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  • Organic Chemistry  (133)
  • 1
    Electronic Resource
    Electronic Resource
    Komplexone XXV. Die polarographische Untersuchung von Austauschgleichgewichten. Neue Daten der Bildungskonstanten von Metallkomplexen der Äthylendiamin-tetraessigsäure und der 1,2-Diaminocyclohexan-tetraessigsäure (1954)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 37 (1954), S. 937-957 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polarograms of the metal complexes of Ethylenediaminetetraacetic Acid and of 1,2-Diaminocyclohexane-tetraacetic Acid are described. In a mixture, containing the metal complex MYv-4 as well as the uncomplexed cation M+v, it is usually possible to determine the concentration of the latter with high accuracy with the aid of a polarograph. Such measurements have been used for the determination of the ratios of the formation constants of the complexes of two metals M and M′, and from these ratios the individual formation constants of 49 complexes have been obtained. The best values of the formation constants (20°, μ = 0,1) of metal complexes are tabulated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19540370402
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  • 2
    Electronic Resource
    Electronic Resource
    Komplexone XXVII. Dielektrische Wirkung der Hydrathüllen des Wasserstoffions und verschiedener Metallkationen in wässeriger Lösung (1955)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 38 (1955), S. 1931-1940 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two otherwise identical complexing agents, carrying the groups (CH3)3C—and \documentclass{article}\pagestyle{empty}\begin{document}$$ \left({{\rm CH}_3 } \right)\mathop {\rm N}\limits^{{\rm (+)}} $$\end{document}—respectively, are compared with each other. The difference in stability of the complexes of the two agents is interpreted electrostatically and the conclusion is reached thereby that the charge of metal cations is shielded dielectrically very much better from the surroundings than the charge of the hydrogen ion. The trimethylammonium-charge needs less energy to approach a bivalents metal cation than is needed to bring it up within the same distance (∼ 5 Å) to the proton.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19550380732
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  • 3
    Electronic Resource
    Electronic Resource
    Die Komplexbildung des Zinks mit Dithioweinsäure (1955)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 38 (1955), S. 1920-1930 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In solutions containing dithiotartaric acid (denoted by H4D) and zinc at various pH-values, the following complexes have been shown to exist: ZnD2-, ZnHD-, ZnH2D, ZnDOH3-, Zn2D, ZnD26-, ZnD2OH7-. The formation constants of these specieses are given and their possible structures are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19550380731
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  • 4
    Electronic Resource
    Electronic Resource
    Metallkomplexe mit Polyaminen XI: Mit cis- und trans-1,2-Diaminocyclohexan (1956)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 39 (1956), S. 722-728 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complex formation of cis- and trans-1,2-Diaminocyclohexan with the ions H+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+ has been studied. The metal complexes of the trans-diamine are slightly more stable than the corresponding complexes of ethylenediamine, which is probably due to a somewhat more positive entropy term of the formation reaction. The complexes of the cis-compound are somewhat less stable than those of the trans-diamine. The distance between the two basic nitrogen atoms are almost certainly the same in both diamine molecules. The cis-compound, however, has a less favourable geometry for complex formation, because the chelate ring and the 6-membered carbon ring do not lie in the same plane as will be the case with the complexes of the trans-diamine.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19560390312
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  • 5
    Electronic Resource
    Electronic Resource
    Die Komplexe der Seltenen Erdkationen und die Gadoliniumecke (1956)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 39 (1956), S. 1589-1599 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The stability constants of the complexes of nitrilotriacetic acid with La, Ce, Pr, Nd, Sm, Gd, Dy, Yb and Y have been defermined and the polarographic method applied was proved to give good results by a redetermination of the stabilities of the complexes of Cd, Pb, Zn, Co and Ni. There again is a break at Gadolinium in the curve obtained by plotting stability constants versus atomic number of the rare earths.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19560390618
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  • 6
    Electronic Resource
    Electronic Resource
