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  • 1
    Electronic Resource
    Electronic Resource
    Enhydrazine, 39. Einige stabile 1,4,5,6-Tetrahydro-1-methylpyridazin-3,4,5,6-tetracarbonsäureester mit axialen Ester-Gruppen (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 2007-2012 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Enehydrazines, 39. - Some Stable 1,4,5,6-Tetrahydro-1-methylpyridazine-3,4,5,6-tetracarboxylic Esters with Axial Ester GroupsThe title compounds 2a,b, 3a,b, 4a,b and 7a,b are prepared from methylhydrazine and acetylenedicarboxylic esters. In 3a,b the ester group at C-6, in 2a,b the two ester groups at C-4 and C-6, and in 4a,b and 7a,b the three ester groups at C-4 to C-6 are axially orientated. These findings derived from the NMR spectra are confirmed for the crystalline state by structure analyses of 2b and 7a.
    Notes: Aus Methylhydrazin und Acetylendicarbonsäureestern werden die Titelverbindungen 2a,b, 3a,b, 4a,b und 7a,b dargestellt. In 3a,b steht die Ester-Gruppe an C-6, in 2a,b stehen die beiden Ester-Gruppen an C-4 und C-6 und in 4a,b und 7a,b die drei Ester-Gruppen an C-4 bis C-6 axial. Die aus den NMR-Spektren abgeleiteten Befunde werden für den kristallinen Zustand an 2b und 7a durch Strukturanalysen bestätigt.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881211117
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  • 2
    Electronic Resource
    Electronic Resource
    Protonenaustausch in Re(CO)4(μ-H)(μ-PPh2)Mo(η5-C5H5)(CO)2 gegen Triphenylphosphan-IB-Metallkationen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2191-2195 
    Details
    ISSN: 0009-2940
    Keywords: Heterodimetallic complexes ; phosphido-bridged ; Molybdenum complexes ; Rhenium complexes ; Proton exchange, isolobal ; Voltammetry, cyclic ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Proton Exchange in Re(CO)4(μ-H)(μ-PPh2)Mo(η5-C5H5)(CO)2 Against Cationic IB Metal Phosphane SpeciesDecacarbonyldirheniumreacts with hexacarbonylbis(η-cyclopentadienyl)dimolybdenum and diphenylphosphane to give Re(CO)4(μ-H)(μ-PPh2)Mo(η5-C5H5)(CO)2 (1) with a Mo  -  Re bond as ascertained by an X-ray structure analysis. The bridging H atom of the heteronuclear metal-metal bond in 1 is deprotaned with DBU. The redox condensation reaction of the obtained anion1 and triphenylphosphane IB metal cations gave Re(CO)4(μ-H)(μ-PPh2)Mo(η5-C5H5)(CO)2 [M = Au (2), Ag (3), and Cu (4)] containing an MReMo triangle. Their yields increase in the sequence of compounds 4 〈 3 〈 2. 1, 1-, and 2 were characterized by cyclovoltammetric measurements, NMR, IR, and UV/Vis spectra.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241008
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  • 3
    Electronic Resource
    Electronic Resource
    Oxidative Trimerisierung von Alkinylgruppen an Trimethylphosphan-Palladium-Komplexen (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 9-14 
    Details
    ISSN: 0009-2940
    Keywords: Alkynyl groups ; Palladium, trimethylphosphane complexes ; Trimerization, oxidative ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidative Trimerization of Alkynyl Groups at Trimethylphosphane Palladium ComplexesAlkynylpalladium halides trans-PdX (C ≡ CR)(PMe3)2 [1, 2, 4, X = Cl, R = SiMe3, (CH2)2CH3, (CH2)5CH3; 3, X = Br, R = (CH2)2CH3] were synthesized by routine methods, while further examples of the series trans-PdX (C ≡ CR)(PMe3)2 [5, 7, 8, 10, X = Br, R = SiMe3, CMe3, (CH2)2CH3, Ph; 7, 9, 11, X = I, R = SiMe3, SiPh3, OEt] and trans-PdX (C ≡ CR)(PPh3)2 (12-14, X=I, R=SiMe3, CMe3, CH2OH) were obtained by oxidative addition of 1-halogeno-1-alkynes to PdL4 (L=PMe3, PPh3). Just above the melting point or decomposition point 5-7 are transformed by oxidative trimerization of the alkynyl groups to give enediynyl complexes trans-PdX[C(C ≡ CR)=C(C ≡ CR)R](PMe3)2 (15, 16, R=SiMe3, X=Br, I; 17, X=Br, R=CMe3). According to an X-ray structure analysis 17 has E configuration.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250103
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  • 4
    Electronic Resource
    Electronic Resource
    Thermisch kontrollierte oxidative Lineartrimerisierung von Alkinylgruppen in (Trimethylphosphan)nickel-Komplexen: Strukturen und die Rolle ligandreicher Vorstufen NiX(C≡CR)PMe3)n (n = 2-4) (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 1569-1578 
    Details
    ISSN: 0009-2940
