Activity Of Mixed Ligand Complexes Research Articles

Synthesis, Characterization, and Biological Activity of Mixed ligand Complexes from 8-Hydroxyquinoline and new Ligand for β-Enaminone

The synthesized ligand [4-chloro-5-(N-(5,5-dimethyl-3-oxocyclohex-1-en-1-yl)sulfamoyl)-2-((furan-2-ylmethyl)amino)benzoic acid] (H2L1) was identified utilizing Fourier transform infrared spectroscopy (FT-IR), 1 H, 13 C – NMR, (C.H.N), Mass spectra, UV-Vis methods based on spectroscopy. To detect mixed ligand complexes, analytical and spectroscopic approaches such as micro-analysis, conductance, UV-Visible, magnetic susceptibility, and FT-IR spectra were utilized. Its mixed ligand complexes [M(L1)(Q)Cl2] [ where M= Co(II), Ni(II), and Cd(II)] and complexes [Pd(L1)(Q)] and [Pt(L1)(Q)Cl2]; [H2L1] =β-enaminone ligand =L1 and Q= 8-Hydroxyquinoline = L2]. The results showed that the complexes were synthesised utilizing the molar ratio M: L1:L2 (1 :1 :1). The formation of six-coordinate octahedral geometry was proposed for metal complexes Co (II), Ni (II), Cd (II), and Pt (IIII), while the Pd (II) complex was square planar. By using the agar well diffusion method, the ligands and complexes were evaluated for antibacterial activity against Staphylococcus aureus, Escherichia coli. The studies demonstrate that the ligand and its complexes have variable activity against the bacterial types, Some of the complexes had an effect on bacteria, while others had less inhibitory action than the ligand. Also, the produced ligand and its metal complexes have been tested for fungi (Candida albicans );the complexes exhibited suppressing activity against fungi compared to the ligand prepared from them. Keywords: β-enaminones, 5,5-dimethylcyclohexane-1,3-dione , Furosemide, Mixed-ligand complexes, 8-Hydroxyquinoline.

Synthesis, characterization and antibacterial activity of mixed ligand complexes of Nicotinamide and 2,2′-Bipyridine

No Abstract.

Structural, molecular docking computational studies and in-vitro evidence for antibacterial activity of mixed ligand complexes

A novel bis-bidentate azo dye ligand, formed by the diazotized reaction of 1,4-diaminobenzene and 8- hydroxyquinoline in 1:2 M ratio resulted the formation of 5,5′-{(1E, 1E`)-1,4-phenylenebis(diazene-2,1-diyl)}bis(quinoline-8-ol) (H2L1) as primary ligand and its Cu(II), Ni(II), Co(II), Mn(II), Cr(III), UO2(II) and Cd(II) complexes. Incorporating of 8-hydroxyquinoline (HL2) as co-ligand with the formed mixed-ligand complexes of the composition, [M2(L1)(L2)2(OH2)4] (M = Cu(II), Co(II), Ni(II), Mn(II), UO2(II), Cd(II) and [Cr2(L1)(L2)2(OH2)2(Cl2)] were synthesized and characterized. H2L1, HL2, and their mixed ligand complexes were screened against two local gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and three local gram-negative bacteria (Klebsiella pneumoniae Escherichia coli and Pseudomonas sp). Antifungal activities were determined against Fusarium oxysporum Aspergillus niger, and Candida albicans. Cr(III), Mn(II) and UO2(II) mixed ligand complexes showed higher activity than H2L1 and HL2; their cytological effects on S. aureus and B. cereus along with the in-silico docking showed that these complexes represent antibacterials targeting FtsZ and DltA proteins; hence, affect cell divisions and gram-positive cell walls. The XRD patterns of the Mn(II) and UO2(II) mixed ligand complexes are polycrystalline natures.

