Free Schiff Base Ligand Research Articles

Synthesis, Molecular Docking, and antibacterial evaluation of Quinoline-Derived Ni(II), Cu(II) and Zn(II) complexes

We hereby report the synthesis of novel Ni(II), Cu(II) and Zn(II) complexes of (E)-2-(((7-chloro-2-hydroxyquinolin-3-yl)methylene)amino)-3-methylbutanoic acid ligand obtained by reacting 2,7-dichloroquinoline-3-carboaldehyde and amino acid, valine for antibacterial applications. The ligand and the metal complexes were characterized using FT-IR, UV–Vis, TGA/DTA, pXRD spectroscopic techniques and density functional theory (DFT) calculations. The Schiff base ligand was tridentate with ONO active binding sites as confirmed from its FT-IR spectral analysis. Disc diffusion method was used to assess the antibacterial potential of the Schiff base ligand and its metal complexes. The Schiff base ligand shows antibacterial activities of 8.33 ± 0.471 mm at concentration of 100 µg/ml and 9.33 ± 0.471 mm at concentration of 200 µg/ml against S. aureus. However, the copper complex exhibited zone of inhibition of 11.50 ± 0.408 mm at concentration of 100 µg/ml and 12.67 ± 0.471 mm at concentration of 200 µg/ml against S. aureus. This indicates that the copper complex has better antibacterial activity than the free Schiff base ligand. The overall result revealed the promising potential of the metal complexes for application as antibacterial agents. The DFT calculated absorption spectra agree with the corresponding experimental results. The molecular docking analyses also provided important insights on the interaction of the synthesized complexes with the target proteins.

Synthesis, Characterization, Biological Properties, ADMET and Drug-likeness Analysis of Mn (II) complexes with Schiff Bases Derived from Sulphathiazole and 4-diethylaminosalicyaldehyde/Salicyaldehyde

Mn (II) complexes were synthesized with the Schiff base ligand obtained by the condensation of sulfathiazole with 4-diethylaminosalicyaldehyde/Salicyaldehyde. Their characterization was performed by elemental analysis, molar conductance, melting points, magnetic susceptibility, infrared, and UV–Vis spectral analysis. The results suggest that the Schiff bases and their complex are synthesized in excellent yield, molar conductance studies on the complexes indicated they were non-electrolytic. The IR data indicated that the Schiff base ligand is tridentate coordinated to the metallic ion with two N atoms from the azomethine group and thiazole ring and one O atom from the phenolic group. The electronic spectral study showed octahedral geometry for all the complexes which are further supported by magnetic moment values. The ligand and its complexes were screened against four bacterial and two fungal strains using the disk diffusion method. The antimicrobial evaluation results revealed that the metal (II) complexes exhibited higher antimicrobial activity than the free Schiff base ligand. The ADMET and drug-likeness studies of the synthesized ligands indicated that the Schiff base ligands fulfill Lipinski’s, Ghoose, Veber, Egan, and Mugge rules but the complexes showed some deviations. They also displayed low toxicity levels.

Microwave assisted synthesis, characterization and bioactivity evaluation of a cobalt (II) complex with a novel Schiff base ligand derived from phenylacetyl urea and salicylaldehyde

