Preparation, Spectroscopic, Bioactive and Theoretical Studies of Mixed Ligand Complexes (original) (raw)
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Open Journal of Inorganic Chemistry, 2020
Schiff base derived from 2-aminophenol and 3-formyl-2-hydroxy-6-methoxyquinoline and its Mn(II) and Fe(II) complexes were synthesized and characterized by melting point and decomposition temperature, elemental analysis, molar conductivity, infrared (IR) spectral analysis, atomic absorption spectroscopy (AAS) analysis, solubility test, and magnetic susceptibility. The Fourier-transform infrared spectroscopy (FTIR) spectral data of the Schiff base determined showed a band at 1622 cm −1 and this was assigned to the v (C=N), which is a feature of azomethine group. The same band was observed to shift to lower frequencies 1577 and 1599 cm −1 in the complexes suggesting coordination of the Schiff base with the respective metal(II) ions. Molar conductance values 14.58 and 12.65 Ω −1 •cm 2 •mol −1 show that the metal complexes were non-electrolyte in nature. The magnetic susceptibility of the complexes was determined and the gram magnetic susceptibility of the complexes was found to be positive, revealing that they are paramagnetic. The elemental analysis of the complexes for C, N and H determined suggested 1:1 metal to ligand ratio. The result of the antimicrobial studies showed that, the metal(II) complexes exhibited better antibacterial and antifungal activity than the Schiff base.
The present article deals with the synthesis of new tridentate O, N and O donor Schiff base ligand via condensation of 3-amino-5-bromobenzofuran-2-carboxamide with 2-hydroxyquinoline-3-carbaldehyde under suitable experimental conditions. The complexes were found to have the general composition ML 2 , where M = Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and L = Schiff base. The chelation of the complexes has been elucidated in the light of analytical, IR, mass, ESR spectral and magnetic data. The measured molar conductance values shows that, the complexes are non-electrolytic in nature. The Schiff base ligand and its metal complexes screened for their antimicrobial activity against Bacillus subtilis, Escherichia coli, Aspergillus niger and Aspergillus flavus to assess their inhibiting potential by minimum inhibitory concentration (MIC) method. In addition, the DNA cleavage activities of all the complexes were studied by agarose gel electrophoresis method.
Sys Rev Pharm, 2020
The ligand Schiff base [(E)-3-(2-hydroxy-5-methylbenzylideneamino)-1-phenyl-1H-pyrazol-5(4H)-one] with some metals ion as Mn(II); Co(II); Ni(II); Cu(II); Cd(II) and Hg(II) complexes have been preparation and characterized on the basic of mass spectrum for L, elemental analyses, FTIR, electronic spectral, magnetic susceptibility, molar conductivity measurement and functions thermodynamic data study (∆H°, ∆S° and ∆G°). Results of conductivity indicated that all complexes were non electrolytes. Spectroscopy and other analytical studies reveal distorted octahedral geometry for all complexes. The antibacterial activity of the ligand and preparers metal complexes was also studied against gram and negative bacteria.
Bioinorganic Chemistry and Applications, 2013
A novel Schiff base ligand N-(4-phenylthiazol-2yl)-2- ((2-thiaxo-1,2-dihydroquinolin-3-yl)methylene)hydrazinecarboxamide (L) obtained by the condensation of N-(4-phenylthiazol-2-yl)hydrazinecarboxamide with 2-thioxo-1,2-dihydroquinoline-3carbaldehyde and its newly synthesized Cu(II), Co(II), Ni(II), and Zn(II) complexes have been characterized by elemental analysis and various spectral studies like FT-IR, 1 H NMR, ESI mass, UV-Visible, ESR, TGA/DTA, and powder X-ray diffraction studies. The Schiff base ligand (L) behaves as tridentate ONS donor and forms the complexes of type [ML(Cl) 2 ] with square pyramidal geometry. The Schiff base ligand (L) and its metal complexes have been screened in vitro for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleavage activity of ligand and its metal complexes were studied using plasmid DNA pBR322 as a target molecule by gel electrophoresis method. The brine shrimp bioassay was also carried out to study the in vitro cytotoxicity properties for the ligand and its metal complexes against Artemia salina. The results showed that the biological activities of the ligand were found to be increased on complexation. complexes, their characterization by various spectroscopic techniques, and their antimicrobial, DNA cleavage, and in vitro cytotoxicity property.
