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  • 1
    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.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    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.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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