Synthesis and spectral studies of a 12-membered tetraimine macrocyclic ligand and its complexes

Abstract

[2 + 2] Condensation between 3,4-diaminobenzophenone and benzil in a 1:1 molar ratio in methanol at room temperature resulted in the formation of a novel Schiff base tetraimine macrocyclic ligand, (L): 5,6;11,12-dibenzophenone-2,3;8,9-tetraphenyl-1,4,7,10-tetraazacyclo-dodeca-1,3,7,9-tetraene. The macrocyclic complexes of the type, [FeLCl2]Cl and [MLCl2] [M = Co(II) and Cu(II)] have been prepared by reacting iron(III) chloride or metal(II) chlorides with the ligand, L in 1:1 molar ratio in methanol. The stoichiometry corresponding to the formation of the ligand framework, L was ascertained on the basis of results of elemental analyses,1H-NMR and FAB-mass measurements while that of complexes were ascertained by results of elemental analyses and in solution by Job’s method. The mode of bonding and the geometry of the complexes have been confirmed on the basis of i.r., u.v.–vis spectral findings and magnetic susceptibility measurements which revealed an octahedral geometry for all the complexes. The nature of the complexes was confirmed by conductometric studies.