The study comprehensively focusses on the synthesis and characterization of a novel Co(II) metal complex formed by the condensation of phenylacetyl urea and salicylaldehyde with Thiocyanate ion using an eco-friendly microwave irradiation technique, which resulted in a higher yield. The molecular formula and geometry of the complex were deduced through an array of techniques including UV–Vis spectra, FT-IR, Far IR, Cyclic voltammetry, thermal analysis, and Powder XRD. The molar conductance data revealed a non-electrolyte [1:0] type complex. Notably, the FT – IR spectral peaks obtained at 3388 cm−1, 2914 cm−1,1622 cm−1 shows that Schiff base and Thiocyanate ions were coordinated to the metal ion in a monodentate manner. Furthermore, electronic spectra values confirmed a pseudo tetrahedral geometry for the complex. Intriguingly, our study also encompassed an exploration of the biological activities of both the Schiff base ligand and the Co(II) metal complex. By subjecting them to antimicrobial assays against various microorganisms, including Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeurginosa, Staphlococcus aureus, Bacillus cereus, Aspergillus favus, Aspergillus niger, Aspergillus sojae, Aspergillus oryzae, and Candida albicans. It was found that the complex exhibited moderate activity against bacteria and remarkably enhanced activity against fungi when compared to the free Schiff base ligand. Additionally, we investigated the DPPH free radical scavenging activity of the complex and the ligand, unveiling that the Co(II) complex demonstrated significantly higher antioxidant activity in comparison to the ligand. These results highlight the potential of the synthesized Co(II) complex as a promising candidate for biomedical applications. Overall, this study not only sheds light on the synthesis and characterization of the Co(II) metal complex with a novel Schiff base ligand but also unravels its distinct biological activities, indicating its potential significance in antimicrobial and antioxidant applications.

A study of in vitro antimicrobial activities and antioxidant of lanthanide complexes with a tri dentate Schiff base ligand

The tridentate N3-type Schiff base 4-(anthracen-10-yl)-2,6-di(pyridin-2-yl)pyridine was synthesized from the condensation reaction of 2-acetyl pyridine and anthracene-10-carbaldehyde with ammonia using one pot methodology. This hybrid ligand was used for synthesis of lanthanide complexes (La, Sm and Eu) as novel potential biological agent. The lanthanide complexes were characterized on the basis of elemental, FT-IR, UV-Visible, mass spectrometry as well as molar conductivity. The complexes were screened for in vitro antibacterial and antifungal activities against the multidrug resistant pathogens such as Escherichia coli, Staphylococcus aureus and Aspergillus niger. The antimicrobial results revealed that Sm+3 complex has a good potency against different gram positive and gram negative bacteria in comparison with other complexes. All lanthanide complexes showed a moderate antioxidant activity with IC50. The DPPH· radical scavenging effects of the Schiff base ligand and its Ln (III) complexes were screened. The Ln (III) complexes were significantly more efficient in quenching DPPH· than the free Schiff base ligand.

Green Synthesis, Characterization, Antimicrobial and Anticancer Screening of New Metal Complexes Incorporating Schiff Base.

A Schiff base ligand of o-vanillin and 4-aminoazobenzene and its transition metal complexes of Ni(II), Co(II), Zn(II), Cu(II), Mn(II), and Zr(IV) were prepared under microwave irradiation as a green approach compared to the conventional method. The structures of new compounds have been characterized and elucidated via elemental and spectroscopic analyses. In addition, magnetic susceptibility, electron spin resonance, and electronic spectra of the synthesized complexes explained their geometrical structures. The thermal stability of Cu(II), Zn(II), and Zr(IV) complexes was studied by thermo-gravimetric analyses (TGA). Coats–Redfern and Horowitz–Metzger equations were used to calculate the thermal and dehydration decomposition activities of proposed structures kinetically. Surface morphologies of the solid compounds were imaged by scanning electron microscopy (SEM). The particle size of prepared complexes was measured by using a particle size analyzer at a diffraction angle of 10.9°. The geometry structures of the synthesized compounds were verified utilizing electronic spectra, ESR spectrum, and magnetic moment value. The newly synthesized compounds were screened for antimicrobial activity. Also, the anticancer activity of the free Schiff base ligand and its metal complexes were studied against two cell lines: human colon (HCT-116) and human liver cancer cells (HepG-2). The obtained results showed that the Cu(II) complex displayed the highest cytotoxic activity (IC50 = 18 and 22 μg/mL for HepG-2 and HCT, respectively) compared to the free Schiff base ligand.

