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  • 1
    Electronic Resource
    Electronic Resource
    Complexes macrocycliques des lanthanides: Stabilité et comportement électrochimique dans le méthanol et le carbonate de propylène (1983)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 66 (1983), S. 1296-1306 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Macrocyclic Complexes of Lanthanides: Stability and Electrochemical Behaviour in Methanol and Propylene CarbonateThe stabilities of the 1:1 complexes of the trivalent lanthanides with the diazapolyoxamacrocycles (2.1.) and (2.2.1.) in anhydrous methanol and propylene carbonate have been determined at 25°, by competitive potentiometric methods using H+ or Ag+ as auxiliary cations, with Et4NClO4 as supporting-electrolyte. Additional data are also reported for the crown ethers 15C5 and 18C6 in propylene carbonate.It is shown that the diazapolyoxamacrocycles are much stronger complexing agents for trivalent lanthanides than macrocyclic polyethers, and that the bicyclic (2.2.1.) cryptates are more stable than the monocyclic (2.1.) complexes. With increasing atomic number of the lanthanides, the stability increases with diazapolyoxamacrocycles and decreases with cyclic polyethers.The electrochemical reduction of the trivalent samarium and europium cryptates has been investigated by polarography on a dropping Hg-electrode, in water and methanol. In both solvating solvents, the +2 oxidation states of the cations are stabilized by complexation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19830660429
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  • 2
    Electronic Resource
    Electronic Resource
    Stabilité dans le méthanol et propriétés thermodynamiques de transfert des cryptates de certains cations de transition et de métaux lourds (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2287-2294 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stability in Methanol and Thermodynamic Transfer Properties of the Cryptates of some Transition Cations and Heavy MetalsThe nature and stability of the macrocyclic and macrobicyclic complexes of Ag+, Cd2+, and Pb2+ (Mn+) with 21, 22, 211, 221 and 222 in anhydrous methanol 0.05M in Et4N+ClO-4, at 25° (see Scheme) have been determined by potentiometry and spectrophotometry. Binuclear complexes M2L2n+ have been observed in all cases, besides the mononuclear MLn+ complexes. The macrobicyclic 1:1 complexes MLn+ exhibit an important ‘cryptate effect’ with Mn+=Ag+, Pb2+ and Cd2+, but not with Cu2+ and Zn2+; their stability is in all cases maximum with 221.The applicability to our results of the recent extrathermodynamic hypothesis involving MLn+ cryptates is examined.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19800630818
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  • 3
    Electronic Resource
    Electronic Resource
    Surface modification of soft-glass capillaries for gas chromatography by treatment with water vapour (1980)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 537-544 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Chromatographic properties of glass surfaces ; Fluorad FC 431 ; Glass capillary GC of basic compounds ; Modification of glass surfaces ; Deactivation of glass surfaces ; Acid-base behaviour of GC columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: “Leaching” or “etching” by strong mineral acids seems to be a necessary pretreatment step for the most commonly used deactivation procedures of glass capillaries by reaction with either polyethylene glycol or silylation reagents. The acidic sites which are formed on the surface during this acid treatment cannot be completely removed by the subsequent deactivation process. This drawback can be overcome by performing the leaching with water vapour, resulting in an accumulation of cations at the surface and a decrease in the number of silanol groups. Capillaries of this type show excellent properties for the chromatography of strongly basic compounds. After the wash-out of the alkaline surface layer, the acidity of the support is suited for the chromatography of strongly basic as well as strongly acidic compounds. Due to a lack of reactive acidic sites, special deactivation procedures have to be applied to capillaries produced in this way.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240031102
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  • 4
    Electronic Resource
    Electronic Resource
    A novel technique for thermal desorption from active charcoal (1982)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 5 (1982), S. 382-384 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Trapping by active charcoal ; Thermal desorption system ; Microwave oven ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240050713
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  • 5
    Electronic Resource
    Electronic Resource
    Influence of carrier gas humidity on the elution of amines from fused silica capillary columns (1980)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 311-312 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Fused silica capillaries ; Free amines ; Humidity of carrier gas ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240030615
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