scholarly journals Synthesis, Spectroscopy, Theoretical, and Electrochemical Studies of Zn(II), Cd(II), and Hg(II) Azide and Thiocyanate Complexes of a New Symmetric Schiff-Base Ligand

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Morteza Montazerozohori ◽  
Kimia Nozarian ◽  
Hamid Reza Ebrahimi

Synthesis of zinc(II)/cadmium(II)/mercury(II) thiocyanate and azide complexes of a new bidentate Schiff-base ligand (L) with general formula of MLX2(M = Zn(II), Cd(II), and Hg(II)) in ethanol solution at room temperature is reported. The ligand and metal complexes were characterized by using ultraviolet-visible (UV-visible), Fourier transform infrared (FT-IR),1H- and13C-NMR spectroscopy and physical characterization, CHN analysis, and molar conductivity.1H- and13C-NMR spectra have been studied in DMSO-d6. The reasonable shifts of FT-IR and NMR spectral signals of the complexes with respect to the free ligand confirm well coordination of Schiff-base ligand and anions in an inner sphere coordination space. The conductivity measurements as well as spectral data indicated that the complexes are nonelectrolyte. Theoretical optimization on the structure of ligand and its complexes was performed at the Becke’s three-parameter hybrid functional (B3) with the nonlocal correlation of Lee-Yang-Parr (LYP) level of theory with double-zeta valence (LANL2DZ) basis set using GAUSSIAN 03 suite of program, and then some theoretical structural parameters such as bond lengths, bond angles, and torsion angles were obtained. Finally, electrochemical behavior of ligand and its complexes was investigated. Cyclic voltammograms of metal complexes showed considerable changes with respect to free ligand.

2019 ◽  
Vol 31 (10) ◽  
pp. 2331-2336 ◽  
Author(s):  
Manoj Kumar ◽  
Anita Rani ◽  
Hardeep Singh Tuli ◽  
Rajshree Khare ◽  
Vinit Parkash

This report describes the synthesis and exploration of novel Schiff base ligand in the form of a polymer (heptamer) which was prepared by reaction between 3,4-diacetyl-2,5-hexanedione and hydrazine hydrate in ethanol. On further reaction of Schiff base with transition metals ions (Co and Cu) leads to formation of its transition metal complexes. The structural identification of Schiff base ligand and its transition metal complexes were characterized by classical structural techniques like FT-IR, NMR and mass spectra. The free ligand and its transition metal complexes have been screened for in vitro biological activities against various strains of bacteria and fungi. The prepared Schiff base and its metal complexes were also screened for antiangiogenic activity. The results have shown the remarkable antimicrobial and antiangiogenic activities of the Schiff base and its metal complexes.


2021 ◽  
Vol 11 (1) ◽  
pp. 3249-3260

Herein, we describe the synthesis and characterization of a Schiff base ligand (E)-N'-(2-hydroxybenzylidene)-4-methoxybenzohydrazide (HBMB) and its Mn(II), Ni(II), and Cu(II) metal complexes (C1-C3) respectively. The ligand HBMB was synthesized by reacting condensation of salicylaldehyde and 4-methoxy benzohydrazide in a 1:1 molar ratio. The structure of HBMB and its metal complexes (C1-C3) were evaluated by using UV-Vis, FT-IR, 1H-NMR, mass spectroscopy as well as on the basis of elemental analysis, conductivity measurements, and thermogravimetric techniques (TGA). The synthesized molecules' tumoricidal properties were performed against human breast cancer (MCF-7) and colon cancer (HT 29) cell lines. The biological results indicated that the ligand, HBMB, and metal complexes possess dose-dependent selective cytotoxicity against the tested carcinoma cells. The synthesized compounds were further evaluated for their in vitro antimicrobial activities against Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Escherichia coli), and fungal strains (Aspergillus niger).


2020 ◽  
Vol 85 (2) ◽  
pp. 215-225 ◽  
Author(s):  
Palaniswamy Venkittapuram ◽  
Mahalakshmi Dhandapani ◽  
Jonekirubavathy Suyambulingam ◽  
Chitra Subramanian

A Schiff base ligand L was synthesized by condensation of 1,2-diaminoethane with creatinine. The reaction of the ligand with metal chloride salt gives Co(II) and Cu(II) complexes. The synthesized ligand and its metal complexes were characterized by elemental analysis, FT-IR, NMR, UV?Vis, conductivity and magnetic susceptibility measurements as well as thermal analyses. Based on spectral data, tetrahedral geometries have been proposed for the Co(II) and Cu(II) complexes. The molar conductivity data show that the complexes are non-electrolytic in nature. In DFT studies, the geometry of the Schiff base ligand and its Co(II) and Cu(II) complexes were fully optimized using the B3LYP functional together with 6-31g(d,p) and LANL2DZ basis sets. The ligand and its metal complexes were tested against four bacterial species and two fungal species. The results revealed that the metal complexes are more potent against the microbes than the parent ligand.


