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  • Hydrazides  (3)
  • Palladium  (3)
  • Ab initio calculations  (2)
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  • 1
    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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  • 2
    Electronic Resource
    Electronic Resource
    Bis(tetramethylpiperidino)aluminum Halide Adducts tmp2AlX · Do and Tetrahaloaluminates of Tricoordinated Aluminum Cations [tmp2Al(Do)]AlX4 (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 927-939 
    Details
    ISSN: 1434-1948
    Keywords: Bis(tetramethylpiperidino)aluminum halide complexes ; Tricoordinated aluminum cations ; 27Al-NMR spectroscopy ; X-ray crystal structure analysis ; Ab initio calculations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Upon treatment with Lewis bases Do (Do = pyridine bases or THF), the Lewis acids tmp2AlX (X = Cl, Br, I) are converted exclusively to the monoadducts tmp2AlX · Do (2-4). The Al-X bonds of these addition compounds are considerably elongated, indicating a tendency towards the formation of ionic species [tmp2Al(Do)]X. Due to the steric requirements of the bulky tmp ligands, addition of an excess of the Lewis base does not force these compounds to form tetracoordinated aluminum cations [tmp2Al(Do)2]+ or pentacoordinated adducts tmp2AlX · Do2. Attempts to prepare ionic representatives by reaction of tmp2AlX · Do with “ate” complexes of comparatively low nucleophilicity [MY = NaBPh4, AgBPh4, LiB(C6F5)4, AgBF4, AgOtos] result in phenylation products [e.g. tmp2AlPh (5a) and BPh3 · py (5b)] or tetracoordinated addition compounds tmp2AlY · Do (Y = anion). However, addition of one equivalent of AlX3 (X = Br, I) initiates halide abstraction with formation of the ionic [tmp2Al(Do)]AlX4 species 6a-f, as indicated by 27Al-NMR data and conductivity measurements. Solid [tmp2Al(py)]AlI4 (6b) decomposes readily into tmpAII2 and tmpAlI2 · py (7c). Addition of non-polar aliphatic solvents to solutions of [tmp2Al(Do)]AlX4 (6) leads to slow decomposition into tmp2AlX and AlX3 · Do (7a-b, d). This also occurs in polar donor solvents, where compounds AlX3 · Do are favoured due to the formation of penta- or hexacoordinated species AlX3 · Do · Solvn (n = 1, 2). Semiempirical AM1 calculations reveal the gas-phase stability of the tricoordinated bis(tmp)aluminum cation in the salt [tmp2AlPy]AlCl4 as the only representative in a series of calculated aluminum cations [(R2N)2AlPy]AlCl4 (R2N = Me2N, Et2N, iPr2N, tmp). According to these calculations, the stability of a given cation increases when tetrachloroaluminate is replaced by tetraiodoaluminate. Ab initio calculations have been performed on two cations [(H2N)2Al(Do)]+ (Do = NH3, py) and indicate very short Al-N bond lengths owing to ionic bonding contributions.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxidative Addition of α-Bromoglycine to Palladium(0) and Platinum(0) Complexes: α-Metallated Amino Acids as Models for Intermediates in the Metal-Catalyzed Hydrogenation of Dehydroamino Acids (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 375-379 
    Details
    ISSN: 1434-1948
    Keywords: α-Metallated amino acids ; Palladium ; Platinum ; Oxidative addition ; α-Bromoglycinate ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidative addition of methyl N-benzoyl-2-bromoglycinate to bis(dibenzylideneacetone)palladium, in the presence of 2,2′-bipyridyl, and to (Ph3P)2Pt(η2-C2H4) gives the α-metallated glycine esters 1a and 2a. Abstraction of bromide from 1a, 2a, using AgSbF6 or AgBF4, affords the cationic C,O-chelate complexes [(bpy)Pd-CH(CO2Me)NHC(Ph)O]+ (1b,c) and [(Ph3P)2Pt-CH(CO2Me)NHC(Ph)O]+ (2b), respectively, featuring coordination of the amide O atom. The complexes 1b and 2b have been characterized by X-ray diffraction.
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  • 4
    Electronic Resource
    Electronic Resource
    The Molecular Structure of Some Transition-Metal Complexes with 1,2,3,4-Tetrazole-5-thiolate Anions (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 93-99 
    Details
    ISSN: 1434-1948
    Keywords: 2-Methyl-1,2,3,4-tetrazole-5-thiolates ; 2-Phenyl-1,2,3,4-tetrazole-5-thiolates ; Palladium ; Platinum ; Copper ; Silver ; Gold ; Molecular structures ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular structures of nine transition metal tetrazolethiolates have been determined by X-ray structure determinations. The ligand is invariably coordinated through its sulfur atom to the metal center [M = PdII, CuI, AgI, AuI, AuIII, and Hg]. The M-S-C bond angles vary considerably, but this cannot be correlated with variations in the C-S bond lengths. Intermolecular association occurs for Ph3PAu(SCN4Me) via Au-S contacts, leading to dimeric strands in the solid state. The copper compound (Ph3P)3Cu4(SCN4Me)4 (5), possesses a rather asymmetric structure: one Cu atom is tricoordinated by 3 sulfur atoms, the other three are tetracoordinated by P and N as well as by S atoms.
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  • 5
    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.
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  • 6
    Electronic Resource
    Electronic Resource
    Characterization of Palladium(II) Azide and Crystal Structure of Bis(azido)bis(pyridine)palladium(II) and Tetramminepalladium Tetraazidopalladate(II) (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 523-526 
    Details
    ISSN: 1434-1948
    Keywords: Palladium ; Azide ; Pyridine ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Palladium(II) azide (1) was synthesized by reaction of palladium nitrate and sodium azide. 1 was characterized by AAS, IR, and 14N-NMR spectroscopy. Bis(azido)bis(pyridine)palladium(II) (2) and tetramminepalladium tetraazidopalladate(II) (3) were synthesized by a high-yield reaction. Both were characterized by X-ray structural analysis, IR, Raman, and NMR spectroscopy.
    Additional Material: 4 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    (N-lithioamino)diorganophosphanes and Bis(N-Lithioamino)organophosphanes: Synthesis and Structures (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 2355-2368 
    Details
    ISSN: 1434-1948
    Keywords: Phosphane complexes ; Lithium ; Aminophosphanes ; Hydrazides ; (N-lithioamino)diorganophosphanes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Butyllithium (nBuLi) deprotonates Ph2P-NHtBu in ether to give (Ph2P-NLitBu)2·OEt2. There is no Li···P interaction in this molecule. Three compounds of the type R′P(NLiR)2 have been obtained by lithiation of R′P(NHR)2, isolated as [BuP(NLitBu)2·OEt2]2, [PhP(NLiPh)2·OEt2]2 and [PhP(NLiPh)2]2. Reaction of nBuLi with MeP(NHiPr)2 in hexane/THF leads to [MeP{N(Li)iPr]2·THF}4 with an asymmetric cluster structure comprising one LiP3, three LiPN2, three LiP2N and one LiN3 cluster units. The molecular structures of these compounds as determined by X-ray structure analysis show that they are best depicted as N-lithioaminophosphanes and not as the isomeric P-lithioiminophosphoranes.
    Additional Material: 13 Ill.
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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.
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