- Thermal decomposition of platinum(IV)-silicon, -germanium, and -tin complexes
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The thermal decomposition of a number of complexes of the type [PtMe2(Me3E)X(diimine)] (E = Si, Ge, Sn; X = Cl, Br, I) has been studied. The thermal stability of complexes, as determined by thermogravimetric analysis (TGA), varies depending on the diimine ligand in the order 2,2′-bipyridyl (bpy) > 4,4′-di-tert-butyl-2,2′-bipyridyl (bpy-tbu2) > N-(2-(dimethylamino)ethyl)pyridine-2-aldimine (paen-me2) > (2-imino-n-propyl)pyridine (py-n-pr). Stability also varies according to the trends E = Sn ≈ Ge > Si and X = I > Br > Cl. The products of thermal decomposition have also been determined by 1H NMR and three distinct modes of decomposition are evident: reductive elimination of Me3EX, reductive elimination of Me4E, and α-elimination of Me2E. The competition between reductive elimination of Me3EX and Me4E depends primarily on the halide, X, with the ratio Me3EX:Me4E highest for X = Cl and lowest for X = I. The competition between reductive elimination and α-elimination depends primarily on E, with the tendency to α-elimination of Me2E increasing as E = Si 2(Me3Si)(bpy)] as 233 ± 14 kJ mol-1.
- Levy, Christopher J.,Puddephatt, Richard J.
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p. 4115 - 4120
(2008/10/08)
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- Complexes with PtAu and PtAg bonds: Catalysis by silver(I) of alkyl exchange reactions between platinum centers
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The electron-rich platinum(II) complex [PtMe2(2,2′-bpy)] (1, bpy = bipyridine) reacts with [Au(NO3)(PPh3)], [Au(BF4)(PPh3)], [Au(PF6)(PPh3)], [Ag(BF4)(PPh3)], and AgBF4 to give the Pt-M bonded complexes [PtMe2(bpy)(AuPPh3)]NO3 (3a), [PtMe2(bpy)(AuPPh3)]BF4 (3b), [PtMe2(bpy)(AuPPh3)]PF6 (3c), [PtMe2(bpy)(AgPPh3)]BF4 (3d), and [{PtMe2(bpy)}2Ag]BF4 (4), respectively. These compounds are shown to contain PtAu or PtAg bonds by their 1H, 31P, and 195Pt NMR spectroscopic properties. Complexes 3c and 4 were isolated in analytically pure form, but 3a, 3b, and 3d were too unstable thermally to characterize by elemental analysis. The Pt-Au bonded complexes appear to be the first such binuclear complexes to have been characterized unambiguously. Decomposition of the complexes occurs with formation of Ag or Au metal and equimolar amounts of Me3PtIV and MePtII derivatives. AgBF4 catalyzes the exchange of CH3 and CD3 groups between [PtMe2(bpy)] and [Pt(CD3)2(bpy)], as analyzed by MS, or between [PtMe2(1,10-phen)] (phen = phenanthroline) and [Pt(CD3)2(bpy)], as analyzed by 1H NMR.
- Arsenault, Gilles J.,Anderson, Craig M.,Puddephatt, Richard J.
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p. 2094 - 2097
(2008/10/08)
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