Al-Jeboori, M. et al. 2017. Structural and Spectroscopic Study of Novel Tetradentate Macrocyclic Ligand Type N4 and It’s Complexes with CrIII, MnII, FeII, CoII, NiII ,CuII, PdII and CdII. Ibn AL-Haitham Journal For Pure and Applied Sciences. 22, 4 (Jul. 2017).