13C-Kernresonanzspektroskopische Untersuchung der Komplexierung von synthetischen «Carrier»-Molekeln mit Ca2+-Ionen

The complex formation between CaCl₂ and the ion carrier ligands 1 and 2 was investigated with ¹³C-NMR. spectroscopy. In methanol as solvent, the ligands form complexes with both 1:2- and 1:1-stoichiometry (Ca²⁺/ligand). In the latter case, apart from solvent molecules, the ligand's two amide carbonyl groups and two ether oxygenatoms probably take part in the coordination of the metal cation. In contrast, when using a non polar solvent (CDCl₃), 2 forms only a complex with 1:2-stoichiometry, whereas 1 may also form a 1:1-complex in which the ester carbonylgroups participate in the coordination too.     

Transport of Ca2+, Sr2+, Ba2+, Na+, K+ and Cs+ through hollow fiber supported liquid membrane

The transport of metal ions (Ca²⁺, Sr²⁺, Ba²⁺, Na⁺, K⁺, Cs⁺) through hollow fiber supported dichlorobenzene liquid membrane has been studied. The transport of cations using 8-crown-6 ether as a carrier and picrate as co-counter ion as well as a pertraction device and capillary isotachophoresis (ITP) measurement of the cation concentration is described.     

13C-Kernresonanzspektroskopische und elektromotorische Untersuchungen der Wechselwirkung von neutralen Carriern mit Ionen in Membranen

Investigation of the interaction of neutral carriers with ions in membranes by ¹³C-NMR. and EMF.-measurements. Applying a simple model, information on the interaction of neutral carriers with cations as well as on the ion pair formation may be obtained through ¹³C-NMR. and potentiometric studies of PVC-supported ion selective liquidmembranes in contact with aqueous solutions. The results indicate that carriers for K⁺ (nonactin) and synthetic ionophores for Ca²⁺ show an association of the carrier-complexes with lipophilic anions. The extent of complex formation of the carrier in the presence of lipophilic anions in the sample solution is in agreement with earlier interpretations of the anion interference of cation selective liquid-membrane electrodes.     

Spektrophotometrische Untersuchung der Komplexbildung von Eisen(III) mit Ethylendiamintetraessigsäure und einigen Thioliganden

Spectrophotometric Investigation of the Complexation of Iron(III)with Ethylene Diamine Tetraacetic Acid and Some Thioligands . In the system Fe^III/EDTE/R? SH (Thiophenol, Toluen-3,4-dithiol, Thioethanol bzw. Thioglycollic acid) ternary complexes could be detected in solution. By means of spectrophotometric measurements the ratio of components in the species Fe:L:L′=1:1:1 was determined. The optical properties of the complexes are discussed.     

Elektrometrische Untersuchung der Zusammensetzung und Stabilität von Thiomilchsäurekomplexen mit Zn2+ und UO 2 2+

The complexation of thiolactic acid with Zn²⁺ and UO₂ ²⁺ has been investigated by potentiometric and conductometric titration techniques. Both the metals form 1∶1 and 1∶2 complexes in different pH ranges. Their logK _stab values have been determined byCalvin andMelchior's extension ofBjerrum's method and were further refined by alternative methods at temperatures 20, 30, and 40°C. The values of overall changes in ΔG, ΔH and ΔS for complexation have also been reported.     

Untersuchung der magnetostrukturellen Eigenschaften gemeinsam gefällter Hydroxide von Cd2+, Ni2+ und Fe3+

Zusammenfassung Aus einer Reihe gemeinsam gefällter und in siedendem Wasser gealterter Hydroxide, deren Mischungsverhältnis die Bildung von Cd _x Fe_1–x [Ni_1–x Fe_1+x ]O₄-Ferriten möglich machte, wurden Präparate erhalten, welche charakteristische Sättigungs-Magnetísierungskurven zeigen. Röntgenographische Analyse und magnetische Untersuchungen zeigten, daß der primäre Ferromagnetismus dieser Präparate dem -Fe₂O₃ zuzuschreiben ist.

