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  • 1965-1969  (8)
  • 1
    Electronic Resource
    Electronic Resource
    Die Entwicklung der Valenzlehre und Alfred Werner (1966)
    Springer
    Cellular and molecular life sciences 22 (1966), S. 633-646 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Surveying the various concepts of valency which have been put forward sinceDalton for the classification of chemical phenomena, it is found that the principles have been either dualistic (Berzelius, Blomstrand, Arrhenius, Kossel) or unitarian (Gerhard, Couper, Kekulé). The phenomena of inorganic chemistry can be classified only by using dualistic concepts, whereas unitarian systems proved to be superior for the phenomena of organic chemistry. In the conceptions of G. N.Lewis and N.Sidgwick, a combination of dualistic and unitarian concepts in one theory was achieved by distinguishing two types of bonds (mobile-immobile, polar-non-polar, ioniccovalent). With the octet rule, ions as well as molecules (uncharged and charged) may be derived and it is readily understood that bonds may vary from extreme polarity to non-polar links. The coordination theory ofWerner neither fits into the dualistic nor the unitarian class of valency principles.Werner derives the compounds by using principal and auxiliary valencies (‘Haupt- und Nebenvalenzen’) and distinguishes addition and insertion compounds (‘Anlagerungs- und Einlagerungsverbindungen’). However, he avoids making any statement concerning the nature of the bonds, which makes his system very adaptable but difficult to grasp. Today it is readily understood thatWerner's principal valency characterizes the stoichiometry and his coordination number characterizes the structure of the compound in question without making any statement about the nature of the bonds involved. Because of thatWerner's concepts have survived and are indispensable even today, in spite of the rise of atomic physics which has changed our views on the nature of the chemical bonds so drastically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01902415
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  • 2
    Electronic Resource
    Electronic Resource
    Die Komplexchemie des Methylquecksilber-Kations (1965)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 48 (1965), S. 28-46 
    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 methylmercury complexes CH3HgL1-λ with a considerable number of ligands Lλ- have been determined (Table 1). Like H+, the cation CH3Hg+ reveals the coordination number 1 almost exclusively. Some ligands form also binuclear adducts (CH3Hg)2L2-λ and sulfide even forms (CH3Hg)3S+. The coordination behaviours of CH3Hg+ and H+ however are very different concerning the selection of ligands, the former being a soft and the latter a hard acid in the sense of PEARSON. The entropy ΔS of the reaction: H+ + L- → HL is more positive by about 14 c.u. than ΔS of the reaction: CH3HG+ + L- → CH3HgL. The hydrogen ion in aqueous solution has a far greater order producing action on the solvent than CH3Hg+. Two dyes also have investigated, which may serve as indicators for CH3HG+ and for the determination of pCH3Hg (= -log[CH3Hg+]).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19650480104
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  • 3
    Electronic Resource
    Electronic Resource
    Komplexe XXXVII. Die EDTA-Komplexe des Vanadiums(V) (1965)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 48 (1965), S. 1556-1565 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By adding EDTA to a solution of metavanadate, the complex VO2Y3- or its protonated forms VO2HY2- and VO2H2Y- are produced. A number of cristallized salts containing these anions have been prepared and characterized. The stability constants of the complexes have been obtained photometrically. In the reaction of the complex with alkali, VO2Y3- is in equilibrium with H2VO4- and HVO42-, and its study furnishes also the equilibrium: 2 H2O + VO2+ ⇌ H2VO4- + 2 H+. The effective stability of the 1:1-Vanadium(V)-EDTA complex over the entire pH-range is given.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19650480716
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  • 4
    Electronic Resource
    Electronic Resource
    Kobalt(III)-Komplexe von N, N, N′, N′-Tetrakis-(β-aminoäthyl)-äthylendiamin (= «penten»)Experimentelle Einzelheiten siehe Dissertation Emmenegger [1]. (1966)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 49 (1966), S. 625-643 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several salts containing the cation Co(penten)3+, in which the hexamin «penten» (formula: page 625) acts as a sexadentate ligand, have been synthesized and characterized. Its optical antipodes have been separated in some of the salts (Fig. 4), and the rate of racemization studied. In strongly alkaline solution one of the 5 chelate rings slowly opens and Co(penten)OH2+ is produced (Fig. 1), to which a first proton can be attached at the terminal NH2-group (→ Co(Hpenten)OH3+), and a second which converts the hydroxo-complex into the aquo-complex (→ Co(Hpenten)OH4+). The equilibria between Co(penten)3+, Co(penten)OH2+, Co(Hpenten)OH3+ and Co-(Hpenten)OH24+ have been elucidated, and the kinetics of the ring opening and ring closing reactions have been studied. Ring opening and ring closure take place with retention of configuration. It proved impossible to open two of the chelate rings of Co(penten)3+. Cristalline salts with cations of the general formula Co(penten)X3-λ or Co (Hpeten)X4-λ, with Xλ- = OH-, H2O, F-, Cl-, Br-, J-, SCN-, NO2,- and CO32-, have been obtained and characterized (Fig. 1, 2, 7 and Table 1).
