ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Chemistry  (56)
  • Life and Medical Sciences  (4)
  • Fisheries
  • 1995-1999  (60)
  • 1996  (60)
  • 1
    Electronic Resource
    Electronic Resource
    Reaktionen des Tripod-Co-Templats CH3C(CH2PPh2)3Co(II) mit funktionalisierten HydrazinenMax Herberhold zum 60. Geburtstag gewidmet. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1107-1113 
    Details
    ISSN: 0009-2940
    Keywords: Tripod ligands ; Hydrazines, substituted ; Diazenes ; Cobalt(III), fivefold coordination of ; Cobalt(II), fivefold coordination of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The coordination behaviour of ligands having the same basic constitution RN=NC(=X)R′ (X = O, NR″, S) in their tripod cobalt derivatives has been analyzed. The ligands themselves may be considered as neutral heterodiene compounds and are in this respect vinylogues to diazenes RN=NRy′. Two- electron reduction of these neutral species results in dianionic heterosubstituted heteroolefins RN- -N=C(X-)R′. Due to their redox ambiguity the oxidation state of the metal M in chelate complexes is not a priori evident. Compounds tripod [5: X, R′ = O, Ph; 6; (X, R′) = (py); 7: X, R′ = S, NH2] are best described as containing low-spin Co(III) and dianionic ligands. Co(II) species are obtained with diethyl azodicarboxylate EtOOCN=NCOOEt as the ligand. In the mononuclear compound, with only one nitrogen and one carbonyl oxygen of the ligand acting as donor groups, the neutral ligand is coordinated to give the high-spin cobalt(II) species tripod (8). In the dinuclear compound 9 with both of the nitrogen atoms and carbonyl groups involved in coordination the dianionic ligand bridges two high-spin cobalt(II) centers to give tripod (9) as a derivative with two fused five-membered chelate rings. In addition to the conventional analytical techniques X-ray structure analyses, cyclovoltametric measurements, magnetic susceptibility and ESR data are used to characterize the compounds.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290921
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The chemistry of metallacyclic alkenylcarbene complexes, 3Part 2: Ref.[2].. C=C bond formation with carbon nucleophiles. stereoselective dienylation of lithium enolates and cuprates and a novel cascade synthesis of highly substituted cyclopentenones from lithium acetylides (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 427-433 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Metallacycles ; Claisen rearrangement ; Cascade reaction ; Cyclopentenones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cationic ferracyclic carbene complexes 1 react with carbon nucleophiles like lithium enolates and organocuprates to give the corresponding 4-substituted 1, (3E)-diene tricarbonyl-iron complexes 6 and 9. The reaction is thought to proceed by initial attack on the allyl terminus and subsequent ferra Claisen-Ireland rearrangement of the intermediate (η2 alkene)carbene complex 4. This rationale is supported by the isolation and characterisation of analogous aminooxocarbene derivatives 8. With sterically demanding enolates products 6 are formed in diastereomeric ratios of up to 90:10, thus demonstrating the inductive power of the chiral metallacycle in 1. Lithium acetylides as carbon nucleophiles react with 1 according to a novel cascade to give regio- and stereospecifically 2,5,5-trisubstituted-cyclopentenones 10 suggesting a concerted formation of four C=C bonds together with a CO insertion and a formal carbene transfer step.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290411
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Activation of Carbon Dioxide, VIPart V: Ref.. Ligand Effects in the Catalytic Hydrogenation of Carbon Dioxide to Formic Acid Using in situ Catalysts Formed from [{(cod)Rh(μ-Cl)}2] and Monodentate and Bidentate Phosphorus Ligands (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 91-96 
    Details
    ISSN: 0009-2940
    Keywords: Carbon dioxide, catalytic hydrogenation of ; Ligand effects ; Rhodium catalysts ; Formic acid ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Highly active catalysts for the hydrogenation of CO2 to formic acid in DMSO/NEt3 are formed in situ from [{(cod)Rh(μ-Cl)}2] and various monodentate or bidentate ligands with phosphorus as the donor atom. Formic acid concentrations up to 2.3 · 0.2 mol l-1 can be obtained in less than 6 hours at ambient temperature under a total initial pressure of 40 atm by using rhodium concentrations of 5 · 10-3 mol l-1. The changes in catalytic activities observed upon structural changes of monodentate ligands are discussed in terms of classical ligand parameters like basicity and steric demand of the PR3 group, while with bidentate ligands R2P(CH2)nPR2 the chain length n plays a dominant role for the activity of the catalyst. The effects cannot be explained by a direct impact of the ligand on catalytically active intermediates only, but influences on the formation of these species must also be taken into account.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290118
