Synthesis and characterization of mono- and heterodinuclear complexes with dicompartmental macrocyclic ligand containing hexa- and pentadentate coordination sites

A novel macrobicyclic heterobinuclear Zn(II)–Ni(II) complex with a phenol based dicompartmental ligand possessing contiguous hexa- (N4O2) and pentadentate (N3O2) coordination sites was prepared by a stepwise method. The prepared mono- and bimetallic macrocyclic complexes were characterized by elemental analysis, IR, NMR spectroscopies, and molar conductance measurements. Characterization results confirms the expected C2 symmetric geometry for mononuclear macrocyclic zinc complex. The 1H NMR spectrum and X-ray crystal structure of the macrocyclic Zn(II)–Ni(II) complex demonstrated a C1 symmetric geometry with a five-membered heterocycle ring attached to the diethylenetriamine link as a result of an intramolecular rearrangement. The explanation for these topological transformation and intramolecular rearrangement as well as electrochemical behavior of dinuclear complex are discussed.