Library

You have 0 saved results.
Mark results and click the "Add To Watchlist" link in order to add them to this list.
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    ISSN: 1572-901X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Thermal substitution of chloride in Ru(bipy)2Cl2 · 2H2O with diazadienes (dad) R′N=CR-CR=NR′ yields the mixed [(bipy)2Ru(dad)]2+ complexes, which are analogous to the [Ru(bipy)3]22+ cation. Full n.m.r. assignments are given for several complexes; conformational rigidity is displayed by dad-attached phenyl groups in one of them. The u.v. spectra, which show dad-dependent first c.t.-absorption bands, are compared to that of [Ru(bipy)3]2+.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1572-901X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Diazadienes (DAD) (RN=CR′CR′=NR with R′=H or Me and R=n-,i- ort-alkyl, aryl oro,o′-substituted aryl) easily form the thermally inert title compounds [(DAD)-Ru(CO)2I2] (2). Their stereochemistry is unambiguously derived from1H-n.m.r. and i.r. data. One of the complexes (2h) cocrystallizes with the free diazadiene (1h) in a 1∶1 molar ratio. An x-ray diffraction study, which allows a comparison of the free and bound diazadiene. was performed with the monoclinic crystal and gave the following cell parameters: space group C 2/c, a=2237.0(5), b=1017.4(3) and c=1824.9(4) pm, β=105.13(2)°, Z=4. From 2781 observed reflections 293 parameters were refined, leading to a final R-value of 0.0346 (Rw=0.0340). The tilting of thep-tolyl group is a consequence of an intra-ligand repulsion R/R′, the R-conformation being almost equal in the (E,E,E)-shaped molecule (1h) (68°) and the (E,Z,E)-chelate in (2h) (72°). Complexes (2) are photolabile (with loss of CO), and on reduction they lose iodide, thus offering selective ways for the exchange of π-acceptor or σ-donor ligands for precatalyst formation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photoelectron Spectra of Group V Compounds. VIII. Stiboranes Me3SbX2 (X = Me, Cl, Br, I) and SbCl5  -  Compared with Group Vb Analogs TaMe5, TaCl5, and NbCl5The gas phase HeI photoelectron spectra of Me5Sb, Me3SbCl2, Me3SbBr2, Me3SbI2, and SbCl5 are assigned on the basis of a qualitative D3h m. o. model and by comparison with the p. e. data of Me3Sb and SbCl3. The type of the three-centre-four-electron bond of the model compound SbH5 is discussed with respect to the axial bond of a typical sp3d molecule. The highest occupied m.o. of Me5Sb has non-bonding character; d-orbital participation may be excluded PE-spectroscopically. The differences between iso(valence)-electronic analogs EX5 of groups Va and Vb are investigated by means of the known p. e. ionisation potentials of TaMe5, TaCl5, as well as of NbCl5; their p. e. spectra are correlated. EHMO calculations for SbH3, H3SbHal2, SbH5, and NbH5 are performed to confirm the assignments and the interpretation.
    Notes: Die Gasphasen-HeI-Photoelektronenspektren von Me5Sb, Me3SbCl2, Me3SbBr2, Me3SbI2 und SbCl5 werden nach einem qualitativen MO-Modell für D3h-Systeme und durch Vergleich mit den PE-Daten von Me3Sb und SbCl3 zugeordnet. Der Typ der axialen Dreizentren-Vierelektronen-Bindung wird am Modell SbH5 vorgestellt und dem des sp3d-Moleküls gegenübergestellt. Übereinstimmend damit ist das oberste besetzte MO von SbMe5 nichtbindend; nach PE-Daten ist eine d-Orbitalbeteiligung nicht anzunehmen. Die Unterschiede zwischen isovalenzelektronischen Analoga EX5 der Gruppen Va und Vb werden anhand literaturbekannter Ionisierungsenergien von TaMe5, TaCl5 und NbCl5 untersucht, ihre PE-Spektren korreliert. EHMO-Rechnungen an SbH3, SbH3Hal2, SbH5 und NbH5 bestätigen Zuordnung und Interpretation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 3025-3029 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular cis-trans Exchange of Carbonyl Ligands in (L—L)M(CO)4 ComplexesTetracarbonyl complexes of VIb-metals with glyoxal bis(arylimines) as bidentate ligands show cis/trans exchange of the carbonyl ligands as found by means of the 13C n.m.r. spectrum. The i.r. data indicate a distorded octahedron in the ground state and the 13C n.m.r. spectrum a trigonalprismatic transition state. The activation barrier has been determined in 13CO-enriched compounds.
