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  • 1975-1979  (15)
  • 1970-1974  (14)
  • 1965-1969  (3)
  • 1945-1949
  • Organic Chemistry  (17)
  • Polymer and Materials Science  (15)
  • Physics  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Metal complexes with macrocyclic ligands. XIIIPart XII, see [1].. The complexation of Cu2+ with triazacycloalkanesHerrn Prof. Dr. E. Giovannini zum 70. Geburtstag gewidmet (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1089-1096 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potentiometric study of the complexation of Cu2+ with 1,4,7-triazacyclononane (1), 1,4,8-triazacyclodecane (2) 1,5,9-triazacyclododecane (3) has shown that CuL, CuL2 and (CuLOH)2 are the main species present in solution. Their stabilities (Table 1) and their absorption spectra (Table 2) indicate facial coordination of the cyclic triamines in a distorted octahedral geometry.The formation and dissociation kinetics have been measured by stopped-flow techniques. The formation in acetate buffer can be described by the reaction of Cu2+ and CuAcO+ with the monoprotonated species of the ligand. The bimolecular rate constants for these complexations (Table 3) decrease when the ring size increases. In contrast the dissociation induced by acid is only little affected by the ring size. Thus for these complexes the rate of formation and not that of the dissociation determines the overall stability.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620417
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  • 2
    Electronic Resource
    Electronic Resource
    Metal Complexes with Macrocyclic Ligands. IXFor part VIII see [1].. Synthesis and properties of a new class of branched N4-macrocycles with an additional ligating group in the side chain (1978)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 61 (1978), S. 1376-1387 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the presence of Ni2+ the template reaction between 2,6-diacetylpyridine and 4-(2-dimethylaminoethyl)- or 4-(2-hydroxyethyl)-1, 7-diamino-4-azaheptane yields the complexes of either the open-chain ligand (3 and 11) or of the macrocycle (4 and 12). Reduction of the imino group in 4 and 12 with PtO2/H2 gives 5 and 13, respectively. In the case of the dimethylamino derivative 5 a mixture of at least four isomers was obtained. These were partially separated by chromatography on Sephadex SP-25 cation exchanger. Through demetalation of the Ni2+ complexes by cyanide the new macrocycles 7 and 14 were isolated, from which the corresponding Zn2+ and Cu2+ complexes were prepared.The macrocyclic Ni2+-complexes 4, 12, 5 and 13 can exist in two forms depending on the pH of the solution. At low pH protonation of the dimethylamino or hydroxy group in the side chain occurs. The metal ion is then bound to the four nitrogen atoms of the macrocycle in a square planar ligand field. At higher pH, however, the dimethylamino or hydroxy group (the last one also in its deprotonated form) can coordinate to one of the axial positions, whereby pseudooctahedral coordination geometry is induced. This reaction can be quantitatively described by a reversible acid-base equilibrium, the pKH of which greatly depends on the nature of the functional group, the degree of unsaturation of the macrocycle and the metal ion.The acid-base reaction and the concomitant structural change are a direct consequence of the unique combination of the rigid and kinetically stable structure of the macrocycle and of the flexible and kinetically labile functional group of the side chain.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19780610421
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  • 3
    Electronic Resource
    Electronic Resource
    Metal Complexes of Macrocyclic Ligands. XIIPart XI, see [1].. A Complexone-like Tetraazamacrocycle (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 683-688 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexone-like tetraazamacrocycle 1 (LH4) forms a series of metal complexes with Co2+, Ni2+, Cu2+ and Zn2+ (M2+) of the type MLH2, ML2- and M2L, which have been isolated and characterized by VIS., IR. and NMR. spectroscopy. Based on these results tentative structures for the different species are proposed.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620306
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  • 4
    Electronic Resource
    Electronic Resource
    Metal Complexes with Macrocyclic Ligands. XIV. Formation, dissociation and metal exchange with an N2S2-macrocyclePart XIII, see [1]. (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2562-2568 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 10, 10, 12-Trimethyl-3,4-benzo-1,6-dithia-9,13-diazacyclopentadecen-dihydrochloride (LH22+, 2) and its Ni2+ complex were synthesized and their reactivity studied. The formation kinetics of 2 with Cu2+ were found to be a second order reaction between Cu2+ or CuACO+ and the monoprotonated form of the ligand LH+. The rate constant kCuLH = 29 M-1S-1 is 105-106 times smaller than those of monoprotonated tetraazamacrocycles either because of second bond formation or because of a strong electrostatic interaction between the positive charges of the Cu2+ and the ammonium group. The metal-metal exchange between NiL+ and Cu2+ was also investigated. The reaction is independent of [Cu2+] and has the same rate and activation parameters as the dissociation of NiL2+. In contrast to open chain ligands, no mixed complex CuNiL4+ as intermediate was observed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620809
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  • 5
    Electronic Resource
    Electronic Resource
    Pharmacologically active polymers, 13Part 12, cf. G. Franzmann, H. Ringsdorf, Makromol. Chem. 177, 2547 (1976).. Elucidation of the tumour affinity of poly[sulfadiazineacrylamide] (1976)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 2669-2674 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Poly[sulfadiazinacrylamid] (5) mit 14C-Hauptkettenmarkierung wurde synthetisiert und sein Molekulargewicht viskosimetrisch durch Vergleich mit inaktiven Proben von Poly-[sulfadiazinacrylamid] mit membranosmometrisch ermittelten Molekulargewichten ähnlicher Größe bestimmt.In seinem systemischen Verhalten bei Mäusen zeigte die Verbindung einen polymerspezifisch protahierten Verlauf. Die Ausscheidungsraten des Polymeren waren vernachlässigbar gering, seine Toxizität erheblich. Es wurde im Untersuchungszeitraum in der Leber akkumuliert, aber eine Tumoraffinität zum PC6 Plasmazelltumor bei Mäusen war nicht feststellbar.
