Template synthesis and structural characterization of homo binuclear chromium(III), manganese(III), iron(III), cobalt(III), and ruthenium(III) complexes with octaazamacrocyclic ligands

The Schiff base octaazamacrocyclic ligands derived from primary diamines and 3,6-dimethyl/diphenyl4,5-diazaocta-3,5-diene-2,7-dione, and their binuclear complexes [M2LCl4]Cl-2 [M = Cr(III), Fe(III), Co(III), or Ru(III)] and [Mn2L(AcO)(4)](AcO)(2) were synthesized by template condensation reactions. Attempts to synthesize the corresponding metal-free macrocyclic ligands did not prove successful. The overall geometry and stereochernistry of these complexes were elucidated by elemental analyses, magnetic susceptibilities, electronic spectra, infrared spectra, molar conductance measurements, H-1 NMR, and thermogravimetric analysis. All the trivalent metal ion complexes appear to be 1:2 electrolytes. An octahedral geometry is proposed for all the complexes.