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  • 1
    Electronic Resource
    Electronic Resource
    Transition-Metal Complexes of the Optically Active Cyclopentadienyl Ligand PinCp*: Crystal Structure of (SRe)-(η5-PinCp*)Re(NO)(PPh3)[CONHCH(CH3)C10H7] (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1497-1505 
    Details
    ISSN: 1434-1948
    Keywords: Half-sandwich complexes ; Molybdenum ; Optically active complexes ; Rhenium ; Tungsten ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of (η5-PinCp*)Re(CO)3 [PinCp* = tetramethyl(pinanyl)cyclopentadienyl] is described. Successive substitution of two CO ligands by NO+ and PPh3 generates a 1:1 diastereomeric mixture of chiral-at-metal [(SRe)/(RRe)-(PinCp*)Re(CO)(NO)(PPh3)]BF4. The diastereomers are converted with sodium methoxide into the derivative “esters” (SRe)/(RRe)-(PinCp*)Re(COOCH3)(NO)(PPh3), and then with (+)-(R)-(1-naphthylethyl)amine to the “amides” (SRe)/(RRe)-(PinCp*)Re(NO)(PPh3)[CONHCH(CH3)C10H7] [(SRe)/(RRe) = 1:1]. Fractional crystallisation separates the (SRe) isomer with an optical purity of 〉 98%. The latter compound has been characterized by X-ray structure analysis. By treating the (SRe)-amide with CF3CO2H and NaBF4, (SRe)-(PinCp*)Re(CH3)(NO)(PPh3) can be generated. Protolysis of this compound with HBF4/Et2O in CD2Cl2 at -78 °C leads to the solvent-stabilized complex (SRe)-[(PinCp*)Re(NO)(PPh3)(ClCD2Cl)]+BF4-. The thermal and configurational stability of this chiral Lewis acid is investigated at various temperatures. The syntheses of [PinCp*RhCl2]2, PinCp*TiCl3 and PinCp*M(CO)2(NO) (M = Mo, W) are also described. Starting with PinCp*M(CO)2(NO), the relatively stable 16-VE complexes PinCp*MCl2(NO) and PinCp*W(CH2SiMe3)2(NO) are synthesized.
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and Structure of Trinuclear Boryloxycarbyne Complexes (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 2277-2281 
    Details
    ISSN: 1434-1948
    Keywords: Boron ; Iron ; Nickel ; Carbyne complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The μ3-boryloxycarbyne complexes [{Fe(CO)3}3{μ3-COBCl{NtBu(SiMe3)}}2] (1) and [{(η5-C5H5)Ni}3{μ3-COBX(NR2)}μ3-CO] (2a: NR2 = NtBu(SiMe3), × = Cl; 2b: NR2 = N(SiMe3)2, × = Cl; 2c: NR2 = NMe2, × = BNMe2Cl) were obtained by reaction of the anionic complexes K2[{Fe(CO)3}3{μ3-CO}2] and K[{(η5-C5H5)Ni(CO)] with the corresponding chloroboranes Cl2BNR2 {NR2 = NtBu(SiMe3), N(SiMe3)2}, or 1,2-dichlorodiboranes(4) B2(NMe2)2Cl2, respectively. The products are formed by a nucleophilic attack of the CO oxygen atom at the boron centres with subsequent salt elimination. All compounds were characterized by IR and multinuclear NMR spectroscopy, and the structures of 1 and 2c in the solid state were determined by single-crystal X-ray diffraction studies.
    Additional Material: 2 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Stanna-closo-dodecaborate: A Nucleophile in Transition Metal Chemistry (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1563-1566 
    Details
    ISSN: 1434-1948
    Keywords: Stannaborate cluster ; Transition metal complexes ; Tin ; Coordination modes ; Clusters ; Boron ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of the stannaborate salt [NBu4]2[SnB11H11] (1) with the organometallic electrophiles [CpFe(CO)2Br], [(C7H7)Mo(CO)2I], and [CpNi(PPh3)Cl] resulted in substitution of the halide to give the stannaborate coordination products [NBu4][CpFe(CO)2(SnB11H11)] (2), [NBu4][(C7H7)Mo(CO)2(SnB11H11)] (3), and [NBu4][CpNi(PPh3)(SnB11H11)] (4) in high yields. Single crystals of the air- and moisture-stable products have been characterized by X-ray crystal structure analyses.
