119478-62-5Relevant articles and documents
Electronic and steric effects in the dissociative displacement of thioethers from mixed phenyl(thioether)platinum(II) complexes
Alibrandi, Giuseppe,Minniti, Domenico,Scolaro, Luigi Monsù,Romeo, Raffaello
, p. 1939 - 1943 (2008/10/08)
A series of compounds of the type cis-[PtPh2L2], where L encompasses a wide range of thioethers of different steric and electron-donating characteristics, have been prepared and characterized. Most of these monomeric compounds exist in solution in equilibrium with the sulfur-bridged dimer [Pt2Ph4(μ-L)2] and the free thioether. Addition of small amounts of ligand in solution allows the stabilization of the monomeric form. Kinetic studies of the displacement of the thioethers with 2,2′-bipyridine (bpy) to yield [PtPh2(bpy)] in CH2Cl2 at 298.16 K, carried out in the presence of sufficient excess of [L] and [bpy] to ensure pseudo-first-order conditions, showed that the reactions follow a bivariate nonlinear rate law kobsd = a[bpy]/(b[L] + [bpy]) + c[bpy], which has the same form as that of similar systems for which a dissociative mechanism has been proposed. The reactivity decreases linearly with increasing σ-donor ability of the leaving thioether, with bulky substituents on sulfur playing an accelerating role. The relative sensitivities of the dissociative and associative processes to the inductive effects of the leaving group are compared and related to the degree of lengthening and weakening of the bond with the metal produced by the trans-activating group.