Objectives: To evaluate the biological activity of newly synthesized Schiff base ligand (E) 3-2-(1-(1 hydroxynaphthalen-2-yl) methyleneamino) phenyl)-2 methylquinazoline-4 (3H)-One (HNMAPMQ) and its transition metal complexes. Methods: The newly synthesized ligand (HNMAPMQ) was prepared by the condensation of 3-(2-aminophenyl)-2-methylquinazolin-4 (3H)-one and 2-hydroxy-1-naphthaldehyde. The spectral and structural characterization of the ligand (HNMAPMQ) and its metal complexes were attained by the aid of their elemental analyses and various spectral studies such as IR, 1 H NMR and Mass. The biological activities such as antioxidant, antitubercular and antimicrobial of ligand (HNMAPMQ) and its metal complexes were also studied. Results: According to the analytical and spectroscopic studies, the ligand (HNMAPMQ) acts as tridentate ONO donor towards divalent metal ions (Cu (II), Co (II), Ni (II) and Mn (II)) with the involvement of phenolic oxygen, azomethine nitrogen, carboxylato oxygen there by suggesting the octahedral geometry, whereas Zn(II) complex show tetrahedral geometry. All the metal complexes shows promising antioxidant activity than the ligand (HNMAPMQ) as compared with Butylated hydroxy anisole (BHA), Tertiary Butylated hydroxyl quinoline (TBHQ) and Ascorbic acid (AA). Similarly the antitubercular activity of ligand (HNMAPMQ) and its metal complexes showed good results. The results obtained from the antimicrobial studies clearly reveals that all the metal complexes show superior activity than the ligand (HNMAPMQ). Conclusion: The newly synthesized ligand (HNMAPMQ) and its metal complexes shows good antioxidant, antitubercular and antimicrobial activities thus, can be used as a new drug of choice in the field of pharmacy.
Pharmaceutics
Designing new metallodrugs for anticancer therapy is a driving force in the scientific community. Aiming to contribute to this field, we hereby report the development of a Schiff base (H2L) derived from the condensation of 2-carbaldehyde-8-hydroxyquinoline with 2-hydrazinobenzothiazole and its complexation with transition metal ions. All compounds were characterised by analytical and spectroscopic techniques, which disclosed their structure: [Cu(HL)Cl], [Cu(HL)2], [Ni(HL)(acetate)], [Ni(HL)2], [Ru(HL)Cl(DMSO)], [VO(HL)2] and [Fe(HL)2Cl(H2O)]. Different binding modes were proposed, showing the ligand’s coordination versatility. The ligand proton dissociation constants were determined, and the tested compounds showed high lipophilicity and light sensitivity. The stability of all complexes in aqueous media and their ability to bind to albumin were screened. Based on an antiproliferative in vitro screening, [Ni(HL)(acetate)] and [Ru(HL)Cl(DMSO)] were selected for further studies aiming ...