Synthesis, characterization and antiproliferative activity of mixed ligand complexes of Cu2+ and Co2+ with lapachol

Mixed ligand complexes [Cu(phen)(Lap)2] (1) and [Co(dppeO)(Lap)2] (2) were synthesized from the reaction of lapachol (Lap) with [Cu(phen)Cl2] or [Co(dppe)Cl2] in the presence of Et3N. Complexes (1) and (2) were fully characterized by X-ray crystallography, elemental analyses, and infrared spectroscopy. Antiproliferative activities of complexes (1) and (2) against several tumor cell lines were also determined alongside those of [Cu(Lap)2(EtOH)2] (3) and [Co(Lap)2(EtOH)2] (4).

DNA binding and biological activity of mixed ligand complexes of Cu(II), Ni(II) and Co(II) with quinolones and N donor ligand

Abstract Mixed ligand complexes of Cu(II), Ni(II) and Co(II) have been synthesized by using levofloxacin and bipyridyl and characterized using spectral and analytical techniques. The binding behavior of the Ni(II) and Cu(II) complexes with herring sperm DNA(Hs-DNA) were determined using electronic absorption titration, viscometric measurements and cyclic voltammetry measurements. The binding constant calculated for Cu(II) and Ni(II) complexes are 2.0 x 10 4 and 4.0 x 10 4 M -1 respectively. Detailed analysis reveals that these metal complexes interact with DNA through intercalative binding mode. The nuclease activity of Cu(II) and Ni(II) complexes with ct-DNA was carried out using agarose gel electrophoresis technique. The antioxidant activities for the synthesized complexes have been tested and the antibacterial activity for Ni(II) complex was also checked. Key words: Intercalation, hypochromism, red shift and peak potential.

Physicochemical studies and biological activity of mixed ligand complexes involving bivalent transition metals with a novel Schiff base and glycine as a representative amino acid

The mixed-ligand complexes of Co(II), Ni(II), Mn(II) and Zn(II) with 2-aminomethyl thiophenyl-4-bromosalicylaldehyde Schiff base (ATS) and glycine as a representative example of amino acids have been achieved. These complexes namely [Ni(ATS)(Gly)] (1), [Co(ATS)(Gly)].H 2 O (2) [Mn(ATS)(Gly)].2H 2 O (3), and [Zn(ATS)(Gly)] (4) were characterized by elemental, molar conductance, infrared, magnetic moment, and electronic spectra. ATS behaves as mononegatively charged bidentate ligand with coordination through azomethine nitrogen and phenolate oxygen groups while glycine acts as monobasic bidentate ligand is coordinated via amino and ionized carboxylate group after deprotonation. The low molar conductance values suggest the non-electrolytic nature of these complexes. The magnetic and spectral data indicates a square planar geometry for Ni(II) complex, tetrahedral geometry for Zn(II) and octahedral geometry for both Mn(II) and Co(II) complexes. The isolated chelates have been screened for their antimicrobial activity.

Synthesis, characterization, molecular modeling and biological activity of mixed ligand complexes of Cu(II), Ni(II) and Co(II) based on 1,10-phenanthroline and novel thiosemicarbazone

A combined experimental and computational study of novel mixed ligand Cu(II), Ni(II) and Co(II) complexes of 2-(1-(2-phenyl-hydrazono)-propan-2-ylidene)hydrazine-carbothioamide (TPHP) and 1,10-phenanthroline (1,10-Phen) have been synthesized. The complexes have been characterized by elemental analyses, IR, solid reflectance, magnetic moment, 1HNMR and molar conductance. Spectral data showed that the 1,10-phenanthroline acts as neutral bidentate ligand coordinating to the metal ion through two nitrogen donor atoms and thiosemicarbazone acts as monobasic tridentate coordinating through two imine-N and thiolate sulphur groups. The geometry of the studied M(II) complexes has been fully optimized using parameterized PM3 semiempirical method. It was observed that the M–S bond length is longer than that of M–Cl in the isolated complexes and the M–N bond length is shorter than that of M–Cl. Also, valuable information is obtained from calculations of molecular parameters for all complexes including net dipole moment of the metal complexes, values of binding energy, which proved that the complexes are more stable than the free ligand. The metal chelates have been screened for their antimicrobial activities using the disc diffusion method against different selected types of bacteria (G+: Bacillus subtillis RCMB 010067, Staphylococcus aureus RCMB 010028); G−: Pseudomonas aeuroginosa RCMB 010043, Escherichia coli RCMB 010052)) and fungi (Aspergillus flavus RCMB 02568, Pencicillium italicum RCMB 03924, Candida albicans RCMB 05031, Geotricum candidum RCMB 05097). Finally, structure–activity relationship studies were investigated with the aim to correlate physico-chemical properties that may be related to the antimicrobial action of the studied compounds. Protonation constant of (TPHP) ligand and stability constants of its M(II) complexes were determined by potentiometric titration method in 70%:30% DMSO–water mixture at 0.1moldm−3 NaCl.

