Self-assembly of Pd2L2 Metallacycles Owning Diversely Functionalized Racemic Ligands.

We present herein the efficient palladium(II)-directed self-assembly in water of a series of nine new diversely functionalized metallacycles, owning hydroxy/alkoxycarbonyl/azidoalkyl exo pendant groups attached to ditopic N-monoalkyl/aryl-4,4'-bipyridinium/2,7-diazapyrenium ligands. The highly convergent and versatile synthetic route for the ligands uses the Zincke reaction between (dinitrophenyl)bipyridinium/diazapyrenium salts and racemic amines as the key step. The stereochemical outcome of the self-assembly of the Pd2L2 species is discussed on the basis of density functional theory quantum-chemical calculations.