    Keywords: Alkynylnickel halides ; Nickel complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidative Linear Trimerization of Alkynyl Groups in (Trimethylphosphane)nickel Complexes: Structures and the Role of Ligand-Rich Precursors NiX(C≡CR)(PMe3)n (n = 2-4)Oxidative additions of 1-halogenoalkynes XC≡CR; to Ni(PMe3)4 afford high yields of pentacoordinate ionic alkynylnickel compounds [Ni(C≡CR)(PMe3)4]+X- [R = SiMe3, X = I (1); R = CMe3, X = I (2), Br (3); R = SiEt3, X = I (6), Br (7); R = SiiPr3, X = I (10), Br (11), R = Ph, X = I (21), Br (22)] or complex molecules Ni(C≡CR)X(PMe3)3 [R = SiPh3, X = I (14), Br (15); R = Ph, X = I (19), Br (20)]. Dissociation of trimethylphosphane gives square planar trans-Ni(C≡CR)X-(PMe3)2 [R = CMe3, X = Br (4), Cl (5); R = SiEt3, X = Br (8), Cl (9); R = SiiPr3, X = Br (12), Cl (13); R = SiPh3, X = I (16), Br (17), Cl (18); R = Ph, X = I (23), Br (24), Cl (25)] but with R = SiR'3, X = I the title reaction dominates with formation of trans-Ni[C(C≡CR)=CR(C≡CR)]I(PMe3)2 [R = CMe3 (26), SiEt3 (29), SiiPr3 (32)]. Thermal activation is necessary in order to obtain trans-Ni[C≡CR)=CR(C≡CR)]X(PMe3)2 [R = CMe3, X = Br (27), Cl (28); R = SiEt3, X = Br (30), Cl (31); R = SiiPr3, X = Br (33), Cl (34)], while only thermal decomposition is observed with trans-Ni(C≡CR)X(PMe3)2 (R = Ph, SiPh3). Examples for both types of reactivity including structural data are given: trans-Ni(C≡CRSiMe3)Br(PMe3)2 and 25 crystallize in the space group P1. Pentacoordinate 19 (space group P21) adopts a trigonal pipyramid of ligand donor atoms with equatorial phenylethynyl and iodo ligands.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270904
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  • 5
    Electronic Resource
    Electronic Resource
    Intermediates and Side-Reactions in the Synthesis of Molecular Diphenolatonickel Compounds Containing Trimethylphosphane Ligands (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 2027-2032 
    Details
    ISSN: 1434-1948
    Keywords: Nickel(0) ; Oxidation ; Phenols ; Structure ; Ion pairs ; Hydrogen bonds ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Admission of molecular oxygen to a solution containing Ni(PMe3)4 and substituted phenols (ArOH) affords bisphenolatonickel compounds trans-Ni(OAr)2(PMe3)2 [ArOH = 2-chlorophenol (1), 2-bromophenol (2), 2,4,6-trichlorophenol (3)]. In the absence of dioxygen the phenols reversibly protonate the nickel complex to form ionic compounds [NiH(PMe3)4]+ Y- containing hydrogen-bonded anions Y = [H2(2-Cl-C6H4O)3] (4), [H(2-OH-C6H4COO)2] (5). As a side-reaction, formal insertion of nickel to give 2-hydroxyphenylnickel compounds Ni(Ar′)X(PMe3)3 [Ar′ = 2-OH-C6H4; × = Br (6), I (7)], trans-Ni(Ar′)Cl(PMe3)2 [Ar′ = 2-OH-3,5-Cl2-C6H2 (8)] and trans-Ni(OAr)Cl(PMe3)2 [Ar = 2,4,6-Cl3-C6H2 (9)] is observed. An X-ray crystal structure determination of 1 shows a trans square planar arrangement of donor atoms, that of 6shows a distorted square pyramid, while 4 contains tetrahedral nickel cations with a delocalized hydrogen atom and triphenolate anions H2(ArO)3-.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Syntheses and Structures of Molecular Diphenolatonickel Compounds Containing Trimethylphosphane Ligands (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 621-627 
    Details
    ISSN: 1434-1948
    Keywords: Nickel ; Oxidation ; Phenols ; Structure ; Dynamic NMR spectroscopy ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of substituted phenols and dioxygen with Ni(PMe3)4 yields the low-spin tetracoordinate diphenolatonickel compounds Ni(OAr)2(PMe3)2 [ArOH = 2-tert-butylphenol (1), 2-tert-butyl-4-methylphenol (2), 2-tert-butyl-6-methylphenol (3), 2,4-di(tert-butyl)phenol (4), 2-tert-butyl-4-methoxophenol (5), 2-chloro-4-tert-butylphenol (6), 2-isopropylphenol (7), 3-tert-butylphenol (8)]. As is revealed by variable temperature 1H- and 13C-NMR spectroscopy the complexes constitute a mixture of two isomers, each of which can be observed separately at lower temperatures when interconversion is slower. An additional 6-carbaldehyde function transforms the phenolate into a chelating ligand, giving rise to a high-spin hexacoordinate compound Ni(OAr)2(PMe3)2 (9). X-ray crystal-structure determinations of 2 and 3 show a trans square-planar structure, and that of 9 shows a trans octahedral arrangement of donor atoms P2O4. Bulky substituents in the 3- or 4-position, or non-demanding substituents in the 2-position, are less effective in stabilizing molecular diphenolatonickel complexes.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Methyl(2-phosphanylphenolato[P,O])nickel(II) Complexes - Synthesis, Structure, and Activity as Ethene Oligomerization Catalysts (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 431-440 
    Details
    ISSN: 1434-1948
