Nucleophilic attack of methanol on bis(benzonitrile)dichloroplatinum: formation of mono- and bis-imido ester derivatives

Abstract

The trans and cis isomers of [PtCl₂(NCPh)₂] react stepwise with methanol, under basic conditions, to give the mono- and bis-imido ester derivatives [PtCl₂(NCPh){HNC(OMe)Ph}] and [PtCl₂{HNC(OMe)Ph}₂]. The isomerization about the CN double bond is slow enough to allow separation of species with different conformations of the imido ester ligands (E or Z). Under basic conditions the isomerization becomes faster and takes place through reversible addition of an extra methoxide ion to the carbon atom of the azomethine residue. The composition of the isomeric mixture, in the case of the bis(imido ester) derivatives, indicates that the E conformation is slightly preferred over Z. This preference is more marked in the cis than in the trans complexes.