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  • Wiley-Blackwell  (11)
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  • 1
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of α-Ketoenamines to 2-Acetyl-p-benzoquinoneAddition of 2-morpholino-2-cyclohex-1-en-one 2 to 2-acetyl-quinone 1 yields benzo[c][4 H]chromen-4,7,10-trion 4 which is unstable and rearranges to 5. 4 is converted to 3-(2,5-dihydroxy-phenyl)-2-morpholino-2-cyclohex-1-en-on 3 thermically and to dibenzo[b,d]furan-4-on 7 acid catalyzed. The structure of 7 is secured by independent synthesis. Dibenzo[b,d]furan-4-on 14 is the product of reaction from 2-(p-toluidino)-2-cyclohex-1-en-on 9 and 1 with benzo[c][4 H]chromen-4,7,10-trion 10 as intermediate. By proton catalysis 5-acetyl-6-hydroxy-carbazol-1-on 13 and 4-oxo-cyclohexa[c]isochinolinium hydrochlorid 15 is obtained from 10. 1 H-cyclopenta[d]furan-3-on 17 is formed by addition of 2-(p-toluidino)-2-cyclopent-1-en-on 16 to 1. It is rearranged by proton catalysis to 3-oxo-1 H-cyclopenta[c]isochinolinium salt 18. Reaction of cyclopentan-1,2-dione and 1 yields 3 aH-cyclopenta[c]isochromen-3,6,9-trion 20, rearranging to 1 H-cyclopenta[b]benzo[d]furan-3-on 21. The stereochemistry of adducts is discussed in connection with the course of the reaction, spectroscopical evidence, molecular modelling and calculation of HOMO/LUMO and AO-coefficients.
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  • 2
    ISSN: 0044-2313
    Keywords: Chromium carbonyl complexes of the iPr2(Me3Si)P7: iPr2(H)P7[Cr(CO)5] ; iPr2(Me3Si)P7[Cr(CO)5] ; iPr2(H)P7[Cr(CO)5]2 ; iPr2(Me3Si)P7[Cr(CO)5][Cr(CO)4] (three isomers) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. VII Carbonyl Complexes of the Heptaphosphane(3) iPr2(Me3Si)P7From the reaction of iPr2(Me3Si)P7 1 with one equivalent of Cr(CO)5THF the yellow products iPr2(H)P7[Cr(CO)5] 2 and iPr2(Me3Si)P7[Cr(CO)5] 3 were isolated by column chromatography on silicagel. The P—H group in 2 results from a cleavage of the P—SiMe3 bond during chromatography. The Cr(CO)5 group in 2 is linked to an iPr—Pe atom, in 3 to the Me3Si—Pe atom of the P7 skeleton. The substituents do not force the formation of a single isomer; nevertheless 3 ist considerably favoured as compared to 2. From the reaction of 1 with 2 equivalents of Cr(CO)5THF the yellow iPr2(H)P7[Cr(CO)5]2 4 was isolated bearing one Cr(CO)5 group at an iPr—Pe atom, the other one at a Pb atom of the P7 skeleton.Compound 3 yields with Cr(CO)4NBD the red iPr2(Me3Si)P7[Cr(CO)5][Cr(CO)4] 5. Three isomers of 5 appear. Two Pe atoms of 5 are bridged by the Cr(CO)4 group, the third Pe atom is linked to the Cr(CO)5 ligand. iPr2(H)P7[Fe(CO)4] was isolated from the reaction of 1 with Fe2(CO)9. 31P NMR and MS data are reported.
