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  • 1
    Electronic Resource
    Electronic Resource
    Radical Ions in the Pentalene Series [1]. Part II. Dibenzo [b,f]pentaleneThe IUPAC name for dibenzo [b,f]pentalene (III) is indeno [2, 1-a]indene. and its 5, 10-dimethyl derivative (1978)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 61 (1978), S. 2981-2988 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Proton hyperfine data have been determined for the radical anions and cations of dibenzo [b,f]pentalene (III) and its 5, 10-dimethyl derivative (IV). The assignment of the coupling constants to pairs of equivalent protons follows from a simple MO model, the use of which enables one to reproduce satisfactorily the experimental values. The proton hyperfine data, aHμThe meaning of aHμis aH—C(x),H—C(y),whereas only x and y are given in the particular cases., for the radical anion III⊖. correlate fairly well with the π-charge populations ∊μ derived from 1H-NMR. spectra for the carbon centres μ in the dianion III2⊖. The analogous correlation is less good in the case of the radical cation III⊕. and the dication III2⊕., presumably due to the rough approximations involved in the evaluation of the numbers ∊μ for the latter species. The coupling constants aH5,10 for III⊖. and III⊕. are very close to the corresponding values aH4,6 for the radical ions of 1,3,5-tri-t-butylpentalene (II), in accord with the prediction of the MO model. A similarity is also found between the proton hyperfine data for III⊖. and those for the radical anions of structurally related 1,4-diphenyl-1,3-butadiene (V). On the other hand, there are striking changes in the coupling constants of the analogous protons on passing from III⊖. to the radical anions of dibenzo [a,e] cyclooctene (VI) and [16] annulene (VII), as a consequence of raising the symmetry from C2h to D2h and D4h, respectively.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19780610823
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  • 2
    Electronic Resource
    Electronic Resource
    Segregation of Charge in Ions of Dibenzo[a,c]naphthacene: Relation of Topology and Electronic Structure. An NMR, ESR, and ENDOR Study (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 2048-2057 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1H- and 13C-chemical shifts of the dianion of dibenzo[a,c]naphthacene (1) have unambiguously been assigned by 2D-NMR spectroscopy. They indicate a remarkable charge distribution, as most of the negative charge is localized on the ‘anthracenic’ moiety, while the ‘phenanthrenic’ moiety is almost neutral. Association of 12- with alkali-metal counterions has only a minor effect on the chemical shifts. The charge partitioning in 12-, which is reproduced by ωβ calculations in the frame of the Hückel model, must, thus, be considered as an intrinsic property of the 4nπ-electron system of 12-. It is rationalized in terms of differing energy contents of the constituent anthracenic and phenanthrenic moieties. ESR and ENDOR studies of the radical anion 1\documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\scriptstyle {{\relbar}\kern-4pt {.} }} $\end{document} and the radical cation 1\documentclass{article}\pagestyle{empty}\begin{document}$ 1^{+ \atop \dot{}} $\end{document} show that the π-charge distribution in 12- is reflected by the π-spin distributions in the two radical ions of the alternant hydrocarbon 1.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730725
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  • 3
    Electronic Resource
    Electronic Resource
    Cyclophanes, XXXVIII. [2]Metacyclo[2]indenophanes: Synthesis, Anions and Iron ComplexesDedicated to Professor Klaus Hafner on the occasion of his 65th birthday. (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 167-175 
    Details
    ISSN: 0009-2940
    Keywords: Cyclophanes ; Indenyl anions ; Iron complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [2.2]Metacyclophane can be directly formylated according to the Rieche method to give 4-formyl[2.2]metacyclophane (12) in 44% yield. The synthesis of the [2]metacyclo[2]indenophane 8 from the aldehyde 12 by the pathway previously employed for the corresponding [2.2]paracyclophanes failed due to the harsh conditions of the cyclization step. An alternative synthesis of 8 and its isomer 9 involving the construction of the five-membered ring prior to that of the cyclophane unit succeeded. Compounds 8 and 9 were obtained as an 82:18 mixture, deprotonation of which afforded the anion 10, which shows long-term stability. The 1H-NMR spectrum of this anion does not exhibit a through-space charge transfer due to its structure. The 1H-NMR parameters and molecular mechanics calculations are discussed. Both faces of 10 react in the presence of FeCl2 · 2 THF and a twentyfold excess of LiCp to give a 70:30 mixture of the ferrocene derivatives 7 and 35.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260125
