Synthesis of chiral atropoisomeric square-planar nickel(II) and copper(II) complexes formed by macrocyclic ligands containing pendant polyether groups and a quaternary ammonium group

Abstract

Novel copper(II) and nickel(II) complexes of macrocyclic Schiff bases formed from derivatives of N,N′-bis(2-benzoylphenyl)oxamide and 1,2-diaminoethane have been prepared. In one case, separation of atropoisomeric chiral complexes has been achieved by preparative chromatography on SiO₂. Quaternization of some of the complexes with an excess of MeI affords chiral complexes possessing a positively charged quaternary ammonium group and polyether podands in addition to a weakly electrophilic metal site.