C-H bond activation of methane with gaseous [(CH3)Pt(L)]+ complexes (L = pyridine, bipyridine, and phenanthroline)

Electrospray ionization of solutions of dimethyl(1,5-cyclooctadiene)platinum(II) in methanol with traces of nitrogen-containing ligands L provides gaseous complexes of the type [(CH3)Pt(L)](+) with L = pyridine (py), 2,2'-bipyridine (bipy), and 1,10-phenanthroline (phen). These [(CH3)Pt(L)](+) cations ire capable of activating the C-H bond in methane as shown by H/D exchange when using CD4 as a neural reactant. Most reactive is the complex [(CH3)Pt(py)](+) bearing a monodentate nitrogen ligand. The cationic complexes [(CH3)Pt(bipy)](+) and [(CH3)Pt(phen)](+) also bring about activation of methane, though at a lower rate, whereas the bipyridine complex [(CH3)Pt(PY)(2)](+) does not reach with methane at thermal conditions. A detailed analysis of the experimental data by means of kinetic modeling provides insight into the underlying mechanistic steps, but a distinction whether the reaction occurs as a bond metathesis or via an oxidative addition cannot be made on the basis of the experimental data available.