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  • 4
    Electronic Resource
    Electronic Resource
    Cyclophanes, XXVII. [2.2]Indenophane Mono- and Dianions: Preparation and Nuclear Magnetic Resonance Spectra (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 737-744 
    Details
    ISSN: 0009-2940
    Keywords: Cyclophane anions ; Indene derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclophane, XXVII. - [2.2]Indenophan-Mono-und Dianionen: Darstellung und kernmagnetische Resonanz-SpektrenDie Darstellung, chemischen und physikalischen Eigenschaften negativ geladener polycyclischer Cyclophane werden beschrieben. Through-space-elektronische Wechselwirkungen und through-space-Anisotropieeffekte werden aus den Protonen- und Kohlenstoffkernresonanzspektren abgeleitet. Die untersuchten Systeme gehören zu zwei Hauptgruppen: a) paratrope 4nπ-polycyclische Dianionen, z. B. [2.2]Benzo[g]chrysenocyclophan-Dianion (122-) und b) (4n + 2)π-polycyclische Mono- und Dianionen, die diatrop sind. In den Dianionen sind beide Decks geladen: z. B. syn-[2.2]Indenocyclophan-Dianion (132-) und sein anti-Isomer (142-). Bei den untersuchten Monoanionen handelt es sich um die des [2.2]-Benzoindenocyclophans (151-), 4,5,17,18-Tetramethyl[2.2]benzoindenocyclophans (161-) und des 12-Methyl[2.2]benzoindenocyclophans (171-). Die spektroskopischen Eigenschaften der lagigen Anionen werden mit denjenigen von 1,4-Dimethylindenyl-Anion (111-) und mit Literaturwerten der neutralen Cyclophane 1-11 verglichen. Es wird eine Trennung von Anisotropie- und chargetransfer-Effekten durchgeführt, die es erlaubt, die Netto-through-space-Wechselwirkung abzuschätzen.
    Notes: The preparation and chemical and physical properties of negatively charged polycyclic cyclophanes are reported. The throughspace electronic interactions and the through-space anisotropy effects were deduced from proton and carbon nuclear magnetic resonance data. The systems studied belong to two main groups: a) 4nπ-polycyclic dianions which are paratropic, e.g. [2.2]benzo-[g]chrysenophane dianion (122-), and b) (4n + 2)π-polycyclic mono- and dianions, which are diatropic. In the dianions both layers are charged, e. g. syn-[2.2]indenocyclophane (132-) and its anti isomer (142-). The monoanions studied are [2.2]benzoindenocyclophane (151-), 4,5,17,18-tetramethyl[2.2]benzoindenocyclophane (161-), and 12-methyl[2.2]benzoindenocyclophane (171-). The spectroscopic properties of the layered anions were compared with those of 1,4-dimethylindenyl anion (111-) and with literature data of neutral cyclophanes, viz. 1-11. A differentiation between the anisotropy and charge-transfer effects has been made and it enables the estimation of the net through-space interaction.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220422
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  • 5
    Electronic Resource
    Electronic Resource
    π-Conjugated Anions: From Carbon-Rich Anions to Charged Carbon Allotropes (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1091-1106 
    Details
    ISSN: 1434-193X
    Keywords: Polycyclic anions ; Aromaticity ; Annulene anions ; Corannulene ; Fullerene anions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -Stable π-conjugated anions are formed in the reaction of π-conjugated systems with alkali metals. Reactivity, aromatic properties and aggregation of the anions are described. Bowl-shaped and fullerene anions, as well as helicene and planar polycyclic anions, are discussed vis-à-vis their aromaticity and charge delocalization pattern.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Molecular complexes between octaethyltetrathiaporphyrin dication and electron donors: A spectroscopic and electrochemical study (1995)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 8 (1995), S. 647-658 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Octaethyltetrathiaporphyrin dication, OTP2+, is electrochemically reduced by two successive electron-transfer processes to OPT0. OPT2+ forms intermolecular complexes with a series of π-donors. The association constants of the resulting complexes are controlled by the oxidation potentials of the π-donors and solvent properties. OTP2+ was incorporated into a Nafion membrane cast on a Pt electrode. Formation of OTP2+-π-donor complexes in the polymer membrane was followed by electrochemical and spectroscopic means. The association constants of the OTP2+-π-donor complexes in the Nafion membrane exhibit lower values than a homogeneous phase owing to the high ionic strength in the polyelectrolyte.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610081004