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19660490102
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  • 5
    Electronic Resource
    Electronic Resource
    Nickel- und Palladiumkomplexe mit Phosphinothioäthern (1966)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 49 (1966), S. 1927-1931 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new terdentate ligand bis-(diphenylphosphinoethyl)-sulfide (PSP) and a new quadridentate ligand 1, 2-bis-(diphenylphosphinoethylthio)-ethane (PSSP) (structures see page 1928) have been synthesized and their NiII- and PdII-complexes have been studied. There is good evidence that the metal has coordination number five in some of these complexes containing halogen (Cl, Br, J).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19660490629
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  • 6
    Electronic Resource
    Electronic Resource
    Die Deprotonierung von Metall-Aquoionen I.: Be · aq2+ Solvatations-Isomerie (1969)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 52 (1969), S. 644-665 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of Be · aq2+ with OH- leeds not only to loss of protons by the metalaquo ion but also to structural changes in the solvation sphere. These can be studied by following the pH variations during the first decisecond after mixing the solutions of metal salt and alkali hydroxide. The equilibrium Be2+ ⇌ BeOH+ is reached within 5 milliseconds if acid free Beryllium solutions are used. If the metal solution is strongly acidic, however, the establishment of the equilibrium needs more time because of the slowness of the process H+ + BeOH+ → Be2+ (k ∼ 105 M-1, s-1). The extraction of two protons produces in the first instance an unstable Be(OH)2* species which transforms into the stable isomer Be(OH)2 (solvatation isomerism) in a first-order reaction of half-life of 7 ms. This isomerisation causes almost complete disappearance of BeOH+ from the equilibrium Be2+ ⇌ BeOH+ ⇌ Be(OH)2. (KAKIHANA & SILLEN state that the relaxed solutions contain only Be2+, Be(OH)2, Be3(OH)33+ and some Be2OH3+.) The formation of the polynuclear species Be3(OH)33+ needs about 30 seconds to go to completion.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19690520313
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  • 7
    Electronic Resource
    Electronic Resource
    Salzkrykopie III. Eine verbesserte Apparatur zur Bestimmung der Depression des Umwandlungspunktes von GLAUBER-Salz (1965)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 48 (1965), S. 1249-1259 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new apparatus is described which allows the determination of the depression of the transition point of Na2SO4,10H2O, due to foreign solutes, with a higher precision than attained before. An investigation of the various sources of error shows that the greatest uncertainty is caused by the slowness with which the final equilibrium between the two solid phases and the liquid phase is reached.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19650480606
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  • 8
    Electronic Resource
    Electronic Resource
    Die Öffnung des Chelat-Vierrings vom Tetrammincarbonatokobalt(III)-Ion (1965)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 77 (1965), S. 462-462 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19650771025
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