Synthesis and Characterization of Novel Tetradentate ligand Type N4 and its Complexes With CoII,NiII,and PdII.

A new Schiff base ligand [2,3,8,9–tetra -phenyl-1,4,5,7,10,12-hexa azo-5,12- dihydro -6,11- dione 1,3,7,10-dudec-tetra-ene] [H2L] and its complexes In general formula [M (H2L)]Cl2 (where : M= Co^II, Ni^II, and Pd^II) were prepared. This ligand was prepared in two steps,in the first step a solution of benzil in methanol was reacted under reflux with semicarbazidhydrochlorid to give an (intermediate compound)[benzy l bis–(Semicarbazone)] which was reacted in the second step with benzil giving the mentioned ligand. The complexes Co^II, Ni^II, and Pd^II were sy nthesized by direct reaction of the corresp onding metal chloride with the ligand [H2L].The ligand and complexes were characterized by sp ectroscopic methods (IR, UV-Vis, and atomic absorption), chloride content and conductivity measurement.From the data of these measurements, we suggestred a tetrahedral geometry for Co^II, Ni^II complexs and a square planar for Pd^II complex.