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  • Inorganic Chemistry  (7)
  • 1-Formylalkanesulfonates  (1)
  • Analytische Methoden  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of Novel Tridentate N,O,S and N,N,O Ligands of the Tripod Type in Racemic and Enantiomerically Pure Form (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 59-68 
    Details
    ISSN: 0009-2940
    Keywords: Glyceraldehyde ; Ligands, tridentate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of seven chiral, tripodal N,O,S and N,N,O ligands were prepared in which N stands for a secondary amine or imidazole donor, O for a phenol, and S for a thioether or thiol metal-binding group. Key steps are (1) the construction of ortho-hydroxyacetophenones bearing the phenolic binding group and either a thioether, a protected thiol or an imidazole substituent in the α-position, and (2) subsequent reductive amination with a primary amine. The modular synthesis allows a rapid construction of a variety of structurally related ligands. In three cases, the enantiomers of the racemic products could be separated after condensation with (R)-glyceraldehyde acetonide as chiral auxiliary. The relative configurations of the cyclic N,O- and N,N-acetals thus obtained were established by NOE spectroscopy. X-ray structural analysis of two crystalline N,O- and N,N-acetals allowed the assignment of absolute configurations. Hydrolysis of the dia-stereomerically pure acetals afforded the enantiomerically pure ligands in high yield. By comparison of their CD spectra, absolute configuration could also be assigned to the third pair of enantiomerically pure ligands.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290113
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and Homo-Diels-Alder Cleavage of the Epoxy-azoalkane exo-3-Oxa-6,7-diazatricyclo[3.2.1.02,4]oct-6-ene (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 5018-5023 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthese und Homo-Diels-Alder-Spaltung des Epoxy-azoalkans exo-3-Oxa-6,7-diazatricyclo[3.2.1.02,4]oct-6-enexo-3-Oxa-6,7-diazatricyclo[3.2.1.02,4]oct-6-en (1a) wurde durch Epoxidierung des Diels-Alder-Addukts 3 und nachfolgende reduktive Verseifung und Oxidation synthetisiert. Das Epoxy-azoalkan 1a spaltete über -20°C leicht Stickstoff ab, und 4H-Pyran bildete sich als einziges Produkt. Die Versuche, das endo-Isomere 1b durch basenkatalysierte Cyclisierung von Bis(2,2,2-trichlorethyl)-endo-5-acetoxy-exo-6-brom-2,3-diazabicyclo[2.2.1]heptan-2,3-dicarboxylat (5) oder endo-5-Acetoxy-exo-6-brom-N-phenyl-2,3-diazabicyclo[2.2.1]heptan-2,3-dicarboximid (6) darzustellen, schlugen fehl. Addition von 4-Phenyl-4H-1,2,4-triazol-3,5-dion (PTAD) an 1,1,4,4-Tetraphenyl-1,3-butadien ergab das 2:1-Addukt 2-Hendo-5-(2,2-Diphenylvinyl)-N,N′,6-triphenyl-3,4,9,10-tetraazatricyclo[6.2.2.02,7]dodeca-6,11-dien-3,4:9,10-bisdicarboximid (10) anstelle des erwarteten 1,2,3,6-Tetrahydro-N,3,3,6,6-pentaphenylpyridazin-1,2-carboximids (9).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851181234
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis, X-Ray Crystal Structure and Magnetic Characterization of the First “Ni3S4N3” Nickel Thiolate Cluster (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 125-129 
    Details
    ISSN: 0009-2940
    Keywords: Nickel cluster ; Nickel thiolate ; Hydrogenase ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tridentate N,O,S-ligand (RS)-2-[(2-mercapto-1-methylamino)ethyl]phenol (rac-1) was prepared from ortho-hydroxy-chloroacetophenone in three steps. When this ligand was treated with nickel(II) acetate, the novel “Ni3S4N3” cluster rac-3 was obtained. The X-ray crystal structure of rac-3 unambiguously revealed the pseudo-C3 symmetric structure of this novel nickel cluster, which is made up by three nickel ions, one sulfide sulfur atom, and three homochiral ligand molecules, each contributing one thiolate sulfur atom and one amine nitrogen atom to the ligation of the metal ions. According to NMR-spectroscopic results, this highly symmetric structure is maintained in solution. The magnetic studies revealed diamagnetic behavior in the solid state, although antiferromagnetic interaction of the metal centers cannot absolutely be excluded.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19951280207
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  • 4
    Electronic Resource
    Electronic Resource
    1-Formyl- and 1-Diazoalkanesulfonates (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 1147-1151 
    Details
    ISSN: 0009-2940
    Keywords: 1-Formylalkanesulfonates ; 1-Diazoalkanesulfonates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1-Formyl- und 1-DiazoalkansulfonateDurch Deprotonierung der Neopentyl-, Isobutyl- und Isopropylester der Methan- und Ethansulfonsäure mit n-Butyllithium und nachfolgende Reaktion mit Ameisensäure-ethylester wurden die entsprechenden 1-Formylalkansulfonsäureester in 77-90% Ausbeute erhalten. Am Beispiel des 1-Formylethansulfonsäure-neopentylesters wurde gezeigt, daß durch weitere Umsetzung mit Dimethylsulfat und Base 1-(Methoxymethylen)alkansulfonsäureester zugänglich sind. Die 1-Formylalkansulfonsäureester konnten mit Arylsulfonylaziden durch entformylierende Diazogruppen-übertragung in 28-65% Ausbeute zu den stabilen 1-Diazoalkansulfonsäureestern umgesetzt werden. Die chemischen Eigenschaften dieser neuen Diazoverbindungen gleichen denen der 1-Diazoalkanphosphonsäureester, so führt z. B. die Entschützung zum Sulfonatanion zur spontanen Stickstoffabspaltung. Die Thermolyse des 1-Diazoethansulfonsäure-isobutylesters in inertem Lösungsmitel ergab Vinylsulfonsäure-isobutylester als Hauptprodukt.