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Hybrid Diborolyl/Dicarbaboranyl Triple-Deckers: [(μ5-Cyclopentadienyl)cobalt][μ,η5-1,3-diborolyl)cobalt[dicarba-heptacarboranyl and -nonacarboranyl ComplexesDedicated to Prof. H. Roesky on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 213-217 
    Details
    ISSN: 0009-2940
    Keywords: Triple-decker complexes ; Cobaltadicarba-closo-octaborane ; Cobaltadicarba-closo-decaborane ; Rearrangements ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The three-component reactions of the sandwich anion [(η5-C5H5)Co(η5-Et4MeC3B2)]- (4-H)- and various dicarbaborane anions with metal halides are described. Thus, (4-H)-, nido-4,5-C2B6H9- (5), and CoCl2 form the 30VE triple-decker [η5-C5H5)Co(μ,η5-Et4MeC3B2)Co(η5-2,3-C2B5H7)] (6). An analogous three-component reaction of (4-H)-, arachno-4,5-C2B7H-2 (7), and CoCl2 yields [(η5-C5H5)Co(μ,η5-Et4-MeC3B2)Co(η5-6,9-C2B7H9)] (8), which rearranges on heating (57°C) to give the 1,6-isomer [(η5-C5H5)Co(μ,η5-Et4-MeC3B2)Co(η5-1,6-C2B7H9)] (9) with an activation energy of 127 · 10 kJ/mol. The thermodynamically most stable 1,10-isomer [(η5-C5H5)Co(μ,η5-Et4MeC3B2)Co(η5-1,10-C2B7H9)] (10) is formed by heating of 9 at 180°C. An alternative route to 9 is provided by the reaction of arachno-6,8-C2B7H12- (11) with (4-H)- and CoCl2. The analogous reaction with RhCl3 leads to [(η5-C5H5)Co(μ,η5-Et4MeC3B2)Rh(1,6-C2B7H9)] (15) and unexpectedly to closo-2-(η5-C5H5)Co(1,6-C2B7H9) (12). The constitutions of the described compounds are derived from their 1H-, 11B-, 13C-NMR data as well as mass spectral data. The X-ray structure analyses of 10 and 12 show the expected metal complexes with a CoC2B7H9 framework. In 10 the carbon atoms occupy the capping positions of a bicapped square antiprism. The short Co-Co distance of 3.20 Å is in agreement with the 30VE configuration of 10. In both 10 and 12, the distance from the cobalt to the four-coordinate C4 is the shortest Co-to-cage atom distance.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290215
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Chirale Tripodliganden mit Phosphor- und Schwefeldonoren. Synthese und Komplexchemie (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 97-108 
    Details
    ISSN: 0009-2940
    Keywords: Tripod ligands ; Chiral ; Oligodentate P,S-ligands ; Nickel-sulfur Compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral Tripod Ligands with Phosphorus and Sulfur Donors. Synthesis and Complex ChemistryNeopentane based tripod ligands CH3C(CH2X)(CH2Y)-(CH2Z) with mixed donor groups X,Y,Z (PR2, SR, SH) are accessible via two different strategies. The functionalized thietane CH3(CH2X)ČH2SCH2 allows stepwise introduction of P or S donors by substitution of the mesylate function and subsequent nucleophilic cleavage of the thietane ring. Tripod ligands 5 [CH3C(CH2X)(CH2Y)(CH2Z)] with up to three different donor groups (X = SH; Y = PPh2; Z = P(4-Tol)2, SCH2Ph, PPh2) are thus available. As an alternative the neopentane derivatives 8 [CH3C(CH2X)(CH2Y)(CH2Cl)] which are easily assessible from CH3C(CH2OSO2Me)(CH2Br)-(CH2Cl) (7) by stepwise substitution with phosphides LiPAr2 (Ar = aryl) may be transformed to 9 [CH3C(CH2X)(CH2Y)(CH2SBzl)]. Under controlled conditions the S - benzyl bond of 9 is cleaved reductively without concomitant cleavage of P - Ar bonds. Ligand 5a [CH3C(CH2PPh2)2(CH2SH)] reacts with Ni(BF4)2 · 6 H2O to yield the dinuclear species [(CH3C(CH2PPh2)2-(CH2S)Ni)2]2+ (10). The two ligands are bonded in an equivalent way with each of the two nickel centers interacting with one of the two phosphane functions of the ligand; the thiolate functions form μ2-SR bridges between the two nickel atoms. The SCH2 group at the four-membered S2Ni2 ring are in mutual cis position with the four-membered ring bent along the sulfur-sulfur axis by 70°. The internal strain in 10 is analyzed by comparing its structure with the ones of [(CH3C(CH2-PPh2)3NiSPh)2]2+ (11) and [(CH3C(CH2OH)(CH2PPh2)2-NiOH)2]2+ (12).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290119
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Tripod-Cobalt-Formiat-Komplexe in den Oxidationsstufen +II und +I (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 243-245 
    Details
    ISSN: 0009-2940
    Keywords: Tripodal ligands ; Cobalt complexes ; Formate complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tripod-Cobalt Formate Complexes of Oxidation States +II and +IThe syntheses of the (tripod)cobalt formate complexes [(tri-pod)Co(O2CH)]n+ (1/1+; n = 0, 1; tripod = CH3C(CH2PPh2)3) are presented. The structures are established by X-ray analyses as well as the usual analytical techniques.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290221
