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  • NMR  (14)
  • Wiley-Blackwell  (14)
  • 1995-1999  (14)
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  • 1995  (14)
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 1358-1364 
    ISSN: 0044-2313
    Keywords: Phosphorus tin heterocycles ; syntheses ; crystal structure ; NMR ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure Analysis of (tBuP)4Sn(CH3)2 and (CH3)2Sn[(tBu)P—P(tBu)]2Sn(CH3)2The diphosphides K2[(tBu)P—(tBuP)2—P(tBu)] 7 or K2[(tBu)P—P(tBu)] 8 react with (CH3)2SnCl2 in a molar ratio of 1 : 1 to form the binary 5-membered ring system P4Sn 4 a and the 6-membered ring system Sn(P2)2Sn 5 a respectively. When (CH3)2SnCl2, however, is treated with 8 in a molar ratio of 2 : 1 the 4-membered ring system P3Sn 2 a is formed which includes the fragmentation of the intermediate K2[(CH3)2Sn ((tBu)P—P(tBu))2] 9. 4 a and 5 a could be obtained in a pure form and characterized NMR spectroscopically and by X-ray structure analyses; 2 a was identified only NMR spectroscopically.
    Notes: Die Diphosphide K2[(tBu)P—(tBuP)2—P(tBu)] 7 bzw. K2[(tBu)P—P(tBu)] 8 reagieren mit (CH3)2SnCl2 im Molverhältnis 1 : 1 zu dem binären Fünfringsystem P4Sn 4 a bzw. dem Sechsringsystem Sn(P2)2Sn 5 a. Wird jedoch (CH3)2SnCl2 mit zwei Äquivalenten 8 umgesetzt, so erhält man nach einer Fragmentierung des Intermediats K2[(CH3)2Sn ((tBu)P—P(tBu))2] 9 das binäre Vierringsystem P3Sn 2 a. 4 a und 5 a konnten in reiner Form isoliert, NMR-spektroskopisch und durch Röntgenstrukturanalysen charakterisiert werden; 2 a konnte bisher nur NMR-spektroskopisch identifiziert werden.
    Additional Material: 2 Ill.
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  • 2
    ISSN: 0749-1581
    Keywords: NMR ; 1H NMR spectroscopy ; photocycloaddition ; meta photocycloadducts ; 4-phenoxybut-1-enes ; 3-benzyloxyprop-1-enes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1H NMR data (400 and 500 MHz) are reported for the intramolecular meta photocycloaddition products from 4-phenoxybut-1-enes and 3-benzyloxyprop-1-enes. The structures of these photoproducts, and in particular the discrimination between the 1,6- and 7,8-bridged isomers, are deduced from COSY 45 and 60 experiments and spin-decoupling techniques.
    Additional Material: 5 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 33 (1995), S. 497-499 
    ISSN: 0749-1581
    Keywords: NMR ; 1H NMR ; 13C NMR ; 6-s-trans-retinoids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new class of vitamin A analogs (retinoids) was synthesized containing a dimethylene bridge to maintain a 6-s-trans conformation of the terminal double bonds. The 1H and 13C NMR spectra were assigned for 15 new compounds, including E-Z isomers (all-E, 13Z, 9Z and 9Z,13Z) of retinoids containing an ethyl ester and car-boxylic acid polar end groups, and also the (all-E)-isomer of the retinoids with an alcohol and aldehyde polar end-groups and five C15 intermediates. The assignments were based on long-range 1H—13C heteronuclear 2D experiments.