Spectroscopic Characterization and Biological Activity of Mixed Ligand Complexes of Ni(II) with 1,10-Phenanthroline and Heterocyclic Schiff Bases.

Mixed ligand complexes of Ni(II) with 1,10-phenanthroline (1,10-Phen) and Schiff bases L1(MIIMP); L2(CMIIMP); L3(EMIIMP); L4(MIIMNP); L5(MEMIIMP); L6(BMIIMP); L7(MMIIMP); L8(MIIBD) have been synthesized. These metal chelates have been characterized by elemental analysis, IR, 1H-NMR, 13C-NMR, Mass, UV-Vis, magnetic moments, and thermogravimetric (TG&DTA) analysis. Spectral data showed that the 1,10-phenanthroline act as neutral bidentate ligand coordinating to the metal ion through two nitrogen donor atoms and Schiff bases acts as monobasic bidentate coordinating through NO donor atoms. All Ni(II) complexes appear to have an octahedral geometry. The antimicrobial activity of mixed ligand complexes has been studied by screening against various microorganisms, it is observed that the activity enhances upon coordination. The DNA binding studies have been investigated by UV-Vis spectroscopy, and the experimental results indicate that these complexes bind to CT DNA with the intrinsic binding constant Kb = 2.5 ± 0.2 × 105 M−1. MTT is used to test the anticancer effect of the complexes with HL60 tumor cell. The inhibition ratio was accelerated by increasing the dosage, and it had significant positive correlation with the medication dosage.

INVESTIGATIONS ON NUCLEASE ACTIVITY OF TRANS MIXED LIGAND- COPPER(II) COMPLEXES WITH ORTHO SUBSTITUTED AROMATIC OXIMES AND HETEROCYCLIC BASES

Mixed ligand complexes of copper(II) with salicyladoxime (SAO), 2-hydroxy acetophenone oxime (HAO) as primary ligands and pyridine( Py), imidazole (Im) as secondary ligands have been synthesized and characterized by molar conductivity, magnetic moments, electronic, IR and ESR spectral data. Cyclic voltammetric studies show quasi-reversible reduction attributable to Cu2+/ Cu+. The binding interactions between metal complexes and calf thymus DNA have been investigated by using UV –Visible titrations and cyclic voltammetry studies. The cleavage activity of complexes was carried out on double-stranded pBR322 circular plasmid DNA by using gel electrophoresis. All complexes show increased nuclease activity in the presence of oxidant (H 2 O 2 ). The nuclease activity of mixed ligand complexes are compared with that of the parent copper(II) complexes. Controlled experiments suggest that the complexes cleave DNA predominantly via an oxidative mechanism.