    Notes: iPr2(Me3Si)P7 1 bildet mit einem Mol Cr(CO)5THF die gelben Verbindungen iPr2(H)P7[Cr(CO)5] 2 und iPr2(Me3Si)P7[Cr(CO)5] 3, die nach der chromatographischen Trennung auf einer Kieselgelsäure isoliert wurden. Die Ausbildung der P—H-Gruppe in 2 wird auf die Spaltung der P—SiMe3-Gruppe der Komplexverbindung bei der chromatographischen Trennung zurückgeführt. Die Cr(CO)5-Gruppe in 2 ist an die iPr—Pe-Gruppe, in 3 an die Me3Si—Pe-Gruppe des P7-Gerüstes gebunden. Die Substituenten beeinflussen die Komplexbildung nicht streng selektiv, jedoch ist Verbindung 3 gegenüber 2 deutlich begünstigt. Mit 2 Mol Cr(CO)5THF bildet 1das iPr2(H)P7[Cr(CO)5]2 4, in dem eine Cr(CO)5-Gruppe an eine iPr—Pe-Gruppe, die andere an ein Pb-Atom des P7-Gerüstes gebunden ist.Verbindung 3bildet mit Cr(CO)4NBD das rote iPr2(Me3Si)P7[Cr(CO)5][Cr(CO)4] 5, von dem drei Diastereomere auftreten. In 5 überbrückt die Cr(CO)4-Gruppe zwei Pe-Atome, an das dritte Pe-Atom ist die Cr(CO)5-Gruppe gebunden. Mit Fe2(CO)9 bildet 1das iPr2(H)P7[Fe(CO)4]. Es werden die Daten der 31P-NMR-Spektren und der massenspektrometrischen Untersuchung angegeben.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 602 (1991), S. 73-78 
    ISSN: 0044-2313
    Keywords: 1,2,3,4-Tetrakis(di-tert-butylphosphanyl)-cyclo-tetraphosphane ; 31P n.m.r. ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Cyclotetraphosphane P4[P(tBu)2]4P4[P(tBu)2]4 1 is obtained by thermal decomposition (20°C) of (tBu)2P—P = P(tBu)2Br which is formed from [(tBu)2P]2PLi and 1,2-dibromoethane. The 31P NMR spectrum of 1 shows two complex signal patterns of the AA′ A″ A‴ XX′X″X‴ type; δ = +63 ppm (exocyclic) and δ = -43 ppm (cyclic).1 crystallizes monoclinic in the space group C2/c, (a = 2240.8(17) pm, b = 885.6(7) pm, c = 2221.8(14) pm, β = 101.72(5)°) with Z = 4 molecules in the elementary cell. The molecule has E conformation. The four-membered ring is folded (dieder angle 61°) to give the P(tBu)2 groups nearly equatorial and the lone pairs nearly axial positions.
    Notes: P4[P(tBu)2]4 1 entsteht bei der thermischen Zersetzung des (tBu)2P—P = P(tBu)2Br bei 20°C, das sich aus [(tBu)2P]2PLi und 1,2-Dibromethan bildet. Das 31P-NMR-Spektrum von 1 enthält zwei komplexe Signalgruppen; δ = +63 ppm (exocyclisch) und δ = -43 ppm (cyclisch). Es liegt ein AA′ A″ A‴ XX′X″X‴ Spinsystem vor. 1 kristallisiert monoklin in der Raumgruppe C2/c, a = 2240,8(17) pm, b = 885,6(7) pm, c = 2221,8(14) pm, β = 101,72(5)° mit Z = 4 Molekülen in der Elementarzelle. Das Molekül besitzt E-Konformation. Der Vierring ist gefaltet, Diederwinkel 61°. Dadurch nähern sich die P(tBu)2-Gruppen einer äquatorialen und die nichtbindenden Elektronenpaare am Phosphor einer axialen Position.
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  • 4
    ISSN: 0044-2313
    Keywords: Tetrakis(di-tert.-butylphosphino)diphosphane ; [(tBu)2P]2P—P[P(tBu)2]2 ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Crystal Structure of Tetrakis(di-tert.-butylphosphino)diphosphane [(tBu)2P]2P—P[P(tBu)2]2[(tBu)2P]2P—P[P(tBu)2]2 1 obtained at -20°C from a solution of (tBu)2P—P=P(Br)tBu2 forms yellow crystals (regular hexagons). 1 crystallizes monoclinic in the space group C2/c with a = 2145.6pm, b = 1137pm, c = 1696.1pm, β = 110.075° and Z = 4 formula units in the elementary cell. Due to high steric load the bond angles at the tertiary P atoms with δ = 115.7° are significantly larger than those at the primary P atoms with δ = 108.6°.
    Notes: [(tBu)2P]2P—P[P(tBu)2]2 1 sich aus (tBu)2P—P(Br)tBu2 (toluolische Lösung, -20°C) und fällt als gelbe Kristalle (regelmäßige Sechsecke) aus. 1 kristallisiert monoklin in der Raumgruppe C2/c mit den Gitterkonstanten a = 2145,6pm, b = 1137pm, c = 1696pm, β = 110,75°. Die Elementarzelle enthält 4 Formeleinheiten. Die Bindungswinkel an den tertiären P-Atomen mit δ = 115,7° sind infolge der hohen sterischen Belastung der tert. P-Atome gegenüber denen an den primären P-Atomen mit δ = 108,6° deutlich aufgeweitet.
