Zinc(II) Complexes of Symmetrical Tetradentate Schiff Base Ligands Derived From 2,2'-Diamino-6,6'-dibromo-4,4'-dimethyl-1,1'-biphenyl-salicylaldehyde: Synthesis, Characterization and Computational Study

Abstract

: Five new complexes (1-5) of the general formula ZnL were prepared by refluxing the new Schiff base ligands (L1-L5) with Et2Zn in THF. The new ligands (L1-L5) were prepared by reacting two equivalents of salicyladehyde derivatives (3,5-ditert-butyl-, 3-tert-butyl-, 5-tert-butyl-, 3,5-dinitro- and 3,5-dibromo-salicylaldehyde) with 2,2'-diamino-6,6'-dibromo-4,4'-dimethyl-1,1'-biphenyl. The new Schiff base ligands and their zinc complexes were characterized by 1H-, 13C-NMR and IR spectroscopy as well as elemental analysis. Additionally, the molecular geometries of all prepared zinc complexes were fully optimized and examined using density functional theory (DFT) calculations at the B3LYP/6-31G(d) level of theory. Infrared vibrational analysis was conducted, and the results are in good agreement with the experimental data.