Synthesis of novel schiff bases derived from 4-chloro-2-nitrophenol and salicylaldeyhde; preparation their metal complexes, and theoretical nmr computations by gaussian program

In this study, nitrogen compounds were prepared by reaction of 4-chloro-2-nitrophenol with 1,2-dibromoethane and 1,3-dibromopropane in DMF medium. Then 1,2-bis(4-chloro-2-aminophenoxy)ethane and 1,3-bis(4-chloro-2-aminophenoxy)propane amines were synthesized by the reduction of nitrogen compounds with hydrazinhydrate and Pd/C. Then Schiff bases N,N′-bis(5-bromo-2-hidroxy-salicylaldehydene)-1,2-bis(4-chloro-2-aminofenoxy)ethane and N,N′-bis(5-bromo-2-hidroxy-salicylaldehydene)-1,3-bis(4-chloro-2-aminofenoxy)prophane were synthesized by reaction of 1,2-bis(4-chloro-2-aminofenoxy)ethane and 1,3-bis(4-chloro-2-aminofenoxy)prophane with 5-bromosalicylaldehyde. Then their complexes were synthesized by the reaction of the Schiff bases and metal salts, such as Cu(CH3COO)2.H2O, Ni(CH3COO)2.4H2O, Co(CH3COO)2.4H2O, Zn(CH3COO)2.2H2O, Mn(CH3COO)2.4H2O, TiCl3, VCl3, Fe(NO3)3.9H2O in DMF medium. The structure of the ligands and their complexes were characterized by Elemental Analysis, Magnetic Susseptibility, FT-IR, UV-Vis, Conductance Measurements, 1H-NMR and 13C-NMR spectra and TGA techniques. In addition, antioxidant studies, theoretical NMR computations, and cyclic voltammetry studies were also done. Ligand and complexes were studied for their antioxidant activity by investigating DPPH radical scavenging effect and metal chelating effect on ferrous ion. As well as ligand and complexes were studied cyclic voltammetry by electrochemical behaviors which redox reactions analyse. Theoretical NMR computations were calculated and compared experimental and theoretical values of ligands and discussion to confirm the suggested structures.