Journal of Thermal Analysis and Calorimetry, 2000
Ten mixed ligand complexes of the type [M(X-QA)(aa)] and [Ni(X-QA)2(Haa)(H2O)],where X-HQA=5-arylazo-8-hydroxyquinoline derivatives, M=Co(II) orCu(II) and Haa=glycine (gly), alanine (ala) or methionine (met), have been prepared. The complexes have been characterized by elemental analysis, IR and electron spectra and thermal analysis. A tetrahedral structure has been proposed for the cobalt(II) and copper(II) complexes with bidentate coordination of amino acids. The nickel(II)
Frontiers in Chemistry, 2022
Interest is increasingly focused on the use of transition metal complexes as biochemical, medical, analytical, pharmaceutical, agronomic, anticancer, and antibacterial agents. In this study, three complexes of [Zn(H 2 L)Cl] (1), [Cu(H 2 L)(H 2 O)(NO 3)] (2) and [Ni(H 2 L)(NO 3)].2H 2 O (3) were synthesized from a 2-chloroquinoline-3-carbaldehyde derived ligand [H 3 L = ((E)-2-(((2-((2hydroxyethyl)amino)quinolin-3-yl)methylene)amino)ethanol. The compounds were characterized using physicochemical and spectroscopic methods. The results demonstrate that the free ligand behaves as a tridentate ligand with one oxygen and two nitrogen (ONN) donor atoms in 1:1 metal:ligand ratio. The formation constants of the complexes were found to be (K Zn(II) = 2.3 × 10 6 , K Cu(II) = 2.9 × 10 6 , and K Ni(II) = 3.8 × 10 5). The thermodynamic parameters indicated that the reactions were spontaneous with exothermic nature of metal-ligand interaction energies. Based on the analyses of the experimental (EDX, FTIR, PXRD, MS and TGA) and DFT results, a distorted tetrahedral, a distorted square pyramidal and square planar geometry for Zn(II), Cu(II) and Ni(II) complexes, respectively, were proposed. The B3LYP calculated IR frequencies and TD-B3LYP calculated absorption spectra were found to be in good agreement with the corresponding experimental results. The powder XRD data confirmed that the Zn(II), Cu(II) and Ni(II) complexes have polycrystalline nature with average crystallite sizes of 27.86, 33.54, 37.40 Å, respectively. In vitro antibacterial activity analyses of the complexes were studied with disk diffusion method, in which the complexes showed better activity than the precursor ligand. Particularly the Cu(II) complex showed higher percent activity index (62, 90%), than both Zn(II) (54, 82%) and Ni(II) (41, 68%) complexes against both E. coli and P. aeruginosa, respectively. Using the DPPH assay, the complexes were further assessed for their antioxidant capacities. All metal complexes showed improved antioxidant activity than the free ligand. Zn(II) and Cu(II) complexes, which had IC 50 values of 10.46 and 8.62 μg/ml, respectively, showed the best antioxidant activity. The calculated results of
Structural and spectroscopic studies on some metal complexes of an 8-hydroxyquinoline derivative
Inorganica Chimica Acta, 2010
Mononuclear metal complexes of 2-[(2-hydroxyethylimino)methyl]quinolin-8-ol (H 2 L) were obtained by reaction of 8-hydroxyquinoline-2-carboxaldehyde, 2-aminoethanol and the corresponding metal(II) acetate (M = Co, Ni, Cu, Zn or Cd) in 2:2:1 molar ratios. The Schiff base ligand is acting as a monodeprotonated O,N,N-donor in the helical complex Ni(HL) 2 , which could be crystallographically characterised. This crystal structure contains homochiral chains of Ni(HL) 2 connected through double O-HÁ Á ÁO connections, which relate both non-coordinated hydroxy groups of the ethanolic arms with both phenolic O atoms of a neighbouring complex, in a ''head-to-tail" disposition. A study of the luminescence properties in methanol solution showed that the quantum yields of Zn(HL) 2 ÁH 2 O (U F = 0.02) and Cd(HL) 2 ÁH 2 O (U F = 0.04) are lower than that of 8-hydroxyquinoline-2-carboxaldehyde (U F = 0.06).
Metal Complexes with 8-Hydroxyquinoline: Synthesis and In Vitro Antimicrobial Activity
Open Journal of Applied Sciences, 2021
In this paper, three complexes with 8-hydroxyquinoline (8-HQ) were synthesized, their spectral analysis was performed and the antimicrobial effect was examined in vitro. The stoichiometric ratio of the complex was determined conductometrically and spectrophotometrically. FTIR and UV/VIS spectroscopy were used for structural characterization. Antimicrobial activity was examined by diffusion technique on selected gram-positive and gram-negative bacteria, and C. albicans. Square planar and octahedral geometry complexes were synthesized by mixing in a molar ratio of 1:2 (M:L). Based on the spectral data, it is concluded that both oxygen and nitrogen atoms from 8-HQ are involved in the formation of the complex. The antimicrobial activity of the complexes is high, with zones of inhibition in the range of 15-28 mm. 8-HQ was shown to have a significantly higher ability to inhibit the growth of the tested microorganisms.