Eleştirel dinleme becerisinin kapsamının incelenmesi (original) (raw)
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Chintan Research Journal (ISSN : 2229-7227\), 2024
In present study the complexes of the type MLXn, where M= Cu(II), Co(II), Ni(II), Zn(II) and X= H 2 O/Cl and L is the schiff base ligand prepared from 2,4-dihydroxy-5-Acetylacetophenone and 1,4-diaminobutane have been synthesized, as they are widely used as chelating ligands in coordination chemistry. All complexes isolated in solid, are stable in air and characterized by the elemental analysis, metal content determination, magnetic measurements, thermo gravimetric analysis (TGA), IR, and electronic spectral data. The physicochemical data suggest a pseudo octahedral structure to Cu(II) and an octahedral for Co(II), Ni(II), and Zn(II) complexes. The ligand field parameters have been calculated and related to the electronic environment. The Schiff base and its complexes were screened for their antimicrobial activities against various microorganisms.
Communication in Physical Sciences, 7(2): 73-81, 2021
Schiff base ligand derived from condensation of 2-hydroxy-1-naphthaldehyde and 2-aminobenzothiazole were synthesized via mechanochemical technique and used for the preparation of Cu(II) and Zn(II) complexes. The Schiff base and complexes were characterized by infrared spectroscopy, powder x-ray diffraction, Thermogravitric/thermal analysis, CHN analysis, solubility test, conductivity measurement and magnetic susceptibility measurement. Infrared spectral study indicated a strong band in the spectra of the Schiff base at 1603 cm-1 assigned to azomethine stretching vibration. The azomethine band shifted to 1621 and 1599 cm-1 in the IR spectra of Cu(II) and Zn(II) complexes respectively indicating the formation of complex compounds. The decomposition temperatures of the complexes are in the range of 240 - 264 oC indicating good thermal stability. Molar conductance values are in the range of 6.34 - 9.8 Ohm-1cm2 mol-1, indicating non electrolytic nature of the synthesized complexes in ethanol. Magnetic susceptibility measurement indicated that Zn(II) complex is diamagnetic while Cu(II) complex is paramagnetic and exhibit magnetic moment of 2.059 BM, the values correspond to the square planar geometry. The theoretical and experimental analytical data of C, H and N for the Schiff base and complexes are in good agreement. The Schiff base ligand and metal complexes have been studied for microbial activity using pathogenic bacteria (Escherichia coli and Staphylococcus aureus) and fungal pathogens (Candida albican and Asperigillus fumigatus) by agar well diffusion method. The results indicated that metal complexes (07 - 19 mm diameter inhibition zones) are more active than Schiff base ligand (07 - 14 mm diameters) against the test organisms.
Journal of the Chilean Chemical Society, 2021
A series of transition metal complexes having general formula [M(L1)(L2)](NO3)2, (where, M = Cu(II), Ni(II), and Zn(II)) of mixed ligands, L1 = Isonicotinamido-Thiophene-2-Carbaldimine, L2 = 1, 10-phenanthroline, were synthesized. The obtained compounds were successfully characterized by different spectroscopic techniques. Conductivity measurements indicated that all complexes were 1:2 electrolytes in nature. IR spectra indicated that ligands coordinated to metals via the carbonyl oxygen atom and the azomethine nitrogen atom. Magnetic moment values and UV-Visible spectra confirmed square planar structure around the Cu(II), and Ni(II) ions, and a tetrahedral geometry around the Zn(II) ion.The metal complexes were tested against Escherichia coli and Pseudomonas sp. Among the tested compounds, Zn(II)complex showed higher antibacterial activity over both bacterial strains against reference drug Kanamycin. Moreover, synthesized metal complexes exhibited moderate antioxidant activity than the Schiff base. Cu(II) complexes were found to be most active whereas, Zn(II) complexes showed the lowest antioxidant activity comparable to the BHT.
2017
A new Schiff base (R,E)-2(dimethylamino)-3-(4-hydroxyphenyl) -N,2,3-trimethyl-N’-(1-ptolylethylidene) butanehydrazide, Tmbh and Mn(II), Ni(II), Co(II), Cu(II) and Zn(II) complexes were synthesized and characterized on the basis of analytical, magnetic, cyclic voltammetric, conducto metric, UV-Visible, TG/DTA, IR, NMR, EPR and mass spectral data. Tmbh acts as a uninegative/neutral bidentate ligand in all the complexes bonding through carbonyl oxygen and azomethine nitrogen. Half field signal observed in the ESR spectrum of Ni(II) complex is indicative of its dimeric nature and the trend in g-values suggests tetragonally distorted octahedral geometries for Co(II), Ni(II) and Cu(II) complexes. All the complexes exhibit irreversible redox behavior. Morphology of Tmbh and the complexes have also been investigated through SEM and powder XRD data. Antimicrobial effects of the ligand and the complexes against the microbes Bacillus subtilis, Escherichia coli, Psuedomonas aeruginosa and Klebs...