Synthesis, Characterization, Antimicrobial, Anti-Diabetic, Anti-Inflammatory and Anti-Cancer studies of Schiff Base metal(II) complexes derived from 4-hydroxy-3,5 dimethoxybenzaldehyde and 3-aminoquinoline

The new Schiff base ligand (E)-2,6-dimethoxy-4-((quinolin-3-ylimino)methyl )phenol (HL) and its Cu(II), Co(II), Ni(II) and Zn(II) metal complexes were synthesized and characterized by various spectroscopic (UV-vis, IR, NMR), SEM, Mass and magnetic susceptibility measurement. The ligand (HL) was synthesized by condensation of 4-hydroxy-3,5-dimethoxybenzaldehyde and 3-aminoquinoline. On the basis of electronic spectral data and magnetic susceptibility measurement the tetrahedral geometry has been proposed for all the complexes. The ligand and metal complexes have been screened for their antimicrobial activities against bacteria ( Staphylococcus aureus, Escherichia coli) and antifungal activity against the fungi ( Candida albicans) . Further the ligand and its Cu(II) complex was also screened for anticancer activity on human cancer cell lines such as breast (MCF7) by MTT assay method . Interestingly, Cu(II) complex shows better anticancer activity than the free schiffbase ligand . The in vitro anti-inflammatory and anti-diabetic activities of the ligand and Cu(II) complex were studied. The Cu(II) complex show higher inhibition activity than that of the free ligand.

In Vitro Evaluation of the Potential Pharmacological Activity and Molecular Targets of New Benzimidazole-Based Schiff Base Metal Complexes.

Metal-based drugs, including lanthanide complexes, have been extremely effective in clinical treatments against various diseases and have raised major interest in recent decades. Hence, in this work, a series of lanthanum (III) and cerium (III) complexes, including Schiff base ligands derived from (1H-benzimidazol-2-yl)aniline, salicylaldehyde, and 2,4-dihydroxybenzaldehyde were synthesized and characterized using different spectroscopic methods. Besides their cytotoxic activities, they were examined in human U-937 cells, primate kidney non-cancerous COS-7, and six other, different human tumor cell lines: U251, PC-3, K562, HCT-15, MCF-7, and SK-LU-1. In addition, the synthesized compounds were screened for in vitro antiparasitic activity against Leishmania braziliensis, Plasmodium falciparum, and Trypanosoma cruzi. Additionally, antibacterial activities were examined against two Gram-positive strains (S. aureus ATCC® 25923, L. monocytogenes ATCC® 19115) and two Gram-negative strains (E. coli ATCC® 25922, P. aeruginosa ATCC® 27583) using the microdilution method. The lanthanide complexes generally exhibited increased biological activity compared with the free Schiff base ligands. Interactions between the tested compounds and model membranes were examined using differential scanning calorimetry (DSC), and interactions with calf thymus DNA (CT-DNA) were investigated by ultraviolet (UV) absorption. Molecular docking studies were performed using leishmanin (1LML), cruzain (4PI3), P. falciparum alpha-tubulin (GenBank sequence CAA34101 [453 aa]), and S. aureus penicillin-binding protein 2a (PBP2A; 5M18) as the protein receptors. The results lead to the conclusion that the synthesized compounds exhibited a notable effect on model membranes imitating mammalian and bacterial membranes and rolled along DNA strands through groove interactions. Interactions between the compounds and studied receptors depended primarily on ligand structures in the molecular docking study.

Synthesis, structural characterization, and biological studies of ATBS–M complexes (M(II) = Cu, Co, Ni, and Mn): Access for promising antibiotics and anticancer agents

