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  • 1
    Electronic Resource
    Electronic Resource
    Zur Dissoziation der Tetraarylhydrazine (1965)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 98 (1965), S. 844-850 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch ESR-Spektren und optische Spektren läßt sich die Dissoziation von Tetrakis-[p-methoxy-phenyl]-hydrazin und Tetrakis-[p-dimethylamino-phenyl]-hydrazin bei Raumtemperatur und von Tetrakis-p-tolyl-hydrazin bei erhöhter Temperatur in die entsprechenden Diarylstickstoff-Radikale feststellen. Dagegen konnte eine Dissoziation von Tetraphenyl-, Tetrakis-[p-fluor-phenyl]- und Tetrakis-[p-brom-phenyl]-hydrazin bis 90° weder mit der Elektronenresonanz noch im optischen Spektrum nachgewiesen werden.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19650980323
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  • 2
    Electronic Resource
    Electronic Resource
    Darstellung, ESR- und ENDOR-Untersuchung von Radikalkationen des Tetraphenylhydrazins, des 5,6-Dihydro-5,6-diphenylbenzo[c]cinnolins und des Benzo[c]benzo[3,4]cinnolino[1,2-a]cinnolins (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 980-990 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Generation, ESR and ENDOR Study of Radical Cations Derived from Tetraphenylhydrazine, 5,6-Dihydro-5,6-diphenylbenzo[c]cinnoline, and Benzo[c]benzo[3,4]cinnolino[1,2-a]cinnolineRadical cations of the title compounds (1a·+, 2·+, 3·+) and of a series of derivatives (1b·+, 1ċ+, 6a·+ - ċ+) representing hydrazine radical cations were generated by oxidation. ENDOR studies of the tetraarylhydrazine radical cations 1a·+ - ċ+ confirm the hindered rotation of the aryl groups and yield a partial assignment of the hyperfine splitting constants. According to the ESR-ENDOR results of 1a·+ and 3·+ linkage of the N,N′-phenyl groups through their o-positions does not considerably flatten the conjugation system.
    Notes: Die Hydrazin-Radikalkationen der Titelverbindungen (1a·+, 2·+, 3·+) sowie einer Reihe von Derivaten (1b·+, 1c·+, 6a·+ - e·+) wurden durch Oxidation erzeugt. ENDOR-Untersuchungen der Tetraarylhydrazin-Radikalkationen 1a·+ - c·+ bestätigen die gehinderte Rotation der Arylreste und liefern eine partielle Zuordnung der HFS-Kopplungskonstanten. Nach den ESR- und ENDOR-Ergebnissen von 1a·+ und 3·+ führt die Verknüpfung der N,N′-Phenylreste über ihre o-Positionen zu keiner beträchtlichen Einebnung des Konjugationssystems.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190321
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  • 3
    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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  • 4
    Electronic Resource
    Electronic Resource
    1,8-Bis(diphenylamino)- and 1,8-Bis(methylphenylamino)naphthalene: Molecular Structure and Dynamic Behavior (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 723-728 
    Details
    ISSN: 0009-2940
    Keywords: 1,8-Diaminonaphthalenes, X-ray structure analysis of, conformational barriers of, dynamic behavior of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compounds 2 and 3 have been synthesized from 1,8-diaminonaphthalene. The molecular structure of 2 has been determined by X-ray structure analysis and is discussed with regard to the arrangement of the peri-diphenylamino substituents in the crystalline state and the steric strain in the molecule. NMR studies of 3 reveal two conformational processes. Their nature is discussed and barriers are reported.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250327
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  • 5
    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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  • 6
    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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  • 7
    Electronic Resource
    Electronic Resource
    Isomeric Tetrakis(dimethylamino)naphthalenes: Syntheses, Structure-Dependence of Basicities, Crystal Structures, and Physical Properties (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1617-1622 
    Details
    ISSN: 1434-193X
