Pentacoordinate [PtCl2(eta(2)-C2H4)(N-N')] complexes with asymmetrically hindered nitrogen donor chelates. Stereospecific synthesis of syn- and anti-[PtCl(eta(1)-CH2CH2OMe)(Mebpy)]

Synthesis and characterization of the new pentacoordinate [PtCl2(eta(2)-C2H4)(Mebpy)] and square planar [PtCl2(Mebpy)] complexes both containing the asymmetrically hindered nitrogen donor chelate Mebpy = 6-Methyl-2,2'-bipyridil are reported. By nucleophilic addition of MeO- to the coordinated ethene of [PtCl2(eta(2)-C2H4)(Mebpy)], syn-[PtCl(eta(1)-CH2CH2OMe)(Mebpy)] and anti-[PtCl(eta(1)-CH2CH2OMe)(Mebpy)] complexes have been obtained as the kinetic and thermodynamic product, respectively. The mechanism for selective formation of both stereoisomers is also reported. This synthetic route opens new perspectives for the stereospecific synthesis of syn- and anti-square planar organometallic complexes.