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Studies of the magnetostructural properties of coprecipitated hydroxides of Cd²⁺, Ni²⁺ and Fe³⁺

From a series of coprecipitated hydroxides, aged by boiling in water, and in which the mixing proportions enabled the formation of Cd _x Fe_1–x [Ni_1–x Fe_1+x ]O₄-ferrites, preparations were obtained which show characteristic saturation magnetization curves. X-ray analysis and magnetic studies showed that the primary ferromagnetism of these preparations must be assigned to -Fe₂O₃.

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Mit 6 Abbildungen     

Zur konformation von frangulanin : Untersuchung mit hilfe der 13c- und 1h-nmr-spektroskopie

From the ¹³C-NMR-Spectrum of Frangulanin (1) and ¹H NMR-measurements solvent induced conformational changes can be observed.     

啤酒酵母生理代谢过程中钠、钾、镁、钙离子含量变化的跟踪检测

采用空气-乙炔火焰原子吸收光谱法分别测定了啤酒酵母发酵液中的Na^ 、K^ 、Mg^2 、Ca^2 离子动态变化中的含量,用La^3 盐消除P对Ca^3 的干扰,以Sr^2 盐作为Na^ 、K^ 的消电离剂。本实验室采用配制培养基,通过对不同种类及不同发酵阶段培养的发酵液样品进行测定,以研究在啤酒酵母生长代谢过程中Na^ 、K^ 、Mg^2 、Ca^2 离子代谢动态变化。方法的Na^ 、K^ 、Mg^2 、Ca^2 相对标准偏差(RSD)分别为0．31％,0．73％。1．78％,0．28％;样品加标回收率为98％-107％;检出限：Na^ 为0．159mg／L,K^ 为0．789nag／L,Mg^2 为0．039mg／L,Ca^2 为0．029mg／L。该方法简便快速,具有很好的精密度。     

Silylphosphane mit Adamantan-Struktur durch Umsetzung von P4 und Na/K mit Dichlorsilanen sowie deren 31P-NMR-Spektren

Silylphosphanes with an Admantane Skeleton Formed in Reactions of P₄ and Na/K with Dichlorsilanes, and their ³¹P NMR Spectra The reactions of P₄ and Na/K (molar ratio 1:3) with EtMeSiCl₂, Et₂SiCl₂, and PhMeSiCl₂ give access to the silylphosphanes with adamantane structure (EtMeSi)₆P₄ 1 , (Et₂Si)₆P₄ 2 , and (PhMeSi)₆P₄ 3 . Likewise, the Si-functional adamantanes [Vinyl(Me)Si]₆P₄ 4 , (MeHSi)₆P₄ 5 , and (MeHSi)(Et₂Si)₆P₄ 6 can be obtained by the reaction of alkali phosphides with Vinyl(Me)SiCl₂, MeHSiCl₂, or Et₂SiCl₂/MeHSiCl₂ (molar ratio 5:1), respectively. The compounds form colorless crystals ( 3 crystallies reluctantly). The reactions of the alkali phosphides with t-Bu₂SiCl₂ and Ph₂SiCl₂ do not lead to the corresponding adamantanes; t-Bu₂SiCl₂ doesn't react product mixture of the more reactive Ph₂SiCl₂ traces of (Ph₂Si)₆P₄ could not be detected. The ³¹P-NMR-spectra of the compounds 1–6 are interpreted.     

Untersuchung der Reaktionen von H- und D-Atomen mit NO2 mittels gekreuzter Molekularstrahlen

Ohne Zusammenfassung     

Theoretical study of interaction of 2,6-dithiopurine with Li+, Na+, K+, Be2+, Mg2+, and Ca2+ metal cations

The geometries of the complexes of Li⁺, Na⁺, K⁺, Be²⁺, Mg²⁺, and Ca²⁺ metal cations with different possible 2,6-dithiopurine anions (DTP) were studied. The complexes were optimized at the B3LYP level and the 6-311++G(d, p) basis set. The interactions of the metal cations at different nucleophilic sites of various possible 2,6-dithiopurine anions were considered. It was revealed that metal cations would interact with 2,6-dithiopurine anions in a bicoordinate manner. In the gas phase, the most preferred position for the interaction of Li⁺, Na⁺, and K⁺ cations is between the N₃ and S₂ sites, while all divalent cations Be²⁺, Mg²⁺, and Ca²⁺ prefer binding between the N₇ and S₆ sites of the corresponding 2,6-dithiopurine. The influence of aqueous solvent on the relative stability of different complexes has been examined using the Tomasi’s polarized continuum model. The basis set superposition error (BSSE) corrected interaction energy was also computed for complexes. The AIM theory has been applied to analyze the properties of the bond critical points (electron densities and their Laplacians) involved in the coordination between 2,6-dithiopurine anions and the metal cations. It was revealed that aqueous solution would have significant effect on the relative stability of complexes obtained by the interaction of 2,6-dithiopurine anions with Mg²⁺ and Ca²⁺ cations. The effect of metal cations on different NH and CS stretching vibrational modes of 2,6-dithiopurine has also been discussed.     

