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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 1736-1742 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Cycloalkeno[b]pyridines from 2-(Aminomethylene)cycloalkanones and 1,3-Dicarbonyl Compounds2-(Aminomethylene)cycloalkanones react with 1,3-dicarbonyl compounds to give the cycloalkeno[b]pyridines 4-7, the 1H and 13C n.m.r. spectra of which are discussed. The chemical shift values of the heteroaromatic bridge-head carbon atoms are found to alternate on variation of the fused cycloaliphatic ring.
    Notes: Aus 2-(Aminomethylen)cycloalkanonen und 1,3-Dicarbonylverbnidungen werden die Cycloalkeno[b]pyridine 4-7 dargestellt, deren 1H- und 13C-NMR-Spektren diskutiert werden. Die chemischen Verschiebungen der heteroaromatischen Brückenkopf-Kohlenstoffatome alternieren bei Variation des ankondensierten Cycloaliphaten.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Spin-Spin Coupling Constants by Platinium-195 as Criteria for a Configuration Determination in Platinum Organic CompoundsThe platinum organic compounds [Pt(η4-1,5-cyclooctadiene)(XC6H4)2] and cis-[Pt(P(n-Bu)3)2-(XC6H4)2] (X = H, 4-CH3, 4-(CH3)3C, 4-(CH3)2N, 3-F, 4-F, 4-CH3O, 4-CF3; 3a - 4, cis-4a - h) as well as trans-[Pt(P(n-Bu)3)2(4-CH3OC6H4)2] (trans-4g) and trans-[Pt(P(n-Bu)3)2(4-CF3C6H4)2] (trans-4h) have been studied by 31P-, 13C-, and 1H NMR spectroscopy. The coupling constants 1J[195Pt, 31P], nJ[195Pt, 13C], nJ[195Pt, H], and 2J[31P, 13C] show a clear correlation to the ligand configuration at the dsp2-hybridized platinum and can therefore be used as basis for configuration determination.
    Notes: Die platin-organischen Verbindungen [Pt(η4-1,5-cyclooctadien)(XC6H4)2] und cis-[Pt(P(n-Bu)3)2-(XC6H4)] (X = H, 4-CH3, 4-(CH3)3C, 4-(CH3)2N, 3-F, 4-F, 4-CH3O, 4-CF3; 3a - h, cis-4a - h) sowie trans-[Pt(P(n-Bu)3)2(4-CH3OC6H4)2] (trans-4g) und trans-[Pt(P(n-Bu)3)2(4-CF3C6H4)2] (trans-4h) wurden 31P-, 13C- und 1-NMR-spektroskopisch untersucht. Die Kopplungskonstanten 1J[195Pt, 31P], nJ[195Pt, 13C], nJ[195Pt, H] und 2J[31P, 13C] zeigen eine eindeutige Abhängigkeit von der Konfiguration der Liganden am dsp2-hybridisierten Platin; sie können daher zur sicheren Konfigurations-Bestimmung verwendet werden.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 87 (1975), S. 152-168 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die chemischen Verschiebungen und Kopplungskonstanten der 13C-Kernresonanz gehören zu den aussagekräftigsten Meßgrößen, die der Organiker zur Lösung von Strukturproblemen heranziehen kann. Daneben gewinnen die 13C-Spin-Gitter-Relaxationszeiten T1 als Strukturparameter zunehmendes Interesse. In Verbindung mit den durch Protonenentkopplung von 13C-NMR-Spektren hervorgerufenen Kern-Overhauser-Effekten gestatten die T1-Werte der 13C-Kerne eines Moleküls Rückschlüsse auf Relaxationsmechanismen. Sie reflektieren die inter- und intramolekulare Beweglichkeit eines Moleküls und ergänzen so die Aussagen der temperaturabhängigen NMR-Spektroskopie. Aus den T1-Unterschieden innerhalb eine Moleküls ergibt sich u.a., ob die Molekülbewegung in Lösung anisotrop ist, ob die innermolekulare Bewegung von Gruppen sterisch behindert wird, inwieweit starke intermolekulare oder interionische Wechselwirkungen die Flexibilität des Moleküls beeinflussen, welche Teile des Moleküls starr und welche flexibel sind. Schließlich geben die Unterschiede der für die 13C-Kerne eines Moleküls gemessenen T1-Werte oft eine sichere Hilfe bei der Zuordnung der 13C-NMR-Spektren, besonders bei dichter Signalfolge und Multiplettüberlappung.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 14 (1975), S. 144-159 
    ISSN: 0570-0833
    Keywords: Relaxation ; Mobility ; 13C NMR spectroscopy ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: While the chemical shifts and coupling constants of 13C NMR belong to the most powerful tools available to the organic chemist for the solution of structural problems, increasing interest is being shown in 13C spin-lattice relaxation times T1 as structural parameters. Together with the nuclear Overhauser effects arising by proton decoupling of 13C NMR spectra, the T1 values of 13C nuclei in a molecule permit conclusions to be drawn with regard to relaxation mechanisms. They reflect the inter- and intramolecular mobility of a molecule, and thus complement the results of temperature-dependent NMR spectroscopy. The T1 differences within a molecule show, for instance, whether the molecular motion is anisotropic in solution, whether the internal motion of groups is subject to steric hindrance, the extent to which strong intermolecular or interionic interactions affect the flexibility of the molecule, and which parts of the molecule are rigid and which are flexible. Finally, differences between the T1 values measured for the 13C nuclei of a molecule frequently provide a reliable aid in the assignment of 13C NMR spectra, particularly in cases of signal crowding and multiplet overlapping.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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