Copper(II)-oxaloyldihydrazone complexes: Physico-chemical studies: Energy band gap and inhibition evaluation of free oxaloyldihydrazones toward the corrosion of copper metal in acidic medium

Abstract

A series of oxaloyldihydrazone ligands were prepared essentially by the conventional condensation reaction between oxaloyldihydrazide and different aldehydes e.g., salicylaldehyde, 2-hydroxy-1-naphthaldehyde, 2-hydroxyacetophenone and 2-methoxybenzaldehyde in 1:2 M ratio. The synthesized compounds were purified to give bis(salicylaldehyde)oxaloyldihydrazone (L 1 ), bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone (L 2 ), bis(2-hydroxyacetophenone)oxaloyldihy drazone (L 3 ) and bis(2-methoxybenzaldehyde)oxaloyldihydrazone (L 4 ). All the oxaloyldihydrazones (L 1 -L 4 ) and their relevant solid copper(II) complexes have been isolated and characterized by various physicochemical techniques. The identity of the synthesized compounds has been ascertained on the basis of elemental analyses, spectral (UV-Vis, IR, ESR, mass, 1 H NMR), magnetism and thermal (TG) measurements. The dihydrazones coordinate to the metal center forming binuclear complexes. Upon chelation, the metal center can form a trigonal distorted octahedral structure with L 1 and pseudo tetrahedral configuration with L 2 & L 3 & L 4 . The optical band gap energy for all compounds underlies the range of semiconductor materials. The investigated ligands were assayed for their corrosion inhibitive and adsorptive properties on copper surface in 1 M HCl solution using weight loss technique. The results pointed out that, the ligands have a plausible inhibition toward the corrosion of copper specimen. The adsorption reaction on copper surface was found to be spontaneous first

Novel metal complexes of 3‐acetylcoumarin‐2‐hydrazinobenzothiazole Schiff base: Design, structural characterizations, DNA binding, DFT calculations, molecular docking and biological studies

“…The X‐band ESR spectrum of the Cu (II) complex was recorded in the solid‐state at room temperature. The spectrum (Figure 2) showed a broad symmetrical signal around g iso = 2.138 without hyperfine splitting, indicating the absence of any Cu‐Cu interaction and confirming the mononuclear nature of the Cu (II) complex 61, 62 . Also, the complex exhibits a g av value of 1.97 (< 2.0023) suggesting the covalent nature of the Cu (II)‐ligand bond 63 …”

Synthesis, characterization, density functional theory, X‐ray study, thermal stability, and biological and MOE relevance of metal complexes of griseofulvin

“…The MO stretching band appeared in the range 523–528 cm −1 for the six metal complexes. Therefore, it was concluded from the FT‐IR spectra of the GFV ligand and its metal complexes that GFV behaved as a neutral ligand and coordinated to the metal ions via the three oxygen atoms of the two methoxy groups and furan ring …”

N,N′-Bis[2-hydroxynaphthylidene]/[2-methoxybenzylidene]amino]oxamides and their divalent manganese complexes: Isolation, spectral characterization, morphology, antibacterial and cytotoxicity against leukemia cells

“…Obviously, this requires great effort to refine and separate their chelates. Some complexes of N,N′-bis[2-hydroxynaphthylidene]/ [2-methoxybenzylidene] amino]oxamides with Cu(II), Ni(II) and Pd(II) have been reported elsewhere [8][9][10], and this study is an expansion of the past work. In terms of biological activity, hydrazones including oxalic dihydrazone and their complexes offer a wide scope of pharmacological applications as antitumoral, antiviral and antimicrobial agents [8,[11][12][13].…”

“…In continuation of ongoing reports on some oxalic dihydrazones and their chelates [8][9][10], the present work portrays preparation, characterization and morphological investigations of divalent manganese complexes with two hydrazones as ligands. Antimicrobial and antileukemia activities of the manganese complexes and their corresponding ligands have been researched to show the plausibility of using them in pharmacology science.…”