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  • 1
    Electronic Resource
    Electronic Resource
    Anwendungen der 13C-Resonanz-Spektroskopie, IX. Substituenten-Effekte im System 7-Phenylnorcaradien-7-carbonsäureester/7-Phenyl-1,3,5-cycloheptatrien-7-carbonsäureester (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 3683-3694 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Applications of 13C Resonance Spectroscopy, IX. Substituent Effects in the System 7-Phenylnorcaradiene-7-carboxylate/7-Phenyl-l,3,5-cycloheptatriene-7-carboxylateThe valence tautomerisms methyl 7-phenylnorcaradiene-7-carboxylate/methyl 7-phenyl- 1,3,5-cycloheptatriene-7-carboxylate (3a = 4a), methyl 7-(p-nitrophenyl)norcaradiene-7-carboxylate/methyl 7-(p-nitrophenyl)-l,3,5-cycloheptatriene-7-carboxylate (3b = 4b), methyl 7-(p-methoxyphenyl)norcaradiene-7-carboxylate/methyl 7-(p-methoxyphenyl)-1,3,5-cycloheptatriene-7-carboxylate (3c = 4c), and ethyl 7-phenylnorcaradiene-7-carboxylate/ethyl 7-phenyl-1,3,5-cycloheptatriene-7-carboxylate have been investigated using 13C n.m.r. spectroscopy. The following thermodynamic parameters, in the order given above, have been obtained: ΔHo = 2.1, 2.2,2.1, and 1.6 kcal/mole; ΔSo = 6.2, 5.6, 6.2, and 5.2 Clausius. The conformity of the ΔHo values in the case of 3a-c = 4a-c is attributed to the endo-position of the phenyl group that is derived on the basis of 1H n.m.r. results. The reduction of ΔHo in the case of 3d = 4d is most likely of steric origin.
    Notes: Die Valenztautomerien 7-Phenylnorcaradien-7-carbonsäure-methylester/7-Phenyl-1,3,5-cycloheptatrien-7-carbonsäure-methylester (3a = 4a), 7-(p-Nitrophenyl)norcaradien-7-carbonsäure-methylester/7-(p-Nitrophenyl)-1,3,5-cycloheptatrien-7-carbonsäure-methylester (3b = 4b), 7-(p-Methoxyphenyl)norcaradien-7-carbonsäure-methylester/7-p-Methoxyphenyl)-l,3,5-cycloheptatrien-7-carbonsäure-methylester (3c = 4c) und 7-Phenylnorcaradien-7-carbonsäure-äthylester/7-Phenyl-1,3,5-cycloheptatrien-7-carbonsäure-äthylester (3d = 4d) wurden mit Hilfe der 13C-NMR-Spektroskopie untersucht. Folgende thermodynamische Daten, jeweils in der oben gewählten Reihenfolge, sind bestimmt worden: ΔHo = 2.1, 2.2, 2.1 und 1.6 kcal/mol; ΔSo = 6.2, 5.6, 6.2 und 5.2 Clausius. Die Übereinstimmung der ΔHo-Werte für 3a-c = 4a-c wird auf die endo-Stellung der Phenylgruppe, die auf der Basis von 1H-NMR-Befunden abgeleitet wurde, zurückgeführt. Die Verringerung von ΔHo im Fall von 3d = 4d dürfte sterische Ursachen haben.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731061129
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  • 2
    Electronic Resource
    Electronic Resource
    Über Inhaltsstoffe von Euphorbiaceae, IV. Zur Konstitution der isomeren O-(ß-Hydroxy-γ-Hydroxy-carbonyl-ß-methylbutanoyl)shikimisäuren aus Euphorbia biglandulosa Desf. (1978)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 1905-1912 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Constituents of Euphorbiaceae, IV1).  -  Constitution of the Isomeric O-(ß-Hydroxy-γ-hydroxycarbonyl-ß-methylbutanoyl)shikimic Acids from Euphorbia biglandulosa Desf.The composition and structure of the isomeric O-(ß-hydroxy-γ-hydroxycarbonyl-ß-methylbutanoyl)shikimic acids 7 and 8 isolated from Euphorbia biglandulosa have been determined (74% 5-O-, 26% 3-O-derivative) by comparative 1H-NMR spectroscopy of the shikimic acid derivatives methyl 3,4,5-tri-O-acetylshikimate (3), methyl 3,4-O-(phenylboranediyl)shikimate (4), and methyl 5-O-acetylshikimate (6). The conformation of the shikimic acid derivatives is discussed.
