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  • Acetylacetone, hexafluoro-  (1)
  • Dinuclear complex  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Specific Chelate Tuning of the Substitution Kinetics of Platinum(II) Complexes in Aqueous Solution (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 389-396 
    Details
    ISSN: 1434-1948
    Keywords: Substitution mechanism ; Platinum ; Pressure dependence ; Kinetics ; Dinuclear complex ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Both reaction steps observed for the substitution of water by thiourea in the complexes [Pt(en)(OH2)2]2+ and [Pt(phen)(OH2)2]2+ (en = ethylenediamine, phen = 1,10-phenanthroline) were investigated under pseudo-first-order conditions using the stopped-flow technique. The substitution of the second water molecule in each complex was also studied under high pressure. The observed pseudo-first-order rate constants kobs (s-1) obeyed the equation k1,2obs= k1,2[tu] (tu = thiourea), where “1” and “2” refer to the first and the second substitution reactions, respectively. Kinetic parameters associated with the substitution process are: k1en (25.0°C, pH = 3.0, I = 0.1 M) = 25.6 M-1 s-1, ΔH# = 51 kJ mol-1, ΔS# = -48 J K-1 mol-1; k2en (same conditions) = 12.1 M-1 s-1, ΔH# = 30 kJ mol-1, ΔS# = -124 J K-1 mol-1, ΔV# = -7 cm3 mol-1; k1phen (25.0°C, pH = 1.0, I = 0.1 M) = 2900 M-1 s-1, ΔH# = 41 kJ mol-1, ΔS# = -41 J K-1 mol-1; k2phen (same conditions) = 1170 M-1 s-1, ΔH# = 37 kJ mol-1, ΔS#= -61 J K-1 mol-1, ΔV# = -5 cm3 mol-1. The temperature and pressure dependence of all the processes studied suggest an associative substitution mechanism. The hydroxo-bridged dinuclear complex [{Pt(phen)(μ-OH)}2]2+ is formed from [Pt(phen)(OH2)2]2+ in aqueous solution unless the solution is very dilute and highly acidic. The X-ray structure of [{Pt(phen)(μ-OH)}2](F3CSO3)2 · 2 H2O was determined. It belongs to the triclinic space group P1­ and has one formula unit in the unit cell. The unit cell dimensions are a = 7.126(5), b = 9.665(5), c = 12.774(7) Å; α = 71.85(5), β = 85.52(5), γ = 73.12(5) deg; V = 799.9(8) Å3. The structure was solved with the Patterson method and refined to R = 0.061. A square planar coordination of the platinum centers is observed, with no deviations from planarity but distortions due to the small bite angle of phen and the four-membered ring. No significant lengthening of the Pt-O bond [mean value: 2.03(1) Å] is observed in comparison with [{Pt(NH3)2(μ-OH)}2]2+.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    A Spectroscopic and Mechanistic Study of the Enolization and Diol Formation of Hexafluoroacetylacetone in the Presence of Water and Alcohol (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 315-320 
    Details
    ISSN: 0009-2940
    Keywords: Acetylacetone, hexafluoro- ; Diol formation / Enolization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Eine spektroskopische und mechanistische Untersuchung der Enolisierung und Diol-Bildung von Hexafluoracetylaceton in Gegenwart von Wasser und AlkoholDie Reaktionen von Hexafluoracetylaceton (Hfac) (6) mit Wasser, Methanol, Ethanol und Isopropylalkohol wurde im einzelnen anhand von 1H-, 13C-, 17O-, 19F-NMR- und UV-VIS-Spektroskopie untersucht. Dabei konnten die Zwischen- und Reaktionsprodukte bei der Enolisierung und Diol-Bildung spektroskopisch identifiziert werden. Die vorgeschlagenen Reaktionswege werden unter Bezug auf früher in der Literatur berichtete Daten diskutiert. Ein wichtiges Ergebnis dieser Untersuchung ist der direkte Nachweis für die Bildung der Addukt-Spezies Hfac(OH)4 (10), Hfac(OMe)2 (13a) und Hfac(OEt)2 (13b).
    Notes: The reactions of hexafluoroacetylacetone (hfac) (6) with water, methanol, ethanol, and isopropyl alcohol were studied in detail using 1H-, 13C-, 17O-, 19F-NMR, und UV-VIS spectroscopy. The reported spectra enable the identification of intermediate and product species, and allow a mechanistic analysis of the enolization and diol formation. The suggested mechanisms are discussed with reference to earlier data reported in the literature. An important feature of this study is the direct evidence presented for the formation of the adduct species hfac(OH)4 (10), hfac(OMe)2 (13a), and hfac(OEt)2 (13b).
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220218
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    Paper (German National Licenses)
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