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  • 4
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 63-69 
    ISSN: 0887-6266
    Keywords: orientational order ; poly(ethylene terephthalate) ; NMR ; fibers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Determination of the orientational order of morphological components in polyethylene terephthalate (PET) is sought through quantitative application of two-dimensional rotor synchronized magic angle spinning (ROSMAS) 13C NMR technique. Previous study in our laboratories had established a procedure for resolution of the carbonyl carbon (CA) and glycol ethylene carbon (GE) resonances into those corresponding to four morphological components.1 Due to paucity of sidebands in the GE resonances, the focus has been on the CA resonances in this attempt to obtain orientation distributions. A set of PET fibers possessing a broad range of crystalline and orientational order has been used to infer the meaning of NMR-based orientation measurements vis-a-vis other techniques. A surprising finding of this study is the observation that the orientational orders of the broad component in the 13C CP/MAS spectrum and the narrow component are very similar in these fibers. ©1995 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 1235-1247 
    ISSN: 0887-6266
    Keywords: NMR ; poly-1-butene ; NMR line shape ; spin-lattice relaxations ; Williams Watt correlation function ; polymorphism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The temperature dependance of the proton NMR line shape, T1 and T1ρ of isotactic poly-1-butene forms I, I′, II, and III have been studied between 100 and 400 K (up to melting). The usual line shape decompositions concerning rigid vs. crystalline and mobile vs. amorphous phases are discussed. The rigid-lattice second moments were calculated introducing a fast rotation of the methyl group.Complex spin-lattice decays were analyzed as a continuous distribution of rates. Relaxation behavior was analyzed in terms of a Williams-Watt correlation function. Motions in the crystalline parts of samples in forms II and III very similar to the amorphous one were revealed, leading us to compare form II to a condis crystal during the crystal form transformation. © 1995 John Wiley & Sons, Inc.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 877-888 
    ISSN: 0044-2313
    Keywords: Barium ; Bis(trimethylsilyl)phosphanide ; Phosphanide ; Tin ; NMR ; X-ray Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Characterization of Hetero-bimetallic Bis(trimethylsilyl)phosphanides of Barium and TinThe reaction of barium bis[bis(trimethylsilyl)amide] with one equivalent of bis(trimethylsilyl)phosphane in 1,2-dimethoxyethane (dme) yields the heteroleptic dimeric (dme)barium bis(trimethylsilyl)amide bis(trimethylsilyl)phosphanide. This colorless compound crystallizes in the monoclinic space group P21/n with a = 1 259.1(3), b = 1 822.7(4), c = 1 516.1(3) pm, β = 110.54(3)° and Z = 4. The central moiety of the centrosymmetric molecule is the planar Ba2P2-cycle with Ba—P-bond lengths of 329 and 334 pm. In the presence of bis[bis(trimethylsilyl)amino]stannylene hetero-bimetallic bis(trimethylsilyl)phosphanides of tin(II) and barium are isolated. If the reaction of Ba[N(SiMe3)2]2 and Sn[N(SiMe3)2]2 in the molar ratio of 1:2 with six equivalents of HP(SiMe3)2 is performed in toluene, barium bis{tin(II)-tris[bis(trimethylsilyl)phosphanide]} can be isolated. This compound crystallizes in the orthorhombic space group P212121 with a = 1 265.1(1), b = 2 290.1(3), c = 2 731.9(3) pm and Z = 4. The anions {Sn[P(SiMe3)2]3}- bind as two-dentate ligands to the barium atom which shows the extraordinary low coordination number of four. The addition of tetrahydrofuran (thf) to the above mentioned reaction solution leads to the elimination of tris(trimethylsilyl)phosphane and the formation of thf complexes of barium bis{tin(II)-bis(trimethylsilyl)phosphanide-trimethylsilylphosphandiide}. The derivative crystallizes from toluene in the monoclinic space group P21/c with a = 1 301.9(2), b = 2 316.3(3), c = 3 968.7(5) pm, β = 99.29(1)° and Z = 8.
    Notes: Bei der Reaktion von Barium-bis[bis(trimethylsilyl)amid] mit einem Äquivalent Bis(trimethylsilyl)phosphan in 1,2-Dimethoxyethan (DME) wird heteroleptisches, dimeres (1,2-Dimethoxyethan-O,O′)barium-bis(trimethylsilyl)-amid-bis(trimethylsilyl)phosphanid isoliert. Diese farblose Verbindung kristallisiert in der monoklinen Raumgruppe P21/n mit a = 1 259,1(3), b = 1 822,7(4), c = 1 516,1(3) pm, β = 110,54(3)° und Z = 4. Das zentrale Strukturelement des zentrosymmetrischen Moleküls ist der planare Ba2P2-Cyclus mit Ba—P-Bindungslängen von 329 und 334 pm. In Gegenwart des Bis[bis(trimethylsilyl)amino]stannylens erhält man heterobimetallische Bis(trimethylsilyl phosphanide von Zinn(II) und Barium. Wird die Umsetzung von Ba[N(SiMe32]2 and Sn[N(SiMe3)2]2 im molaren Verhältnis 1:2 mit sechs Äquivalenten HP(SiMe3)2 durchgeführt, kann Barium-bis{zinn(II)-tris-[bis(trimethylsilyl)phosphanid]} isoliert werden. Diese Verbindung kristallisiert in der orthorhombischen Raumgruppe P212121 mit a = 1 265,1(1), b = 2 290,1(3), c = 2 731,9(3) pm und Z = 4. Die Anionen {Sn[P(SiMe3)2])3}- binden als zweizähnige Liganden an das Bariumatom, das dadurch die ungewöhnlich niedrige Koordinationszahl vier aufweist. Die Zugabe von THF zu der oben beschriebenen Reaktionslösung führt zur Eliminierung von Tris(trimethylsilyl)phosphan und der Bildung von Barium-bis{zinn(II)-bis(trimethylsilyl)phosphanid-trimethylsilylphosphandiid). Das Derivat kristallisiert aus Toluol in der monoklinen Raumgruppe P21/c mit a = 1 301,9(2), b = 2 316,3(3), c = 3 968,7(5) pm, β = 99,29(1)° und Z = 8.