A new bidentate Schiff base ligand (ATBS [4-bromo-2-(thiazole-2-yliminomethyl)phenol]) was synthesized via the condensation reaction of 2-aminothiazole with 5-bromosalicylaldehyde in ethanol. The reaction of ATBS with transition metal salts of Cu(II), Co(II), Ni(II), and Mn(II) afforded the corresponding ATBS-M complexes. Results from physicochemical and spectral analyses, such as elemental analysis, infrared, UV-Vis spectroscopy, magnetic susceptibility, and molar conductance, revealed a nonelectrolytic nature with octahedral (Oh ) geometry and a metal/ligand ratio of 1:2 for Cu(II), Co(II), and Ni(II), but 1:1 for the Mn(II) complex. The density functional theory (DFT) calculations are correlated very well with the proposed structure and molecular geometry of the complexes as [M(ATBS)2 ] (M = Cu, Co, and Ni) and [Mn(ATBS)(H2 O)2 ]. Significantly, the prepared compounds showed strong inhibition activity for a wide spectrum of bacteria (Escherichia coli, Bacillus subtilis, and Staphylococcus aureus) and fungi (Candida albicans, Aspergillus flavus, and Trichophyton rubrum), with the ATBS-Ni complex being the most promising antibiotic agent. Molecular docking studies of the binding interaction between the title complexes with the bacterial protein receptor CYP51 revealed clear insights about the inhibition nature against the studied microorganisms, with the following order: ATBS-Cu > ATBS-Mn > ATBS-Ni > ATBS-Co for complex stability. Moreover, the cytotoxicity measurements of all prepared metal complexes against the colon carcinoma (HCT-116) and hepatocellular carcinoma (Hep-G2) cell lines showed exceptional anticancer efficacy of the complexes as compared with the free ATBS Schiff base ligand. Significantly, the results attested that ATBS-Cu is the most effective complex against HCT-116 cells, whereas ATBS-Mn has the highest cytotoxic efficiency against Hep-G2 cells. Furthermore, electronic spectra, viscosity measurements, and gel electrophoresis techniques were employed to probe the interaction of all prepared ATBS-metal complexes with calf thymus (CT)-DNA. Results confirmed that all complexes are strongly bound to CT-DNA via intercalation mode, with the ATBS-Co complex having the highest binding ability.

Synthesis and spectral analysis of some metal complexes with mixed Schiff base ligands 1-[2-(2-hydroxybenzylideneamino)ethyl]pyrrolidine-2,5-dione (HL1) and (2-hydroxybenzalidine)glycine (HL2)

In this paper, new metal ions complexes of [chromium (III), iron (III), cobalt(II), nickel(II), copper(II) and cadmium(II)] were prepared from mixed Schiff base ligands 1-(2-aminoethyl) pyrrolidine-2,5-dione ligand which was prepared form the reaction of the succinic anhydride with ethylenediamine then reacted with salicyaldehyde to form a new Schiff base ligand1-[2-(2-hydroxybenzylideneamino)ethyl]pyrrolidine-2,5-dione (HL1) . The amino acid (glycine) was reacted with salicyaldehyde to form another new Schiff base ligand (2-hydroxybenzaldine)glycine (HL2) . The two types of Schiff bases ligands (HL1) , (HL2) were mixed with some metal ions [(Cr+3, Fe+3, Co+2, Ni+2, Cu+2 and Cd+2)] to obtain a new metal complexes. The Schiff base ligands were characterized by physic-chemical spectroscopic techniques such as: FT-IR Spectra, UV-Vis. Spectra, mass spectroscopy, 1HNMR and microanalysis techniques (C.H.N). Which is indicated the purity of Schiff base ligands. The fragments of the prepared free Schiff base ligand (HL1) were identified by mass spectrometer technique. The metal complexes were characterized by spectroscopic techniques such as: FT-IR Spectra, UV-Vis. Spectra, molar conductivity, magnetic moment and microanalysis techniques (C.H.N) and chloride ion percentage. All the analysis of ligands and their metal complexes were in good agreement with the theoretical values which indicated the purity of Schiff base ligands and their metal complexes. From the above data, the molecular structures for all the metal complexes were proposed to be octahedral. The values of magnetic moments showed that all metal complexes are paramagnetic except cadmium (II) complex which is diamagnetic. The values of molar conductivity also appeared that all metal complexes are non-electrolytic nature except iron (III) complex which is electrolytic.

