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  • 1
    ISSN: 1434-1948
    Schlagwort(e): Aluminum ; Chalcogens ; Cubanes ; Gallium ; Main group elements ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1889-1897 
    ISSN: 1434-1948
    Schlagwort(e): Osmium ; Carbene complexes ; Hydrido complexes ; Diazoalkane complexes ; Vinyl complexes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 869-872 
    ISSN: 1434-1948
    Schlagwort(e): Adamantane ; Liquid ammonia ; Oxygen ; Sulfur and selenium ; Tin ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 2115-2121 
    ISSN: 0947-3440
    Schlagwort(e): Cyclophanes ; Macrocycles ; Phanes ; Pyridinophanes ; Ring compounds ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 339 (1997), S. 243-249 
    ISSN: 0941-1216
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Conformation and Rotation Barriers of Substituted Glyoxylic Acid AmidesSemiempirical calculations predict an orthogonal orientation of the carbonyl groups in tertiary glyoxylic acid amides, which is in good agreement with an X-ray structure analysis of 5. Due to the influence of the α-carbonyl group, the rotation barrier in the substituted glyoxylic acid amides 2a-d, 3a, 3b, and 4-6 (ΔG#c = 84-92 kJ mol-1) is about 10 kJ/mol higher than in simple acid amides, as was found by dynamic NMR line shape analysis.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 6
    ISSN: 0009-2940
    Schlagwort(e): Bulky substituents ; Aluminum compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis and Structure of CpAlCl2 Compounds with Sterically Demanding Substituents (Cp = Me5C5, EtMe4C5)[1]The compounds Cp*AlCl2 (3) (Cp* = Me5C5) and Cp′AlCl2 (4) (Cp′ = EtMe4C5) have been prepared by the reaction of Cp*SiMe3 (1) and Cp′SiMe3 (2) with AlCl3. The single-crystal X-ray structures of 3 and 4 are reported.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2255-2257 
    ISSN: 0009-2940
    Schlagwort(e): Gallane, chlorobis(supermesityl) ; Rearrangement ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis, Structure, and Rearrangement of Chlorobis(2,4,6-tri-tert-butylphenyl)gallaneThe title compound 1 is easily obtained from GaCl3 and 2 equvialents of supermesityllithium. According to an X-ray structure analysis one of the supermesityl rings shows a large deviation from planarity. Heating of 1 in vacuo gives mainly two products: an isomer of 1 in which one of the supermesityl groups is bound to Ga by one of its tert-butyl groups (2) and a benzo[b]gallolane (3) formed by elimination of HCl, X-ray structure analyses and full NMR (1H, 13C) data are provided for 1 and 2, MS and characteristic NMR (1H, 13C) data for 3.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 8
    ISSN: 0009-2940
    Schlagwort(e): Lanthanides, organo-, complexes ; Cyclooctatetraenyl complexes ; Benzamidinate ligands ; Diimidophosphinate ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 823-828 
    ISSN: 0009-2940
    Schlagwort(e): Aminosilanes ; Lithium compounds ; 1,3-Diaza-2,4-disilacyclobutanes ; 1-Aza-2,4-disilacyclobutane ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 10
    ISSN: 0009-2940
    Schlagwort(e): (Diisoalkylamino)boradiylbenzene derivatives ; Borolo[3,2-b]borole ; 2,8-Diborabicyclo[3.2.1]octa-3,6-diene ; Borylation of benzene derivatives ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Twofold Borylation of Benzene Derivatives with (Diisoalkylamino)boradiyl UnitsThe reaction of subvalent boron species generated by the defluorination of difluoro(diorganylamino)borane with Na/K alloy in the presence of 1,4-disubstituted benzene derivatives leads to products which contain two (diorganylamino)boradiyl units and two remaining double bonds which are located on the substituted C atoms. Compounds 5 to 8 exhibit structures based on a 2,8-diborabicyclo[3,2,1]octa-3,6-diene skeleton while 9 shows a skeleton with a 1,3a,4,6a-tetrahydroborolo[3,2-b]borole structure. The latter structure corresponds to that of 1 obtained in the same reaction with benzene. The compounds are characterized by elemental analyses and spectroscopically [MS, NMR (1H, 11B, 13C, 15N, 19F, 29Si)]. X-ray structure analyses are presented for 1, 6, 7, 8, and 9.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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