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  • 5
    ISSN: 0044-2313
    Keywords: Reaction of (tBu)2P—P=PX(tBu)2 (X = Br, Cl) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation and Reaction of the Phosphanylidene-phosphorane (tBu)2P—P = PX(tBu)2 (X = Br, Cl)The formation of (tBu)2P—P = P(Br)tBu2 1 from [(tBu)2P]2PLi and BrH2C—CH2Br begins with an exchange of Li against Br and is then determined by the migration of Br from the secondary P atom in [(tBu)2P]2PBr 6 to the primary P in 1. Similarly, (tBu)2P—P = PC1(tBu)2 2 is obtained starting from PCl3 and LiP(tBu)2. The formation of Phospanylidene - phosporane is not influenced by the choice o the halogene substituent, but the presence of the tBu groups is strongly required. (tBu)2P—P(Li)—P(SiMe3)2 e. g., yields (tBu)2P—P(br)—P(SiMe3)2 with BrH2C—CH2Br; however neither this nor (tBu)2P—P(Cl)—P(SiMe3)2 do rearrange to a Phosphanylidene-phosphorane. The F3C substituent could be neglected in this investigation as [(F3C)2P]2P—SiMe3 cannot be lithiated by means of BuLi.Compounds 1 and 2 display a charateristic temperature dependent behavior. While 1 at +20°C decomposes via the reactive intermediate (tBu)2P—P to from the cyclophosphanes P3[P(tBu)2]4, it gives crystals of [(tBu)2P]2P—p[P(tBu)2]2 at -20°C (from a solution in toluene).Reacting 1 with tBuLi produces (tBu)2P—P = P(H)tBu2 20 and (tBu)2P—P(H)—P(tBu)2 14. Initially, a transmetallation yield tBuBr and (tBu)2 P—P=Pli(tBu)2 21,then LiBr and isobutene are eliminated and 20 is formed which can rearrange to produce 14. Without the elimination of isobutene, 1 react with nBuLi to give 21 witch can be trapped with Me3SiCl as (tBu)2P—P(tBu)223. The main product in in this reaction is however [(tBu)2P]2P—nBu 22.
    Notes: Dei Bildung von (tBu)2P—P = P(Br)tBu2 1 aus [(tBu)2P]2PLi und BrH2C—CH2Br wird eingeleitet durch den Lithium-Brom-Austausch und ist bedingt durch die anschließende Br-wanderung vom sekundären P-Atom im [(tBu)2P]2PBr 6 zum primären P-Atom in 1 Entsprechend bildet sich (tBu)2P—P = P(CI)tBu2 2 bei de Synthese von [(tBu)2P]2PC1 7 aus PC13 und Lip(tBu)2. Der Reaktionsablauf it unabhängig von den Halogensubstituenten, wird aber entscheidend beeinflußt durch die tBu-Gruppen. So bildet (tBu)2P—P(Li)—P(SiMe3)2 mit BrH2C—CH2Br das (tBu)2P—P(br)—P(SiMe3)2, das aber ebenso wie (tBu)2P—P(CI)—P(SiMe3)2 keine Umlagerung zm Phosphanyliden-Phosphoran eingeht. Der Ein1Uß der F3C-Gruppe auf die Umlagerung war nicht zu untersuchen, da [(F3C)2P]2P—SIMe3 auch mit BuLi nicht in das lithiierte Derivat zu überführen ist.1 und 2 zeigen charakteristische Reaktionen in Abhängigkeit von der Temperatur. Während 1 bei +20°C über das Reaktiv (tBu)2P—P die Cyclophosphane P3[P(tBu)2]4 bildet, Kristallisiert aus den Lösungen von 1 (z. B. Toluol) bei -20°C [(tBu)2P]2P—P[P(tBu)2]2.Die Umsetzungen von 1 mit tBuLi führen zu (tBu)2P—P=(H)tBu2 20 und (tBu)2P—P(H)—P(tBu)2 14. Dei Reaktion wird durch die Umlithiierung zwischen 1 und tBuLi zu tBuBr und (tBu)2P—P=P(Li)tBu2 21 eingeleitet, der unter LiBr-Abspaltung und Isobuten-Eliminierung die Bildung von 20 folgt, das zu 14 umlagert. 21 wird durch Reaktion von 1 mit nBuLi faßbar [Ausblieben der Buten-Eliminierung], das mit Me3SiCl zu (tBu)2P—P(SiMe3)—P(tBu)2 23 abreagiert. Hauptprodukt der Umsetzung ist [(tBu)2P]2P-nBu 22.
