Synthesis, characterization and biological evaluation of an asymmetric NNO donor Schiff base and its transition metal structures

Abstract

A tridentate Schiff base ligand was manufactured via the concentration of 4-nitrobenzaldehyde, 2-hydroxybenzaldehyde, and p-phenylenediamine and structures were equipped and classified. Structural elucidation of the synthesized Schiff base ligand and its metal structures was determined by spectroscopic methods. The NMR spectroscopy confirmed the development of Schiff base ligand, manifesting the azomethine protons at 8.91 and 9.04 ppm in ¹HNMR spectrum and the azomethine carbons at 160.77, and 159.14 ppm in ¹³CNMR spectrum. Moreover, The FT-IR spectroscopy assisted the detection of the prepared SB ligand and its metal structures. For instance, Absorption bands at 1662 cm^-1 and 1530 cm^-1 in the FT-IR spectrum of the SB ligand detected the formation of the azomethine groups, and these bands shifted to either lower or higher frequencies in the ranges of the structures, proving the management of Schiff base to the selected metals.  Meanwhile, the UV-Vis spectroscopy has revealed the excitations of the n → p* transition of azomethine group at 325 nm, and therefore this transition has been shifted upon structureation along with the apparent d-d transitions. Molar conductivity and magnetic moment capacities were utilized to support the evidence of the development of the polymeric Schiff base structures. The Ni(II) and Cu(II) structures exhibited antibacterial and antifungal activities, whereas all the structures demonstrated considerable anticancer activities against SKOV3 and HeLa human cancer cells.