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  • 1
    Electronic Resource
    Electronic Resource
    Crystal Structures of Two Modifications of [3,O-didehydro-mebmt1, val2]-cyclosporin and comparison of three different X-ray data sets (1995)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 78 (1995), S. 355-366 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structure of [3,O-didehydro-MeBmt1, Val2]cyclosporin (PSC-833; 1) was investigated by X-ray analysis. Data were collected from two different crystal modifications. Modification I crystallizes in P3121, a = b = 21.419 (2) Å, c = 32.101 (3) Å with one molecule in the asymmetric unit, modification II in P3221, a = b = 21.313 (2) Å, c = 62.053(3) Å with two molecules per asymmetric unit. This non-immunosuppressive analogue of cyclosporin A adopts a similar backbone conformation to that found in the crystal structure of cyclosporin A and other analogues. Three different data sets of modification I were collected using an Enraf-Nonius-CAD4 diffractometer with CuKα radiation at 20°, a Stoe-Siemens four-circle diffractometer with MoKα radiation at - 120°, and an EMBL image-plate scanner with synchrotron radiation at 12°. The quality of the data sets was evaluated by internal consistency, independent structure solution, and refinement. The structural parameters reported here for modification I are based on the synchrotron data.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19950780208
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  • 2
    Electronic Resource
    Electronic Resource
    Metallorganische Verbindungen der Lanthanoide, 89. Cyclooctatetraenyl-Komplexe der frühen Übergangsmetalle und Lanthanoide, 6. (Cyclooctatetraenyl)[N,N′-bis(trimethylsilyl)benzamidinato]-und -[diphenylbis(trimethylsilylimido)phosphinato]-Komplexe der Seltenen Erden; Röntgenstrukturanalyse von (C8H8)Tm[PhC(NSiMe3)2](THF), (C8H8)Lu[4-MeOC6H4C(NSiMe3)2](THF) und (C8H8)Nd[Ph2P(NSiMe3)2](THF) (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 395-404 
    Details
    ISSN: 0009-2940
    Keywords: Lanthanides, organo-, complexes ; Cyclooctatetraenyl complexes ; Benzamidinate ligands ; Diimidophosphinate ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organometallic Compounds of the Lanthanoids, 89. - Cyclooctatetraenyl Complexes of the Early Transition Metals and Lanthanoids, 6. - (Cyclooctatetraenyl)[N,N′-bis(trimethylsilyl)benzamidinato]- and -[diphenylbis(trimethylsilylimido)-phosphinato] Complexes of the Rare Earths; X-Ray Structural Analyses of (C8H8)Tm[PhC(NSiMe3)2](THF), (C8H8)Lu[4-MeOC6H4C(NSiMe3)2](THF), and (C8H8)Nd[Ph2P(NSiMe3)2](THF)[(C8H8)Ln(μ-Cl)(THF)2]2 or [(C8H8)Ln(μ-O3SCF3)(THF)2]2 (Ln = Y, Ce, Pr, Nd, Sm, Tm, Lu) react with Na[4-RC6H4C(NSiMe3)2] (R = H, OMe, CF3) or Li[PhC(NSiMe3)2] to give the monomeric (cyclooctatetraenyl)lanthanide benzamidinates (C8H8)Ln[4-RC6H4C(NSiMe3)2](THF) [R = H, Ln = Y (1), Ce (4), Pr (6), Nd (8), Sm (10), Tm (12), Lu (15); R = OMe, Ln = Y (2), Ce (5), Pr (7), Nd (9), Sm (11), Tm (13), Lu (16); R = CF3, Ln = Y (3), Tm (14), Lu (17)]. The reaction of [(C8H8)Ln(μ-Cl)(THF)2]2 (Ln = Ce, Pr, Nd, Sm) with Li[Ph2P(NSiMe3)2] in THF leads directly to the monomeric compounds (C8H8)Ln[Ph2P(NSiMe3)2](THF) [Ln = Ce (18), Pr (19), Nd (20), Sm (21)] in good yields. The 1H-, 13C-, 31P- and 29Si-NMR and mass spectra of the new compounds as well as the molecular structures of 12, 16, and 20 are discussed. The Raman spectra of the complexes 1-3, 12, and 14-17 have been studied in detail.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19951280411
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  • 3
    Electronic Resource
    Electronic Resource
    (Di-tertbutylmethylsilyl)amide - a Building Block for Azasilacyclobutane Synthesis (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 823-828 
