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  • 1
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Organometallics 13 (1994), S. 4121-4123 
    ISSN: 1520-6041
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Monatshefte für Chemie 131 (2000), S. 383-392 
    ISSN: 1434-4475
    Schlagwort(e): Keywords. Alkaloids; β-Carboline; Chrysotricine; Hydroborations.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary.  The racemates of the rubiacea alkaloid Chrysotricine (1) and its diastereomer are synthesized from the isomeric mixture of linalyl oxides 3 and tryptamine in six steps, followed by separation of the diastereomers.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 57 (2001), S. 151-153 
    ISSN: 1600-5759
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Notizen: The CuI atom in the title complex, [Cu(NH2SO3)2(C3H8N)(H2O)], is coordinated by the C=C bond of the allylammonium cation, two N atoms of the sulfamate anions and the O atom of the H2O molecule in the apical position. Thus, the central atom is in a distorted trigonal–pyramidal environment. Strong N—H...O and O—H...O contacts connect separate moieties of the complex into a three-dimensional framework. The title compound is representative of hitherto unknown copper(I)–sulfamate π-complexes.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 57 (2001), S. o330-o331 
    ISSN: 1600-5368
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Notizen: Ethane-1,2-diyl S,S′-bis(thioacetate), H3CC(O)SCH2CH2SC(O)CH3 or C6H10O2S2, forms centrosymmetric molecules in the solid state and the molecular structure determined by X-ray crystallography is in good agreement with that obtained by density functional geometry optimization. The planarity of the O=C—S—C fragment, which is also found in structures of other thioacetates, is attributed to a strong np(S)–π*(C—O) orbital interaction.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 56 (2000), S. 684-686 
    ISSN: 1600-5759
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Notizen: The crystal structures of the [6]helicenes 4,13-(1,10-decamethylenedioxy)hexahelicene, C36H34O2, (I), and 4,13-(1,8-octamethylenedioxy)hexahelicene, C34H30O2, (II), show strong steric interactions between the terminal benzene rings and the polymethylenedioxy chains. The shortest ring A and F distances amount to 2.941 (3) and 2.902 (3) Å, respectively. The increased steric energy of the ground state is responsible for a significantly lower racemization barrier of (I) and (II) in comparison to the unsubstituted [6]helicene.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 41 (1996), S. 43-52 
    ISSN: 0959-8103
    Schlagwort(e): double Diels-Alder and Diels-Alder-ene polymerization ; 1,1-diphenylethylene ; triazolinediones ; step-growth reaction ; intrinsic viscosities ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The reactions of 4-ethyl-1,2,4-triazoline-3,5-dione (ETD) (1) and 4-phenyl-1,2,4-triazoline-3,5-dione (PhTD) (2) with 1,1-diphenylethylene (DPE) (3) were investigated at room temperature. The reactions are very fast and are completed in less than 4 min. These reactions lead to the formation of two 2 : 1 adducts via double Diels-Alder and Diels-Alder-ene reactions in a ratio of 1.35 : 1. The structure of these adducts where R = Et were determined by X-ray analysis of a single crystal. These compounds were used as models for the polymerization reactions. The reaction of bistriazolinediones (1,6-bis-(3,5-dioxo-1,2,4-triazoline-4-yl)hexane and bis-(p-3,5-dioxo-1,2,4-triazoline-4-ylphenyl)methane) with (3) were carried out in dimethylformanide (DMF). The reactions are fast and gave novel copolymers via repetitive double Diels-Alder and Diels-Alderene polyaddition reactions. These polymers have intrinsic viscosities in a range about 0.08 to 0.31 dl g-1 in DMF. Some physical properties and structural characterization of these copolymers have been studied and are reported.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 791-795 
    ISSN: 1434-193X
    Schlagwort(e): Cyclophanes ; Sulfur heterocycles ; Cyclisations ; Cesium effect ; ππ* transitions ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Two series of [8]metacyclophanes with cis or trans configurated double bonds or triple bonds in the bridges were prepared; the first series 6, 8, and 10 contains phenylethynyl, the second series 13, 14, and 15 phenylethenyl substituents so that ππ interactions between the π centres in the bridge and the π centres of the basic chromophores tolan and trans-stilbene, respectively, can be studied.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 8
    ISSN: 0947-6539
    Schlagwort(e): iron complexes ; LIESST ; spin crossover ; tetrazoles ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The [Fe(etz),](BF,), spin-cross-over system (etz = 1-ethyl-1 H-tetrazole) crystallizes in space group P1, with the following lattice constants at 298 K: a 10.419(3), b=15.709(1), c = 18.890(2) Å = α = 71.223(9), β =77.986(10), and γ = 84.62(1)° V = 2862.0(9) Å3 and Z = 3. Two nonequivalent lattice sites, one without (site A) and one with (site B) inversion symmetry, are observed. The population of the two sites nA:nB is 2:l. Iron(II) on site A undergoes a thermal low-spin (LS) → high-spin (HS) transition with T1/2I, = 105 K. whereas that on site B remains in the high-spin state down to cryogenic temperatures. Application of external pressure of up to 1200 bar between 200 and 60 K does not cause formation of the low-spin state on site B. On site A the high-spin state can be populated as a metastable state at 20 K by irradiating the sample with λ = 514.5 nm; on site B a light-induced population of the low-spin state can be achieved with λ = 820 nm.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 409-412 
    ISSN: 0947-3440
    Schlagwort(e): Azides ; Azirines ; Tetrazenes ; 15N-NMR spectroscopy ; Nitrogen heterocycles ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In contrast to the addition of iodine azide to cyclooctene (1) or 1,3-cyclooctadiene (5), its reaction with 1,5-cyclooctadiene (12) leads mainly to the surprisingly stable tetraazido-substituted 2-tetrazene 14 The structure of this was established by 15N-NMR studies and an X-ray structural analysis. Treatment of 14 with hydrochloric acid yields the diazido-substituted 9-azabicyclo[3.3.1]nonane 20.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1173-1177 
    ISSN: 0947-3440
    Schlagwort(e): Dithiaheptacenes ; Molecular ribbons, bent, cyclic ; [8 + 2] Cycloaddition reactions ; Arenes ; Polycycles ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Benzo[1,2-b:4,5-b′]bisthiete (1) undergoes stepwise thermal opening of the 4-membered rings, thereby generating two highly reactive 8π systems (Scheme 1). In the presence of 1,4-dihydro-1,4-epoxynaphthalenes 2, the dithiaheptacene derivatives 3 are formed, dehydration of which leads to the compounds 4 and 5 (Scheme 2). Repetitive cycloaddition reactions of 1 with the twofold 2π component 11 (Scheme 3) yield the oligomers 15 with statistically bent (and possibly cyclic) structures (Schemes 4 and 5). While 15 and the related oligomers 14 are freely soluble in many organic solvents, the dehydrated systems 16 (Scheme 6) are totally insoluble.
    Materialart: Digitale Medien
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