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  • 1995-1999  (6)
  • Organic Chemistry  (3)
  • Syntheses  (2)
  • 27.40.+z  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Partial charge-changing cross sections for neutron-deficient isotopes from58Ni fragmentation (1995)
    Springer
    The European physical journal 352 (1995), S. 77-83 
    Details
    ISSN: 1434-601X
    Keywords: 21.10.Ft ; 25.70.Np ; 27.40.+z
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract At the projectile-fragment separator FRS of GSI, relativistic secondary beams of about 520 MeV/nucleon were produced by fragmentation of a primary beam of58Ni at 650 MeV/nucleon in a beryllium target. By means of aΔE—Bρ—TOF measurement, the fragments were identified and their charge-changing probabilities in targets of (CH2) n , C, Al, and Pb placed at the exit of the FRS were determined. Whereas a first article dealt with the total charge-changing cross sections, we describe in this second article the element distributions of these secondary fragments, which are found to depend strongly on the isospin of the secondary projectile as well as on the target material. In the case of the lead target, the influence of the electromagnetic dissociation is clearly visible in the one-proton and two-proton removal channels. The preference for the formation of even-Z fragments is much more pronounced for exotic secondary projectiles than for projectiles close to stability. Calculations with a geometrical abrasion-ablation model allow to understand the global features of the experimental data. However, far from stability, the discrepancies between calculations and experimental data increase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01292762
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Pyromellitic Diimide-Porphyrin Cyclophanes: Syntheses, Transannular Interactions, and Structure Analysis (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 1459-1470 
    Details
    ISSN: 1434-193X
    Keywords: Cyclophanes ; Donor-acceptor systems ; Syntheses ; Conformation analysis ; X-ray structure analysis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -The acceptor-porphyrin cyclophanes 2 and 4 with pyromellitic diimide (1) as strong electron-acceptor, and the corresponding porphyrin zinc complexes 3 and 5 were prepared by a route which differs considerably from that in the syntheses of previously prepared electron-acceptor porphyrin cyclophanes. The conformations of these electron-acceptor-porphyrin cyclophanes are discussed based on 1H-NMR and the X-ray structural analysis of 2. According to the results obtained, the plane of 1 and that of the porphyrin unit (at least in the crystalline state) are neither close nor parallel to each other. An unusual dihedral orientation of the donor and acceptor planes was detected for 2.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    π…π interactions of flavins, 5. Syntheses, structures and physical properties of flavin systems with covalent bonding to π donors and π acceptors (quinones) (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 1827-1836 
    Details
    ISSN: 0947-3440
    Keywords: Isoalloxazinophanes ; Flavins ; π Donors ; π Acceptors ; Quinones ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: To study π…π interactions of flavins of different redox states with π-electron donors and acceptors, the syntheses of compounds in which such π systems are linked to flavins by using the „cyclophane concept“ were attempted and partially achieved. The syntheses of the metacyclo-isoalloxazinophanes 1 and 2 are reported as well as the X-ray structure analysis of 2. The conversion of 1 or 2 to the benzoquinono-isoalloxazinophanes 3 or 4, respectively, was not achieved, obviously due to the specific sterical shielding of the methoxy groups in the isoalloxazinophanes. Benzoquinone-isoalloxazine systems in which the two components are linked by only one triethylene chain were obtained. Spectroscopic and electrochemical properties related to intramolecular interactions are reported.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1995199510256
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    New Electron Donor-Acceptor Compounds, 51. [3](N,N′)-1,8;4,5-Naphthalenetetracarboxdiimido- [3](2,7)Pyrenophane and Its [4,4]Cyclophane Homologue (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1551-1556 
    Details
    ISSN: 0947-3440
    Keywords: Intramolecular electron donor-acceptor interactions ; [3.3]- and [4.4]Cyclophanes of pyrene and 1,4;5,8-naphthalenetetracarboxdiimide ; Charge transfer ; Through-space interactions ; UV/Vis spectroscopy ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron donor-acceptor cyclophanes 1 and 2, consisting of pyrene as the donor component and 1,8;4,5-naphthalenete-tracarboxdiimide as the acceptor component fixed by methylene chains in parallel face-to-face orientations, have been synthesized. The structures, based on an X-ray analysis of 1 and on spectroscopic properties, are discussed with reference to intramolecular charge-transfer interactions and are compared to those of the related excimer models [3.3]- and [4.4]pyrenophanes 3 and 4.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970735
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  • 5
    Electronic Resource
    Electronic Resource
    Photoinduced Electron-Transfer in Porphyrin-quinone Cyclophanes, 15.Part 14: Ref. Distance Dependence of Photoinduced Electron-Transfer: Syntheses and Structures of Naphthalene-Spacered Porphyrin-Quinone Cyclophanes (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 2321-2336 
    Details
    ISSN: 0947-3440
    Keywords: Photoinduced electron-transfer, distance dependence ; Naphthalene-spacered porphyrin-quinone cyclophanes ; Synthesis, conformations, structural analysis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses, conformational and structural analyses of porphyrin-quinone cyclophanes 2 with naphthalene-spacers are presented and the findings are compared with data for previously investigated analogous benzene-spacered compounds 1. In combination with data for the biphenylene- and anthracene-spacered porphyrin-quinone cyclophanes 3 and 4, to be published in following papers, the results reported herein allow some appraisal to be made of the distance dependences of photoinduced electron-transfer from porphyrin to quinone units.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719971121
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Distance Dependence of Photoinduced Electron Transfer: Syntheses and Properties of Anthracene-Spacered Porphyrin-Quinone Cyclophanes (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 631-642 
    Details
    ISSN: 1434-193X
    Keywords: Electron transfer, distance dependence of ; Anthracene-spacered porphyrin-quinone cyclophanes ; Syntheses ; Characterizations ; Structures ; Physical properties ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In our previous work on benzene- and naphthalene-spacered porphyrin-quinone cyclophanes[1][2], the dependence of electron-transfer rates on reduction potentials of the acceptors and oxidation potentials of the porphyrins was studied. The present paper, dealing with the distance dependence of electron transfer, reports on the synthesis of anthracene-spacered analogues and on the electron-transfer rates, which are found to be drastically reduced.
    Type of Medium: Electronic Resource
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