    Notes: Durch vergleichende Analyse der 1H-NMR-Spektren der Shikimisäurederivate 3,4,5-Tri-O-acetylshikimisäure-methylester (3), 3,4-O-(Phenylborandiyl)shikimisäure-methylester (4) und 5-O-Acetylshikimisäure-methylester (6) wurden die Zusammensetzung des Isomerengemisches und die Konstitution der aus Euphorbia biglandulosa gewonnenen O-(β-Hydroxy-γ-hydroxycarbonyl-β-methylbutanoyl)shikimisäuren 7 und 8 aufgeklärt (74% 5-O-, 26% 3-O-Derivat). Die Konformation der Shikimisäurederivate wird diskutiert.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197819781204
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  • 3
    Electronic Resource
    Electronic Resource
    Bis(P,P-di-tert-butylphosphinsäure-N-isopropylamidato-N,O)nickel(II), ein paramagnetischer planarer Komplex (1992)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 104 (1992), S. 632-633 
    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.19921040526
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  • 4
    Electronic Resource
    Electronic Resource
    Paramagnetic Planar Complexes of NiII: Influence of R and R′ on the Formation, Coordination Geometry and Magnetic Properties of Phosphinic Amidato Bischelates [R2P(O)NR′]2Ni (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 551-555 
    Details
    ISSN: 0009-2940
    Keywords: Paramagnetic planar complexes of NiII ; Phosphinic amidato ligands ; NMR spectroscopy ; Magnetic measurements ; Vis spectra ; Crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: After a brief review of previous work the results of the metathesis reaction between Ni(dme)Br2 and R2P(O)NR′Li [R = tBu, iPr, Ph; R′ = Et, Pr, iPr, (±)-sBu, tBu, tPen, Cy, Ph, (-)-α-methylbenzyl = Mb, 1-adamantyl = Ad] are reported. Complex formation occurred only with lithiated amides of tert-butylphosphinic acid, and bischelates [tBu2P(O)NR′]2Ni were obtained when R′ = sBu, Mb, tPen, Ad (1d - g). With R′ = Et, Pr bischelation was incomplete. Vis spectroscopy showed the paramagnetic compounds 1d - f to be planar in the solid state but tetrahedral in solution. 1g is tetrahedral in both phases. The planar structure of 1f was confirmed by X-ray single-crystal analysis (monoclinic, space group P21/n). The magnetic moments μeff of 1d, e, g are ca. 3.2-3.5 μB in both phases and the Curie-Weiss law is obeyed in the range 293-183 K. The same is valid for dissolved 1f. The μeff values of solid 1f are however, strongly temperature-dependent, varying from 1.38 to 0.55 μB (300-90 K). NMR data (31P, 1H, 13C) are reported. Obviously, a favorable combination of electronic and steric factors of substituents R and R′ produces with ligands [R2P(O)NR′]- the donor quality necessary for bischelation as well as the singular field strength required for the formation of planar paramagnetic species. As the combination of paramagnetism and planarity is bound to the solid state, lattice energy effects may be finally decisive for this unique constellation of tetracoordinated NiII complexes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290512
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  • 5
    Electronic Resource
    Electronic Resource
    Thiophosphinsäure-organylamidato-Komplexe[Et2P(S)NR]2Ni, planar-tetraedrische Chelate mit Metall-Stickstoff-Schwefel-Chromophoren (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1569-1580 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phosphinothioic Organylamidato Complexes [Et2P(S)NR]2Ni, Planar-Tetrahedral Chelates with Metal-Nitrogen-Sulfur ChromophoresReaction of [Et2P(S)NR]-Li+ with NiHal2 in inert solvents gave extremely hydrolyzable complexes [Et2P(S)NR]2 Ni (R=Me, Et, iPr, tBu, cHex, Ph) 3a - f containing four-membered chelate rings and NiN2S2-chromophores. It is shown by magnetic measurements, electronic and 31P NMR spectroscopy that 3d (R=tBu) is purely tetrahedral over a wide range of temperature as well in the solid state as in solution. In solutions of the other compounds 3, there exists an equilibrium planar ⇌ tetrahedral, the latter isomer prevailing with larger R and with increasing temperature. 3a and 3b (R=Me, Et) are almost entirely planar at room temperature. In solid state 3a is most probably pentacoordinated and 3c a mixture of both isomers, while 3e is tetrahedral and 3f planar.