The meal complexes of Co(II), Ni(II), Cu(II), Cd(II) and Zn(II) derived from hydroxyl benzophenone and o-phenylenediamine have been synthesised and characterized by elemental analysis, 1 H NMR, FT-IR, UV-visible, Mass spectroscopy, molar conductometry, magnetic susceptibility and thermal analysis study. The FT-IR spectral study reveals that the ligand behaves as a dibasic tetradentate ligand with N 2 O 2 donor atoms sequence towards central metal ion. The physico-chemical study reveals octahedral geometry for the complexes. The results show the formation of 2:1(ligand: metal chloride) complexes with amine and screened for anti-inflammatory, antimicrobial, DNA binding properties.During the past two decades, considerable attention has been paid to the chemistry of metal complexes containing nitrogen and other donor 1. The tetradentate Schiff base complexes are well known to form stable complexes, where coordination takes place through the N 2 O 2 donor set 2-4. N, O-bidentate and N 2 O 2-tetradentate ligands (soft and hard donor) possess many, advantages such as facile approach, relative tolerance, readily adjusted ancillary ligands, and tunable steric and electronic coordination environments on the metal center 5. This may be attributed to their potential application in many fields such as oxidation catalysis 6 and electrochemistry 7. Transition metals are involved in many biological processes which are essential to life process. The metals can coordinate with O-or N-terminals from proteins in a variety of models and play a crucial role in the conformation and function of biological macromolecules 8, 9. This paper reports the synthesis, characterization, thermal and biological studies of metal(II) complexes derived from the reaction of hydroxyl benzophenone and o-phenylenediamine in alcohol. Experimental section:-Materials and Methods:-All the chemicals used in the preparation of Schiff base and its metal complexes were of AR grade. A Perkin-Elmer CHN analyzer (model 2400) was used for C, H and N analyses. The room temperature molar conductance was determined using a Century digital conductivity meter (model cc 601) with a dip type cell and a smooth platinum electrode. The electronic absorption spectra of the complexes were recorded as dilute solutions on a Shimadzu 160A/240A UV-visible spectrophotometer. The 1 H NMR spectra were recorded using Bruker DRX 400 spectrometer at 400 MHz with TMS as the internal standard. Mass spectra were obtained with a VG70-70H
Bioinorganic Chemistry and Applications, 2006
A series of antibacterial and antifungal amino acid-derived compounds and their cobalt(II), copper(II), nickel(II), and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments, and IR, and electronic spectral measurements. Ligands (L 1 )-(L 5 ) were derived by condensation of β-diketones with glycine, phenylalanine, valine, and histidine and act as bidentate towards metal ions (cobalt, copper, nickel, and zinc) via the azomethine-N and deprotonated-O of the respective amino acid. The stoichiometric reaction between the metal(II) ion and synthesized ligands in molar ratio of M : L (1 : 1) resulted in the formation of the metal complexes of type [M(L)(H 2 O) 4 ]Cl (where M = Co(II), Cu(II), and Zn(II)) and of M : L (1 : 2) of type [M(L) 2 (H 2 O) 2 ] (where M = Co(II), Cu(II), Ni(II), and Zn ). The magnetic moment data suggested for the complexes to have an octahedral geometry around the central metal atom. The electronic spectral data also supported the same octahedral geometry of the complexes. Elemental analyses and NMR spectral data of the ligands and their metal(II) complexes agree with their proposed structures. The synthesized ligands, along with their metal(II) complexes, were screened for their in vitro antibacterial activity against four Gram-negative (Escherichia coli, Shigella flexeneri, Pseudomonas aeruginosa, and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains and for in vitro antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani, and Candida glaberata. The results of these studies show the metal(II) complexes to be more antibacterial/antifungal against one or more species as compared to the uncomplexed ligands. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties. Five compounds, (3), (7), (10), (11), and (22), displayed potent cytotoxic activity as LD 50 = 8.974 × 10 −4 , 7.022 × 10 −4 , 8.839 × 10 −4 , 7.133 × 10 −4 , and 9.725 × 10 −4 M/mL, respectively, against Artemia salina.