    Additional Material: 3 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Boryl- and Bridging Boryleneiron Complexes from Aminodichloroboranes (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 465-468 
    Details
    ISSN: 1434-1948
    Keywords: Boron ; Iron ; Boryl complexes ; Borylene complexes ; Iron-boron bond ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Depending on the nature of the amino group bound to the boron atom, the reactions of various aminodichloroboranes R2NBCl2 with Na[(η5-C5R′5)Fe(CO)2] yield either boryl or bridging borylene complexes of iron. The compounds [(C5R′5)(CO)2Fe{BCl(NR2)}] (1a, C5R′5 = C5H5, R = Me; 1b, C5R′5 = C5H4Me, R = Me; 1c, C5R′5 = C5Me5, R = Me) and [(η-BNR2)(μ-CO){(C5R′5)Fe(CO)}2] (2a, C5R′5 = C5H5, R = SiMe3; 2b, C5R′5 = C5H4Me, R = SiMe3) were isolated as orange (1a-c) or red (2a, b) crystalline solids, and characterized by multinuclear NMR methods and IR spectroscopy. The structures of 1c and 2b in the crystalline state were determined by single-crystal X-ray studies.
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis and Structure of [1]Borametallocenophanes of Titanium, Zirconium, and Hafnium (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1899-1904 
    Details
    ISSN: 1434-1948
    Keywords: Boron ; Titanium ; Zirconium ; Hafnium ; Metallocenophanes ; Metallocenophanes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Various [1]borametallocenophane complexes of all the group IV metals were obtained in high yield by a very efficient multistep, one-pot synthesis. By this method not only the biscyclopentadienyl and diindenyl complexes [{R2NB(η5-C5H4)2}MCl2] (M = Zr, R = Me, SiMe3, 4a, b; M = Hf, R = SiMe3, 5) and [{(Me3Si2)NB(η5-C9H6)2}MCl2] (M = Ti, 6; M = Zr, 7) were obtained, but also complexes with two different η5-coordinated ligands such as [{iPr2NB(η5-C5H4)(η5-C9H6)}MCl2] (M = Zr, 8; M = Hf, 9). Some of compounds 4-9 were chosen to investigate their catalytic properties with respect to Ziegler-Natta-type polymerisation of olefins, and proved to be highly efficient for the preparation of polyethylene.
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  • 6
    Electronic Resource
    Electronic Resource
    Adducts of o-Silaborane With Water and Methanol (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 735-739 
    Details
    ISSN: 1434-1948
    Keywords: Silaboranes ; Cluster compounds ; Siloxanes ; Silicon ; Boranes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of alkoxide adducts of o-silaborane [(TMPDAH)2][(Me2Si2B10H10)2O] (3) and [TMPDAH][(Me2Si2B10H10)OMe] (4) are presented (TMPDA = tetramethylpropylenediamine). For both silaborate clusters 3 and 4 the results of the NMR spectroscopic investigations together with the X-ray single crystal structure determinations are discussed. The geometries of ab initio calculations (HF and B3LYP methods) on the hydroxide adduct [Si2B10H12(OH)]- are compared with the structures of 3 and 4. The dynamic behaviour of the adducts 3 and 4 in solution is discussed with respect to the calculated energy profile for the rotation of the HSi(OH) group.
    Additional Material: 5 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Enantiomerically Pure Complexes of Manganese, Iron, and Zirconium with Pinene-Fused Boratabenzene Ligands - Structures ofexo-FeCp*(C13H17BNMe2) and exo,exo-ZrCl2(C13H17BNMe2)2 (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 979-986 
    Details
    ISSN: 1434-1948
    Keywords: Boron ; Transition metals ; Sandwich complexes ; Boratabenzene ; Pinene ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexes of pinene-fused boratabenzene ligands [(1R,9R)6,10,10-trimethyl-4-boratatricyclo[7.1.1.02,7]undeca-2,4,6trienes] C13H17BX (with a: X = NMe2; b: X = OMe; c: X = Me) are described. The lithium salt Li(C13H17BNMe2) [Li(1a)] reacts with [Cp*Fe(NCMe)3]PF6 and with Mn(CO)3Br(py)2 to give diastereomeric mixtures FeCp*(C13H17BNMe2) (4a) and Mn(CO)3(C13H17BNMe2) (7). The mixture 4a undergoes solvolysis in methanol to produce methoxy compounds 4b, which in turn react with LiMe in Et2O to give methyl derivatives 4c. The lithium salts Li(C13H17BX) [Li(1a-c)] react with ZrCl4 in toluene or Et2O to give exo,exo-ZrCl2(C13H17BX)2 complexes (8a-c). The dimethyl derivative exo,exo-ZrMe2(C13H17BNMe2)2 (9) can also be prepared from 8a/LiMe in Et2O. NOE difference spectra have been analyzed to determine the configurations of the diastereomers and to establish a chemical shift criterion for assessing the configuration of the metal-ligand coordination. An independent confirmation of the product stereochemistries has been obtained by single-crystal X-ray structure determinations of exo-4a and 8a.
