Abstract: The interaction of zinc(II) and cadmium(II) with 17- and 18-membered ring macrocycles incorporating nitrogen and oxygen hetero-atoms is reported. These ligands constitute an array of related macrocyclic structures in which the position of the donor atoms, their spacing and the macrocyclic ring size all vary in a systematic manner. Physical measurements confirm the 1:1 metal to ligand stoichiometry of the respective complexes. The complexes, [ML 1–2H2O] X2; [M = Zn(II) or Cd(II); X = Cl or NO3], have been synthesized via the templated cyclocondensation reactions of salicylaldehyde with 1,2-dibromoethane or 1,3-dibromopropane and diethylenetriamine in 2:1:1 molar ratio. The stoichiometries and coordination modes of the complexes have been deduced from IR, 1H, and 13C NMR, conductivity and microanalytical data. Tetrahedral geometry is suggested for Zn(II) compounds, where three nitrogen atoms are coordinated to the metal and the fourth being occupied by a water molecule, while octahedral geometry is suggested for Cd(II) where three nitrogen and two oxygen atoms are coordinated to the metal, the sixth being occupied by a water molecule.
Keywords: Zn(II), Cd(II), template syntheses, 17- and 18-membered, macrocyclic complexes
