Haloalkane C−X Bond Activation by a Ruthenium(II) Complex:  X-ray Characterization of a Ruthenium(III) Intermediate Species in the Atom Transfer Radical Polymerization of Methyl Methacrylate

The binuclear Ru(II) N 2 -bridged complex [{RuCl 2 (NN‘N)} 2 (μ-N 2 )] ( 1; NN‘N = 2,6-bis[(dimethylamino)methyl]pyridine) promotes the atom transfer radical polymerization (ATRP) of methyl methacrylate under mild conditions. The intermediate paramagnetic Ru(III) species mer -[RuCl 3 (NN‘N)] ( 2 ) has been isolated and characterized by X-ray diffraction methods. The reaction of 1 with CH 2 Cl 2 gives the dichloromethyl Ru(II) complex [RuCl(CHCl 2 )(NN‘N)] ( 3 ).