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  • 7
    Electronic Resource
    Electronic Resource
    Molecular aggregates between octaethyltetrathiaporphyrin dication (OTP2+) and octaethylporphyrin (H2OEP) and its metal complexes (1995)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 8 (1995), S. 659-670 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The octaethyltetrathiaporphyrin dication, OTP2+, forms 1:1 intermolecular donor-acceptor complexes with NiII-, VIVO- and FeIII-octaethylporphyrins. The association constants of the complexes are governed by the oxidation potential of the metallo-octaethylporphyrins and by secondary electrostatic interactions. Octaethylporphyrin, H2OEP, forms intermolecular complexes with OTP2+. Kinetic analyses of the formation of the various complexes revealed the formation of a primary complex exhibiting the stoichiometry (OTP2+)2(H2OEP). This intermolecular complex transforms into a thermodynamically stabilized intermolecular assembly with a stoichiometry corresponding to (OTP2+)4H2OEP. The activation barrier associated with the conversion of the primary complex to the thermodynamically stabilized assembly is Ea = 16·5 kcal mol-1 (1 kcal = 4·184 kJ). The association constant of the complex (OTP2+)2(H2OEP) is K1 = 1·3 × 1010 M-2 and the equilibrium constant between the two coexisting intermolecular complexes (OTP2+)4(H2OEP) and (OTP2+)2(H2OEP) is K2 = 7·4.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610081005
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  • 8
    Electronic Resource
    Electronic Resource
    π-Conjugated Benzoperylenes: Sequential C-S Bond Cleavage and Charge Distribution Patterns of the Anions (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 37-48 
    Details
    ISSN: 1434-193X
    Keywords: Benzoperylenes ; Reduction of PAH ; Flavophen ; Reductive sulfur extrusion ; Sulfur heterocycle ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -Chemical reduction of polyaromatic hydrocarbons yielded solutions of long-lived polyanionic species. Reduction of a sulfur heterocycle afforded a stable sulfur-containing dianion. Sulfur extrusion from this dianion proceeded upon further contact with the reducing metal. NMR and UV studies indicate a sulfur extrusion mechanism different than that previously observed in THF. Electron transfer to the already reduced hydrocarbon skeleton results in the stepwise cleavage of the two C-S bonds and the extrusion of a sulfur atom. Dimers of aromatic hydrocarbons such as pyrene and phenanthrene have been reduced as well. The interplay between coulombic repulsions and resonance energies is described.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Additivity of proton and carbon nmr chemical shifts in protonated benzene carboxylic acids (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 587-589 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The additivity of the proton and carbon chemical shift increments due to structural changes in a series of conjugate acids derived from benzene polycarboxylic acids is reported. In the acids, two sets of increments had been applied, one to the ortho diacids and one to acids which do not bear ortho substituents. In the conjugate acids only one set of increments is required. The disappearance of the ‘ortho’ effect may be the outcome of properties inherent to these conjugate acids.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270111202
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  • 10
    Electronic Resource
    Electronic Resource
    Fulvenes and thermochromic ethylenes - LVI:For part LV, see Ref. 1. The mass spectra of some fluorenylidene-triphenylphosphoranes (1970)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 4 (1970), S. 89-95 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of several fluorenylidene-triphenylphosphoranes have been studied and the fragmentation reactions have been interpreted. An intramolecular rearrangement leading to the 9-phenylfluorenium ion has been discovered.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210040110
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