Synthesis and Physicochemical Properties of Schiff Base Macrocyclic Ligands and Their Transition Metal Chelates

Fouzia Rafat, K.S. Siddiqi
2011 Journal of the Korean Chemical Society  
Tetraaza Schiff base macrocyclic ligands, L 1 ,L 2 and their transition metal chelates have been synthesized and characterized by elemental analyses, IR, electronic, EPR and 1 H NMR spectra, TGA and magnetic measurements. The molar conductance of one milli-molar solution of the complexes measured in DMF indicates that the divalent metal complexes are nonelectrolyte while those of trivalent metal ion, are 1:1 electrolytic in the same solvent. The reduction of Racah parameter from the free ion
more » ... ue confirms the presence of considerable covalence of metal ligand sigma bond in the Co(II) and Mn(II) complexes. The EPR spectra of Cu(II) complexes at room temperature shows axial symmetry indicating a dx 2 -y 2 ground state with significant covalent character. The thermal analysis suggests that the complexes do not contain water molecules because only the metal is left as residue.
doi:10.5012/jkcs.2011.55.6.912 fatcat:etaxpnphizcqrjforajc6z3p4m