Synthesis, spectral and antimicrobial activity of Zn(II) complexes with Schiff bases derived from 2-hydrazino-5-[substituted phenyl]-1,3,4-thiadiazole and benzaldehyde/2-hydroxyacetophenone/indoline-2,3-dione (original) (raw)
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Synthesis and Spectroscopic Characterization of some Mixed Schiff Base Complexes
Two different Schiff bases have been synthesized, the first Schiff base derived from the reaction of 2-hydroxyacetophenone and amino acid (tyrosine) as primary ligand (HL1) and the second Schiff base formed from the condensation of 4-dimethylaminobenzaldehyde and of 2-aminobenzoic acid as secondary ligand (HL2). These Schiff bases were used to form mixed Schiff base complexes with Co(II), Ni(II), Cu(II), Zn(II) and Fe(III) ions in the presence of alkaline media. The synthesized Schiff bases and their complexes have been investigated by using several techniques; in terms, CHN elemental analyses, molar conductivity, magnetic moment and spectroscopic studies [IR, UV-Vis, 1 HNMR, MS and EPR spectra]. The CHN elemental analysis data showed the formation of the mixed Schiff base complexes in 1:1:1[M:L1L2] ratio.The molar conductance measurements revealed that the mixed Schiff base complexes are electrolytes confirming the existence of sodium ions outside the frame of the complexes except Iron(III) complex which is non-electrolyte in nature. Room temperature magnetic moment values suggested that the complexes have six-coordinate geometry. Infrared spectral results exhibitedtheSchiff bases coordinated to the metal ion via the oxygen atom of-COOH and the nitrogen atom of azomethine and phenolic groups. The signals which obtained from The 1 HNMR spectra of the Schiff bases and their Zn(II)Schiff base complex supported the complexation between the Schiff bases and Zn(II) ion. Whereas, The UV spectral results of the Schiff bases showed π→π* (Phenyl ring) and n→π* (C=N,-COOH and –OH) transitions and the UV-Vis spectral data of the mixed Schiff base complexes suggested the geometrical structure which is an octahedral geometry around the metal ions. The mass spectral fragmentations of the Schiff bases and their Cu(II) complex were studied and confirming the formation of the Schiff bases and the iron(III) mixed Schiff base complex. The electron paramagnetic resonance spectral values confirmed the data which are obtained from UV-Vis study.
Synthesis and bioactivity studies of novel Schiff bases and their complexes
Journal of Physical Organic Chemistry, 2019
The new Schiff base (L) "4-[(2,4-dimethoxy-benzylidene)-amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one" was synthesized from 2,4-dimethoxybenzaldehyde and 4-amino-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one, and the geometry of Schiff base was characterized and determined by proton nuclear magnetic resonance (1 H-NMR), mass, Fourier transform infrared (FT-IR), and ultraviolet-visible (UV-vis) spectroscopy. Schiff complexes of Ni(II), Pd(II), Pt(IV), Zn(II), Cd(II), and Mg(II) have been prepared by reaction of ion metals with as-prepared Schiff base. The results showed that synthesized complexes offered 1:2 metal-ligand ratios. Furthermore, the Schiff complexes were a tetrahedral in complexes Ni(II), Zn(II), Cd(II), and Hg(II), octahedral Pt(II), and square planer complex Pd(II). Additionally, density functional theory (DFT) was applied for calculations of both spectroscopic properties and electronic structure of prepared Schiff bases. Moreover, the Schiff base and its metal complexes have been verified in vitro against Streptococcus, Esherichia coli, Candida albicans, and Candida tropicalis in order to assess their antibacterial potential. The findings indicate that the biological activity augments on complexation reaction.
