ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 11
    Electronic Resource
    Electronic Resource
    The structure of α-(1,2-dithiole-3-ylidene) ketones and α-(1,2-dithiole-3-ylidene) aldehydes studied by means of n.m.r. spectroscopy (1977)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 9 (1977), S. 546-552 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1H and 13C n.m.r. studies of a series of twelve 1,2-dithiole-3-ylidene ketones and aldehydes have shown that the geometry of the carbon backbone is the same as found in 1,6,6aλ4-trithiapentalenes. No evidence has been found which favours a bicyclic structure for the system. A linear correlation of observed 13C chemical shifts with calculated charge densities is found to be valid. The observations are in agreement with a structure which is a hybrid between a true ketonic structure and a true mesoionic structure.By using the difference in the 13C chemical shifts of ortho and meta carbon atoms in substituent phenyl groups it is possible to qualify the degree of coplanarity of the phenyl groups with the backbone of the molecule.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270090912
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Sels de Pyrylium. XVIII.Pour le XVIIéme mémoire, voir la Ref. 1. Etude par RMN du Carbone-13 de Sels d'Aminopyrylium et des Barrières de Rotation dans quelques Cations N,N-Diméthylaminopyrylium (1979)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 12 (1979), S. 71-76 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The C-2 - N bond of 2-N,N-dimethylaminopyrylium cations has a partial π character due to the conjugation of the nitrogen lone-pair with the ring. The values of ΔG≠, ΔH≠, ΔS≠ parameters related to the corresponding hindered rotation have been determined by 13C NMR total bandshape analysis. This conjugation decreases the electrophilic character of carbon C-4 so that the displacement of the alkoxy group is no longer possible. Such a hindered rotation also exists in 4-N,N-dimethylaminopyrylium cations and the corresponding ΔG≠ parameters have been evaluated. Comparison of these two cationic species shows that hindered rotation around the C - N bond is larger in position 4 than in position 2. Furthermore, the barrier to internal rotation around the C-2—N bond decreases with increasing electron donating power of the substituent at position 4. ΔG≠ values decreases from 19.1 kcal mol-1 (79.9 kJ mol-1) to 12.6 kcal mol-1 (52.7 kJ mol-1) according to the following sequence for the R-4 substituents: -C6H5, -CH3, -OCH3, -N(CH3)2.
    Notes: Dans les cations N,N-diméthylamino-2 pyrylium, la conjugaison du doublet de l'azote avec le cycle confère à la liaison C-2—N un caractère partiel de double liaison. Les valeurs des paramètres ΔG≠, ΔH≠ ΔS≠ relatifs à l'empěchement de rotation correspondant ont été déterminées par analyse de la forme des bandes. Cette conjugaison diminue le caractère électrophile du carbone C-4, ce qui rend impossible les réactions de transalcoylation. Dans les cations N,N-diméthylamino-4 pyrylium il existe de měme une barrière de rotation autour de la liaison C-4—N, dont les paramètres ΔG≠ ont été évalués. La comparaison de ces deux types de cations montre que l'empěchement de rotation autour de la liaison C—N est plus important en position 4 qu'en position 2. Par ailleurs, plus le substituant en position 4 est électrodonneur, moins la barrière de rotation autour de la liaison C-2—N est élevée: la valeur du paramètre ΔG≠ décroǐt de 19,1 kcal mol-1 (79,9 kJ mol-1) à 12,6 kcal mol-1 (52,7 kJ mol-1) selon l'ordre suivant des substituants R-4: -C6H5, -CH3, -OCH3, -N(CH3)2.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270120206
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Elimination reactions of ions in the gas phase (1976)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1976), S. 458-467 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The loss of water from the molecular ion of 2-adamantanol was investigated using specifically labelled deuterium derivatives, and, in particular that stereospecifically labelled in position 4. Water is lost predominantly in a stereospecific 1, 3 fashion by two clearly distinguishable mechanisms. Determination of metastable ion characteristics proved to be essential for drawing this distinction.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210110503