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  • 6
    ISSN: 0044-2313
    Keywords: Cr carbonyl complexes of Tris(trimethylsilyl)heptaphosphanortricyclene; ; (Me3Si)3P7[Cr(CO)5]1-3; ; (Me3Si)3P7[Cr(CO)5][Cr(CO)4]; ; (Me3Si)3P7[Cr(CO)5]2 × [Cr(CO)4]; ; (Me3Si)3P7[Cr(CO)5]3[Cr(CO)4] ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation and Structures of Chromium Carbonyl Complexes of Tris(trimethylsily)heptanortricyclane (Me3Si)3P7(Me3Si)3P7 1 reacts with one equivalent of Cr(Co)5THF 2 to give the yellow (Me3Si)3P7[Cr(Co)5]4. The Cr(Co)5group is attached to a Pe atom. Yellow (Me3Si)3P7[Cr(CO)5]2 5 is obtained either from reacting 1 with two equivalents of 2, or from 4 with one equivalent of 2. One Cr(CO)5 groups in 5 is coordinated to a Pe atom, the other one to a P,b atom. Similarly, Yellow (Me3Si)3P7[Cr(CO)5]3 6 results from reacting 5 with one equivalent of 2. Two Cr(CO)5 groups in 6 are linked to Pb atoms, and the third one either to a Pe or the Pa atom (assignment not completely clear).Derivatives containing a Pe bridge appear in reactions of 1 with higher amounts of 2. Such, 5 forms mixtures of the red compounds (Me3Si)3P7 × [Cr(CO)5]2[Cr(CO)4] 8 and (Me3Si)3P7[Cr(CO)5] × [Cr(CO)4] 9, and even preferably 9 with four equivalents of 2. In 8, one Cr(CO)5 group is attached to that pe atom which is not engaged in the Cr(CO)4 bridge, and the second to one of the Pb atoms directly adjacent to the bridge. The additional Cr(CO)5 group in 9 is coordinated to the remaining Pb atom directly adjacent to the bridge. In reactions of 5 with even higher amounts of 2, four Cr(CO)5 groups and one Cr(CO)4 bridge attach to the basic P7 skeleton to from the less stable Me3P7[Cr(CO)5]4[Cr(CO)4]. (Me3Si)3P7 1 reacts considerably slower with Cr(CO)5THF 2 than R3P7 (R = Et, iPr).Cr(CO)4NBD 3 reacts with 1, but it was not possible to isolate (Me3Si)3P7[Cr(CO)4]. However, 4 with 3 forms (Me3Si)3P7[Cr(CO)5][Cr(CO)4] 7, and 5 with 3 yields (Me3Si)3P7[Cr(CO)5]2[Cr(CO)4] 8.The structures of 4, 5, 7, 8 or 9 are quite analogous to those of the derivatives of Et3P7 but there exist significant differences in stability and reactivity. While Et3P7[Cr(CO)5]2 in solution rearranges to give the stable Et3P7[Cr(CO)5][Cr(CO)4], the analogous (Me3Si)3P7[Cr(CO)5][Cr(CO)4] 7 is not stable and is not obtained from (Me3Si)3P7[Cr(CO)5]2 5. Et3P7[Cr(CO)5]3 can just be detected spectroscopically and rearranges easily to give Et3P7[Cr(CO)5]2 [Cr(CO)4] whereas (Me3Si)3P7[Cr(CO)5]3 6 can be isolated. These differences are caused by the greater steric requirements of Me3Si groups. The formation of a Pe-Cr(CO)4-Pe bridge, e.g., requires a Me3Si group in 1 to switch from the s to the as position.Whereas many of the complex compounds of R3P7 (R = Et, iPr) crystallize easily, the analogous derivatives of (Me3Si)3P7 did not yield crystals. The structures of the products were assigned by evaluating the coordination shift in their 31P NMR spectra and by comparision of these spectra with those of such derivatives of Et3P7 which previously had been investigated by single crystal structure determinations.