Bioinorganic Chemistry and Applications, 2012
Two new heterocyclic Schiff bases of 4-amino-5-mercapto-3-H/propyl-1,2,4-triazole and 5-nitrofurfuraldehyde [HL 1-2 ] and their cobalt, nickel, copper, and zinc complexes have been synthesized and characterized by elemental analyses, spectral (UV-Vis, IR, 1 H NMR, Fluorescence, and ESR) studies, thermal techniques, and magnetic moment measurements. The heterocyclic Schiff bases act as bidentate ligands and coordinate with metal ions through nitrogen and sulphur of the thiol group. The low molar conductance values in DMF indicate that the metal complexes are nonelectrolytes. The magnetic moments and electronic spectral data suggest octahedral geometry for the Co(II), Ni(II), and Zn(II) complexes and square planar for Cu(II) complexes. Two Gram-positive bacteria (Staphylococcus aureus MTCC 96 and Bacillus subtilis MTCC 121), two Gram-negative bacteria (Escherichia coli MTCC 1652 and Pseudomonas aeruginosa MTCC 741), and one yeast, Candida albicans, were used for the evaluation of antimicrobial activity of the newly synthesized compounds.
Synthesis, Spectroscopic and Antimicrobial Studies of Co(II), Ni(II), Cu(II) and Zn(II) Complexes
The Schiff base was synthesized by condensation of 2-hydroxy-1-naphthaldehyde with 3aminobenzoic acid in 1:1 molar ratio. The Schiff base ligand formed complexes with Co (II), Ni (II), Cu (II) and Zn (II) acetate via mechanochemical synthesis. The synthesized compounds were characterized by solubility test, thermal analysis, FT-IR, powder x-ray diffraction, molar conductance measurement, magnetic susceptibility and elemental analysis. The Schiff base has a melting point of 190 o C. The decomposition temperature of complexes was found to be in the range 289-302 o C. The Schiff base and its metal (II) complexes were soluble in DMF, DMSO and sparingly soluble in acetonitrile, chloroform, diethyl ether and insoluble in n-hexane which indicate the polar nature of the synthesized compounds. The IR spectral analysis of the free Schiff base shows a band at 1622 cm-1 , assigned to v(C=N) stretching vibrations. This band was shifted in the spectra of complexes (1607-1633 cm-1), indicating coordination of the Schiff base to the metal ion through the azomethine group. The molar conductance of complexes determined are in the range 9.51-14.87 Ohm-1 cm 2 mol-1 which indicate the non-electrolytic nature in DMF. Magnetic susceptibility measurements of Co (II), Ni (II) and Cu (II) complexes exhibit a magnetic moment in the range 1.25-3.08 BM. The values correspond to square-planar geometry. The magnetic moment value of Zn (II) complex indicates a diamagnetic behaviour. The elemental analysis of the complexes for C, H and N determined showed that the observed and the calculated percentages of the elements are in good agreement.
Journal of The Serbian Chemical Society, 2009
A new series of Cu(II), Co(II) and Ni(II) complexes with the 1-(2--hydroxyphenyl)-3-phenyl-2-propen-1-one, N 2 -[(3,5-dimethyl-1H-pyrazol-1--yl)methyl]hydrazone ligand, C 21 H 22 N 4 O (LH), were synthesized by the reaction of 1-(2-hydroxyphenyl)-3-phenyl-2-propen-1-one, hydrazone with (3,5-dimethyl-1H-pyrazol-1-yl)methanol and characterized. The nature of the bonding and geometry of the complexes were deduced from elemental analysis, IR, electronic and 1 H-NMR spectroscopy, and magnetic susceptibility and conductivity measurements. The studies indicated square-planar, tetrahedral and octahedral geometry for the copper(II), cobalt(II) and nickel(II) complexes, respectively. The ESR spectra of the copper(II) complex in acetonitrile at 300 and 77 K were recorded and their salient features are reported. The electrochemical behavior of the copper (II) complex was studied by cyclic voltammetry. The antimicrobial activity of the ligand and its metal complexes were studied against the following strains of microorganism: Staphylococcus aureus, Salmonella enterica typhi, Escherichia coli and Bacillus subtilis by the well diffusion method. Metal complexes showed enhanced antimicrobial activity compared with that of the free ligand.