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Elimination reactions of ions in the gas phase. IVPart III: Th. Kuster and J. Seibl, Org. Mass Spectrom. 11, 458 (1976). - Comparative investigation of water elimination in odd and even electron hydroxyl cations of 6-undecanol (1976)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1976), S. 644-651 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactivity differences between odd ([M]+) and even electron ions (α-cleavage product) were studied by comparing water elimination mechanisms in 6-undecanol. The compounds specifically labelled with deuterium in positions 6, 5 + 7, 4 + 8 and 3 + 9 were made, and a detailed investigation of tghe metastable ion transitions carried out. A highly specific 1,4 elimination of water without preceding intramolecular hydrogen exchange occurs from [M]+, but equal amounts of 1,3 and 1,4 elimination of water preceded by specific hydrogen exchange between -OH and the hydrocarbon chain occurs from the α-cleavage ion [M - C5H11]+. To make such distinctions a thorough examination of metastable ions is essential.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210110612
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Accuracy of X-ray fluorescence spectrometric determination of Rb and Sr concentrations in rock samples (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 6 (1977), S. 117-122 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: It is shown that application of the Compton scattering method for matrix correction in the X-ray fluorescence spectrometric determination of the trace elements Rb and Sr in rock samples can provide concentrations at a relative accuracy level of 1%. The empirical method applies to rock samples showing differences in mass absorption up to a factor of two. The accuracy of the method has been tested by analysis of 57 samples analysed for Rb and Sr by mass spectrometric isotope dilution. In addition a few of the U.S. Geological Survey (U.S.G.S.) reference rock powders, showing significantly different mass absorption, were analysed for Rb and Sr. It is demonstrated that the mica effect, if significant, is smaller than 1% relative. There is no advantage in the use of the LiF(220) analysing crystal as a substitute for the LiF(200). The method appears to be insensitive to the pellet thickness.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300060304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Fluoraustauschreaktionen an Metalltrifluorphosphin-Komplexen. IX. Zum Reaktionsverhalten von Tetrakis(trifluorphosphin)nickel(0) gegenüber Alkyl(trimethylsilyl)aminen und -amiden (1975)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 412 (1975), S. 239-245 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fluorine Exchange in Trifluorophosphine Metal Complexes. IX1. (Reactions of Tetrakis(trifluorophosphine)nickel(0) with Alkyl(trimethylsilyl)amines and Amides2)Alkylaminodifluorophosphine complexes Ni(PF3)4-n(PF2NHR)n (n = 1, 2, 3) 8-11 and Me3SiF are obtained, if alkyl(trimethylsilyl)amines NHR(SiMe3) (R=CH3 and n-C4H9) are reacted with Ni(PF3)4 (1). The mechanism of these peripheric reactions is discussed by assuming a four centered type intermediate. However reactions of 1 with the lithium amides LiNR(SiMe3) (R = CH3, C2H5, n-C4H9, and C6H5) yield LiF and the difluorotrimethylsilylaminophosphine complexes Ni(PF3)4-n[PF2NR(SiMe3)]n (n = 1, 3, 4) 12-18.
    Notes: Ni(PF3)4 (1) reagiert mit Alkyl(trimethylsilyl)aminen NHR(SiMe3) (R=CH3 und n-C4H9) unter Me3SiF-Abspaltung zu den Alkylaminodifluorphosphinkomplexen Ni(PF3)4-n(PF2NHR)n (n = 1, 2 und 3) 8-11. Der Reaktionsablauf wird anhand eines Vierzentren-Synchron-Mechanismus diskutiert. Hingegen liefern die Lithiumamide LiNR(SiMe3) (R=CH3, C2H5, n-C4H9 und C6H5) mit 1 unter LiF-Abspaltung die Organyl(trimethylsilyl)-aminodifluorphosphinkomplexe Ni(PF3)4-n[PF2NR(SiMe3)]n (n = 1, 3 und 4) 12-18.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19754120307
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Phosphors. 5958. Mitt.: M. Baudler u. M. Bock, Angew. Chem. 86, 124 (1974).. Zur Synthese und Struktur von (C6H5PS)3 (1975)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 413 (1975), S. 239-251 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus. 59. Synthesis and Structure of (C6H5PS)31,2,4-Triphenyl-1-thio-cyclo-3,5-dithia-1,2,4-triphosphane (C6H5PS)3 (1) is obtained in very good yield by the reaction of dipotassium triphenyltriphosphide (4) with dichloro trisulfane, as well as by the reaction of phenylphosphine with sulphur dichloride. Besides, 1 is formed, together with the cyclothiaphosphane (C6H5P)4 (3), by the reaction of a 1,2-diphenyl-1,2-dihalogen-diphosphane with hydrogen sulphide or disulfane and by the reaction of 4 and disulphur dichloride. - All of the spectroscopic data, especially the 31P nmr spectra, indicate unambiguously the heterocyclophosphane structure V with a five-membered P3S2-ring with isolated sulphur atoms, and with one of the directly connected phosphorus atoms bearing another sulphur atom in exo-position, in addition to the phenyl group.