Abtrennung von Na, K und P mit Hilfe anorganischer Separatoren bei der Neutronenaktivierungsanalyse von biologischem Material

Zusammenfassung Zur Entfernung hochaktiver Komponenten aus neutronenaktivierten biologischen Proben wurden 2 Sorptionsprozesse eingehender untersucht. Zur Abtrennung von ²⁴Na wurde unterschiedlich hergestelltes Hydratisiertes Antimon Pentoxid (HAP), für die Abtrennung von ³²P Zirkoniumphosphat (ZP) getestet. Für die Abtrennung von ⁴²K wurden handelsübliche Titanphosphatpräparate (TiP) benutzt. Aufgrund der Sorptionsversuche und einiger physiko-chemischer Eigenschaften der Präparate wurden die Parameter zur Herstellung und Anwendung dieser Substanzen optimiert. Durch kombinierte Anwendung von HAP, ZP und TiP waren bei den gewählten Arbeitsbedingungen, z. B. bei aktivierten Kartoffelproben, keine dieser 3 störenden Komponenten nachweisbar. Eine halbautomatische Trennapparatur wurde konstruiert, welche aus folgenden Hauptteilen besteht: Destillationsapparatur, Sorptionskolonne, Ionenaustauschersäule, GradientelutionsAufsatz, elektropneumatische Ventile und Fraktionssammler. Die Aufarbeitung der Probe erfolgt ferngesteuert, der Zeitbedarf beträgt ca. 7 h.Frl. I. Berg, Frau E. Haller und Herrn B. Bauer wird für die wertvolle Mitarbeit bei den Untersuchungen gedankt.     

Comprehensive study on the solvation of mono- and divalent metal cations: Li+, Na+, K+, Be2+, Mg2+ and Ca2+

Hydration of mono- and divalent metal ions (Li(+), Na(+), K(+), Be(2+), Mg(2+) and Ca(2+)) has been studied using the DFT (B3LYP), second-order M?ller-Plesset (MP2) and CCSD(T) perturbation theory as well as the G3 quantum chemical methods. Double-zeta and triple-zeta basis sets containing both (multiple) polarization and diffuse functions were applied. Total and sequential binding energies are evaluated for all metal-water clusters containing 1-6 water molecules. Total binding energies predicted at lower levels of theory are compared with those from the high level G3 calculations, whereas the sequential binding energies are compared with available experimental values. An increase in the quality of the basis set from double-zeta to triple-zeta has a significant effect on the sequential binding energies, irrespective of the geometries used. Within the same group (I or II), the sequential binding energy predictions at the MP2 and B3LYP vary appreciably. We noticed that, for each addition of a water molecule, the change of the M-O distance in metal-water clusters is higher at the B3LYP than at the MP2 level. The charge of the metal ion decreases monotonically as the number of water molecules increase in the complex.     

Komplexe mit makrocyclischen Liganden I. Mechanismus der Komplexbildung zwischen Ni2+ und 1,4,8,11-Tetraazacyclotetradecan

The kinetics of the formation of the Ni^II-complex with 1,4,8,11-tetraazacyclotetradecan (Cyclam) are studied by spectrophotometric and potentiostatic methods. The reaction of Ni²⁺ with the cyclic ligand is about 30000 times slower than with the open chain triethylenetetraamine (Trien). Therefore the rate determining step with Cyclam can not be the dissociation of the first coordinated water molecule, as it is usually in complexation reactions, but it must be the formation of the second coordinative bond. This is considered to be due to the more rigid structure of Cyclam in comparison with Trien.