    Notes: The deprotonation of the neopentyl, isobutyl and isopropyl esters of methane- and ethanesulfonic acid with n-butyllithium and subsequent reaction with ethyl formate afforded the corresponding 1-formylalkanesulfonates in 77-90% yield. 1-(Methoxymethylene)alkanesulfonates could be obtained by additional treatment with dimethyl sulfate and base, as examplified in the case of neopentyl 1-formylethanesulfonate. Furthermore, the formylated sulfonates were converted into the stable 1-diazoalkanesulfonates in 28-65% yield employing arylsulfonyl azides as diazo group transfer reagents. The chemical behaviour of the novel 1-diazoalkanesulfonates resembles that of 1-diazoalkanephosphonates, e.g., deprotection to the 1-diazoalkanesulfonate anion resulted in rapid denitrogenation. The thermolysis of isobutyl 1-diazoethanesulfonate in an inert solvent afforded isobutyl vinylsulfonate as the major product.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220621
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis and X-ray Crystal Structure of the First Mononuclear Nickel(II) Alkane Thiolate Complex with a Mixed (S,N,N,O) Ligand FieldDedicated to Professor Rolf Gleiter on the occasion of his 60th birthday (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1183-1189 
    Details
    ISSN: 0009-2940
    Keywords: Nickel complexes ; Thiolates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The six-step synthesis of a chiral, pentadentate dihydrosalen ligand, carrying a mercaptomethyl group as additional binding site, is described. When this ligand was treated with nickel(II) salts, a planar tetracoordinated nickel chelate was obtained, and not the expected pentacoordinated species. This complex was fully characterized, including X-ray crystallography. The crystal structure revealed that the nickel ion is coordinated by the thiolate anion, both the amine and the imine nitrogen atoms of the ligand, and by one phenolate anion. The second phenolic oxygen atom of the ligand does not participate in the coordination of the nickel ion. This chelate is the first mononuclear nickel(II) thiolate complex having a mixed (S,N,N,O) ligand field. Cyclic voltammetry did not indicate a reduction up to -2.1 V (vs. Fc/Fc+). In the anodic range, no reversible but two irreversible oxidation processes were observed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291007
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  • 6
    Electronic Resource
    Electronic Resource
    Nickel(II) Complexes of Chiral Tripodal N,O,S-Ligands: Square-Planar vs. pseudo-Octahedral Coordination in the Solid State and in Solution, Metal-Induced Racemization of the Ligand (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 891-897 
    Details
    ISSN: 0009-2940
    Keywords: Ligands, tridentate ; Nickel ; Thioethers ; Bioinorganic chemistry ; Racemization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexation behavior of three chiral, tripodal N,O,S-ligands with nickel(II) salts was examined. It was found that the coordination mode of the ligands (bidentate N,O and N,S; tridentate N,O,S) and of the central nickel ion (square-planar vs. pseudo-octahedral) is not simply an intrinsic property of the ligand-metal combination, but also a function of the counter ions and of the solvent of crystallization. In the case of one ligand, a diamagnetic square-planar and a paramagnetic pseudo-octahedral form could be switched back and forth, by just changing the solvent of crystallization from methanol to ethanol. By using an enantiomerically pure tripodal N,O,S-ligand, a metal induced racemization was unveiled which would have otherwise remained undetected.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300713
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  • 7
    Electronic Resource
    Electronic Resource
    Preparation and X-ray Crystal Structure of the First Trimeric Nickel Thiosemicarbazone Complex: The First Example of Oligomerization by both Ni—O—Ni and Ni—S—Ni Bridging (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1421-1423 
    Details
    ISSN: 0009-2940
    Keywords: Nickel cluster ; Nickel complex ; Thioamide ; Thiosemicarbazone ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomeric nickel(II) thiosemicarbazone complexes are an attractive new class of homogeneous catalysts for the activation of silanes. However, their activity is limited by the formation of inactive oligo- and polymers. The pathway by which aggregation takes place was elucidated by the preparation and X-ray structural analysis of the first trimeric nickel(II) thiosemicarbazone complex. Aggregation was shown to proceed via Ni—O—Ni and Ni—S—Ni bridging, giving rise to both fourfold planar and pseudooctahedral coordination of the nickel ions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291203
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  • 8
    Electronic Resource
    Electronic Resource
    Fluoreszenz-Reporter für Phosphodiesterase-AktivitätDiese Arbeit wurde vom Fonds der Chemischen Industrie unterstützt. (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 109 (1997), S. 1518-1520 
    Details
    ISSN: 0044-8249
    Keywords: Analytische Methoden ; Enzyme ; Fluoreszenzsensoren ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19971091313
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