    Sterisch behinderte Metallkomplexbildung bei den Kondensationsprodukten von cis- und trans-1,2-Diaminocyclohexan mit Acetylaceton (1957)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 40 (1957), S. 27-40 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Due to increasing steric hindrance, the stability of the metal complexes of ethylenediamine-bis-acetylacetone (AeDAA) and the two stereoisomeric forms of 1,2-diaminocyclohexane-bis-acetylacetone (DCAA) decreases in the following series: M(AeDAA) 〉 M(cis-DCAA) 〉 M(trans-DCAA). A CoII-complex can only be prepared with AeDAA; NiII and CuII form complexes with AeDAA and cis-DCAA but not with trans-DCAA and of PdII and PtII complexes could be prepared with all three complexing agents. These facts agree with decreasing stability of the complexes in the metal-series Pt, Pd 〉 Cu 〉 Ni 〉 Co. The apparent stability constant of the complex Cu(AeDAA) has been evaluated. The striking difference in colour between Cu(AeDAA), purple, and Cu(cis-DCAA), green, is explained by the difference in symmetry of the ligand field in the two complexes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19570400104
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  • 7
    Electronic Resource
    Electronic Resource
    Die Erdalkalikomplexe von Adenosintetraphosphat, Glycerophosphat und FructosephosphatHerrn Prof. Dr. T. Reichstein zum 60. Geburtstag gewidmet. (1957)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 40 (1957), S. 1229-1231 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In completion of earlier measurements the stability constants of the complexes with glycerinphosphate, fructosephosphate and adenosintetraphosphate have been determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19570400513
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  • 8
    Electronic Resource
    Electronic Resource
    Monomolekular gelöstes Quecksilberhydroxyd und seine Basizität (1958)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 41 (1958), S. 988-996 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Supersaturated monomolecular solutions of Hg(OH)2 up to a concentration of 10-2M can be obtained by adding Cu(NO3)2 to a solution of the mercury complex of EDTA, introducing two NaOH and running the mixture through an anion exchanger. Solutions so obtained have been titrated with HNO3 in order to obtain the protonation curve of Hg(OH)2. Measurements were carried out at 13° C, 20° C, 30° C, 40° C and with solution containing various amounts of NaNO3. The results extrapolated to zero ionic strength are:.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19580410411
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  • 9
    Electronic Resource
    Electronic Resource
    Salzkryoskopie I. Eine Apparatur zur Bestimmung von Ionengewichten mit kleinen Substanzmengen (1958)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 41 (1958), S. 2042-2053 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For the cryoscopic investigation of salt-like materials it is of great advantage to use, as solvents, melts of salts, transitition points of salt hydrates or eutectic mixtures. An apparatus is described allowing such measurements to be carried out with small amounts of substance of the order of 10-3 formula weights. Data are given for NaCl, NaOH, ZnSO4, Na2CdY, Na2CoY, [Ag2(en)2]SO4 («en» = ethylendiamine; Y4- = anion of EDTA), using Na2SO4, 10H2O as solvent. The ethylenediamine-silver complex is shown to contain the binuclear cation [Ag2(en)2]2+, in agreement with the result of equilibria measurements carried out earlier.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19580410712
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  • 10
    Electronic Resource
    Electronic Resource
    Salzkryoskopie II. Die Gültigkeit kryoskopischer Gleichungen für Lösungen in GLAUBER-Salz-Schmelzen (1958)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 41 (1958), S. 2425-2435 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermodynamics furnish a relation between the depression of the freezing point of a solvent and the depression of its activity, both caused by the addition of small amounts of a solute. In order to carry out cryoscopic determinations of particle weights, the assumption of validity of RAOULT's law is needed in addition to the thermodynamic relation mentioned. For {Na2SO4, 10 H2O} as a solvent, it can be shown theoretically that only particles other than H2O, Na+ and SO42- give a depression of the transition point at 32,384°. The observed depressions are however somewhat larger on the average than the values calculated thermodynamically using RAOULT's law. Especially cations and anions with high and localized charges are cryoscopically considerably more active than expected according to RAOULT's law. This finding has to be taken into account for the cryoscopic determination of the degree of condensation of polynuclear ionic species.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19580410752
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