    Notes: Die Umsetzung von [Et2P(S)NR]-Li+ mit NiHal2 in inerten Lösungsmitteln ergab die extrem hydrolyseempfindlichen Komplexe [Et2P(S)NR]2 Ni (R=Me, Et, iPr, tBu, cHex, Ph) 3a - f, die 4gliedrige Chelatringe und NiN2S2-Chromophore enthalten. Durch magnetische Messungen, Elektronen- und 31P-NMR-Spektroskopie wird gezeigt, daß 3d (R=tBu) innerhalb eines weiten Temperaturbereichs, sowohl in festem als auch gelöstem Zustand, ausschließlich tetraedrisch ist. In Lösungen der anderen Verbindungen 3 existiert ein Gleichgewicht planar ⇌ tetraedrisch, das sich mit steigender Temperatur und bei sperrigem R nach rechts verlagert. 3a und b (R=Me, Et) sind in Lösung bei Raumtemperatur fast ausschließlich planar. Im Festzustand ist 3a wahrscheinlich pentakoordiniert und 3c ein Gemisch beider Isomeren. 3e ist tetraedrisch und 3f planar.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190512
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  • 6
    Electronic Resource
    Electronic Resource
    Phosphoniumsalze mit Hydrogendihalogenidanionen HCl2-, HBr2- Hl2- oder HBrCl- (1987)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 551 (1987), S. 179-190 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phosphonium Salts with Hydrogen Dihalide Anions HCl2-, HBr2-, HI2-, or HBrCl-Phosphonium hydrogen dihalides [R3PR′][XHY] (X = Y = Cl, Br, I; X = Br, Y = Cl) resp. [R3PH]HBr2 are obtained as extremely hydrolyzable crystals by reaction of phosphonium halides or tertiary phosphanes with hydrogen halide. According to IR spectroscopic results the solid compounds mostly contain anions [XHX]- with symmetric hydrogen bonds. In solution 1H NMR measurements show a slight (X = Cl, Br) or considerable (X = I) dissociation according to HX2- ⇌ X- + HX. On heating the solid compounds decompose with formation of hydrogen halide and [R3PR′]X or [R3PH]X. In this process the hydrogen bromidechlorides [R3PR′][BrHCl] exclusively eliminate HCl. NMR studies (1H und 31P) with solutions containing [R3PH]HBr2 (R = phenyl, 1-naphtyl) or HBr and Ph3P in varying molar ratios show that a fast proton exchange between the competing Lewis bases R3P and Br- exists.
