Complexes of pendant-armed cyclam derivatives with copper(II) perchlorate: Synthesis and crystal structures

A designed series of cyclam type macrocyclic ligands 1–3 that feature a different degree of saturation and number of functional appendages of the macroring, including preparation of the respective Cu(II) perchlorate complexes 1a–3a, was synthesized. Comparative discussion of the X-ray crystal structures of the free ligands and the corresponding complexes shows that dependent on the structure of the compound, transanular, pendant arm and anion involving conventional and weaker H bond contacts are operating. In the complexes, the coordination environment around the Cu(II) cation is distorted octahedral with the nitrogens of the macroring defining the equatorial sites and either two oxygens, each of a perchlorate anion, or the lateral pyridine nitrogens in apical positions. Thus, only the pyridine containing pendants in 3a proved effective in metal ion coordination while the anisyl groups are engaged in H bonding, respectively. The uncomplexed macrocycle 3 yielded an inclusion compound with chloroform, also indicating a special ability relating to this series of compounds.

Preparation and X-ray crystal structures of a designed series of cyclam type macrocyclic ligands that feature a different degree of saturation and number of functional appendages of the macroring, including corresponding complexes with Cu(II) perchlorate are reported and comparatively discussed. Dependent on the nature of the compound, transanular, pendant arm and anion involving conventional and weaker H bond contacts are shown to be operating in the formation of the crystal structures.Figure optionsDownload as PowerPoint slide