2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
F. K. Ommenya ◽  
E. A. Nyawade ◽  
D. M. Andala ◽  
J. Kinyua

A new series of Mn (II), Co (II), Ni (II), Cu (II), and Zn (II) complexes of the Schiff base ligand, 4-chloro-2-{(E)-[(4-fluorophenyl)imino]methyl}phenol (C13H9ClFNO), was synthesized in a methanolic medium. The Schiff base was derived from the condensation reaction of 5-chlorosalicylaldehyde and 4-fluoroaniline at room temperature. Elemental analysis, FT-IR, UV-Vis, and NMR spectral data, molar conductance measurements, and melting points were used to characterize the Schiff base and the metal complexes. From the elemental analysis data, the metal complexes formed had the general formulae [M(L)2(H2O)2], where L = Schiff base ligand (C13H9ClFNO) and M = Mn, Co, Ni, Cu, and Zn. On the basis of FT-IR, electronic spectra, and NMR data, “O” and “N” donor atoms of the Schiff base ligand participated in coordination with the metal (II) ions, and thus, a six coordinated octahedral geometry for all these complexes was proposed. Molar conductance studies on the complexes indicated they were nonelectrolytic in nature. The Schiff base ligand and its metal (II) complexes were tested in vitro to evaluate their bactericidal activity against Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus typhi) using the disc diffusion method. The antibacterial evaluation results revealed that the metal (II) complexes exhibited higher antibacterial activity than the free Schiff base ligand.


2018 ◽  
Vol 16 (1) ◽  
pp. 1115-1121
Author(s):  
Güvenç Görgülü

AbstractA novel Schiff base was synthesized and characterized by spectroscopic and theoretical methods. A potentially active agent 4-(2-hydroxy-5-methylphenylimino)naphthalen-1(4H)-one (PINQ) was designed and synthesized. The synthesis was carried out by a condensation reaction of 1-4-naphthoquinone and 2-amino-4-methyl phenol. The spectral and structural properties of the PINQ molecule were investigated by elemental analysis, 1H- and 13C-NMR, FT-IR and Uv-vis spectroscopies. The energetic, atomic, electronic, molecular, vibrational and magnetic data were theoretically obtained using density functional theory (DFT) at B3LYP level with 6-311++G(d,p) basis set. Chemical shifts were calculated using gauge-invariant atomic orbital (GIAO) method. UV-vis spectrum for the title compound was also obtained by time-dependent density functional theory (TD-DFT). The theoretical and experimental results were compared and interpreted. The theoretical data obtained from 1H- and 13C-NMR, FT-IR and Uv-vis spectroscopies were quite compatible with experimental ones.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Riyadh M. Ahmed ◽  
Enaam I. Yousif ◽  
Hasan A. Hasan ◽  
Mohamad J. Al-Jeboori

A new macrocyclic multidentate Schiff-base ligand Na4L consisting of two submacrocyclic units (10,21-bis-iminomethyl-3,6,14,17-tricyclo[17.3.1.18,12]tetracosa-1(23),2,6,8,10,12(24),13,17,19,21,-decaene-23,24-disodium) and its tetranuclear metal complexes with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) are reported. Na4L was prepared via a template approach, which is based on the condensation reaction of sodium 2,4,6-triformyl phenolate with ethylenediamine in mole ratios of 2 : 3. The tetranuclear macrocyclic-based complexes were prepared from the reaction of the corresponding metal chloride with the ligand. The mode of bonding and overall geometry of the compounds were determined through physicochemical and spectroscopic methods. These studies revealed tetrahedral geometries about Mn, Co, and Zn atoms. However, square planar geometries have been suggested for NiIIand CuIIcomplexes. Biological activity of the ligand and its metal complexes against Gram positive bacterial strainStaphylococcus aureusand Gram negative bacteriaEscherichia colirevealed that the metal complexes become more potentially resistive to the microbial activities as compared to the free ligand. However, these metal complexes do not exhibit any effects on the activity ofPseudomonas aeruginosabacteria. There is therefore no inhibition zone.