    Keywords: Tetrakis(dimethylamino)naphthalenes ; Basicity ; Hydrogen bonds ; Cyclicvoltammetry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---For comparison to the recently described 2,3,6,7-tetrakis(dimethylamino)naphthalene (1) the three isomers 2,3, and 4 were synthesized. The basicities of this group of isomers are strongly dependent upon the different mutual orientations of the pairs of dimethylamino substituents: only the isomers 3 and, partially, 4, both with dimethylamino groups in adjacent peri-positions of the naphthalene, are strong “proton sponges”. For the isomers 1 and 2 with the same number and kind of twofold dimethylamino substituents in neighbouring ortho-positions, however, no significant basicity increase is observed. To explain this difference between the two groups of isomers it is suggested that in the ortho-pairs of 1 and 2 the C-N bonds diverge considerably, leading to an increased N···N distance and consequently to less stable [N···H···N]+ hydrogen bonds in contrast to the parallel C-N bonds in the peri-substituted isomers 3 and 4. X-ray crystal structure analyses of the bases and of some of the salts derived therefrom were solved and are discussed. Cyclic voltammetry indicates that 1 to 4 are strong electron donors, reacting easily to radical cations or dications which with suitable acids have been obtained as salts.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Structural Characterization and Magnetic Behaviour of the Ferro-Antiferromagnetic Alternating Manganese-Azido Chain [Mn(3-Et,4-Mepy)2(μ-N3)2]n (3-Et,4-Mepy = 3-Ethyl-4-methylpyridine) (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 687-691 
    Details
    ISSN: 1434-1948
    Keywords: Bridging ligands ; Manganese ; Azido bridge ; Alternating chain ; Magnetic properties ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ligands 3-ethyl-4-methylpyridine (3-Et,4-Mepy) and azide coordinate to MnII forming an alternating chain with the formula [Mn(3-Et,4-Mepy)2(μ-N3)2]n. This compound crystallizes in the space group P-1. The compound consists of chains of octahedrally coordinated manganese atoms alternately bridged by double end-to-end (μ1,3) and double end-on (μ1,1) azido bridges, which results in a structurally and magnetically alternating chain. The 3-ethyl-4-methylpyridine ligands are arranged trans, completing the six-fold coordination spheres of the manganese atoms. The Mn-Mn distances are distinctly different: Mn(1)-Mn(1A) = 5.149(3) Å (double end-to-end azido bridge) and Mn(1)-Mn(1B) = 3.402(2) Å (double end-on azido bridge). The magnetic properties of the compound, as studied in the temperature range 300-4 K, show bulk antiferromagnetic interaction. Fitting of the magnetic data by using an equation for alternating ferro-antiferromagnetic S = 5/2 1-D systems gives the parameters JAF = -13.7(1) cm-1, JF = 2.4(1) cm-1, g = 2.036(2).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    On the Homoconjugation of Two Acceptor Groups (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 1615-1623 
    Details
    ISSN: 1434-193X
    Keywords: Homoconjugation ; Cyclovoltammetry ; ESR spectroscopy ; Diketones ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyclovoltammetric investigations have been carried out on 3,3,6,6-tetramethylcyclohexane-1,2,4,5-tetrone (4), bicyclo-[3.2.2]nonane-6,7,8,9-tetrone (5), and several of their congeners, such as 6,13-dihydro-6,6,13,13-tetramethylquin-oxalino[2.3-b]phenazine (13), 5,10-dihydro-5,5,10,10-tetra-methylpyrazino[2,3-g]quinoxaline (17), and 6,13-dihydro-6,13-propanoquinoxalino[2,3-b]phenazine (20). For 5 and 20 a large difference (ΔE° ≥400 mV) between the first and second reduction potentials was found. The ESR results of the radical anion 20•- are in support of a strong homoconjugation. ESR studies of 4•-, 13•-, and 17•- also reveal a symmetrical displacement of the unpaired electron over both acceptor groups on the ESR time scale which, however, based on the small potential difference ΔE° ≤ 200 mV can be most likely described to a fast electron exchange.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Hydrazidinyl-Radikale: 1,2,3,5-Tetraazapentenyle, Verdazyle und TetrazolinyleHerrn Professor Theodor Wieland zum 60. Geburtstag gewidmet (1973)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 85 (1973), S. 485-493 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Der Fortschrittsbericht gibt einen Überblick über die Bildung und Darstellung von Hydrazidinylen, über ihre chemischen Reaktionen sowie ihre physikalischen Eigenschaften.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19730851104
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