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Alkylammonium Hexachlorometallates, IVPart III: Ref.[1].. Synthesis and Crystal Structure of Bis(1,4-diammoniobutane) Diaquahydrogen Hexachlororhodate(III) Dichloride, [H3N-(CH2)4- NH3]2[H5O2][RhCl6]Cl2 (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1355-1359 
    Details
    ISSN: 0009-2940
    Keywords: Hexachlororhodates ; 1,4-Diammoniobutane ion ; Diaquahydrogen ion ; Hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis(1,4-diammoniobutane) diaquahydrogen hexachlorohodate(III) dichloride, [H3N-(CH2)4 -NH3]2[H5O2][RhCl6]Cl2 (1), was synthesized by the reaction of rhodium(III) chloride with 1,4-diaminobutane dihydrochloride in concentrated hydrochloric acid. The red compound slowly decomposes at room temperature, but is stable for months and up to 106°C (DTA) under hydrogen chloride. Crystals of 1 were obtained by diffusion-controlled crystallization (space group P,1¯). The solid-state structure can be considered as a sequence of layers linked by hydrophobic interactions between the aliphatic chains of the 1,4-diammoniobutane ions. Within these layers the hydrophilic building blocks (hexachlororhodate and chloride anions, the diaquahydrogen cations and the ammonio groups of the diammoniobutane cations) are connected by a complex system of O—H-Cl and N—H-Cl hydrogen bonds. The H5O2+ ion has a crystallographically imposed Ci symmetry and shows the typical 1:1 disorder of the central hydrogen atom for a symmetrically strong [O-O 2.406(10) Å] doubleminimum potential O-H-O bond.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291107
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Tripod-Rhodium-COD-Komplexe: Synthese, Struktur, Dynamik und Katalyse (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1603-1615 
    Details
    ISSN: 0009-2940
    Keywords: Tripod rhodium(I) complexes ; Pentacoordinate rhodium COD complexes ; Phosphane complexes ; Phosphite complexes ; Hydrogenation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tripod Rhodium COD Complexes: Synthesis, Structure, Dynamics and CatalysisThe reaction of the tripod ligands R′C(CH2PR2)3 (1a-c) and X2POCH[CH2P(Ph)2]2 (2a-c) with [RhI(COD)Cl]2] is investigated. It yields tripod rhodium COD complexes [(1a-c)RhI(COD)]Y (3a-c) and [(2a-c)RhI(COD)]Y [4a-c; Y = B(Ph)4, PF6]. The tripod ligand is coordinated by all three donor groups in each case, irrespective of the different donor capabilities of the coordinating groups. The solid state structure of compounds 3a-c and 4a is determined by X-ray analysis. The observed coordination polyhedra delineate the variation from the idealized trigonal bipyramide to an idealized quadratic pyramide. In solution the analysis of the NMR spectra shows a rapid intramolecular interconversion according to a turnstile pseudo rotation. The complexes 3a and 4a are found to be catalysts for the hydrogenation of prochiral olefines.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291230
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Electrochemistry of novel materials. Edited by Jacek Lipkowski and Philip N. Ross, Frontiers of Electrochemistry, Vol. 3, VCH, New York 1994, hardcover, $145.00, DM 245.00, ISBN 0-89573-7SS-4 (1996)
    Weinheim : Wiley-Blackwell
    Advanced Materials 8 (1996), S. 360-361 
    Details
    ISSN: 0935-9648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/adma.19960080418
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Acetogenic Isoquinoline Alkaloids, LXXXIIPart LXXXI: G. François, G. Timperman, J. Holenz, L. Aké Assi, T. Steenackers, G. Bringmann, Intern. J. Parasitol., in press.. Biomimetic Total Synthesis of Michellamines A-C (1996)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 2045-2058 
    Details
    ISSN: 0947-3440
    Keywords: Michellamines ; Korupensamines ; Alkaloids, naphthylisoquinoline ; Biaryls ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The biomimetic first total synthesis of michellamines A, B, and C (1a-c), naturally occurring quateraryl alkaloids with high anti-HIV activity, is described. Key precursors are the molecular “halves” of michellamines, the antimalarial naphthylisoquinoline alkaloids korupensamine A (2a) and B (2b), which are likewise natural products. These “monomeric” naphthylisoquinoline alkaloids were prepared by Stille-type intermolecular aryl coupling of the O-isopropyl-protected and trialkylstannyl-activated naphthalene building block 4b with the threefold benzyl-protected and brominated, enantiomerically pure tetrahydroisoquinoline building block 3a. Ultimate “dimerization” of the protected korupensamines was achieved by biomimetic oxidative phenolic coupling using silver(I) oxide, followed by deprotection to give authentic michellamines. This synthetic route should allow us to easily prepare a broad series of modified analogs of michellamines for extensive structure-activity investigations.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199619961215
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...