNT.     

On the reduction of oxygen in dimethylformamide

The first reduction process in dimethylformamide containing 0.1 M tetraethylam-moniumperchlorate was studied. The techniques of polarography, controlled potential coulometry and potential sweep voltammetry were applied. The results obtained are consistent with the hypothesis that some chemical reactions are involved in the overall electrode process. In particular of the two chemical reactions considered, i.e. the protonation of the superoxide ion and that of its disproportion, the data seem to favour the first reaction over the second one. Evidences that the tetraethylammonium ion of the supporting electrolyte works as proton donor are provided.