    Details
    ISSN: 0009-2940
    Keywords: Aminosilanes ; Lithium compounds ; 1,3-Diaza-2,4-disilacyclobutanes ; 1-Aza-2,4-disilacyclobutane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Di-tert-butylmethylsilylamide reacts with n-BuLi to give the tetrameric lithium di-tert-butylmethylsilylamide 1. Reactions of lithium (di-tert-butylmethylsilyl)amide 1 with SiF4 give the mono- (2), bis- (3), tris- (4), and tetrakis- (5) -[(di-tert-butylmethylsilyl)amino]silanes. Lithiated 3 reacts with Me3SiCl to form (di-tert-butylmethylsilyl-trimethylsilyl)amino-(di-tert-butylmethylsilyl)amino-difluorosilane (6); the 1,3-diaza-2,4-disilacyclobutane 7 is obtained by LiF elimination. The lithium derivative of 6 (compound 8) crystallizes with formation of a (SiFNLi) four-membered ring system. The 19F-NMR spectrum proves that the Li-F bond fluctuates in solution. Reactions of 1 with (Me3Si)2C(SiF3)2 afford different products (9, 10) by controlling the reaction sequence. An excess of 1 reacts to give a four-membered CSi2N ring system, the 1-(di-tert-butylmethylsilyl)-2,4-bis-[(di-tert-butylmethylsilyl)-amino]-2,4-difluoro-3-bis(trimethylsilyl)-1-aza-2,4-disila-cyclobutane (9), disubstitution with formation of bis[(di-tert-butylmethylsilyl)aminodifluorosilyl]bis(trimethylsilyl)methane (10) occurs in a molar ratio of 2:1. The cyclodisilazane 11 is obtained from dilithiated 10 in an intramolecular interconversion reaction. The crystal structures of 1, 8, 9, and 11 are reported.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290713
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  • 4
    Electronic Resource
    Electronic Resource
    1,3-Di-tert-butyl-2,2,4,4-tetrahalocyclodisilazanes - Synthesis, X-ray Crystal and Gas-Phase Structures (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 835-837 
    Details
    ISSN: 0009-2940
    Keywords: Cyclodisilazanes ; 1,3-Di-tert-butyl-2,2,4,4-tetrafluorocyclodisilazane ; 1,3-Di-tert-butyl-2,2,4,4-tetrachlorocyclodisilazane ; Structure elucidation ; Electron diffraction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The syntheses of 1,3-di-tert-butyl-2,2,4,4-tetrachlorocyclodisilazane (3) and of di-tert-butyl-2,2,4,4-tetrafluorocyclodisilazane (4) are reported. The X-ray crystal structure of 3 and the electron-diffraction gas-phase structure of 4 have been determined. Both cyclodisilazanes possess planar four-membered rings and nearly planar configurations at the nitrogen atoms. The Si-N bond lengths are 171.1(1) pm and 170.6(3) pm and the Si⃛Si transannular distances 245.0(1) and 241.3(13) pm in 3 and 4, respectively.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300704
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  • 5
    Electronic Resource
    Electronic Resource
    The Role of the 2,4,6-Tris(trifluoromethyl)phenylamino Group in Stabilizing New Phosphorus-, Arsenic-, and Germanium-Containing Main-Group Compounds and Transition-Metal Derivatives (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1113-1121 
    Details
    ISSN: 0009-2940
    Keywords: Phosphorus ; Arsenic ; Germanium ; Inorganic heterocycles ; Metal amides ; Fluorinated ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of potassium Rf-amide [Rf = tris(trifluoromethyl)phenyl](2) with PCl3, AsC13, and GeC12 · dioxane yield new four-membered inorganic heterocycles [RfNPCl]2 (3), [RfNAsC1]2 (4), and [RfNGe]2 (5), respectively. On the other hand, the reaction of Rf-amide 2 with two equivalents of RfPCl2 leads to the formation of the imino-γ3-phosphane RfN=PRf (6) and the diamino-γ3-phosphane (RfNH)2PRf (7). The iminophosphane 6 reacts with Ni(CO)2(PPh3)2 and forms the complex [Ni(PPh3)2(RfN=PRf)] (9), in which the imino- phosphane coordinates to the metal through the phosphorus lone pair. Treatment of lithium amide 2 with transition metal