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  • 1995-1999  (12)
  • Structure elucidation  (7)
  • NMR spectroscopy  (6)
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Material
Years
  • 1995-1999  (12)
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Synthesis and Characterization of the Heterometallic Aggregate Pb2Al5(μ3-O)(μ4-O)(μ-OiPr)9(OiPr)3(μ-OAc)3 (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1291-1293 
    Details
    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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  • 2
    Electronic Resource
    Electronic Resource
    Oligomeric Solvent-Free Magnesium Bis(phosphanides) - Molecular Structure of Trimeric Magnesium Bis[bis(trimethylsilyl)phosphanide] (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 517-521 
    Details
    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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  • 3
    Electronic Resource
    Electronic Resource
    A Boron-Boron Double Bond in the Dianions of Tetra(amino)diborates (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1931-1937 
    Details
    ISSN: 1434-1948
    Keywords: Diboron compounds ; B-B double bond ; Dilithium tetra(amino)diborates(2-) ; Structure elucidation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of mixed tetraaminodiborane(4) compounds bearing pyrrolyl, indolyl, and carbazolyl substituents besides dimethylamino groups has been prepared and subjected to reduction with elemental Li in the presence of diethyl ether. Tetraaminodiborates(2-) are formed, which feature a boron-boron double bond. The diborate anion acts as a double bidentate ligand coordinating pairwise through two of its nitrogen atoms to an Li center, which is tricoordinated by one O and the two N atoms. The new diborates are isoelectronic with tetraaminoethylenes and are expected to be electron-transfer reagents.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and Homomolecular Metalation of Trialkylsilylphosphanides of Calcium and Barium (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 743-750 
    Details
    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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  • 5
    Electronic Resource
    Electronic Resource
    Substituted Cyclopentadienides of Magnesium from the Reaction of Dialkylmagnesium with Fulvenes (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 965-971 
    Details
    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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  • 6
    Electronic Resource
    Electronic Resource
    The Aluminum-Nitrogen Bond in Monomeric Bis(amino)alanes: A Systematic Experimental Study of Bis(tetramethylpiperidino)alanes and Quantum Mechanical Calculations on the Model System (H2N)2AlY (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 1095-1114 
    Details
    ISSN: 1434-1948
    Keywords: Aminoalanes ; Alanes ; Ab initio calculations ; 27Al-NMR spectroscopy ; Structure elucidation ; Substituent effects ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of metallated nucleophiles MIY [Y = OR, SR, NR2, PR2, AsR2, CR3, Si(SiMe3)3, R = organyl, H] with bis(2,2,6,6-tetramethylpiperidino)aluminum halides [tmp2AlX, (X = Cl, Br, I)] offer facile access to a variety of bis(amino)alanes of the type tmp2AlY. As indicated by 27Al-NMR spectroscopy, mass spectrometry and X-ray crystal structure determina-tions, all of these compounds are monomeric in the solid state, in solution, and in the gas phase. Even Al-E single bonds (E = Si, P, As etc.) that are not commonly encountered are stabilized by the supporting tmp fragments. The results of a systematic analysis of the bonding parameters determined for the tmp2AlY compounds, combined with a quantum mechanical study on model compounds (H2N)2AlY, not only reveal the presence of a highly polar Al-N bond, but at the same time rule out AlN-pp(π) bonding, in contrast to the situation in the analogous tmp2BY compounds. It is shown that the Al-N bond length depends on the acidic character of the protic species HY: the shorter d(Al-N), the less basic is Y.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis and Structures of Dimesityldiboranes(4) (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 1519-1527 
    Details