    Notes: Phosphoniumhydrogendihalogenide [R3PR′] [XHY] (X = Y = Cl, Br, I; X = Br, Y = Cl) bzw. [R3PH] HBr2 erhält man als extrem hydrolyseempfindliche Kristalle durch Umsetzung von Phosphoniumhalogeniden bzw. tertiären Phosphanen mit Halogenwasserstoff. IR-spektroskopischen Befunden zufolge enhalten die Anionen [XHX]- in den festen Hydrogendihalogeniden zumeist symmetrische Wasserstoffbrücken. Aus der Protonenresonanz der Anionen wird geschlossen, daß in den Lösungen der Substanzen eine geringe (X = Cl, Br) oder auch stäkere (X = I) Dissoziation nach HX2- ⇌ X- + HX erfolgt. Beim Erwärmen spalten die Feststoffe Halogenwasserstoff unter Bildung von [R3PR′] X bzw. [R3PH]X ab. Die Hydrogenbromidchloride [R3PR′] [BrHCl] eliminieren hierbei ausschileßlich HCl. NMR-Untersuchungen (1H und 31P) an Lösungen von [R3PH] HBr2 (R = Ph, 1-Naphthyl) sowie von HBr und Ph3P in CDCl3 mit variierendem Molverhältinis beider Komponenten zeigen, daß hier ein schneller Austausch des Protons zwischen den konkurrierenden Lewisbasen R3P und Br- stattfindet.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19875510820
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  • 7
    Electronic Resource
    Electronic Resource
    Bis(P,P-di-tert-butyl-N-cyclohexylphosphinsäure-amidato-N,O)nickel(II): ob planar oder tetraedrisch - beide Isomere sind paramagnetisch (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 105 (1993), S. 926-928 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19931050626
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  • 8
    Electronic Resource
    Electronic Resource
    Erstmalige Anwendung der 2D-NMR-Technik zur Spektrenanalyse eines paramagnetischen Komplexes; Beispiel: Bis[R-(+)-P,P-diethylthiophosphinsäure-N-α-methylbenzylamido]nickel(II) (1985)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 97 (1985), S. 217-218 
    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.19850970315
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  • 9
    Electronic Resource
    Electronic Resource
    [NiL2X2] oder [HL][NiLX3] - Reaktion sterisch anspruchsvoller Trialkylphosphine L mit NiX2 (X = Cl, Br) in Ethanol (1996)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 1381-1386 
    Details
    ISSN: 0044-2313
    Keywords: Bis(trialkylphosphine)nickel(II) halides ; trialkylphosphonium nickelates ; 1H and 31P NMR of paramagnetic complexes ; magnetic measurements ; Vis spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [NiL2X2] or [HL][NiLX3] - Reaction of Sterically Demanding Trialkylphosphines L with NiX2 (X = Cl, Br) in EthanolThe reaction of some sterically demanding trialkylphosphines L = PR2R′ (R = iPr, R′ = tBu; R = tBu, R′ = iPr, Me) with NiX2 (X = Cl, Br) in ethanol affords instead of the expected non-electrolytes [NiL2X2] tertiary phosphonium nickelates [HL][NiLX3] due to participation of the solvent. In case of the less bulky PtBu2Me both complex types were obtained. [Ni(PtBu2Me)2Cl2] is tetrahedral and therefore one of the two examples of paramagnetic bis(trialkylphosphine)dihalogenonickel(II) complexes known so far. In solution the latter compound undergoes an equilibrium of tetrahedral (paramagnetic) and planar (diamagnetic) conformer.Vis spectra as well as the results of magnetic measurements and 1H and 31P NMR investigations are reported.
    Notes: Die Umsetzung einiger sterisch anspruchsvoller Trialkylphosphine L = PR2R′ (R = iPr, R′ = tBu; R = tBu, R′ = iPr, Me) mit NiX2 (X = Cl, Br) in Ethanol liefert infolge Beteiligung des Solvens statt der erwarteten Nichtelektrolyte [NiL2X2] tertiäre Phosphoniumnickelate [HL][NiLX3]. Im Falle des weniger raumerfüllenden PtBu2Me entstehen beide Komplextypen. [Ni(PtBu2Me)2Cl2] ist tetraedrisch und stellt somit eines der beiden bisher bekannten Beispiele für paramagnetische Bis(trialkylphosphin)dihalogenonickel(II)-Komplexe dar. In Lösungen dieser Verbindung existiert ein Gleichgewicht zwischen tetraedrischem (paramagnetischem) und planarem (diamagnetischem) Konformer.Vis-Spektren sowie Ergebnisse magnetischer Messungen und 1H- bzw. 31P-NMR-Untersuchungen werden mitgeteilt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19966220817
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  • 10
    Electronic Resource
    Electronic Resource
    Bis(P,P-di-tert-butyl-N-cyclohexylphosphinic amidato-N,O)nickel(II): Whether Planar or Tetrahedral - Both Isomers are ParamagneticDedicated to Professor Dietrich Mootz on the occasion of his 60th birthday (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 32 (1993), S. 907-909 
    Details
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.199309071
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