Synthesis and characterization of novel heavy metal (Pd (II), Pt (IV), Au (III)) complexes in the oxidation of benzylic alcohols: investigation of cytotoxicity of them using breast cancer cell line

In this study, a novel amide ligand was synthesized through the two steps. I) Ethyl 4-nitrobenzoate was synthesized through a condensation reaction between p-nitrobenzoic acid and ethanol in the presence of concentrated H2SO4. II) This compound was further transformed into N, N'-(1,2phenylene)bis(4-nitrobenzamide) through a chemical reaction with 1, 2-benzene diamine. Novel chelating amide ligands were created using amide and its complexes with metal ions such as Pd (II), Pt (IV), and Au (III). The structures of the new compounds were thoroughly analyzed in the solid state using spectroscopy methods such as 1 H NMR, UV-Vis, FT-IR, metals and elemental analyses, magnetic sensitivity, and conductance tests at room temperature. The geometry of the resulting complexes was determined to be octahedral for the (Pt-L) complex and square planar for the (Pd-L and Au-L) complexes. The ligand was identified to act as a tetradentate chelate through (N2O2). The Pd catalyst proved to be effective in the selective oxidation of benzylic alcohols to aldehydes when used alongside pyridine and oxygen gas. The reactions primarily produced aldehydes, with minimal conversion to carboxylic acids through further oxidation. Utilizing low catalyst loadings of 1.6 mol% resulted in high conversion rates of up to 100% and remarkable selectivity of up to 97% for the carbonyl derivatives. The Pd-complex catalyst demonstrated effective catalytic activity and maintained its performance over five cycles without any significant loss in activity, suggesting potential economic benefits. Moreover, an in vitro toxicity bioassay was conducted to evaluate the toxicity of the newly synthesized compounds against MDA cell lines, showing promising results as potential novel anticancer candidates, especially in larger quantities.