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  • 1
    ISSN: 1434-4475
    Keywords: Keywords. Ruthenium; Bis(oxazolinyl)pyridine; Coordination chemistry; Isomerization.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Der kationische Komplex [mer,trans-Ru(pybox)(PPh3)2Cl]+ (1; pybox=2,6-bis(oxazolinyl)pyridin) wurde durch die Reaktion von Ru(PPh3)4Cl2 oder Ru(PPh3)3Cl2 mit einem Äquivalent pybox hergestellt. In Lösung ist 1 substitutionslabil und setzt in geringem Maße PPh3 frei. Es entsteht dabei der neutrale Komplex [mer,cis-Ru(pybox)(PPh3)Cl2] (2). Die isomere Verbindung [mer,trans-Ru(pybox)(PPh3)Cl2] (3) wurde durch Reaktion von [Ru(Cumol)Cl2]2 (Cumol=4-Isopropyltoluol) mit zwei Äquivalenten pybox und PPh3 in siedendem Toluol erhalten. Die Verbindung 3 ist thermodynamisch weniger stabil als 2 und kann bei höherer Temperatur quantitativ in 2überführt werden. Eine Röntgenstrukturanalyse von 2ċ(C2H5)2O wird präsentiert.
    Notes: Summary.  The cationic complex [mer,trans-Ru(pybox)(PPh3)2Cl]+ (1; pybox=2,6-bis(oxazolinyl)pyridine has been prepared by the reaction of either Ru(PPh3)4Cl2 or Ru(PPh3)3Cl2 with stoichiometric amounts of pybox. In solution, 1 is substitutionally labile liberating to some extent PPh3 to give the neutral complex [mer,cis-Ru(pybox)(PPh3)Cl2] (2). The isomeric complex [mer, trans-Ru(pybox)(PPh3)Cl2] (3) has been afforded by the reaction of [Ru(cymene)Cl2]2 (cymene)=4-isopropyl toluene) with 2 equiv. of pybox and PPh3 in refluxing toluene. Complex 3 is thermodynamically less stable than 2 and is quantitatively converted to 2 at elevated temperature. The X-ray structure of 2ċ(C2H5)2O is reported.
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  • 2
    ISSN: 1434-4475
    Keywords: Keywords. Activated olefins; Stereoelectronic effects; Stereoselectively ; Michael addition; Mechanism.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Bei der Michael-Addition von S-Phenylethylamin und L-Alaninisopropylester an ω-Nitrostyrol sind die nach der b,pl,H-Regel als BB-Produkte zu bezeichnenden Diastereomere erwartungsgemäß thermodynamisch stabiler als die AB-Isomere. Eine höhere Bildungsgeschwindigkeit für die AB-Produkte, wie sie z.B. bei der Addition von Thiolen auftritt, wurde nicht beobachtet.
    Notes: Summary.  In the Michael addition reaction of S-phenylethylamine and L-alanine-isopropylester to ω-nitrostyrene, the diasteromers which are to be named as BB-products according to the b, pl, H-rule are as expected thermodynamically more stable than the AB-products. A higher reaction rate for the formation of the AB products, as it was found e.g. for the addition reaction of thioles, could not be observed.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 123 (1992), S. 515-520 
    ISSN: 1434-4475
    Keywords: Potassium tetrathioantimonate 4 1/2-hydrate ; Crystal structure ; Hydrogen bond
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Kristallstruktur von K3SbS4·4 1/2 H2O, monoklin, P21/c-C 5 2h ,a=12.732(3),b=7.720(2),c=13.928(4) Å, β=90.19(1)°,V=1369.0(5) Å3,Z=4, wurde mit Röntgen-Einkristalldaten bestimmt und für 3 024 Reflexe aufR=0.031 verfeinert. Die Kristallstruktur ist aus dreidimensional verknüpften KS4 − 5(H2O)3 − 5-Polyedern und SbS4-Tetraedern (Sb-S=2.327 Å) aufgebaut. Die Wassermoleküle sind an zwei bis drei Kaliumionen gebunden und bilden ausschließlich Wasserstoffbrücken des Typs O-H...S aus. Eine der fünf kristallographisch verschiedenen H2O-Lagen ist aus Platzmangel nur zur Hälfte besetzt.
    Notes: Summary The crystal structure of K3SbS4·4 1/2 H2O, monoclinic, P21/c-C 5 2h ,a=12.732(3),b=7.720(2),c=13.928(4) Å, β=90.19(1)°,V=1369.0(5) Å3,Z=4, has been determined from X-ray single crystal data and refined by least-squares methods toR=0.031 for 3 024 reflections. The structure is built up from KS4 − 5(H2O)3 − 5 polyhedra and SbS4 tetrahedra (Sb-S=2.327 Å) which are three-dimensionally linked. The water molecules are bonded to two or three K+ ions and form exclusively O-H ... S-type hydrogen bonds. One of the five crystallographically different water molecule sites is due to space limitations only half occupied.
