Khomutov E. Mechanochemical reactions of platinum halogene complexes with methyl iodide and unsaturated hydrocarbons

Mechanical treatment of solid salt K2PtХ6 (X = Cl, Br) leads to both a homolytic and heterolytic cleavage of Pt-Cl bond accompanied by formation of a paramagnetic complexes Pt(III) and Lewis's acid centers (LAC), respectively. Treatment of K2PtCl4 leads only to heterolytic cleavage Pt-C bond. The pre-activated solid K2PtCl4 consumes methyl iodide with methyl chloride liberation. The reaction mechanism includes MeI oxidative addition to Pt(II) with electrophilic assistance by LAC yeilding methyl platinum(IV) complexes. The latter species decompose in result of reductive elimination. The pre-activated in the atmosphere of acetylene or propylene K2PtCl6/K2PtCl4 mixture (10 mol.%) catalyze, acetylene hydrochlorination by gaseous HCl. The reaction proceed on the contact pair Pt(II)-Pt(IV) via the sequence: chlorplatination acetylene by the coordinatively unsaturated complexes Pt(IV) with ?-chloro vinyl platinum(IV) formation, the complementary reduction of this intermediate by Pt(II) to yield the corresponding Pt(II) derivative, and the protolysis of the latter species forming vinyl chloride and regenerating of active site of the catalyst