    Additional Material: 3 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Nucleophilic Addition of Secondary Phosphines to Cationic Dienyl Tricarbonyliron Complexes: A novel Route to Optically Active PhosphinesOptically Active Transition Metal Complexes, Part 6. Part 5: U. Englert, M. Käser, A. Salzer, Inorg. Chem. 1995, 34, 6231-6232. (1996)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 523-528 
    Details
    ISSN: 0947-6539
    Keywords: carbonyl complexes ; chiral ligands ; iron complexes ; phosphorus ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Secondary phosphines such as HPPh2 and to the cationic iron dienyl complex [η5-(1R)-ethylnopadienyl)Fe-(CO)3]+ (1) by nucleophilic addition. The phosphonium salt initially formed is readily deprotonated to yield an optically active tertiary phosphine [(n4-(1 R)-ethylnopadienePPh2)Fe(CO)3] (2b). A similar reaction also occurs with [C6H7Fe-(CO)3]+ (3) and [C7H9Fe(CO)3]+ (4) to give [(C6H7PPh2)Fe(CO)3] (5) and [(C7H9PPh2)Fe(CO)3] (6) in good yields. The mechanism of formation of these novel phosphines is discussed. Complex 2 b crystallizes in the space group P212121 (no. 19); 5 crystallizes in the space group P21/c (no. 14). Like other monodentate optically active phosphines, 2 b is capable of coordinating to transition metal complexes. It forms palladium complexes on reaction with [{μ-chloro(allyl)palladium}2] as well as with [{μ-chloro[(N,N-dimethylamino-kN-2-methyl)phenyl-kC]palladium}2] (11). The latter reaction product crystallizes in the space group P31 (no. 144).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19960020511
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  • 9
    Electronic Resource
    Electronic Resource
    Zirconium(II)- and Hafnium(II)-Assisted Reductive Coupling of Coordinated Carbonyl Groups Leading to Ketenylidene Complexes of Zirconium(IV) and Hafnium(IV) (1996)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 412-419 
    Details
    ISSN: 0947-6539
    Keywords: carbon-carbon coupling ; carbonyl complexes ; hafnium complexes ; ketenylidene complexes ; zirconium complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The biscyclopentadienyldicarbonyl derivatives of zirconium(II) and hafnium(II) ([MCp2(CO)2]; M=Zr, Hf) promote the reductive coupling of coordinated carbon monoxide to give, in the presence of N,N-dialkylcarbamtes of the tetravalent metals [M(O2CNR2)4], the ketenylidene complexes [M3Cp2(μ2-CCO)-(μ3-O)(O2CNR2)6] (1 a: M=Zr, R=Et; 1 b: M=Zr, R=iPr; 2: M=Hf, R=iPr). The yields of the isolated zirconium complexes are as high as 60%, while that of the hafnium derivative is 40%. The X-ray crystal structure analysis of 1 b shows that it consists of trinuclear molecules, with the three zirconium atoms held together by the bidentate C2O ligand, by the tridentate bridging oxide and by the bidentate carbamato groups. Labelling experiments with [ZrCp2(13CO)2] show that the ketenylidene ligand originates from the coordinated CO groups. These ketenylidene complexes, which are rare examples of compounds containing a CCO but no CO ligand, are characterized by an intense IR band at about 2015 cm-1, associated with the bridging C2O ligand. The ketenylidene group of 1 b was readily removed and replaced by a bidentate μ-oxo ligand of the same hapticity by reaction with carbon dioxide or acetone or by thermal decomposition. The resulting product [Zr3Cp2(μ-O)(μ3-O)-(O2CNiPr2)6] (3) crystallizes in the same space group as 1 b and with similar cell constants and bond parameters.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19960020410
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesen neuer bororganischer Ringe mit zwei Bor-Atomen durch Borylierung des Trimethylenmethan-Dianions (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 23-29 
    Details
    ISSN: 0009-2940
    Keywords: Diboracycloalkanes ; Diboracycloalkenes ; Trimethylenemethane, borylation of the dianion of ; Allylboranes, B - C bond length ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses of New Organoboron Rings with two Boron Atoms by Borylation of the Trimethylenemethane DianionBorylation of Li2[C(CH2)3] (1) provides a versatile starting point for the synthesis of 5-, 6-, 7-, and 8-membered ring systems with two boron atoms and leads to 1,5-bis(dialkylamino)-3,7-dimethylene-1,5-diboracyclooctanes 2a, b (a: R=Et; b: R=iPr), 1,3-bis(dialkylamino)-5-methylene-1,3-diboracyclohexanes 8a, b, 1,3-bis(diethylamino)-5-methyl-1,3-dibora-4-cyclo-hexene (10), and 1,4-bis(dialkylamino)-6-methylene-1,4-dibora-2-cycloheptenes 11a, b. The compounds 2b, 8b, and the 2,3-biboratafulvene derivative [Li(TMEDA)]2[CH2C(CHB)2-(NiPr2)2] are characterized by X-ray diffraction analysis. It is shown that for trigonal boron B - C(allyl) bond distances (typically 160 ± 1 pm) are significantly larger than B - C(alkyl) distances (typically 158 + 1 pm).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250105
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