    Notes: Tetracarbonylkomplexe der VIb-Metalle mit Glyoxal-bis(aryliminen) als Chelatliganden zeigen im 13C-NMR-Spektrum cis/trans-Austausch der Carbonylliganden. Auf Grund des IR-Spektrums wird auf ein verzerrtes Oktaeder als Grundzustand und mit Hilfe des 13C-NMR-Spektrums auf einen trigonal-prismatischen Übergangszustand geschlossen. Die Aktivierungsbarrieren wurden an 13CO-angereicherten Komplexen bestimmt.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 1657-1664 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metalation of a Non-activated Alkyl Group in Nickel ComplexesThe diazadiene (DAD)glyoxalbis(diisopropylmethylimine) (1) reacts with anhydrous nickel bromide to yield (DAD)NiBr2 (2). Its reactions with main group metal alkyls lead to rather unstable intermediates. With the bulky O-tolylmagnesium bromide -under formal HBr abstraction- metalation of the diisopropylmethyl substituent occurs in γ-position to the next activating center (N) with formation of an N—C chelate. Properties and structure of this product 3 from this novel alkane activation reaction are discussed.
    Notes: Aus dem Diazadien (DAD) Glyoxalbis (diisopropylmethylimin) (1) und wasserfreiem Nickelbromid wird (DAD)NiBr2 (2) erhalten, dessen Reaktion mit Hauptgruppenmetall-alkylen zu wenig stabilen Zwischenprodukten führt. Mit dem sperrigen O-Tolylmagnesiumbromid wird unter formaler HBr-Abspaltung die Metallierung des Diisopropylmethyl-Rests von 2 in γ-Stellung zum nächsten aktivierenden Zentrum (N) unter Bildung eines N—C-Chelatrings erreicht. Eigenschaften und Struktur dieses Produkts (3) einer neuartigen Alkanaktivierung werden diskutiert.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0009-286X
    Keywords: Homogene Katalyse ; Diazadiene ; Eisen-Katalysatoren ; Butadien-Cyclodimerisation ; C4-Schnitt ; Butadien/1-Buten-Addition ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diazadienes as Controlling Ligands in Homogeneous Catalysis, VII1). Catalytic Synthesis and Structure of a Cyclooctatetraene with Twofold Vicinal Substitution - 1,4,5,8-Tetrakis[(p-tolyloxy)methyl]-1,3,5,7-cyclooctatetraeneThe catalytic reaction of 2-propynyl p-tolyl ether (propargyl p-tolyl either) with the diazadiene nickel complex 4 gives a highly symmetrical cycloocatetraene derivative 2. 1H NMR and 13C NMR spectra do not allow to distinguish between three possible substitution patterns (1,3,5,7; 1,4,5,8; 1,2,5,6). Double bond and substituent positions were determined by an X-ray structural analysis. The encountered pattern with a twofold vicinal substitution (1,4,5,8) was hitherto unknown for catalytically prepared cycloocatatetraenes. At the same time, 2 is the first cyclotetramer of a propargylic ether.
    Notes: Die katalytische Umsetzung von 2-Propinyl-p-tolylether (Propargyl-p-tolylether) mit dem Diazadien-nickelkomplex 4 führt zu einem hochsymmetrischen Cyclooctatetraenderivat 2. 1H-NMR- und 13C-NMR-Spektren erlauben aus Symmetriegründen keine Unterscheidung zwischen drei möglichen Substitutionsmusten (1,3,5,7; 1,4,5,8; 1,2,5,6). Durch eine Röntgenstrukturanalyse wurden die Substituentenstellung und die Lage der Doppelbindungen bestimmt. Das gefundene, doppelt vicinale 1,4,5,8-Substitutionsmuster war für katalytisch dargestellte Cyclooctatertraene bis jetzt unbekannt; zugleich ist 2 das erste Cyclotetramere eines Propargylethers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 83-85 
    ISSN: 0009-2940
    Keywords: Diazadienes/Carbon-carbon coupling/Ruthenium(0) complexes/Ethylene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexes (dad)2RuCl2 (1) (dad = diazadiene, RN = CR'- CR'=NR) are reduced to (dad)2Ru (2) which react with L = CO or ethylene to give (dad)2RuL (3,5). Reduction of 1b ( R' = H) with magnesium-butadiene or reaction of 2b with butadiene leads to a new type of C-C coupling of butadiene to one of the diazadiene ligands (6b). Addition of CO induces a rearrangement to 7b by a hydride shift.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1943-1950 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Bis(diazadine)iron(0) ComplexesReduction of iron(II) compounds with alkali metal or via an alkylation with Grignard reagents in the presence of 1,4-diaza-1,3-dienes (DAD) yields the brown, paramagnetic, tetracoordinate iron(O) complexes Fe(DAD)2 2. Depending on the bulkiness of the DAD substituents, carbon monoxide does not add or adds more or less readily and reversibly to give deep green diamagnetic (DAD)2Fe(CO) 6, or in an irreversible manner to give red (DAD)-Fe(CO)3 8. A corresponding colour change occurs during the addition reactions of 2 are observed with dicyanogen, nitrosyl chloride, or a diazoalkane. Two molecules of a dialkyl acetylenedicarboxylate are added to sterically not too demanding complexes 2 and with concomitant C—C bond formation an airstable, deeply blue coloured ferracyclopentadiene 9 is formed. A single crystal X-ray investigation of monoclinic 9b was performed. The molecules of symmetry C2 contain two DAD-chelates and a tetrakis(alkoxycarbonyl)-1,3-butadiene-1,4-diyl chelate at the octahedral iron(II) center.