chlorides ZnCl2 and FeCl2 yields the imido/amido spirocyclic metal derivatives 9 and 10, respectively. Compounds 3-10 have been extensively characterized by their analytical and mass, IR, and NMR (1H, 19F, and 31P) spectroscopy. Further, the molecular structures of all the compounds have been unambiguously determined by single-crystal X-ray diffraction studies. The diazadigermetidine 5 crystallizes in a fluorescent-yellow orthorhombic and a yellow monoclinic crystal modification. The results obtained reveal the role of Rf, group in stabilizing new multiple bonded systems and inorganic heterocycles. A skeletal rearrangment of the Rf ligand is observed in the reactions leading to compounds 9 and 10. Moreover, the preparation of compounds 9 and 10 indicates the limitation of the use of this ligand in the preparation of new metal-amide systems, especially where the metal atoms have a strong tendency for the formation of strong M—F bonds.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300813
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  • 6
    Electronic Resource
    Electronic Resource
    Chalcogen Transfer to Bis[2-(dimethylaminomethyl)phenyl]silanediyl by Isocyanates and IsothiocyanatesDedicated to Prof. Dr. H. W. Roesky on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 125-130 
    Details
    ISSN: 0009-2940
    Keywords: Oxidation of silanediyls ; Silanone ; Oligomerization of silanones ; Silanethione ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of hexakis[2-(dimethylaminomethyl)phenyl]cyclo-trisilane (1) with isocyanates results in the clean formation of cyclic di- or trisiloxanes 3 and 4a and the corresponding isonitrile. Single-crystal X-ray analysis of tetrakis[2-(dimethylaminomethyl)phenyl]cyclodisiloxane (4a) reveals each silicon center to interact with two amino groups forming Si⃛N distances, which differ significantly in length. Phenyl isothio-cyanate reacts with 1 with transfer of sulfur to yield penta-coordinated bis[2-(dimethylaminomethyl)phenyl]silanethione (11).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290203
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  • 7
    Electronic Resource
    Electronic Resource
    Hydrido(carbene), Hydrido(diazoalkane), Aqua(carbene), and Vinyl(carbene) Complexes of Osmium(II) (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1889-1897 
    Details
    ISSN: 1434-1948
    Keywords: Osmium ; Carbene complexes ; Hydrido complexes ; Diazoalkane complexes ; Vinyl complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The five-coordinate compound [OsHCl(CO)(PiPr3)2] (1) reacts with CH2N2 and other diazoalkanes RCHN2 (R = Ph, CO2Et, SiMe3) in ether or toluene at 25 °C to give instead of the expected insertion products [Os(CH2R)Cl(CO)(PiPr3)2] the isomeric hydrido(carbene)osmium(II) complexes [OsHCl(=CHR)(CO)(PiPr3)2] (2-5) in excellent yields. With Me3SiCHN2 as the substrate, the 1:1 adduct [OsHCl(N2CHSiMe3)(CO)(PiPr3)2] (6) was detected at low temperature as an intermediate. The reactions of 1 with Ph2CN2 and Cl4C5N2 afford the hydrido(diazoalkane)compounds [OsHCl(N2CR2)(CO)(PiPr3)2] (7, 8), which are quite stable and do not eliminate N2 to give the corresponding hydrido(carbene)metal derivatives. Treatment of 3 (R = Ph) with either HCl or HBF4/H2O leads to the cleavage of the Os-H bond and results in the formation of [OsCl2(=CHPh)(CO)(PiPr3)2] (10) and [OsCl(=CHPh)(OH2)(CO)(PiPr3)2]BF4 (11), respectively. The vinyl compound [OsCl(CH=CHPh)(CO)(PiPr3)2] (12) behaves similarly to 1 and affords the carbene complex [OsCl(CH=CHPh)(=CHPh)(CO)(PiPr3)2] (13) upon treatment with PhCHN2. Compound 13 rearranges in solution at room temperature to give the π-allyl complex [Os(η3-PhCHCHCHPh)Cl(CO)(PiPr3)2] (14) as the dominating species. The crystal and molecular structures of 4, 5, 10, and 11 have been determined by X-ray crystallography.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Reactions of Dimethyl[tris(trimethylsilyl)methyl]metalanes of Aluminum and Gallium with H2S and Elemental Chalcogens - Crystal Structures of [RAl(μ-S)]2·2 THF, [RGa(μ3-S)]4, [{RAl(μ3-S)}3MeAl(μ3-S)], [RAlMe(μ-SeMe)]2, and [RGaMe(μ-TeMe)]2 [R = C(SiMe3)3] (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 2033-2039 