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  • 4
    ISSN: 1434-4475
    Keywords: Keywords. Ruthenium; Tris(pyrazolyl)borate complexes; Nitrogen and oxygen donor ligands; Vinylidene complexes.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Die Synthese und Charakterisierung von RuTp-Komplexen mit den Koliganden N,N′-Bis(phenylmethylen)-1,2-ethylendiamin (NN), 2-Pyridinthiol (NS), N,N-Bis-(2-(dimethylamino)ethyl)-N′,N′-dimethyl-1,2-ethandiamin) (N-crab), Acetylacetonat (acac) und Tetramethylethylendiamin (tmeda) werden beschrieben. Während sich mit NN, N-crab, acac und tmeda einkernige Komplexe bilden, gibt die Umsetzung mit NS einen dimeren Komplex. Röntgenstrukturanalysen repräsentativer Verbindungen wurden durchgeführt. Die Verbindungen mit NN, acac und tmeda bilden mit terminalen Alkinen Vinylidenkomplexe.
    Notes: Summary.  The synthesis and characterization of RuTp complexes containing the chelating ligands N,N′-bis(phenylmethylene)-1,2-ethylenediamine (NN), 2-pyridinethiol (NS), N,N-bis-(2-(dimethylamino)ethyl)-N′,N′-dimethyl-1,2-ethanediamine) (N-crab), acetylacetonate (acac), and tetramethylethylenediamine (tmeda) is described. While with NN, N-crab, acac, and tmeda mononuclear complexes are formed, a dimeric species is obtained with NS. X-ray structures of some complexes are given. The complexes featuring NN, acac, and tmeda react readily with terminal acetylenes to give vinylidene complexes.
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  • 5
    ISSN: 1434-4475
    Keywords: Keywords. Ruthenium; Halfsandwich complexes; Catalysis; C-H Activation.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary.  This article gives an overview of recent chemistry based on the tris-acetonitrile complex [RuCp(CH3CN)3]+. Due to the labile nature of the CH3CN ligands, substitution reactions are a dominant feature of this complex. Important derivatives are the highly reactive complexes [RuCp(PR 3)(CH3CN)2]+ which are a source of the 14e− fragment [RuCp(PR 3)]+. These species are catalytically active in the redox isomerization of allyl alcohols to give aldehydes and ketones. Furthermore, the cationic complex [RuCp(κ1(P),η2-PPh2CH2CH2CH*CH2)(CH3CN)]PF6 derived from the reaction of [RuCp(CH3CN)3]+ with PPh2CH2CH2CH*CH2 is a model compound for studying coupling reactions of olefins and acetylenes. In addition, [RuCp(CH3CN)3]+ is a valuable precursor for the synthesis of configurationally stable chiral three-legged piano-stool ruthenium complexes. These are currently being intensively investigated as Lewis acid catalysts in asymmetric synthesis.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 131 (2000), S. 931-936 
    ISSN: 1434-4475
    Keywords: Keywords. Glycolate; Manganese complexes; X-Ray structure determination; Jahn-Teller effect.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary.  The crystal structure of consists of individual layers in which the anionic complexes form strings of vertex-sharing octahedral units. These strings are interconnected by units to form layers via Na-Cl and Na-O interactions. An outstanding feature of the compound are the unusually strong Jahn-Teller elongated trans- octahedra.
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  • 7
    ISSN: 1434-4475
    Keywords: Keywords. Organocuprate addition; Michael-type addition; Beckmann rearrangement; Ergosterol biosynthesis inhibitors; X-Ray diffraction.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Die Addition von Organocupraten an die aktivierte C*C Doppelbindung in 2H-3,3a,4,5,6,7-Hexahydro-2-indenon, gefolgt von einer Abfangreaktion des anionischen Zwischenprodukts mit MeI als Elektrophil, wurde untersucht. Die Strukturaufklärung des erhaltenen Produktes erfolgte mittels Röntgendiffraktion seines Oxims. Eine anschließende Beckmann-Umlagerung lieferte die gewünschte Titelverbindung.
    Notes: Summary.  The addition of organocuprates to the activated C*C double bond in 2H-3,3a,4,5,6,7-hexahydro-2-indenone followed by trapping of the anionic intermediate with MeI as electrophile is reported. Structural assignment of the resulting product was carried out via its oxime using X-ray diffraction. A subsequent Beckmann rearrangement gave the desired title compound.
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  • 8
    ISSN: 1434-4475
    Keywords: Keywords. Ruthenium; Cyclopentadienone; Oxidation; Ylide complexes.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Die Oxidation von [Ru(η5-C5H5)(η5-C5H3OH-2-PPh3)]CF3SO3 (1a) und [Ru(η5-C5H4PPh3)(η5-C5H4OH)]PF6 (1b) mit Br2 (1 äquiv.) liefert die Cyclopentadienon-Komplexe [Ru(η5-C5H5)(η4-C5H3O-2-PPh3)Br]CF3SO3 (2a) und [Ru(η5-C5H4PPh3)(η4-C5H4O)Br]PF6 (2b) in 79 und 82% Ausbeute. Wird 2a mit Ag+ in CH3CN umgesetzt, so erhält man den dikationischen Komplex [Ru(η5-C5H5)(η4-C5H3O-2-PPh3)(CH3CN)](CF3SO3)2 (3). Im Gegensatz dazu erhält man mit 2b den Tris-acetonitril-Komplex [Ru(η5-C5H4PPh3)(CH3CN)3](PF6)2 (4). Die Röntgenstrukturen von 1a, 2a und 2b wurden bestimmt.