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  • 7
    ISSN: 0749-1581
    Keywords: NMR ; 1H NMR ; 13C NMR ; 15N NMR ; 27Al NMR ; isothiocyanate ; complexes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A multinuclear magnetic resonance (NMR) study of the complexes of aluminum(III) with isothiocyanate ion in water-acetone mixtures has been completed. At temperatures low enough to slow proton and ligand exchange, separate resonance signals are observed for coordinated and bulk H2O (1H) and NCS- (13C, 15N), and Al3+ (27Al) in each complex. The 1H NMR spectra reveal six sets of signals for the complexes, [Al(H2O)6]3+ through [Al(H2O)(NCS)5]2-, including isomers for three of the species. Signal area measurements show a decrease in the Al3+ hydration number with increasing NCS- concentration, as this anion replaces water in the solvation shell. In the 27Al NMR spectra of these systems, signals for seven complexes, [Al(H2O)6]3+ through [Al(NCS)6]3-, are observed, with chemical shifts increasing by about 6 ppm with each additional NCS-. Although broadened somewhat by the Al(III) quadrupole, the 13C and 15N NMR spectra also reveal coordinated NCS- signals for these complexes, including 27Al—N13CS J-coupling in [Al(NCS)6]3-. Area evaluations of the 15N NMR signals provide an excellent complement to the 1H hydration number data. These NMR results demonstrate that a multinuclear approach to the study of solution complexes can provide detailed structural information about the species being formed.
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  • 8
    ISSN: 0749-1581
    Keywords: NMR ; 13C NMR ; chemical shift ; sulphonated compounds ; fluorosulphonic acids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A chemical shift analysis of the 13C NMR spectra of more than 50 acyclic sulphonic acids, alkali metal sulphonates and methyl esters was carried out. Chemical shift increment systems with n-alkanes as reference molecules were established for linear alkanesulphonates and alk-2-enesulphonates. Some short-chain fluorinated sulphonic acids were also studied, especially pentafluorothio derivatives. C—F spin-spin coupling constants were determined. Pauling electronegativity values for SO3H and SF5 groups were derived from α chemical shift increments.
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 33 (1995), S. 523-528 
    ISSN: 0749-1581
    Keywords: NMR ; 13C NMR ; tetralins ; indans ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to perform the analysis of the components contained in fossil fuels, carbon assignments of new methylated derivatives of tetralin and indan were obtained. Their chemical shifts were calculated by applying additivity rules.
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 33 (1995), S. 557-560 
    ISSN: 0749-1581
    Keywords: NMR ; 14N NMR ; 11B NMR ; borazines ; coupling constants 1J(29Si14N),1J(14N11B) ; coupling signs ; 14N electric field gradient ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nuclear spin relaxation rate of the quadrupolar 14N nuclei in N,N′,N″-tris(trimethylsilyl)borazine (1) is surprisingly slow [T1(14N)=0.1 s]. This allows one to measure 1J(29Si14N) (9.6 Hz) directly from the 29Si NMR spectra and also to compare signs of coupling constants 1J(29Si14N) (〈0) and 3J(14NSiC1H) (〉0) by 2D 29Si/1H HETCOR experiments. Since the transverse relaxation time T2(14N) in 1 is governed by scalar relaxation of the second kind, the magnitude of 1J(14N11B) can be evaluated (23 ± 0.5 Hz). 11B, 14N and 29Si NMR data for N,N′-bis(trimethylsilyl)borazine (2) were also obtained, and 11B and 14N NMR spectra of the parent borazine [HBNH]3 (3), and of [HBNMe]3 (4) were remeasured. Calculation of the tensor components of the 14N electric field gradient shows that eqzz in 1 and in 2 for 14N(Si) is significantly smaller than for other borazines [HBNR]3, e.g. with R=H (3) or Me (4), in agreement with the experimental results.
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