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  • Articles: DFG German National Licenses  (8)
  • 1995-1999  (8)
  • NMR spectroscopy  (6)
  • Aluminum  (2)
Source
  • Articles: DFG German National Licenses  (8)
Material
Years
  • 1995-1999  (8)
Year
  • 1
    ISSN: 0009-2940
    Keywords: Bis(tetramethylipiperidino)aluminum halides ; Alkoxy((tetramethylpiperidino)aluminum halides ; 27Al-NMR spectra ; Aluminum ; Amides ; Synthetic methods ; Bridging ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-Lithio-2,2,6,6-tetramethylpiperidine [Li(tmp)] reacts with AlX3 (X = Cl, Br) in diethyl ether/ n-hexane solution to generate the products of substitution and ether cleavage, [tmpAl(X)(μ-OEt)], (la, X = Cl; 1b, X = Br). However, when the reaction is allowed to proceed in n-hexane alone, an almost quantitative yield of compounds tmp2AlX (2a, X = Cl; 2b, X = Br; 2c, X = I) is obtained. According to 27AI-NMR spectroscopy, mass spectroscopy, cryoscopy, and X-ray crystal structure determinations, these compounds are monomeric in the solid state, in solution, and in the gas phase. 2b reacts with AgBF4 yielding the fluoride-bridged dimer (tmp2AlF), 2d, as shown by X-ray crystal structure determination.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1801-1805 
    ISSN: 0009-2940
    Keywords: Phosphene ; cyclophosphane isomerism ; Phosphorus Ylides ; NMR spectroscopy ; Structure elucidation ; Transanular interaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of two specific ylidyl dichlorophosphanes, Ph3P=CR-PCl2, with P(SiMe3)3 yields the ylidyl trimethylsilyl diphosphenes Ph3P=CR.P=P-SiMe3 as primary products which form two different types of dimers: the cyclotetraphosphane 9 (R = SiMe3), and the tetraphosphene 10 (R = 2,6-Cl, 2,/C6H3). The latter compound is readily converted to the bis(ylidyl)biocyclotetraphosphane 11. The molecular structures of 9 and 11 allow a strong transanular interaction between teh ylide-substituted phosphorus atoms, which results in very large two-bond coupling constants (2Jpp = 184 and 332 Hz respectively). The central P bond in 11 is relatively long (220.7 pm); quantum chemical calculations show the lengthening to be a consequence of the perpendicular orientation of the ylidic donor p-orbital.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-1948
    Keywords: Cyclopentadienes ; Magnesium ; Metalations ; NMR spectroscopy ; Sandwich complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of n/sec-dibutyl magnesium with 6-methyl-6-phenyl- and 6,6-dicyclopropylfulvene gives the β-hydride transfer products 1,1′-bis(1-phenylethyl)- and 1,1′-bis-(dicyclopropylmethyl)magnesocene, respectively. The latter crystallizes in the eclipsed conformation, whereas the first one shows an anti conformation in the solid state. Dimethyl-magnesium deprotonates 6-methyl-6-phenylfulvene with formation of 1,1′-bis(1-phenylethen-1-yl)magnesocene, which decomposes upon isolation. The deprotonation of 6,6-dicyclopropylfulvene with MgMe2 in thf solution yields [bis(tetrahydrofuran-O)][iro{cyclopropane-1,2′(1′-η5-cyclopentadienyl-1′,3′,3′-tricyclopropyl-1′,2′,3′,3a′-tetrahydropentalene)}-3a′-6′-η2-enyl]magnesium. In the absence of β-hydrogen atoms at the organometallic reagent as well as at the fulvene the addition reaction is the only possible reaction pathway. Thus, one Mg-C bond of MgMe2 adds to tetramethylfulvene to give quantitatively dimeric methylmagnesium ethyltetramethylcyclopentadienide. The bridging methyl groups are sterically shielded against further attack of the fulvene.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1291-1293 
    ISSN: 1434-1948
    Keywords: Aluminum ; Lead ; O ligands ; Alkoxy carboxylates ; Structure elucidation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel heterometallic aggregate Pb2Al5(μ3-O)(μ4-O)(μ-OiPr)9(OiPr)3(μ-OAc)3 obtained from the interaction of Pb(OAc)2 and Al(O-iPr)3 is the first structurally characterized example based on lead and aluminum. This compound has been isolated in high yield and examined by 1H-, 13C-, and 27Al NMR, and in the solid state by X-ray crystallography.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-1948
