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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 179-181 
    ISSN: 0009-2940
    Keywords: Matrix isolation ; Pyrolysis ; Photochemistry ; Iodine compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Flash pyrolysis of a gas mixture containing iodine, oxygen and argon yields the hitherto unknown iodine superoxide, which can be identified by its UV absorption (λ max= 254 nm) after trapping the pyrolysate at 12 K. Irradiation converts iodine superoxide into iodine dioxide, identified by its IR and UV spectra.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0009-2940
    Keywords: Hybridization ; Lithium coordination ; Structure elucidation ; NMR-spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-(Dimethylamino)benzyllithium (1a) and its complexes, 1b-f, have been characterized by their solid-state 13C-NMR spectra. The spectra are comparable to those recorded in solution and can be used to reveal the structures of the different solvates of the title compound.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1043-1046 
    ISSN: 0009-2940
    Keywords: Matrix isolation ; Ab initio calculations ; Oligosilanes ; Silicon atoms ; Reaction mechanisms ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pulsed flash pyrolysis of 1,1,l-trimethyltetrasilane (5) led to trimethylsilane, silane and a further species which is believed to be dibridged Si2H2 (13). Another route to 13 was found in the cocondensation of hydrogen and silicon atoms in an argon matrix at 12 K. The identification of matrix-isolated 13 is based on observed IR bands at 1475.6, 1092.8 and 890.3 cm-1. These positions are in good agreement with the ab initio calculated wavenumbers for the strongest absorptions of 13. The band shifts for the mono- and dideuterated isotopomers support this assignment.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 153-160 
    ISSN: 0947-3440
    Keywords: Valence isomerization ; Diazoketons ; Cycloadditions ; Steric hindrance ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Small Rings, 87. - Search for Alternative Routes to Tetra-tert-butyltetrahedrane; Synthesis of Sterically Overcrowded MoleculesKetene 3 can be isomerized to triclopentanone 2 by treatment with silica gel. Thus, the yield of tetrahedrane 5, which is formed upon irradiation of 2, has been improved. On the other hand, diazoketone 10 cannot be used as a precursor for 2. This failure is due to steric hindrance. For the same reason cyclobutadiene 4 is a very poor candidate for Diels-Alder cycloadditions.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0947-3440
    Keywords: Matrix isolation ; Photochemistry ; CHNO isomers ; Hydrogen-bonded complexes ; Density functional calculations ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complex photochemistry of matrix-isolated dihaloformoximes 8a, 8b, and 8c, which are transformed upon irradiation into the new hydrogen-bonded complexes HalCN…HOHal 10a-c′, identified by their IR spectra, has been unveiled. An earlier assignment of the experimental IR absorptions to isofulminic acid HONC (4) must be withdrawn. A competitive reaction to the formation of complexes 10a-c′ produces the hydrogen-bonded complexes HalNCO/HHal 12a-c′, which can be regarded as intermediates on the photochemical pathway to the final product isocyanic acid HNCO (1), and are tentatively identified by their IR absorptions. Our findings are supported by deuteration experiments and theoretical calculations using the density functional method BLYP/6-311G*.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0947-3440
    Keywords: Halogen addition ; Autoxidation ; Redox chemistry ; Oxetes, stable ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Small Rings, 88. - Reactions of Tetra-tert-butyltetrahedrane: Oxidation to the Radical Cation as the First StepThe chemistry of tetrahedrane 1 and cyclobutadiene 3 is governed by the initial formation of radical cation 2. In spite of the high steric hindrance 2 cannot be isolated as a radical-ion pair. Reaction of 3 with O2 generates the oxete 21 which is surprisingly stable (up to 200°C).
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 173-186 
    ISSN: 0947-3440
    Keywords: Tetrahedranes ; Cyclobutadienes ; Azetes ; Cyclopropenyldiazomethanes ; Pyridazines: chirality, ring inversion, valence isomers ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Small Rings, 90. - Peralkyl-Substituted TetrahedranesPhotolysis of the diazo compounds 4a, b generates adaman-tyltri-tert-butyltetrahedrane (9a) and tri-tert-butylisopropyltetrahedrane (9b), and the corresponding cyclobutadienes 10a, b. In contrast to tetrahedrane 9a, which results from an intramolecular addition in carbene 7a and also from photoisomerization of cyclobutadiene 10a, the only source for tetrahedrane 9b is the cheletropic cycloaddition of the carbenic center to the cyclopropene double bond in the photochemically produced carbene 7b. Tetrahedrane 9b is remarkable in its kinetic and thermal instability, which is caused by the reduced „corset effect“ in this compound. An additional access to this tetrahedrane is possible via the diazomethanes 34A and 34B. The pyridazines 17b and 41, which are formed by thermolysis of the diazo compounds 4b, 34A and 34B lead to the azetes 19 and 43. Last but not least 17b and 41 are interesting molecules themselves because of their inherent chirality.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0947-3440
    Keywords: Nucleophilic addition ; Sigmatropic rearrangement ; Steric hindrance ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Small Rings, 85.  -  Attempts to Synthesize Alkyltri-tert-butyltetrahedranes by the Cyclopentadienone Route; Synthesis of the CyclopentadienonesStarting from 2-bromotri-tert-butylcyclopentadienone (1) a series of highly substituted cyclopentadienones has been prepared, hoping that they might be suitable candidates for the synthesis of a variety of tetrahedranes with different sterically demanding substituents.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 169-172 
    ISSN: 0947-3440
    Keywords: Cyclobutadiene ; Tetrahedrane ; Azete ; Cyclopropenyldiazomethane ; Valence isomers of pyridazine ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Small Rings, 89. - An Alternative Synthesis of Tetra-tert-butyltetrahedraneCyclopropenyldiazomethane 3 is an ideal precursor for tetra-tert-butyltetrahedrane (6). Both, photochemical and thermal decomposition of 3 lead to cyclobutadiene 7, which can be photoisomerized to tetrahedrane 6. Tetra-tert-butyltetrahedrane (6) is also formed directly by a cheletropic cycloaddition of the carbenic center to the cyclopropene double bond in carbene 4. This is the first example for the synthesis of a tetrahedrane, which does not occur via the corresponding cyclobutadiene. The formation of pyridazine 10 dominates the thermolysis of 3. Azete 12 is obtained both by photolysis as well as by thermolysis of Dewar-pyridazine 11, the irradiation product of 10.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 317-326 
    ISSN: 0947-3440
    Keywords: Matrix isolation ; IR spectroscopy ; Photochemistry ; Ab initio calculations ; Alkene complexes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The matrix-isolated ethylene-bromine complex (1) and the cyclopropene-bromine complex (8) have been chosen to examine which ab initio method (MP2 or BLYP) is more suitable to calculate the IR spectra and structures of π complexes. In addition the photochemistry of 1 and 8 has been investigated and the mechanism of the photochemically induced reactions is discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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