    Notes: 1,2,4-Triphenyl-1-thio-cyclo-3,5-dithia-1,2,4-triphosphan (C6H5PS)3 (1) wird durch Reaktion von Dikalium-triphenyl-triphosphid (4) mit Dichlortrisulfan sowie durch Umsetzung von Phenylphosphin mit Schwefeldichlorid in sehr guter Ausbeute erhalten. Außerdem bildet sich 1 - zusammen mit dem Cyclo-thia-phosphan (C6H5P)4 (3) - bei der Umsetzung von 1,2-Diphenyl-1,2-dihalogen-diphosphanen mit Schwefelwasserstoff oder Disulfan sowie aus 4 und Dischwefeldichlorid. - Die Gesamtheit der spektroskopischen Befunde, insbesondere das 31P-Kernresonanzspektrum, ergibt für 1 eindeutig die Heterocyclophosphan-Struktur V mit fünfgliedrigem P3S2-Ring, in dem die S-Atome isoliert stehen und eines der direkt miteinander verbundenen P-Atome außer der Phenylgruppe noch ein exoständiges S-Atom trägt.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19754130304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Metallkomplexe mit anionischen Liganden von Elementen der 4. Hauptgruppe. XI. Substitutionsreaktionen der Trichlorgermid- und Trichlorstannid-Ionen an Metalltrifluorphosphin-Komplexen (1976)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 422 (1976), S. 59-64 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Complexes with Anionic Ligands of Main Group IV Elements. XI. Substitution Reactions of Trichlorogermide and Trichlorostannide Ions with Metaltrifluorophosphine ComplexesThe photochemical reactions of [SnCl3]- in THF with the metal(0)-trifluorophosphine complexes of Ni, Fe, and Mo result in [Ni(PF3)3SnCl3]-, [Fe(PF3)3(SnCl2]-, and [Mo(PF3)5SnCl3]-. [GeCl3]-, in substitution reactions not as reactive as [SnCl3]-, does react under similar conditions with Fe(NO)2(PF3)2 only, to yield [Fe(NO)2(PF3)GeCl3]-. With CpMn(PF3)3 (Cp = h5-C5H5) by the intermediatly formed CpMn(PF3)2THF both substitution derivatives [CpMn(PF3)2ECl3]- (E = Ge, Sn) are found. The metallate(0) complexes are isolated as [As(C6H5))4]+- and [N(C2H5)4]+ -salts; the i.r.- and 19F-n.m.r.-spectra are reported.
    Notes: Unter UV-Bedingungen in THF liefern [SnCl3]--Ionen mit den Metall(0)-trifluorphosphinen von Nickel, Eisen und Molybdän die Metallat(0)-Komplexe [Ni(PF3)3SnCl3]-, [Fe(PF3)3(SnCl3)2]2- und [Mo(PF3)5SnCl3]-. Hingegen bildet das bei Substitutionsreaktionen hinter dem [SnCl3]-. Ion zurückstehende [GeCl3]-.-Ion unter ähnlich drastischen Bedingungen lediglich mit Fe(NO)2(PF3)2 das Monosubstitutionsprodukt [Fe(NO)2(PF3)GeCl3]-. Aus CpMn(PF3)3 (Cp = h5-C5H5) sind über den intermediär gebildeten Komplex CpMn(PF3)2THF beide Substitutionsderivate [CpMn(PF3)2ECl3]- (E=Ge, Sn) leicht zugänglich. Die Metallatkomplexe werden als [As(C6H5)4]+- bzw. [N(C2H5)4]+ -Salze isoliert; ihre IR- und 19F-NMR-Daten werden mitgeteilt.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19764220108
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Einschiebung einer Äthoxycarbonylmethylen-Gruppierung in eine Ni—N-Bindung von meso-Tetraphenylporphinatonickel(II) (1975)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 87 (1975), S. 545-546 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19750871510
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Ionization and dissociation of C6F6 isomers under electron impact (1977)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1977), S. 297-301 
    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 hexafluorobenzene, hexafluorobicyclo[2.2.0]hexa-2,5-diene (perfluoro-Dewar benzene) and 1,1,1,6,6,6-hexafluorohexa-2,4-diyne, and the fragmentation mechanisms of their parent ions are reported. The behaviour of the two cyclic isomers under electron impact is very similar; the linear one behaves quite differently. The ionization potentials of the molecules and the appearance potentials of the fragment ions (both normal and metastable) have been measured. The heats of formation of [C6F5]+ and [C5F3]+ are calculated. A value for the heat of formation of 1,1,1,6,6,6-hexafluorohexa-2,4-diyne is proposed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210120509
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...