    Keywords: Methylnickel complexes ; 2-Phosphanylphenolate ; Chelates ; Homogeneous catalysis ; Oligomerization ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of various substituted 2-phosphanylphenols 1a-f with half-molar amounts of cis-[MeNi(μ-OMe)(PMe3)]2 have been found to yield square-planar methyl(2-phosphanylphenolato)(trimethylphosphane)nickel(II) complexes 2a-f. 2JPP coupling constants of 305-316 Hz at low temperature indicate a trans-configuration for the products, while broad 31P-NMR signals at room temperature can be attributed to rapid dissociation of PMe3. Reaction with excess 1 gave rigid bis(2-phosphanylphenolato)nickel(II) complexes as exemplified by 3e, whereas addition of PMe3 to 2a led to the pentacoordinate methyl(2-phosphanylphenolato)bis(trimethylphosphane)nickel(II) complex 4a. Higher yields of 4a and 4d were obtained by reactions of 1a and 1d with Me2Ni(PMe3)3. Single-crystal X-ray diffraction analyses of 3e and 4a have revealed the structures as square-planar trans-bis- and trigonal-bipyramidal mono(2-phosphanylphenolato)nickel(II) P1O-chelate complexes, respectively. The methylnickel complexes 2 and 4 have been found to be effective one-component catalysts for the oligomerization of ethene. High conversions (〉 96%) were achieved with the P-basic derivatives 2e, 2f, and 4d bearing one or two branched alkyl groups (isopropyl, tert-butyl), whereas the diphenylphosphanyl derivatives were less active; 4d gave shorter oligomers than 2e or 2f.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    A Triangular Iron(III) Complex Potentially Relevant to Iron(III)-Binding Sites in Ferreascidin (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 193-201 
    Details
    ISSN: 0947-6539
    Keywords: EPR spectroscopy ; exchange coupling ; iron ; Moessbauer spectroscopy ; O ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An asymmetric triangular FeIII complex has been synthesized by an unusual FeII-promoted activation of salicylaldoxime. Formation of the ligand 2-(bis(salicylideneamino)methyl)phenol in situ is believed to occur through the reductive deoximation of salicylaldoxime by ferrous ions. The trinuclear ferric complex has been characterized on the basis of elemental analysis, IR, variable-temperature magnetic susceptibility, and EPR and Mössbauer spectroscopies. The molecular structure established by X-ray diffraction consists of a trinuclear structure with a [Fe3(μ3-O)(μ2-OPh)]6+ core. Two iron ions are in a distorted octahedral environment having FeN2O4 coordination spheres, and the five-coordinated third iron ion, with an FeNO4 coordination sphere, is in a trigonal bipyramidal environment. The magnetic susceptibility measurements revealed an St = 5/2 ground state with the antiparallel exchange interactions J = - 34.3 cm-1, J' = - 4.7 cm-1, and D = - 0.90 cm-1. The EPR results are consistent with a ground state of S = 5/2 together with a negative D5/2 value. The Mössbauer isomer shifts together with the quadrupole splitting also provide evidence for the high-spin state of the three ferric sites. Magnetic Mössbauer spectra lead to the conclusion that the internal magnetic fields possibly lie in the plane of the three ferric ions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030205
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  • 9
    Electronic Resource
    Electronic Resource
    Enhydrazine, 37 Synthese eines Pyrazol-Analogen des 7-Aminomitosens (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1711-1718 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Enehydrazines, 37. - Synthesis of a Pyrazole Analogue of 7-AminomitoseneThe 9-step synthesis of 7-amino-10-azamitosene (2b) from 3a is described. The crystal-structure analysis of the precursor 1b of 3a secures the position of the substituted propyl group at N-1 of compounds 1 and 3-7.
    Notes: Die neunstufige Synthese von 7-Amino-10-azamitosen (2b) aus 3a wird beschrieben. Die Kristallstrukturanalyse des Vorläufers 1b von 3a sichert die Stellung des substituierten Propylrestes an N-1 der Verbindungen 1 und 3-7.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198419841011
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  • 10
    Electronic Resource
    Electronic Resource
    Asymmetrische, heterodinucleare Komplexe [L′Ru(μ-O)(μ-CH3CO2)2ML]2⊕ (M = Fe, Mn, V): Elektronenstruktur und MagnetismusProfessor Wolfgang R. Roth zum 60. Geburtstag gewidmetDiese Arbeit wurde vom Fonds der Chemischen Industrie gefördert - L′ = N,N′,N″-Trimethyl-1,4,7-triazacyclononan, L = 1,4,7-Triazacyclononan. (1990)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 102 (1990), S. 720-722 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19901020636
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