    Notes: (Me3Si)3P7 1 bildet mit einem Mol Cr(CO)5THF2 (Me3Si)3P7[Cr(CO)5] 4 (gelb), in dem die Cr(CO)5-Gruppe an einem Pe-Atom gebunden ist. (Me3Si)3P7[Cr(CO5]2 5 (gelb) entsteht aus 1 mit zwei Mol Cr(CO)5THF 2 bzw. aus 4 mit einem Mol 2. In 5 ist eine Cr(CO)5-Gruppe an ein Pe-Atom, die zweite an ein Pb-Atom gebunden. (Me3Si)3P7[Cr(Co)5]3 6 (gelb) bildet sich aus 5 mit einem Mol 2. In 6 sind zwei Cr(CO)5-Gruppen an Pb-Atome gebunden, die dritte an das Pa- oder ein Pe-Atom (Zuordnung nicht eindeutig).Bei Umsetzungen von 1 mit höheren Molzahlen 2 bilden sich Derivate mit der Pe-Cr(CO)4-Pe-Brücke. So entstehen aus 5 mit zwei bzw. drei Äquivalenten 2 die roten Verbindungen (Me3Si)3P7[Cr(CO)5]2[Cr(Co)4] 8 und (Me3Si)3P7[Cr(Co)5]3[Cr(Co)4] 9, mit vier Äquivalenten 2 bevorzugt 9. In 8 verbrückt die Cr(Co)4- Gruppe zwei Pe- Atome. Eine Cr(Co)5-Gruppe ist an das dritte Pe- Atom Koordiniert, die zweite an ein Pb-Atom, das direkt mit dem Pe- Atom der Cr(Co)4-Brücke verbunden ist. 9 leitet sich von 8 ab durch Einführung einer weiteren Cr(Co)5-Gruppe an das zweite P6-Atom, das mit dem zweiten Pe-Atom an der Cr(Co)4-Brücke verbunden ist. Bei Umsetzungen von 5 mit noch höheren Molzahlen an 2 lagern sich an 1 insgesamt vier Cr(CO)5- und eine Cr(CO)4-Gruppe an unter Bildung einer weniger beständigen Verbindung (Me3Si)3P7[Cr(Co)5]4[Cr(CO)4]. (Me3Si)3P71 reagiert mit Cr(CO)5 THF 2 erheblich langsamer als R3P7 (R = Et, iPr).Die Umsetzung von 1 mit Cr(CO)4NBD 3 ermöglicht nicht die Isolierung von (Me3Si)3 P7[Cr(CO)4]. Jedoch bildet 3 mit (Me3Si)3P7[Cr(CO)5)] 4 (Me3Si)3P7[Cr(CO)5]× [Cr(CO)4] 7 und mit (Me3Si)3P7[Cr(CO)5]2 5 (Me3Si)3P7[Cr(CO)5]2[Cr(CO)4] 8.Die Verbindungen 4,5,7,8,9 entsprechen in ihrem Aufbau weitgehend den Derivaten des Et3P7, jedoch bestehen gravierende Unterschiede bezüglich Stabilität und Reaktivität. Während sich Et3P7[Cr(Co)5]2 in Lösung zum stabilen Et3P7[Cr(Co)5][Cr(Co)4] umlagert, ist das analoge (Me3Si)3P7[Cr(Co)5][Cr(Co)4] 7 instabil und wird nicht aus (Me3Si)3 P7[Cr(CO)5]2 5 gebildet. Et3P7[Cr(CO)5]3 ist nur spektroskopisch nachweisbar und lagert sich leicht um zum Et3P7[Cr(CO)5]2×[Cr(CO)4], während (Me3Si)3P7[Cr(CO)5]3 6 zu isolieren ist. Die Unterschiede sind durch den größeren Raumbedarf der Me3Si-Gruppe bedingt. So gehen die Me3Si- Gruppen am (Me3Si)3P7 bei Einführung der Pe-Cr(CO)4-Pe-Brücke aus ihrer s- in die as- Position über.Während die Komplexverbindungen des R3P7 (R = Et, iPr)teilweise gut kristallisieren, konnten von denen des (Me3Si)3P7 keine kristalle erhalten werden. Die Strukturen der Verbindungen wurden durch Auswertung der Koordinationsverschiebung im 31P-NMR Spektrum und durch Vergleich mit Spektren von - durch Kristallstrukturuntersuchung gesicherten - Derivaten des Et3P7 abgeleitet.