    Details
    ISSN: 1434-1948
    Keywords: Aluminum ; Chalcogens ; Cubanes ; Gallium ; Main group elements ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of the trialkylalane (Me3Si)3CAlMe2 × THF (1) with H2S in toluene at room temperature results in the formation of the dimeric sulfido compound [(Me3Si)3CAl(μ-S)]2 × 2 THF (3), while the reaction of the homologous gallane (Me3Si)3CGaMe2 (2) with H2S under similar conditions affords the heterocubane [(Me3Si)3CGa(μ3-S)]4 (4). Heating of compound 3 in vacuo gives a mixture of the symmetrically substituted [(Me3Si)3CAl(μ3-S)]4 (5) and the unsymmetrically substituted heterocubane [{(Me3Si)3CAl(μ3-S)}3MeAl(μ3-S)] (6). Reaction of the trialkylmetalanes 1 and 2 with elemental selenium in refluxing toluene results in the formation of the corresponding selenolates [(Me3Si)3CMMe(μ-SeMe)]2 (7, M = Al; 8, M = Ga). The compounds exhibit a high thermal stability and can not be converted to the corresponding selenides [(Me3Si)3CM(μ3-Se)]n (M = Al, Ga) upon heating. In contrast, the trialkylalane 1 does not react with tellurium metal in refluxing toluene at all, while the trialkylgallane 2 affords the tellurolate [(Me3Si)3CGaMe(μ-TeMe)]2 (9) under similar conditions. Compounds 3-9 have been characterized by 1H- and 29Si-NMR, mass, and IR spectroscopy. Furthermore, the molecular structures of compounds 3· C6H6, 4· 1.5 C6H6, 6, 7· C6H6 and 9 have been determined by X-ray crystallography.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis of (RSn)4X6 Adamantanes (X = O, S, Se) in Liquid Ammonia and in the Two-Phase System Liquid Ammonia/THF (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 869-872 
    Details
    ISSN: 1434-1948
    Keywords: Adamantane ; Liquid ammonia ; Oxygen ; Sulfur and selenium ; Tin ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of trisSnBr3 (1) [tris = (Me3Si)3C] and nBuSnCl3 with Na2X (X = O, S, Se) yield the heterocyclic adamantanes 2-6. The reaction of 1 with Na2O is carried out in liquid ammonia under normal pressure at -78 °C to give (trisSn)4O6 (2). However, the reaction of 1 with Na2S and Na2Se under pressure at room temperature results in the formation of (trisSn)4S6 (3) and (trisSn)4Se6 (4). nBuSnCl3 reacts with Na2S and Na2Se in liquid ammonia at -33 °C under normal pressure to give (nBuSn)4S6 (5) and (nBuSn)4Se6 (6), respectively.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Molecular Ribbons Containing Pyridine Rings (1996)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 2115-2121 
    Details
    ISSN: 0947-3440
    Keywords: Cyclophanes ; Macrocycles ; Phanes ; Pyridinophanes ; Ring compounds ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first synthesis of the ribbon-like compounds 6-10 is described. The new building block diethyl 2,6-bis(bromomethyl)pyridine-3,5-dicarboxylate 1 was prepared and characterized. Single-crystal X-ray structure analyses indicate that these ribbon-like molecules arrange in a folded conformation, with the pyridine and benzene units being folded in a face-to-face manner, and the tosyl units of 8-10 pointing outwards. The “intramolecular self-assembly” (folding) of these molecular ribbons is primarily attributable to the energetically more favourable syn conformation of both the [3.3]metacyclophanes and the pyridinophanes.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199619961225
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