Metal Complexes of Schiff Bases: Preparation, Characterization, and Biological Activity
Metal complexes of Schiff bases derived from 2-furancarboxaldehyde and o-phenylenediamine (L 1 ), and 2-thiophenecarboxaldehyde and 2-aminothiophenol (HL 2 ) are reported and characterized based on elemental analyses, IR 1 H NMR, solid reflectance, magnetic moment, molar conductance, and thermal analysis (TGA). The ligand dissociation, as well as the metal-ligand stability constants were calculated, pH-metrically, at 25 • C and ionic strength μ = 0.1 (1 M NaCl). The complexes are found to have the formulae [M(L 1 )(H2O)2](Cl)n·yH2O (where M = Fe(III), Ni(II), Cu(II); n = 2-3, y = 2-4); [M(L 1 )](X)2·yH2O (where M = Co(II), Zn(II), UO2(II), X = Cl, AcO or NO3, y = 1-3); [M(L 2 )2]·yH2O
IOSR Journals , 2019
In recent years, discovering new compounds that have biological activity were studied by many researchers. In this paper, four metal complexes have been synthesized from Ni (II) and Zn (II) chloride and ligands 2-((3-nitrophenylimino) methyl) phenol (HL1) and 2-((4-nitrophenylimino) methyl) phenol (HL2) in 1:2 M ratio. FTIR and molar conductance measurements were used to characterize the structure of complexes. The complexes were found to be non electrolytic on the basis of molar conductance studies. The metal complexes have also been tested for their PH activity at different concentrations by used RSM.
Journal of Molecular Structure, 2017
A Novel Schiff base, 3-(((4-chlorophenyl)imino)methyl)benzene-1,2-diol (HL 1) was successfully synthesized along with a structurally similar Schiff base 3-(((4-bromophenyl)imino)methyl)benzene-1,2-diol (HL 2). Both the Schiff bases were used to synthesize their zinc (II) and cobalt (II) complexes. These compounds were characterized by FTIR, 1 H NMR, 13 C NMR and elemental analysis. Metal complexes were confirmed by TGA. Crystals of Schiff bases were also characterized by X-ray analysis and experimental parameters were found in line with the theoretical parameters. Quantum mechanical approach was also used to fine useful structural parameters and to ensure the geometry of metal complexes. The photometric behaviors of all the synthesized compounds were investigated in a wide pH range using BR buffers. The appearance of isosbestic points indicated the existence of Schiff bases in more than one isomeric form. Moreover, these compounds were screened for enzyme inhibition; antibacterial, cytotoxic and in vivo antidiabetic activities and compounds were found active against one or other activity. Results indicate that ZnL 2 2 is a good inhibitor of alkaline phosphatase enzyme and possess highest potential against diabetes, blood cholesterol level and cancer cells. This effort just provides preliminary data for some biological properties. Further investigations are required to precisely determine mechanistic pathways of their use towards drug development.
Applied Organometallic Chemistry, 2017
A new Azo‐Schiff base ligand L was prepared by reaction of m‐hydroxy benzoic acid with (Schiff base B) of 3‐[2‐(1H–indol‐3‐yl)‐ethylimino]‐1.5‐dimethyl‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐ylamine. This synthesized ligand was used for complexation with different metal ions like Ni(II), Co(II), Pd(II) and Pt(IV) by using a molar ratio of ligand: metal as 1:1. Resulted compounds were characterized by NMR (1H and 13C), UV–vis spectroscopy, TGA, FT‐IR, MS, elemental analysis, magnetic moment and molar conductivity studies. The activation thermodynamic parameters, such as ΔE*, ΔH*, ΔS*, ΔG*and K are calculated from the TGA curves using Coats‐Redfern method. Hyper Chem‐8 program has been used to predict structural geometries of compounds in gas phase. The biological activities of Schiff base and its complexes had been tested in vitro against, two Gram positive bacteria (Bacillus subtillis and Staphylococcus aureus) and two Gram negative bacteria (Escherichia coli and Pseudomonas aeruguinosa).
Amino Acid based Schiff Bases and its Zn (II) Complexes
Research and Reviews: Journal of Chemistry, 2016
Metal chelates of Schiff base prepared by combining salicylaldehyde and amino acids could be effectively used in understanding the mechanism of transamination reaction. They can act as biomimetic species. The current article focused on the syntheses, characterization, complexation behaviour and antimicrobial studies of some novel Schiff bases formed from salicylaldehyde with 3-amino benzoic acid and Glycine and Alanine using sodium hydroxide as a catalyst. The synthesized Schiff base ligands have been successfully complexed with the metal Zn (II) and studied by their spectral data. Morphological studies were carried out using SEM. The impact of complexation on the antimicrobial activity of Schiff bases and its Zn (II) complexes has also been studied.