    Notes: Bei der Reduktion von Eisen(II)-Verbindungen mit Alkalimetallen oder über eine Alkylierung mit Grignard-Reagenzien in Gegenwart von 1,4-Diaza-1,3-dienen (DAD) entstehen die paramagnetischen, braunen, vierfach koordinierten Eisen(O)-Komplexe Fe(DAD)2 2. Je nach Größe der DAD-Substituenten addieren sie nicht, langsam oder rasch reversibel Kohlenoxide zu den diamagnetischen, labilen, tiefgrünen (DAD)2Fe(CO) 6 bzw. irreversible zu den stabilen, roten (DAD)Fe(CO)3 8. Auch Isocyanide zeigen unter Addition zu analogen 7 und 10 entsprechende Farbreaktionen. Ebenso wird mit Dicyan, Nitrosylchlorid oder Diazoalkan Addition beobachtet. An sterisch nicht zu anspruchsvolle 2 werden zwei Moleküle Acetylendicarbonester unter C—C-Verknüpfung zu einem tiefblauen, luftstabilen Ferracyclopentadien 9 addiert. Eine Einkristall-Röntgenstrukturanalyse an monoklinem 9b wurde durchgeführt. Das C2-symmetrische Komplexmolekül enthält zwei DAD-Chelatliganden und einen chelatgebundenen Tetrakis(alkoxycarbonyl)-1,3-butadien-1,4-diyl-Liganden am oktaedrisch koordinierten Eisen(II)-Zentrum.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 694-701 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diazadiene als Steuerliganden in der Katalyse, 51). Synthese chiraler Diazadiene R* - N = CR' - CR' = N - R*Die im Prinzip einfache Kondensationsreaktion von Glyoxal (als Hydrat) und 2,3-Butandion mit primären Aminen führt leider bei aliphatischen Aminen mit tertiärem bzw. sekundärem α-Kohlenstoff oftmals zu unerwünschten Additionsprodukten. Unter speziellen Synthesebedingungen können mit (R)-1-Phenylethylamin (1) und (1S,2S,3S,5R)-3-(Aminomethyl)pinan die gewünschten Diimine (Diazadiene (dad): R* - N = CR' - CR' = N - R*, R' = H, CH3) 4, 6 - 8 erhalten werden. Aus (S)-2-Amino-1-butanol (3) werden je nach Dion-Komponente ein Morpholinomorpholin 9 bzw. ein Bioxazolidin 10 gebildet, die von elektronenreichen Metallen in ihrer isomeren Form als Diazadiene gebunden werden ((dad)Mo(CO)4 11 und 12). Die offenkettige dad-Form ist durch O-Silylierung (14, 15) stabilisierbar. Die (dad)Eisen(0)-katalysierte Dimerisierung von Butadien zu 4-Vinyl-1-cyclohexen mit diesen dad-Liganden ergibt Enantiomerenüberschüsse e.e. bis zu 16%.
    Notes: The condensation of glyoxal (as hydrate) or 2,3-butanedione with primary amines is, in principle, a simple reaction. Unfortunately, aliphatic amines with secondary or tertiary α-carbons often give unwanted addition products. Under special reaction conditions the desired diimines (diazadienes (dad): R* - N = CR' - CR' = N - R*, R' = H, CH3) 4, and 6 - 8 are obtained from (R-1-phenyl-ethylamine (1) and (1S,2S,3S,5R)-3-(aminomethyl)pinane (2). Depending on the dione, a morpholinomorpholine 9 and a bioxazolidine 10 are formed from (S)-2-amino-1-butanol (3), which are bound by electron-rich metals in their isomeric dad form ((dad)Mo(CO)4 11 and 12). The acyclic dad structure is stabilized by O-silylation (14, 15). The (dad)iron(0) catalyzed dimerization of butadiene with these controlling ligands to 4-vinyl-1-cyclohexene occurs with an enantiomeric excess up to 16%.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...