Synthesis, Characterization and Evaluation of Biological Activity of new Ligand Derived from 4-Aminoantipyrine, 2-Mercaptobenzoxazole and its Complexes with Some Metal Ions.

Abstract

2-((2-((-4-(benzo[d]oxazol-2-ylamino))-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-ylidene)amino)phenyl (imino)-1,2-diphenylethan-1-ol (LH) was a new Schiff  base ligand  prepared from the reaction of 2-mercaptobenzoxazole with 4-amino-antipyrene dissolved in absolute ethanol, as a first step to form compound-A, while the second step involved the reaction of benzoin with O-phenylene diamine to produce compound- B, The third step involved the reaction of compounds A and B to produce ligand (LH) as a final product. Five complexes of ligand (LH) were prepared from the reaction with various metal ions Hg (II), Cd (II), Ag (I), Cu (II) and Ni (II). Several different spectroscopy methods were used to prove the structure of ligand (LH) and its complexes along with elemental analysis (CHNS), X-RD, FE-SEM, magnetic measurements, molar conductivity. The molar conductivity values of the prepared complexes exhibited that the complexes have non-electrolytic nature and do not have any molar conductivity. According to the results of the above techniques, the ligand (LH) behaves as a tetradentate (N, N, N, O) and coordinates with the metal ion via the nitrogen atoms of the two azomethine groups, the secondary amine group, and the oxygen atom of the hydroxyl group. Biological activity assays of free ligand (LH) and its metal complexes were performed against Gram-positive and Gram-negative bacteria, Staphylococcus aureus, and Escherichia coli, respectively. Based on the above results, the prepared complexes showed highly effective against bacteria, which were compared with a standard antibacterial. LH and the Ag(I)-complex) have been tested in vitro on breast cancer cells (MCF-7) and healthy human cells for their anticancer and toxicity (HEK-293).