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  • Organic Chemistry  (4)
  • Physical Chemistry  (3)
  • Tensor  (2)
  • Wiley-Blackwell  (9)
  • 1985-1989  (9)
  • 1
    Electronic Resource
    Electronic Resource
    Nature et stabilité des complexes métalliques de cryptands dinucléants en solution. I. Polyazapolyoxa macrotricycle cylindrique et monocycle constitutif (1985)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 456-464 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nature and Stability of Some Metallic Complexes of Dinucleating Cryptands in Solution. I. A Polyazapolyoxa Cylindrical Macrotricycle and its Monocyclic SubunitpH-metry and UV spectrophotometry were used to study the complexing properties of the cylindrical macrotricycle, 1,7,13,19-tetraaza-4,16-dioxa-10,22,27,32-tetraoxatricyclo[17.5.5.5]tetratriacontane (1) and of its constitutive monocyclic subunit, 1,7-diaza-4,10-dioxacyclododecane (2) with some transition and heavy metal cations (Cu2+, Co2+, Ni2+, Zn2+, Cd2+, Pb2+, Ag+), in aqueous medium 0.1M Et4NClO4, at 25°. The protonation constants of the ligands as well as the nature and the stabilities of the complexes formed in the pH-regions studied were determined. The tricycle 1 only formed dinuclear M2L complexes with Cu2+, Zn2+, and Ag+, accompanied in the latter case by a protonated mononuclear MLH species, and with Cu2+ and Zn2+ at high pH-values by dinuclear hydroxo complexes. Only mononuclear complexes were evidenced with the other cations, ML being accompanied either by protonated or hydroxy mononuclear species. The mononuclear complexes of 1, when they existed, were more stable than the corresponding complexes of 2, except for cobalt which formed complexes of comparable stability with both ligands. In the other cases (Cd2+, Pb2+, Ag+), the stability differences between the complexes of 1 and 2 increased with the size of the cation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19850680219
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  • 2
    Electronic Resource
    Electronic Resource
    Nature et stabilité des complexes métalliques de cryptands dinucléants en solution. III. Le monocycle [22]-Py2N4 (1985)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 840-845 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nature and Stability of Some Metallic Complexes of Dinucleating Cryptands in Solution III. The Monocycle [22]-Py2N4The nature and stability of complexes formed by a new 22-membered monocycle L = [22]-Py2N4 with the cations Mn+ = Cu2+, Co2+, Ni2+, Zn2+, Cd2+, Pb2+, and Ag+ have been determined in aqueous solutions (0.01M NaClO4, 25°) by pH-metry and also, for the copper system, by UV-absorption spectrophotometry. The stepwise protonation constants of the four amine functions of L were 9.1, 8.3, 7.1 and 3.7 logarithms units, respectively. No evidence was found for the protonation of the two pyridine nitrogen atoms. Mononuclear complexes MLn+ were identified in all systems investigated, but the dinuclear species M2L2n+ were only found with Cu2+ and Ag+. The logarithms of the overall stability constants for the copper and silver complexes are CuL2+, 12.9; Cu2L4+, 18.6; Agl+, 6.3; Ag2L2+, 10.9, respectively. Mononuclear hydroxy species MLOH(n-1)+ were identified in all systems except those of copper and silver. No dinuclear hydroxy complexes were detected. The complexing properties of L are compared to those of the large and less rigid bis-dien.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19850680404
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  • 3
    Electronic Resource
    Electronic Resource
    Tensorial calibration: I. First-order calibration (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 247-263 
    Details
    ISSN: 0886-9383
    Keywords: Calibration ; Tensor ; Multivariate ; PCR ; MLR ; PLS ; Regression ; Multidimensional arrays ; Order ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Many analytical instruments now produce one-, two- or n-dimensional arrays of data that must be used for the analysis of samples. An integrated approach to linear calibration of such instruments is presented from a tensorial point of view. The data produced by these instruments are seen as the components of a first-, second- or nth-order tensor respectively. In this first paper, concepts of linear multivariate calibration are developed in the framework of first-order tensors, and it is shown that the problem of calibration is equivalent to finding the contravariant vector corresponding to the analyte being calibrated. A model of the subspace spanned by the variance in the calibration must be built to compute the contravarian vectors. It is shown that the only difference between methods such as least squares, principal components regression, latent root regression, ridge regression and partial least squres resides in the choice of the model.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020404
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  • 4
    Electronic Resource
    Electronic Resource
    Tensorial calibration: II. Second-order calibration (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 265-280 
    Details
    ISSN: 0886-9383
    Keywords: Calibration ; Tensor ; Multivariate ; Order ; Regression ; Generalized rank annihilation ; GRAM ; Multi order ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tensorial calibration provides a useful approach to calibration in general. For calibration of instruments that produce two-dimensional (second-order) arrays of data per sample, tensoial concepts are as natural a way of solving the calibration problem as vectorial concepts are for the multivariate problem. Similarly, for third- and higher-order data, the tensorial description of calibration is also useful. This paper introduces second-order calibration from a tensorial point of view. Univariate, multivariate and bilinear approaches to calibration are presented. The generalized rank annihilation method (GRAM) is described from the tensorial perspective, and it is shown that GRAM is equivalent to finding a second-order tensorial base that spans both tensors (calibration and unknown) with respective diagonal component matrices. GRAM uses a single calibration sample for multicomponent analysis even in the presence of interference. Second-order bilinear calibration is extended to multiple calibration samples where the effect of collinearities is reduced.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020405
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  • 5
    Electronic Resource
    Electronic Resource
    Heteroaromatic Nucleophilic Substitution Reactions by Phase-Transfer Catalysis- Synthesis of New Alkoxypridazin-3(2H)-ones (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 1465-1473 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heteroaromatische nucleophile Substitutionsreaktionen durch Phasen-Transfer-Katalyse- Synthese von neuen Alkoxypyridazin-3(2H)-onenDie Synthese von einigen 4- und 5-alkoxysubstituierten Pyridazin-3(2H)-onen mit hypotensiver und β-blockierender Wirkung durch Phasen-Transfer-Katalyse aus Halogenpyridazin-3(2H)-onen wird beschrieben. Der nucleophile Austausch verläuft recht glatt in der 5-Stellung aber viel langsamer in der 4-Stellung. Im Falle von 4,5-Dihalogenpyridazin-3(2H)-onen ergibt die Phasen-Transfer-Katalyse eine hohe Regioselektivität für die Substitution in 5-Stellung.
