Mononuclear and Trinuclear Palladium(II) Complexes of Single- and Three-Ring Benzyl- or Xylyl-Substituted Cyclam Derivatives

A selection of 1 : 1 (palladium/ligand) complexes of cyclam derivatives incorporating from one to three N-benzyl groups has been synthesized. Related 3 : 1 species of two symmetrically branched, tri-cyclam species incorporating 1,3,5-?tribenzyl' or phloroglucinol cores are also reported. The X-ray crystal structures of the palladium complexes of two isomeric forms of the N,N?-dibenzylated (single-ring) macrocycle have been determined. In each complex the palladium ion occupies the N4-plane of the respective macrocycles in a square planar arrangement, with each complex cation adopting a stable trans-III configuration.