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  • 1
    Electronic Resource
    Electronic Resource
    Phenazin-5(10H)-yls, 4Parts 1-3: Ref.. 10-Ethylphenazin-5(10H)-yl · H2O: Crystal Structure, Magnetic Susceptibility and Intermolecular π-π Interactions (Pimerization)Dedicated to Professor Rolf Gleiter on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 1867-1870 
    Details
    ISSN: 0947-3440
    Keywords: Phenazin-5(10H)-yl radicals ; Radical pairs ; π-π-Interactions ; Pimerization ; Dimer absorption ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The unit cell of 10-ethylphenazin-5(10H)yl · H2O consists of eight phenazin-5(10H)-yls that are arranged in four independent radical pairs A-D. All pairs show close interplanar distances (3.28-3.36 Å). Furthermore, A, B, and D are characterized by short intermolecular contacts between atoms with significant spin populations. This is not valid for the pair C with the closest interplanar distance of 3.28 Å. Magnetic susceptibility measurements as a function of temperature indicate complete spin pairing (“pimerization”) between 20 and 100 K. Therefore, the radical pair C provides evidence that unspecific close interplanar contacts together with a reasonable overlap of the π systems are sufficient to lead to pimerization.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199619961121
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  • 2
    Electronic Resource
    Electronic Resource
    Das gelbe Isomere der (1,5-Diphenylformazanyl)glyoxylsäure (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1477-1479 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Yellow Isomer of (1,5-Diphenylformazanyl)glyoxylic AcidThe yellow isomer is shown to be 4,4-dihydroxy-l-phenyl-3-phenylazo-2-pyrazolin-5-one (3), the hydrate of the pyrazolin-4,5-dione 4. Treatment of 4 with a solution of potassium -tert- butoxide in dimethylsulfoxide leads to the formation of a radical anion identified as 5 by ESR.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120443
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  • 3
    Electronic Resource
    Electronic Resource
    1,4-Dihydro-1,2,4-benzotriazin-Radikalkationen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2423-2430 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,4-Dihydro-1,2,4-benzotriazine Radical Cations1,4-Dihydro-1,2,4-benzotriazinyl radicals (4) are protonated in the presence of strong acids. The structure of the radical cations was confirmed by ESR studies of deuterated derivatives.
    Notes: 1,4-Dihydro-1,2,4-benzotriazinyl-Radikale (4) werden in Gegenwart starker Säuren protoniert. Die Konstitution der Radikalkationen wurde durch ESR-spektroskopische Untersuchung deuterierter Derivate gesichert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140709
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  • 4
    Electronic Resource
    Electronic Resource
    2,3-Diphenyl-2,3-diazabicyclo[2.2.2]octan (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1076-1079 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,3-Diphenyl-2,3-diazabicyclo[2.2.2]octaneThe title compound 5 was synthesized by twofold arylation of 2,3-diazabicyclo[2.2.2]oct-2-ene (1). The conformational features of 5 are discussed using 1H NMR and PE data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120332
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  • 5
    Electronic Resource
    Electronic Resource
    Verdazyls, 27. 1,1′,5,5′-Tetraphenyl-3,3′-biverdazyl, the Primary Bisverdazyl (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2049-2051 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Verdazyle, 27. 1,1′,5,5′-Tetraphenyl-3,3′-biverdazyl, das primäre BisverdazylDie Titelverbindung 3 wurde dargestellt. Die gefundenen Nullfeldaufspaltungsparameter |D′| = 305 G und |E′| ≍ 0 G entsprechen der Struktur.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801130543
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  • 6
    Electronic Resource
    Electronic Resource
    Darstellung organischer radioaktiver Verbindungen, I L-3-[14C]-Methoxy-ω-[1-hydroxy-1-phenyl-isopropylamino]-propiophenon-hydrochloridProf. Dr. Friedrich Weygand zum Gedenken gewidmet.[14C]-markiertes Oxyfedrin · HCl1) (1970)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 734 (1970), S. 199-202 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of Radioactive Organic Compounds, I. L-3-[14C]-Methoxy-ω-[1-hydroxy-1-phenylisopropylamino]-propiophenone Hydrochloride. [14C]-Labeled Oxyfedrin · HClFor the synthesis of the title compound 4 with 14C-activity located only in the methoxy group, on ethanolic solution of sodium alcoholate 1 is treated with [14C]-CH3I and then the methylation completed with inactive CH3I. By a Mannich synthesis with formaldehyde 2 is condensed with 3. The resulting 4 has been purified.