    Notes: Poly[sulfadiazineacrylamide] (5), labeled with 14C in the main chain, was synthesized and its molecular weight viscosimetrically determined by comparison with unlabeled samples of poly[sulfadiazineacrylamide] with similar molecular weights which were determined by membrane osmometry.The material showed a polymer-specific prolongation of its systemic behaviour in mice. Rates of excretion of the polymer were negligibly low, whereas the toxicity was considerable. It was concentrated in the liver during the course of the experiment, but no affinity toward the PC6 plasmacytoma in mice could be detected.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1976.021770909
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  • 6
    Electronic Resource
    Electronic Resource
    The continuous synthesis of addition polymers with a pricesely controlled average molecular weight and minimum polydispersity (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 1353-1371 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A novel technique for the control of continuous synthesis of addition polymers with precisely controlled average molecular weight and minimum polydispersity has been developed. A control system adjusts the concentration of chain-transfer agent in the reactor feed to compensate for all other upsets, in the reactor inputs: initiator and monomer concentrations, temperature and feed rate. The technique has been evaluated quantitatively on a digital computer using a kinetic model of homogeneous, free-radical solution polymerization. In computational tests, the modeled control system generally held the instantaneous number-average chain length within 1%, and quickly returned it to the desired value in response to a wide variety of upsets. By generalizing the Schulz distributions to include termination by disproportionation, combination and chain-transfer, it is shown that changes in the molecular-weight distribution resulting from the action of the control system are minor.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130703
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  • 7
    Electronic Resource
    Electronic Resource
    Diffusion of gases through polyurethane block polymers (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 201-214 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The diffusivities of simple gases through a series of polyurethane block copolymers of differing aromatic urethane content and type of soft segment were measured using a quadrapole mass spectrometer as a detecting device. Although an Arrhenius expression generally described the temperature dependence of diffusion in this system, a discontinuity was observed in the Arrhenius plots for some materials, and the discontinuity was found to be related to the onset of the glass transition in the hard domains. Increasing the hard segment content of the materials decreased the diffusivity due to the increase in the activation energy of diffusion. Increasing the soft segment length brought about a decrease in the activation energy with an increase in diffusivity. Polyster urethanes had lower activation energies for diffusion than polyether urethanes of similar hard segment composition. Finally, as the penetrant diameter was increased, a decrease in the diffusivity and an increase in the activation energy was noted.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070230118
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of molecular weight on the tensile strength of glassy plastics (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 571-573 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.160100314
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  • 9
    Electronic Resource
    Electronic Resource
    The impact of rigid spheres on rubber (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 1641-1651 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The applicability of Hertz's theory of impact to the case of rigid spheres colliding with rubber has been studied over a wide range of impact conditions. In general, the theory is adequate; but in many practical cases, the influence of the finite thickness of the sample is significant. Using previously published data on the influence of thickness on static indentation measurements, this effect can be predicted and good agreement with experiment is found. Resilience measurements have been made over a range of impact conditions. The time of impact, rather than its severity as such, was found to be the factor governing the resilience for the unfilled materials studied, provided that there was no slip of the sample relative to its holder. Slippage can occur if the sample is too thin, due to the shear stresses developed at the rear surface, and this results in the observed resilience being anomalously low.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160705
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  • 10
    Electronic Resource
    Electronic Resource
    The irradiation of vinyl monomers in the presence of paraffin waxes (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 2519-2522 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The radiation-induced grafting of a series of monomers onto a wide range of paraffin waxes was attempted. Although no grafting could be achieved and only homopolymers were formed, the rates of homopolymerization were greatly enhanced in the presence of the wax. This phenomenon is ascribed to processes of energy transfer from the irradiated wax to the monomer.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070170817
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