- Synthesis and Site-selective Protonation of MoPt and WPt Bimetallic Complexes
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The reaction of PF6 1 (M = Mo or W, cp = η-C6H5) with proceeds rapidly with a 1:2 (M:Pt) stoichiometry to give 4 and PF6 5.However, using an initial 1:1 stoichiometry the final product is PF6 8.The mechanisms of these reactions are shown to involve deprotonation of 1 to give 2 followed by reaction of the latter with and subsequent transfer of CO from M to Pt to give 4.Protonation of 4 with HBF4 is metal (M) dependent and proceeds to give BF4 12a with M = Mo but for M = W the major product is BF4 13b.Variable-temperature (1)H NMR studies show that the terminal hydride cation of 13b is rapidly equilibrating with a small amount of the hydride-bridged isomeric cation (1+).Complex 4 reacts with PPh3 (60 deg C) and 1,2-bis(diphenylphosphino)ethane (dppe) at 20 deg C to give 9 and 10.On bubbling CO through a solution of 9 (20 deg C) complex 4 is rapidly regenerated.Reaction of 4 with HCl gives 15.The molecular structure of 4b has been determined by single-crystal X-ray diffraction.
- Powell, John,Sawyer, Jeffery F.,Smith, Stuart J.
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- Formation of cationic MPt heterobimetallic μ-phosphido μ-hydrido complexes
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The cationic secondary phosphine complexes [CpM(CO)(L)(PR2H)]+X- (M = Ru, PR2H = PPh2H, PPhH2, L = CO; M = Fe, PR2H = PPh2H, L = CO, MeC≡CMe, C2H4; M = Mn PR2H = PCy2H, PPr2H, L = NO; X- = BF4-, PF6-) and [(η7-C7H7)(CO)2Mo(PCy2H]PF6, prepared by following literature procedures for the synthesis of their PPh3 analogues, react with Pt(C2H4)(PPh3)2 to give [Cp(L)M(μ-PR2)(μ-H)Pt(PPh3)2]X and [(η7-C7H7)(CO)Mo(μ-PCy2) (μ-H)Pt(PPh3)2]X as the final products. The reactions proceed by one or both, of two possible reaction pathways. One pathway involves the initial oxidative addition of a P-H bond to the Pt(0) complex to give [Cp(CO)LM(μ-PR2)PtH(PPh3)2]X followed by PPh3 loss from Pt and CO transfer from M to Pt (via a bridging CO). The rate of this CO-transfer step is sterically driven, in a manner similar to that observed for ortho-metalation reactions. The more acidic (P-H) secondary phosphine complexes react with Pt(0) complexes by a route that involves deprotonation of the coordinated secondary phosphine to give a phosphidometal complex, which then substitutes a ligand from Pt(0) followed by CO transfer to Pt. Several complexes of this type (PR3 = PCy3) were prepared and studied from the reaction of [CpM(CO)(L)(PR2H)]+ with Pt(C2H4)2(PCy3).
- Powell,Fuchs,Gregg,Phillips,Stainer
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p. 387 - 393
(2008/10/08)
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- PROTONATION OF TERTIARY PHOSPHINE PLATINUM(0) COMPLEXES BY AMMONIUM ION. CHARACTERIZATION AND SOME REACTIONS OF THE RESULTING HYDRIDES
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The platinum(0) complexes Pt(PR3)2 (R3=(t-Bu)3 and (t-Bu)2Ph) react readily with the ammonium salts NH4X (X=PF6 and ClO4) to give the cationic ammine hydrides trans-X.Reaction of Pt(PPH3)3 with NH4PF6 affords PF6.The ammine hyd
- Goel, Ram G.,Srivastava, Ramesh C.
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p. 303 - 310
(2007/10/02)
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