Innovation of Some Novel Complexes Based on N-[(Ethylcarbamothioyl)amino]-1-(hydrazine Carbonyl)formamide (L2) and (L3) N,N′-Bis-[(ethylcarbamothioyl)amino]ethane Diamide Ligands: Synthesis, Structural Elucidation, DFT Calculations, and Biological Studies

Abstract

Different chelates derived from, N-[(ethylcarbamothioyl)amino]-1-(hydrazinecarbonyl)formamide (L²) and N,N′-bis-[(ethylcabomothioyl)amino]ethanediamide (L³), with metal ions were synthesized and characterized by elemental analyses, spectral (IR, UV–Vis, ¹H NMR, ¹³C NMR, and mass), TGA, and magnetic measurements. The two new ligands (L² and L²) were synthesized using L¹ (oxalic acid dihydrazide [ODH]). Theoretical studies and molecular docking calculations were investigated. IR spectra suggest that L² behaves in a bidentate manner coordinating either via the carbonyl oxygen and the nitrogen atom of the hydrazine group and/or through the sulfur (C=S and/or C–S) and the NH groups. In the case of L³, the metal complexes were obtained in the enol form with the removal of proton or more from either the carbonyl (C=O) and/or thioketo (C=S) or both groups after enolization is occurred, except the Pd²⁺, which was isolated in the keto form without removal of hydrogen atoms. The computational estimation of L², and L³ and their complexes were approved with the Gaussian 09 W program in DFT/B3LYP. DPPH and ABTS were tested against two free radical scavengers that were utilized in order to evaluate the antioxidant potential of complexes in vitro. Biological effectiveness of L² and L³ and their complexes against Gram-positive and Gram-negative bacteria was in vitro investigated. Antifungal action was investigated utilizing inhibition zone diameter. Moreover, the ligands and its complexes were exhibited a broad spectrum of DNA degradation effects, as measured by agarose gel electrophoresis. The antioxidant activity of the complexes was determined based on the radical scavenging ability in reacting with a stable DPPH. Wound healing assay was tested with the most active complexes against liver cancer cell line HepG-2.