Cobalt (II) complexes with a 18-member macrocyclic Schiff base ligand

A number of cobalt (II) complexes of the type [Co (SB)X2] where X=chloride, acetate or nitrate and SB=a 18-member macrocyclic Schiff base ligand obtained by metal ion catalysed template macrocyclization between orthophenylenediamine and 2, 5–diformyl furan. The complexes possess characteristic colors, are non hygroscopic, sparingly soluble in water and can be stored for a long period without decomposition. Low value of molar conductivity in the range 7-10Sm2 mol-1 indicated complexes to be non electrolytic in nature. Absence of N-H stretch of orthophenylenediamine, C=O stretch of 2, 5–diformyl furan and appearance of C=N stretch in the infrared spectra of complexes corroborates Schiff base condensation during macrocyclization. Low molar conductivity alongwith presence of vibrational bands characteristics of M-Cl, M-N and M-O stretch in the far infrared range indicated involvement of anions in coordination.