Alkyl(hydrido)platinum(IV) Complexes: The Mechanism of Pt-C Bond Protonolysis
摘要:
The complexes [PtMe(2)(N-N)] {N-N = (t)bu(2)-bpy (4,4'-di-tert-butyl-2,2'-bipyridine), bpy (2,2'-bipyridine), or phen (1,10-phenanthroline)} react with HX(X = Cl, Br, I, O2CCF3, SO3CF3) to yield [PtXMe(N-N)] and CH4, by an oxidative addition/reductive elimination mechanism. The new alkyl(hydrido)platinum(IV) intermediates [PtCl(H)Me(2)((t)bu(2)bpy)])] (1), [PtBr(H)Me(2)((t)bu(2)bpy)] (2), [PtH(I)Me(2)((t)bu(2)bpy)] (3), and [Pt(Cl(H)Me(2)(bpy)], (4), formed by trans oxidative addition of HX; have been fully characterized at -78 degrees C by H-1 NMR spectroscopy. Rapid reductive elimination of CH4 ensues at higher temperatures to yield the corresponding organoplatinum(II) products [PtXMe(N-N)]; The thermal stability of the platinum(IV) intermediates follows the sequence X = Cl > Br > I > O2CCF3, SO3CF3.