Synthesis, characterization and antifungal activity of mixed ligand complexes of Co11, Ni11 and Cu11 with cis-3,7-dimethyl-2,6- octadiensemicarbazone and amino acids

Synthesis, characterization and antifungal activity of mixed ligand complexes of Co11, Ni11 and Cu11 with cis-3,7-dimethyl-2,6- octadiensemicarbazone and amino acids

Synthesis, characterization, theoretical calculations and catalase-like activity of mixed ligand complexes derived from alanine and 2-acetylpyridine

Mixed ligand complexes [M(2-AP)(Ala)Clx · mH2O]nH2O, where (M = CoII, NiII, CrIII and FeIII, 2-AP = 2-acetylpyridine, Ala = alanine, x = 2–3, m = 0–1 and n = 3–5] are synthesized and characterized by elemental analysis, FTIR, UV/Vis., MS, TG, measurements and semi-empirical calculations ZINDO/1 and PM3. The results suggest an octahedral geometry for all isolated complexes. FTIR spectra show that alanine coordinates to the metal ions as a neutral unidentate through the amino nitrogen where 2-acetylpyridine coordinates to the metal ion in a bidentate manner through carbonyl oxygen and pyridyl nitrogen. Semi-empirical calculations have been used to study the molecular geometry and the harmonic vibrational spectra with the purpose to assist the experimental assignment of the complexes. The Fe complex showed significant activity as a catalase-like model.

Nuclease activity of mixed ligand complexes of copper(II) with heteroaromatic derivatives and picoline

New picoline adducts with carbamic acid [(furan-2-yl)methylene]hydrazide–CuII (CFMH) (1); thiocarbamic acid [(furan-2-yl)methylene]hydrazide–CuII (TFMH) (2); carbamic acid [(furan-2-yl)ethylidene]hydrazide–CuII (CFEH) (3), thiocarbamic acid [(furan-2-yl)ethylidene]hydrazide–CuII (TFEH) (4); carbamic acid [(thiophene-2-yl) methylene]hydrazide–CuII (CTMH) (5), thiocarbamic acid [(thiophene-2-yl)methylene]hydrazide–CuII (TTMH) (6), carbamic acid [(thiophene-2-yl)ethylidene]hydrazide–CuII (CTEH) (7), thiocarbamic acid [(thiophene-2-yl)ethylidene]hydrazide–CuII (TTEH) (8) have been prepared and characterized by analytical, i.r., electronic, e.s.r. and c.v. spectral data. The electronic spectra suggest distorted octahedral geometry for all the picoline adducts. E.s.r. g ∥ values lie between 2.251–2.286 at l.n.t. All the adducts undergo a quasi-reversible one-electron reduction in the range +0.47 to +0.51 V versus s.c.e., attributable to the CuIII/CuII redox couple. The electron transfer is much faster in the semicarbazone complexes than in the thiosemicarbazone complexes. All adducts showed increased nuclease activity in the presence of oxidant; the nuclease activity is compared with that of the parent copper(II) complexes.

Coordination of copperpolyamine complex with imidazoles potentiates it superoxide dismutase mimicking activity and abolishes its interaction with albumin.

Mixed ligand complexes of copper polyamine with biomolecules such as imidazole, substituted imidazoles or pyridine have been synthesized and characterized. These molecules were used because of their low toxicity and high activity. These complexes were found to possess a distorted octahedral microenvironment with a potential SOD mimicking activity. The IC50 values for these complexes were of the order of 2-90 microM. Pyridine and imidazole complexes were most effective as they possess the lowest IC50 values of 2.1 and 6 microM respectively which are higher than the IC50 value of polyamine copper complex. Based on the uric acid estimations, it has also been ascertained that these complexes dismute O2- without inhibiting xanthine oxidase activity. The presence of increasing concentrations of albumin had no effect on the SOD mimicking activity of mixed ligand complexes. Polyamine complex, however lost approximately 80% of SOD mimicking activity in the presence of albumin (1 mg). These results suggest that coordination of polyamine copper complex with imidazoles/pyridine may abolish their binding affinity for albumin while potentiating their SOD mimicking activity.

Antimicrobial activity of mixed ligand complexes based on tridentate salicylic aldehyde imines and thiosemicarbazones

Antimicrobial activity of mixed ligand complexes based on tridentate salicylic aldehyde imines and thiosemicarbazones