2020 ◽  
Vol 71 (4) ◽  
pp. 47-58
Author(s):  
Noreen Mazhar ◽  
Mehwish Aftab ◽  
Tariq Mahmud ◽  
Muhammadasim Raza Basra ◽  
Mansoor Akhtar ◽  
...  

A new Schiff base ligand (L) and its transition divalent metal complexes were prepared by the condensation reaction; Reaction was carried out at 70-80 oC by refluxing equimolar ratio of toluidine and aldehyde by continuous stirring for 5-6 hours. Synthesized ligand and Ni(II), Fe(II), Co(II), Mn(II) and Zn(II) bimetallic complexes were characterized by using FT-IR, UV-visible spectroscopy, AAS, Single crystal X-ray analysis, 1H-NMR, molar conductance. Compounds were screened against two fungus Candida glabrata and Candida albicans by agar tube dilution protocol. In vivo anti-inflammatory activity via induced paw edema method and in vitro results by heat induced protein denaturation method were checked. Synthesized compounds were also showed antioxidant activity by using DPPH (diphenylpicrylhydrazyl) and Trolox was used as standard. These studies show that ligand and almost all metal complexes are reactive towards biological assays against reported standard drugs. Zn-L indicates more activeness for antioxidant activity and free ligand while Co-L recognized as more effective anti-inflammatory drug.


2021 ◽  
Author(s):  
Hanan F. Abd El-Halim ◽  
Gehad Mohamed ◽  
Walaa Mahmoud ◽  
Omnia El-Sayed

Abstract 2,2’-((1Z-1’Z) (1,3-diphenylpropane-1,3-diylidene) bis (azanylylidene)) dibenzoic acid (H2L) Schiff base ligand, was obtained by condensation reaction between anthranilic acid and dibenzoyl methane in 2:1 ratio.A series of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes was resulted from 1:1 (ligand: metal salt) reaction.The structural features of the synthesized ligand and its metal complexes was determined by elemental analyses, IR, 1H NMR, UV-Vis, ESR, mass spectra, conductivity and magnetic susceptibility measurements as well as thermal (TG/DTG) analyses. The analytical and spectroscopic tools showed that the complexes had composition of ML type with octahedral geometry. The IR results confirmed the tetradendate binding of the ligand involving two azomethine nitrogen atoms and two carboxylate oxygens. The Schiff base and its complexes have been screened for their antimicrobial activity against several bacterial organisms as (Streptococcus pneumoniae and Bacillus subtilis; Pseudomonas aeruginosa and Escherichia coli) and fungi (Aspergillus fumigatus; Syncephalastrum racemosum; Geotricum candidum and Candida albicans) by disk diffusion method.All the metal complexes have potent antimicrobial activity than the free ligand. Anticancer activity of the ligand and its metal complexes was evaluated against human cancer (MCF-7 cells viability).


2021 ◽  
Vol 10 (3) ◽  
pp. 2546-2556

The present study deals with the synthesis of a new Schiff base ligand, 4-(((4-chlorobenzo[d]thiazol-2-yl)imino)methyl)-2-methoxyphenol (HL) derived from the condensation of 2-Amino-4-chlorobenzothiazole and 4-Hydroxy-3-methoxybenzaldehyde, and its Co(II), Zn(II) and Ni(II) complexes in 2:1 molar ratio (2HL:M). The Schiff base ligand and its metal complexes were characterized using FT-IR, UV-Visible absorption, mass spectra, and TGA techniques. The spectral analysis results confirmed the molecular structures of the Schiff base ligand and its metal complexes. Further, the metallic Schiff base complexes showed significant growth inhibition in the adenocarcinoma human alveolar basal epithelial cells, A549, with the Co(II), Zn(II), and Ni(II) complexes having IC50 values of 40.78, 42.04, and 44.69 M, respectively.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
J. R. Anacona ◽  
Johan Calvo ◽  
Ovidio A. Almanza

Metal complexes of a Schiff base ligand derived from cefotaxime and salicylaldehyde were prepared. The salicilydene-cefotaxime ligand (H2L) and mononuclear [M(L)] (M(II) = Co, Ni and Cu), dinuclear [Ag2(L)(OAc)2], and tetranuclear metal complexes [M4(L)(OH)6] (M(II) = Ni, Cu) were characterized on the basis of analytical, thermal, magnetic, and spectral studies (IR, UV-visible, 1H NMR, 13C NMR, and EPR). The electronic spectra of the complexes and their magnetic moments suggesttetrahedral geometry for the isolated complexes. The complexes are nonelectrolytes and insoluble in water and common organic solvents but soluble in DMSO.


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