    Notes: Summary.  Oxidation of [Ru(η5−C5H5)(η5-C5H3OH-2-PPh3)]CF3SO3 (1a) and [Ru(η5-C5H4PPh3) (η5-C5H4OH)]PF6 (1b) with Br2 (1 equiv.) affords the cyclopentadienone complexes [Ru(η5-C5H5)(η4-C5H3-O-2-PPh3)Br]CF3SO3 (2a) and [Ru(η5-C5H4PPh3)(η4-C5H4O)Br]PF6 (2b) in 79 and 82% yield. When 2a is treated with Ag+ in CH3CN, the dicationic complex [Ru(η5-C5H5)(η4-C5H3O-2-PPh3)(CH3CN)](CF3SO3)2 (3) is obtained, whereas with 2b the tris-acetonitrile complex [Ru(η5-C5H4PPh3)(CH3CN)3](PF6)2 (4) is formed. X-Ray structures of 1a, 2a, and 2b are reported.
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  • 9
    ISSN: 1434-4475
    Keywords: Keywords. Ruthenium; Cyclopentadienone complexes; Pentamethylcyclopentadienyl complexes; X-ray structure.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Ru(η5-C5Me5)(η4-C5H4O)Brċ2[Et3NH]ċ[Zn(Br,Cl)4] wurde überraschend bei Versuchen erhalten, den Mutterkomplex Ru(η5-C5Me5)(η4-C5H4O)Br in einer Eintopfsynthese herzustellen. Die Kristallstruktur wurde mittels Röntgenbeugung bestimmt: monoklin, Raumgruppe P21/a, a=14.307(2) Å, b=12.819(2) Å, c=19.897(4) Å, β=95.98(1)°, V=3629.3(11) Å3, Z=4, R=0.044 für 3633 Reflexe mit I〉2σ(I). Die Verbindung ist die dritte bisher bekannte kristalline Form von Ru(η5-C5Me5)(η4-C5H4O)Br. Sie ist aus alternierenden Schichten von neutralen Ru-Komplexen, Triethylammoniumkationen und tetraedrischen [Zn(Br,Cl)4]2−-Anionen aufgebaut. Bemerkenswert ist, daß eines der beiden symmetrieunabhängigen Triethylammoniumionen über eine H-Brücke mit dem Cyclopentadienon-Sauerstoff des neutralen Ru-Komplexes verknüpft ist.
    Notes: Summary.  Ru(η5-C5Me5)(η4-C5H4O)Brċ2[Et3NH]ċ[Zn(Br,Cl)4] was unexpectedly obtained during attempts to prepare the parent complex Ru(η5-C5Me5)(η4-C5H4O)Br in a one-pot synthesis. The crystal structure was determined by X-ray diffraction: monoclinic, space group P21/a, a=14.307(2)Å, b=12.819(2) Å, c=19.897(4) Å, β=95.98(1)°, V=3629.3(11) Å3, Z=4, R=0.044 for 3633 data (I〉2σ(I)). The compound represents the third crystalline form of Ru(η5-C5Me5)(η4-C5H4O)Br known so far. It is built from alternating layers of neutral Ru complexes, triethylammonium cations, and tetrahedral [Zn(Br,Cl)4]2− anions. Remarkably, one of the two independent triethylammonium ions is hydrogen bonded to the cyclopentadienone oxygen of the neutral Ru complex.
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  • 10
    ISSN: 1434-4475
    Keywords: Keywords. (Hetero)Aryl methyl ketone guanylhydrazones; Acylation; 1H NMR spectroscopy;13CNMR spectroscopy; X-ray structure analysis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Die Synthese einiger neuer Guanylhydrazone von Aryl-bzw. Heteroarylmethylketonen wird beschrieben. Die Reaktion dieser Verbindungen mit Acetanhydrid führt zu entsprechenden N,N′-Diacetylderivaten. Die Strukturen aller neuen Verbindungen sowie die einiger bereits beschriebener Analoga wurden mit Hilfe von NMR-Untersuchungen (1H, 13C) sowie durch Röntgenkristallstrukturanalysen bestimmt.
    Notes: Summary.  The synthesis of some novel guanylhydrazones of (hetero)aryl methyl ketones is described. Successive reaction with hot acetic anhydride leads to the corresponding N,N′-diacetyl derivatives. Structural assignments of all novel compounds and those of some already known congeners were achieved by means of NMR spectroscopic investigations (1H, 13C) and X-ray structure analysis.
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