Synthesis and characterization of a binuclear copper(II) complex [Cu(H<sub>2</sub>slox)]<sub>2</sub> from polyfunctional disalicylaldehyde oxaloyldihydrazone and its heterobinuclear copper(II) and molybdenum(VI) complexes

Hassan

Gumaa

et al. 2018

J. Chil. Chem. Soc.

Mononuclear manganese complexes of dihydrazone derived from the condensation of oxaloyldihydrazide with 2-hydroxynaphthaldehyde and 2-methoxybenzaldehyde have been synthesized. The hydrazone Schiff base ligands and their chelates were characterized on the basis of their elemental analyses, spectral (UV-Vis., IR, mass, 1 H/ 13 C NMR), magnetism, ESR and thermal (TGA) measurements. The dihydrazone has been suggested to coordinate to the metal center in bi-dentate manner forming 1:1[M:L] complex. The complexes are suggested to have tetrahedral/octahedral stereochemistry. Optical transmission spectra were recorded in the range 190-2100 nm and optical band gap energy was determined. The band gap energy (E g) for all separated compounds lies in the range of semiconductors. On the other hand, the inhibition and adsorptive properties of the ligands for the corrosion of aluminum in 1 M HCl solutions were studied using traditional weight loss measurements. The results revealed that bis(2-methoxy-benzaldehyde)oxaloyldihydrazone has a greater inhibition than bis(2-hydroxy-1naphthaldehyde)oxaloyldihydrazone. The adsorption of the inhibitors on metal surface was found to be spontaneous first order reaction and consistent well with the mechanism of physical adsorption. The adsorption data fitted well to Freundlich, Langmuir and Frumkin adsorption isotherms.

Section: Stereo Chemical Structure Of Mn 2+ -Complexes Ir Spectrasupporting

confidence: 65%

“…Actually, the appearance of new M-O bands in both complexes (Table 3) asserts the formation of metal-ligand bond [41]. The broad bands within the range 3300-3450 cm -1 in the complex I are attributed to the presence of crystalline and coordinated water molecules.…”

Section: Stereo Chemical Structure Of Mn 2+ -Complexes Ir Spectramentioning

confidence: 88%

Mn2+-COMPLEXES OF N,O-DIHYDRAZONE: STRUCTURAL STUDIES, INDIRECT BAND GAP ENERGY AND CORROSION INHIBITION ON ALUMINUM IN ACIDIC MEDIUM

Hassan

Gumaa

et al. 2018

J. Chil. Chem. Soc.

“…Moreover, existence of OH enolic at 3356 cm À1 illustrated that deprotonation of this group did not occur. This conclusion is evidenced by the appearance of new band assignable to m(MAOH enolic ) at 480 cm À1 (Kumar et al, 2011).…”

Section: Resultsmentioning

confidence: 76%

“…The azomethine signals, d(CH‚N), observed only in L 1 , L 2 and L 4 have been assigned at 8.75, 9.73 and 8.95 ppm, respectively. As reported in the literature (Kumar et al, 2011), if the dihydrazone exists in the syn-cis-configuration or staggered configuration, the dOH, dNH and dCH‚N, resonances, each should appear as a singlet. However, the appearance of these signals in the form of six signals (doublet of doublet) indicates anti-cis (chair) configuration.…”

Section: H Nmr Spectramentioning

confidence: 91%

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

Arabian Journal of Chemistry

Hassan

Gumaa

et al. 2019

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

“…In case of Mn-BMO, (1) the perception of C]O groups in the IR spectrum of Mn-BMO with obscure of ν(NH) band demonstrates that the BMO ligand favored its keto form in the chelation process. [28]. But which conformation is true?…”

Section: Ir Spectroscopymentioning

confidence: 99%

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

2020

Open Chemistry

AbstractManganese(ii) complexes of oxalic dihydrazones {N,N′-bis[2-hydroxynaphthylidene]amino]oxamide (BHO) and N,N′-bis[2-methoxybenzylidene]amino]oxamide (BMO)} have been synthesized by a general methodology. Hydrazone ligands (BHO and BMO) were obtained by the condensation of oxalic dihydrazide with 2-hydroxynaphthalene-1-carbaldehyde and 2-methoxybenzaldehyde. From the data obtained from the spectral (mass, IR, 1H-NMR, UV-Vis, ESR), magnetic and thermal measurements in addition to the elemental analyses (CHNM), the structures of ligands and their complexes have been determined. The scanning electron microscope (SEM) was used to characterize the morphology of the complex surface. The ligands coordinated with the metal center in a bi-dentate way forming binuclear Mn–BHO and mononuclear Mn–BMO complexes. The manganese complexes are proposed to have octahedral stereochemistry. The ligands and manganese(ii) complexes have been assessed for their antibacterial and antileukemia activities. The proliferation hindrance for the free ligands was enhanced upon coordination with the manganese(ii) ions.