    Notes: The synthesis of several 4- and 5-alkoxy-substituted pyridazin-3(2H)-ones with hypotensive and β-blocking activities by phase-transfer catalysis (PTC) starting from halopyridazin-3(2H)-ones is described. The nucleophilic displacement reaction proceeds easily at the 5-position and remarkably slower at the 4-position. In the case of 4,5-dihalopyridazin-3(2H)-ones the PTC methods provide a high regioselectivity towards substitution in 5-position.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519850717
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  • 6
    Electronic Resource
    Electronic Resource
    Potential H1-Antihistaminic Drugs: Synthesis of 4-[(2,3-Dihydro-2-oxo-1H-benzimidazol-1-yl)alkoxycarbonyl]-1-(diphenylmethyl)piperazines by Selective Monoalkoxycarbonylation of α,ω-Dichloroalkanes by Phase-Transfer Catalysis (1989)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1989 (1989), S. 539-544 
    Details
    ISSN: 0170-2041
    Keywords: H1-Antihistaminic ; Piperazines ; Phase-transfer catalysis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Potentielle H1-Antihistaminica: Synthese von 4-[(2,3-Dihydro-2-oxo-1H-benzimidazol-1-yl)alkoxycarbonyl]-1-(diphenylmethyl)piperazinen durch selektive Phasen-Transfer-katalysierte Monoalkoxycarbonylierung von α,ω-DichloralkanenDie Synthese einer Reihe von neuen 4-[(2,3-Dihydro-2-oxo-1H-benzimidazol-1-yl)alkoxycarbonyl]-1-(diphenylmethyl)piperazinen 2 durch Phasen-Transfer-katalysierte Monoalkoxycarbonylierung von α,ω-Dichloralkanen wird beschrieben. Die Piperazine 2 ähneln Oxatomid1) (1) und sind potentielle H1-Antihistaminica. Ferner wurde eine Untersuchung zur regioselektiven Synthese von substituierten 1,3-Dihydro-1-isopropenyl-2H-benzimidazol-2-onen (5) durchgeführt.
    Notes: The synthesis of a series of new 4-[(2,3-Dihydro-2-oxo-1H-benzimidazol-1-yl)alkoxycarbonyl]-1-(diphenylmethyl)piperazines 2 by phase-transfer catalysed monoalkoxycarbonylation of α,ω-dichloroalkanes is described. Compounds 2 are related to oxatomide1) (1) and are potential histamine-H1 antagonists. A study on the regioselective preparation of substituted 1,3-dihydro-1-isopropenyl-2H-benzimidazol-2-ones (5) was also carried out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198919890195
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  • 7
    Electronic Resource
    Electronic Resource
    Kinetics of the formation and hydrolysis of the schiff's base of 4-pyridinecarboxaldehyde with N-hexylamine in water-dioxan mixtures (1989)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 21 (1989), S. 51-61 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have carried out a kinetic study of the 4-pyridinecarboxaldehyde plus n-hexylamine system, at 25°C, in water-dioxan mixtures (0-60% v/v) and in the pH range pKa + 1.5 〉 pH 〉 pKa - 1.5, where pKa is the pK value of the conjugate acid of the amine. The results obtained could be interpreted in terms of a rate constant for Schiff's base hydrolysis and a rate constant for the reaction between the nonprotonated n-hexylamine and the nonhydrated form of 4-pyridinecarboxaldehyde. Both constants decrease sharply as the dioxan content of the solvent increases, in a manner consistent with Marshall's model [J. Phys. Chem., 74, 346 (1970)]. It is suggested that the transition state of the rate-limiting step (carbinolamine dehydration) is highly solvated by water molecules and has a high separation of charges.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550210105
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  • 8
    Electronic Resource
    Electronic Resource
    Kinetics and mechanism of the decomposition of N-bromoalcoholamines in aqueous solution (1986)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 18 (1986), S. 1249-1258 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The decomposition reactions of N-bromodiethanolamine, N-bromoethylethanolamine, and N-bromomethylethanolamine in aqueous solution have been studied kinetically under various experimental conditions. The results support a proposed reaction mechanism in which the rate controlling step is assumed to be the formation of an imine which is then hydrolyzed to the final decomposition products.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550181104
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  • 9
    Electronic Resource
    Electronic Resource
    Kinetics of the chlorination of secondary amines by N-chlorosuccinimide (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 20 (1988), S. 397-409 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chlorinations of dimethylamine, diethylamine, methylethanolamine, ethylethanolamine and diethanolamine by N-chlorosuccinimide have been found to be equilibrium reactions of order one with respect to both N-chlorosuccinimide and amine in the forward direction and of order one with respect to succinimide and the resulting N-chloramine in the other. These results are explained by postulating a mechanism in which the rate controlling step consists in direct exchange of positive chlorine between the N-chlorosuccinimide and the amine.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550200506
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