Tetrathiafulvalene-acetylene scaffolding: new pi-electron systems for advanced materials

Novel extended tetrathiafulvalenes (TTFs) with hexa-2,4-diyne-1,6-diylidene spacers between the two 1,3-dithiole rings and laterally appended alkynyl moieties for one- and two-dimensional scaffolding were synthesised and investigated for their electronic properties.     

Anodic synthesis and molecular structure of dodecaethylhexaamidobisphosphonium diperchlorate

The electrochemical oxidation of hexaethyl triamidophosphite in the absence of nucleophiles specially introduced into the electrolyte was studied by anodic voltamperometry and preparative electrolysis. The reversible one-electron oxidation of the triamidophosphite molecule gives an unstable radical-cation, which reacts with a molecule of the starting compound to give a dimeric radical-cation, whose subsequent oxidation leads to dodecaethylhexaamidobisphosphonium diperchlorate. This product is the first example of an acyclic, doubly charged bisphosphonium cation with a . The crystal structure of this compound was obtained by x-ray diffraction structure analysis.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 664–669, March, 1990.     

Applicability of dynamic change of pH in the capillary zone electrophoresis of proteins

A method to extend the separation power of CZE is described. The method is based on the separation of sample components at two different pH values during one separation run, and involves dynamic buffering of the pH inside a separation capillary by controlling the flow of H+ ions from the anodic electrode chamber. By changing the anolyte in the chamber, a dynamic pH step is generated, which proceeds rapidly along the capillary and establishes the required new pH value. The use of the method has been demonstrated by the cationic separation of a model mixture of proteins.     

Determination of Mg,Al, P,Cu and Mn in biological fluids by neutron activation analysis

Thermal and epithermal neutron activation analysis has been applied to determine the concentrations of magnesium, aluminium, phosphorus, copper and manganese in two biological fluids: blood serum and market milk. Both epithermal neutron irradiation and radiochemical separation (a chromatographic column of HAP) were used to get rid of the interferences from 24-Na. Strongly acidic solutions of the irradiated samples were passed through the columns of HAP, where sodium was completely adsorbed while, Al, Cu, Mg and Mn were eluted with an efficiency of 99±1%. Since both Al and P were determined through the formation of²⁸Al (2.24 min) thermal and epithermal neutron activation have been applied in order to determine the contribution of each radionuclide to²⁸Al activity. The determination of Mg, Al and P in milk samples was done instrumentally, whereas in the case of blood serum with higher concentration of Na, a radiochemical separation is essential in both cases. The concentrations of Al, Cu, Mg, Mn and P in blood serum and market milk were found to be 0.24±0.02 and 1.85±0.09 g Al/ml, 1.35±0.04 and 0.068±0.005 g Cu/ml, 22.9±1 and 98.9±8.6 g Mg/ml, 22±3 and 16±2 ng Mn/ml and 167±13 and 865±32 g P/ml, respectively.     

Regiospecifically controlled formation of tetrasubstituted tributyltin ketone enolates catalyzed by a palladium complex

The palladium-catalyzed hydrostannolysis of α-disubstituted allyl β-keto esters yields the corresponding tributyltin β-keto carboxylates which loose carbon dioxide at very moderate temperature, thus leading to the regiospecific formation of tributyltin tetrasubstituted enolates.     

A theory of glass electrode response

Summary The response of glass electrodes to rapid changes in ion concentrations is considered from a theoretieal viewpoint. An expression is derived which describes the potential vs. time behavior of glass eleotrodes in terms of a new constant which may be useful in the characterization and selection of glass compositions. Agreement between glass electrode response predicted by the theory and available experimental data is excellent.

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Zusammenfassung Die Ansprechbarkeit von Glaselektroden auf rasche Änderungen der Ionenkonzentration wird vom theoretischen Standpunkt aus erörtert. Eine Gleichung wird abgeleitet, die das Elektrodenpotential als Funktion der Zeit erfaßt und eine neue Konstante enthält, die zur Beurteilung und zur Auswahl der Zusammensetzung von Gläsern dienen kann. Es besteht eine sehr gute Übereinstimmung zwischen theoretisch vorausgesagter und experimentell geprüfter Ansprechbarkeit von Glaselektroden.

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The financial support of NIH Grant GM-10086-03 and NSF Grant GP-1093 is gratefully acknowledged.

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Alfred P. Sloan Research Fellow.     

Mass spectrometry of 1,1′-diacetylferrocene and 1,1′-dipropionylferrocene: Evidence for intraannular interaction between alkanoyl substituents

The mass spectra of 1,1′-diacetylferrocene, 1,1′-dipropionyl ferrocene and their deuterium and Fe⁵⁷ isotope labeled analogs are herein reported and discussed. Fragmentation pathways are established and evidence is presented that in the process of fragmentation there is extensive interaction between substituents on the two ferrocene rings. This process apparently has little precedent in the mass spectrometry of ferrocene derivatives. Specifically, the experimental results suggest the simultaneous elimination of two molecules of carbon monoxide, or in another case, of carbon monoxide and ethylene from ions produced in the mass spectrometry of the above compounds.     

Ein Automatisiertes Mess-System für die Ge(Li)-Gammaspektrometrie

An automated off-line Ge(Li)-spectrometer is described. Its special features are a sample changer with rotating disk store and pneumatic tube, a self-controlling source—detector distance and an autonomous control programmed by cable connections or by punched tape via a central control unit. The system is meant to do complex routine work in activity supervision and activation analysis.     

The acid-catalyzed and neutral solvolysis of benzoylphenyldiazomethane in water,aqueous t-butanol,and aqueous salt solutions

The acid-catalyzed and water-catalyzed solvolysis ofbenzoylphenyldiazomethane (1) have been studied in water and in t-butanol-water mixtures, the mole fraction of water (n_H2O) being varied from 0·75-1·00. Increasing t-butanol concentrations produce a pronounced decrease in both k_H⊕ and k_H2O. In the “water reaction” mutually compensatory changes of AH

and AS

are associated with the rate variations, with minima in AH

and AS

at about n_H2O = 0·95. In addition it was found that the magnitude of the salt effect of (n-Bu)₄NCl on the rate of hydrolysis of 1 in water at 25° is much larger than that of LiCl, NaCl and NaBr. Assuming that the rate of the “water reaction” is largely determined by water acidity, the data are suggestive for the existence of a relation between water acidity and solvent structural integrity in highly aqueous t-butanol-water solutions.     

Enzymatic hydrolysis reaction of phospholipids in monolayers

The hydrolysis reaction of , and , -dipalmitoylphosphatidylcholine (DPPC) catalized by bee venom phospholipase A₂ was studied in spreading monolayer at the water/air interface. DPPC and the hydrolysis products, palmitic acid and -lysophosphatidylcholine, palmitoyl were characterized at the interface by means of surface pressure, surface potential and ellipsometric measurements. Furthermore, mixed monolayers of reagents and products were investigated to ascertain their miscibility. The results show that the hydrolysis reaction can be followed by the decrease of surface pressure with time on subphases containing β-cyclodextrin, a well-known complexing agent of many amphiphilic compounds. The order of the reaction, the kinetic constant and other kinetic parameters are deduced.