    Keywords: Arsenic ; Barium ; Calcium ; Metalations ; NMR spectroscopy ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metalation of triisopropylsilylphosphane with bis(tetrahydrofuran-O)calcium bis[bis(trimethylsilyl)amide] in tetrahydropyran (thp) in a molar ratio of 3:2 yields (Me3Si)2NCa[μ-P(H)SiiPr3]3Ca(thp)3 (1) containing a trigonal-bipyramidal Ca2P3 core, the metal atoms occupying apical positions. Reaction of two equivalents of triisopropylsilylphosphane or -arsane with bis(tetrahydrofuran-O)barium bis[bis(trimethylsilyl)amide] in tetrahydrofuran gives the corresponding bis(phosphanide) 2 and bis(arsanide) 3, compounds of the type (thf)3Ba[μ-E(H)SiiPr3]Ba(thf)2E(H)SiiPr3 with E = P, As. The equimolar reaction of (tri-tert-butylsilyl)phosphane with (thf)2Ba[N(SiMe3)2]2 in toluene yields heteroleptic dimeric (thf)2Ba[N(SiMe3)2][P(H)SitBu3] (4). Addition of a further equivalent of H2PSitBu3 leads to the formation of homoleptic (thf)nBa[P(H)SitBu3]2 (5). Dissolution of the latter in aromatic hydrocarbons leads to the elimination of H2PSitBu3, yielding dimeric (thf)Ba3(PSitBu3)2[P(H)SitBu3]2 (6). The inner core of 6 consists of the tetramer (BaPSitBu3)4 based on a Ba4P4 heterocubane unit, two opposite faces being capped with (thf)Ba[P(H)SitBu3]2 molecules.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1434-1948
    Keywords: Bis(silyl)phosphanes ; Magnesium ; NMR spectroscopy ; Oligomers ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metathesis reaction of (dme)LiPH2 and chlorodiisopropylsilane yields HP(SiHiPr2)2 (1) and P(SiHiPr2)3 (2). The metalation of 1 by n/sec-dibutylmagnesium in heptane leads to the formation of dimeric magnesium bis[bis(diisopropylsilyl)phosphanide] [(3)2]. A toluene solution of magnesium bis[bis(trimethylsilyl)phosphanide] (4) shows a dimer-trimer equilibrium in the 31P{1H}-NMR spectrum at -40°C with an increasing amount of the dimer with increasing temperature. A molecular mass determination by freezing-point depression in benzene yields a value of 516 g·mol-1, which lies between a monomeric and a dimeric molecule. Cooling of the toluene solution to -30°C leads to the precipitation of single crystals of monoclinic {(Me3Si)2P-Mg[μ-P(SiMe3)2]2}2Mg [(4)3].
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 1519-1527 
    ISSN: 1434-1948
    Keywords: B,B′-Dimesityldiborane(4) dihalides ; B,B′-Diamino-B,B′-dimesityldiboranes(4) ; B,B′-Di-tert-butyloxy-B,B′-dimesityldiborane(4) ; B,B′-Dimesityl-B,B′-di(organylthio)diborane(4) ; NMR spectroscopy ; X-ray structures ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An efficient route to B,B′-dihalo-B,B′-dimesityldiboranes(4) is reported, as well as the conversion of these and of B,B′-dimesityl-B,B′-dimethoxydiborane(4) into other B,B′-dimesityldiboranes B2mes2X2 (X = OR, SR, NR2, NHR). The substituents X influence the shielding of the 11B nucleus in the expected manner. Hindered rotation about the B-N bond is observed for X = pyrrolyl, while in solution there is free rotation about the B-C bond. However, X-ray structural results reveal that the mesityl group is almost orthogonal to the B(B)CY plane in the solid state. The shortest B-B bond is observed in mes2B2I2, indicating that the iodide is the strongest Lewis acid in the reported series of mes2B2Y2 compounds. This is also reflected in short B-C bonds. Moreover, the two mes(Y)B units also approach orthogonality in these diborane(4) compounds, and thus enforce this as a typical structural feature of diborane(4) derivatives. For this reason, the planar C(N)B-B(N)C unit of B,B′-di(benzylamino)-B,B′-dimesityldiborane(4) is regarded as exceptional for aminodiboranes(4).
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0570-0833
    Keywords: heterocycles ; NMR spectroscopy ; phosphorus compounds ; ylides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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