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  • 7
    ISSN: 0044-2313
    Keywords: [Li(DME)3]2{(SiMe3)[Cr(CO)5] 2 P—P = P—P[Cr(CO)5]2[(SiMe3)]} ; Bis[tris(1, 2-dimethoxyethan)lithium(1 +)]-1, 4-bis(trimethylsilyl)-1,1,4,4-tetrakis (pentacarbonylchrom(0))-tetraphos-2-phenat(2-) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. VII. Formation and Structure of [Li(DME)3]2{(SiMe3)[Cr(CO)5]2 P-P = P-P[Cr(CO)5]2(SiMe3)}Deep red crystals of the title compound 1 are produced in the reaction of LiP(Me3Si)2[Cr(CO)5] with 1, 2-dibromoethane in DME. The structure of 1 was derived from the investigation of the 31P-NMR spectra and confirmed by a single crystal structure determination. 1 crystallizes in the space group P1 (no. 2); a = 1307.8(5)pm, b = 1373.1(5)pm, c = 1236.1(4)pm, α = 106.22(4)°, β = 88.00(3)°, γ = 115.52(4)° and Z = 1. 1 forms a salt composed of a dianion R2R4′P42- (R = SiMe3, R′ = Cr(CO)5) and solvated Li+ cations. The zigzag shaped dianion possesses the symmetry 1-Ci. The distances d(P—P) = 202.5(1)pm and d(P—P) = 221.9(1)pm correspond to a double bond and single bonds, respectively. The distances d(Cr—P) = 251.1(1) pm and 255.3(1) pm are larger than those observed so far which might be caused by the charge distribution in the dianion.
    Notes: Bei der Umsetzung von LiP(SiMe3)2[Cr(CO)5] mit 1, 2-Dibromethan in DME entstehen die rubinroten Kristalle der Titelverbindung 1. Die Struktur von 1 folgt aus der Untersuchung der 31P-NMR-Spektren und der Einkristallstrukturbestimmung. 1 kristallisiert in der Raumgruppe P1 (Nr. 2); a = 1 307,8(5) pm. b = 1373,1(5) pm, c = 1236, 1(4) pm, α = 106,22(4)°, β = 88,00(3)°, γ = 115,52(4)° mit Z = 1. 1 bildet ein Salz aus einem Dianion R2R4′P42 (R = SiMe3, R′ = Cr(CO)5) und solvatisierten Li+-Kationen. Das gewinkelte Dianion hat die Symmetrie 1-C1. Die Abstände d(P—P) = 202,5(1) pm und (d)P—P = 221,9(1) pm entsprechen einer Doppelbindung bzw. Einfachbindungen. Die Abstände d (Cr—P) = 251,1(1) pm bzw. 255,3(1) pm sind größer als bisher beobachtete, was auf die Ladungsverteilung im Anion zurückgeführt wird.
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  • 8
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The suitability of an established myogenic line (L6) for the study of skeletal muscle intermediary metabolism was investigated. Myoblasts were grown in tissue culture for ten days at which time they had differentiated into multinucleated myotubes. Myotube preparations were then incubated for up to 96 hours in 10 ml of Dulbecco's modified Eagle medium containing 10% fetal calf serum. Glucose was utilized at a nearly linear rate, 3.0 nmol/min/mg protein. Intracellular glucose was detectable throughout the incubation, even when medium glucose was as low as 16 mg%. During the initial 28 hours of incubation, when net lactate production was observed, only 35% of the glucose utilized was converted to lactate. Alanine was produced in parallel to lactate at an average rate of 0.6 nmol/min/mg protein. In concert with active glutamine utilization, high rates of ammoniagenesis were observed as medium glutamine decreased from 3.3 mM to 0.49 mM and medium ammonia increased from 2.3 mM to 6.2 mM, between zero time and 96 hours of incubation, respectively. The cells maintained stable ATP and citrate levels, and physiologic intracellular lactate/pyruvate ratios (10-24) throughout 96 hours of incubation. These results suggest (1) glucose utilization by skeletal muscle in tissue culture is limited by phosphorylation, not transport; (2) as much as 50% of glucose-derived pyruvate enters mitochondrial pathways; (3) glutamine carbon may be utilized simultaneously with glucose consumption and this process accounts for high rates of ammoniagenesis.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0365-9496
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 10
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for measurement of PGF2α, PGE1, PGE2, 6-keto-PGF1α, TXB2, 2,3-dinor-TXB2 as well as 5-, 8-, 9-, 11-, 12-, 15-HETE and HHT, utilizing negative ion chemical ionization GC/MS is presented. A highly efficient separation and purification procedure prior to the derivatization sequence allows quantification of the arachidonic acid metabolites described in two GC/MS runs. The detection limit was in the femtomole range. Application of the method to the quantitative profiling of arachidonic acid metabolites in various tissues and incubation media is demonstrated.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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