    Notes: Zur Darstellung der Titelverbindung 4 mit 14C-Aktivität ausschließlich in der Methoxy-Gruppe wird 1 in äthanolischer Natriumalkoholat-Lösung mit [14C]-CH3J und anschließend mit inaktivem CH3J methyliert, das gebildete 2 mit Formaldehyd und 3 durch Mannich-Synthese zu 4 umgesetzt und gereinigt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19707340122
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  • 7
    Electronic Resource
    Electronic Resource
    Phenazin-5(10H)-yls, 5Part 4: Ref[1].. - Intermolecular π-π Interactions (Pimerization) of tert-Butyl-Substituted Phenazin-5(10H)-yl Radicals in The Solid State: Syntheses, Crystal Structures and Magnetic Susceptibility Measurements (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 473-483 
    Details
    ISSN: 0947-3440
    Keywords: Phenazin-5(10H)-yl ; ESR spectroscopy ; Radical pairs ; π Interactions ; Dimer absorption ; Magnetic susceptibility ; Nitrogen heterocycles ; Radicals ; Magnetic properties ; Solid-state chemistry ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Introduction of tert-butyl groups into the phenazine frame-work was accomplished by treatment of 5-acetyl-5,10-dihydrophenazine (2a) with tert-butyl chloride in the presence of AlCl3. Starting from the 2,8- or 3,7-di-tert-butyl-substituted derivatives 2c and 2b, a series of phenazin-5(10H)-yl radicals (1c-i) was synthesized and characterized by ESR and EN-DOR spectroscopy. With the exception of 1c, all phenazin-5(10H)-yls were obtained in crystalline form, and for 1d-f the long-wavelength absorption band at λ ≈ 870 nm indicates intermolecular π-π interactions in the solid state. For 1d, 1e and 1h the crystal structure could be determined. The unit cell of 1d consists of eight phenazin-5(10H)-yls. Surprisingly, four of them are arranged in radical pairs, whereas the other four lie independently in the lattice. In agreement with this structure, the magnetic susceptibility results correspond to a content of 50% monoradical and an almost complete spinpairing in the radical pairs up to T = 220 K. In 1e, the four phenazin-5(10H)-yls in the unit cell are arranged in two independent radical pairs, A and B, which are characterized by close interplanar distances and short intermolecular contacts between atoms with significant spin populations. Accordingly, the susceptibility data indicate strong spin-pairing at low temperature. Due to extensive steric shielding of the phenazin-5(10H)-yl framework, the crystal structure of 1h gives no evidence of any π-π interactions between adjacent radicals. As expected, the magnetic susceptibility of 1h corresponds to that of an ordinary monoradical.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970307
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  • 8
    Electronic Resource
    Electronic Resource
    [2.2](2,5)Pyrimidinophanes: Synthesis and molecular structure (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1885-1889 
    Details
    ISSN: 0009-2940
    Keywords: Pyrimidine derivatives ; Sulfur extrusion, photolytic ; Pyrimidinophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compounds 1 and 2 are synthesized by photolytic sulfur extrusion from the 2,11-dithia[3.3](2,5)pyrimidinophane 17. The molecular structures of 1 and 2 are determined by X-ray structure analysis and are discussed with regard to the steric strain in these molecules. Thermolysis of [(5-methyl-2-pyrimidinyl]methyl]- or [(2-methyl-5-pyrimidinyl)methyl]-trimethylammonium hydroxide (10 or 11) does not generate 1 and 2. α-Chlorination of 2,5-dimethylpyrimidine (3) with N-chlorosuccinimide provides the required precursors 4-6.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230921
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  • 9
    Electronic Resource
    Electronic Resource
    6-Oxo- und 6-Thioxoverdazyle (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 815-822 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 6-Oxo- and 6-ThioxoverdazylsA series of persistent 6-oxo- (4a-P) and 6-thioxoverdazyls (5a-g) could be obtained by dehydrogenation of corresponding 1,4,5,6-tetrahydro-1,2,4,5-tetrazin-3(2H)-ones (2a-p) and thiones (3a-g). This reaction can also be used for the preparation of diradicals, e.g. 7 and 10. Reduction, oxidation, and spectra of the radicals were investigated. The ESR results are discussed in detail.
    Notes: Eine Reihe beständiger 6-Oxo- (4a-p) und 6-Thioxoverdazyle (5a-g) konnten durch Dehydrierung der 1,4,5,6-Tetrahydro-1,2,4,5-tetrazin-3(2H)-one (2a-p) bzw. der Thione (3a-g) erhalten werden. Diese Reaktion läßt sich auch auf die Darstellung von Diradikalen, z.B. 7 und 10, übertragen. Reduktion, Oxidation und Spektren der Radikale wurden und Spektren der Radikale wurden Untersucht. ESR-Ergebnisse werden eingehend diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881210502
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  • 10
    Electronic Resource
    Electronic Resource
    [2.2](2,6)- and [2.2](2,5)Pyrazinophanes: Synthesis and Molecular Structure (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 523-533 
    Details
    ISSN: 0009-2940
    Keywords: Hofman 1,6-elimination / Pyrazine derivatives / [2.2]Pyrazinophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compounds 1-3 and their methyl derivatives 4-7 were synthesized 2,11-dithia[3.3]pyrazinophanes 24-26 or by Hofmann 1,6-elimination of the appropriate [(5-methyl-2-pyrazinyl)methyl]trimethylammonium hydroxides followed by dimerization of the generated 2,5-dihydro-2,5-dimethylenepyrazines. α-Chlorination of the methylpyrazines 8-10 with N-chlorosuccinimide gave the required precursors 11, 12, 14, 17 and 18. The results of the X-ray structure determinations for 1-4 and 7 which indicate an unequivocal isomer assignment are discussed with regard to steric strain in these molecules. The electronic spectra of the pyrazinophanes 7-7 are reported and compared with those of the parent methylpyrazines.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230319
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