    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
    Electronic Resource
    Electronic Resource
    Synthesis and Structures of Hydrazinoalanes and Hydrido(hydrazino)aluminates⋆ (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 1931-1938 
    Details
    ISSN: 1434-1948
    Keywords: Aluminium ; Lithium hydridoaluminates ; Alanes ; Hydrazides ; Structure elucidation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several monomeric dimethylaluminium hydrazide ether adducts Et2O/THF × Me2AlNR-NR′R′′ (5-7) were obtained by deprotonating the respective hydrazines with nBuLi, followed by reaction with Me2AlCl. The hydrazines Ph(H)N-N(SiMe3)2 and tBu(H)N-N(H)SiMe3 react with LiAlH4 in the presence of either ether or THF with the formation of dimeric lithium hydrazino(hydrido)aluminates, e.g. 8 and 9. Their structures depend on the number of acidic hydrogen atoms bonded to the nitrogen atoms of the starting hydrazine. The hydrazine Ph(H)N-N(SiMe3)2 (1) reacts with LiAlH4 to form monometallated LiAlH3[(Ph)N-N(SiMe3)2] × 2 Et2O (8) with elimination of one equivalent of H2. The molecule is dimeric and features an (AlHLiH)2 eight-membered ring. In contrast, the reaction of tBu(H)N-N(H)SiMe3 with LiAlH4 in the presence of THF leads to the formation of dimeric 2 THF × LiAlH2[(tBu)N-N(SiMe3)] (9) with a central (AlNN)2 six-membered ring. A dimeric aluminium hydrazide 10 was obtained by allowing tBu(Li)N-N(H)SiMe3 to react with Me2AlCl in a hexane/toluene solution. The structure of 10 features a six-membered Al2N4 ring in chair conformation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis of Boron-Halogenated Diborylamines and Diborylhydrazines by Cleavage of Stannazanes (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1765-1779 
    Details
    ISSN: 1434-1948
    Keywords: Diborylamines ; Diborylhydrazines ; Bis(organohaloboryl)amines ; Bis(organohaloboryl)hydrazines ; Structure elucidation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The diborylamines R′-N(BRX)2 (3; × = Cl, Br) are obtained by stannazane cleavage of distannylorganylamines R′-N(SnMe3)2 (4) with alkyldihaloboranes RBX2 in a 1:2 molar ratio. The presence of the sterically demanding substituents R and R′ also causes carbon-tin bond cleavage, resulting in low yields of 3. However, carbon-tin bond cleavage can be suppressed by the use of bis(dimethylchlorostannyl)organylamines 5 as the nitrogen source for the synthesis of diborylamines. This results in almost quantitative yields of the compounds 3. Treatment of the distannylhydrazines R2N-N(SnMe3)2 (7) with RBX2 in a 1:2 molar ratio leads to the formation of N,N-bis(alkylhaloboryl)hydrazines 8 under mild conditions and in good yield. The molecular structures of 3 and 8 were determined by multinuclear magnetic resonance spectra in solution as well as by X-ray structure analysis in the case of 8d. A typical structural feature of 8d is the intramolecular BN adduct formation. Support for the constitutions of compounds 8c comes from MS fragmentation patterns as well as from IR spectra.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesis and Structures of Sodium Phenylhydrazides (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1053-1062 
    Details
    ISSN: 0009-2940
    Keywords: Lithium ; Hydrazides ; Solvates ; Clusters ; Sodium ; Structure elucidation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomeric Li(Ph)N—N(Ph)SiMe3 · 2 OEt2 was obtained by deprotonating the respective hydrazine with nBuLi in the presence of diethyl ether. Reaction of NaN(SiMe3)2 with PhHN-N(SiMe3)2 in a benzene/tetrahydrofuran mixture provided monomeric Na(Ph)N—N(SiMe · 3 THF, or Nd(Ph)N—N(SiMe3)2 · THF using a small amount of THE Its TI IF ran be replaced by diethyl ether or tert-butyl methyl ether to give 1:l solvates. These associate, forming chains in the solid state via ηn coordination (n = 2, 3) of their phenyl groups to the sodium centers of adjacent molecules. In contrast, not only deprotonation but also desilylation occurs on reaction of NaN(SiMe3)2 with H(Ph)N—N(Ph)SiMe3 or of NaNH2 with (Me3Si)HN—NPh2) The latter reaction results in the formation ot hexameric (NaHN—NPh2)6 which adopts a face-sharing double-cubane structure.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300806
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