An experimental and theoretical investigation of lanthanide complexes [Ln = Nd, Yb, Eu, Dy and tb] with 4-((2-hydroxy-naphthalen-1-yl)methylene amino)benzenesulfonamide ligand

Reaction of lanthanide(III) salts with N, O donors 4-((2-hydroxynaphthalen-1-yl) methyleneamino)benzenesulfonamide (L) Schiff base ligand afforded five new mononuclear lanthanide complexes of type [Ln(NO3)2(L)(H2O)2](H2O)x {where Ln = Nd (1), x = 2, Yb (2), x = 1, Eu (3), x = 2, Dy (4), x = 1, Tb (5), x = 2}. These newly synthesized complexes were characterized by elemental analysis, molar conductance, FT-IR, UV–Vis spectroscopy and mass spectrometry. The thermal behavior of complexes was studied by TGA technique. The computational calculations using density functional theory (DFT) of ligand and their lanthanide complexes were performed to obtain optimized molecular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and other parameters. The fluorescence studies reveal that emission spectra of lanthanide complexes show the characteristic luminescence due to lanthanide ions which indicates that Schiff base ligand can sensitize the Ln(III) ions. The Schiff base and their lanthanide complexes were screened for their in vitro antibacterial studies against Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 29213), Klebsiella pneumoniae (BAA 1705), Acinetobacterr baumannii (BAA 1605) and Pseudomonas aeruginosa (ATCC 27853). The results exhibit that the antibacterial activity of Ln(III) complexes was greater than the free Schiff base ligand.

Synthesis, Characterization and Antibacterial Activity of Schiff Base, 4-Chloro-2-{(E)-[(4-Fluorophenyl)imino]methyl}phenol Metal (II) Complexes

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.

Synthesis, Characterization and Biological Evaluation of Schiff Base (N-4-(thiophene-2-yl-methyleneamino)-2,6-dimethylpyrimidine-4-yl)benzenesulfonamide and its Complexes with Cu(II), Ni(II), Co(II), Fe(II), Mn(II), Zn(II) Ions

Two step synthesis of Schiff base ligand and its transition metal complexes was done by condensation reaction. In first step, the drug and aldehyde in equimolar ratio were refluxed for one hour at pH 8-9 in order to get Schiff base ligand. In second step, ligand and metal salts were refluxed for 2 hour. The ligand and Cu(II), Ni(II), Co(II), Fe(II), Mn(II), Zn(II) complexes were characterized by using different instruments like FT-IR, 1H-NMR, 13C-NMR, Mass, Atomic absorption spectrometer, Elemental analyzer, UV-visible spectrophotometer, Evans balance, Conductivitymeter and Thermogravimeter. In vitro antibacterial, antifungal and anti-inflammatory activities were also studied. The synthesized ligand and transition metal complexes were tested against Escherichia coli, Enterobacter aerogenes, Staphylococcus aureus, Bacillus pumilus, Klebsiella oxytoca, Clostridium butyrium, Mucor and Aspergillus niger. These studies demonstrated the enhanced activity of metal complexes against reported bacterial and fungal strains when compared with free Schiff base ligand. The Cu(II) complex recognized as anti-inflammatory agent while the parent drug showed no activity.

Synthesis, structural characterization, DNA interaction, antibacterial and cytotoxicity studies of bivalent transition metal complexes of 6-aminobenzothiazole Schiff base

Novel Schiff base (L) derived from 6-aminobenzothiazole and 4-methoxy salicylaldehyde and its bivalent Cu(II) (1), Ni(II) (2) and Co(II) (3) metal complexes were synthesized and thoroughly characterized by various analytical and spectral techniques. From the data a square planar geometry is assigned for all complexes. The DNA interaction studies of complexes with CT-DNA were carried out by UV–Vis absorption, fluorescence and viscosity measurements. These studies revealed that the complexes bind to CT-DNA by intercalative mode. DNA cleavage capacity of all the metal complexes was studied by agarose gel electrophoresis method. Further, the antibacterial studies of metal complexes were evaluated and it is observed that all complexes showed grater activity than free ligand. In addition, in-vitro cytotoxicity of these complexes on tumor cell lines HeLa, A549 and MCF-7 have been examined by MTT assay. The complexes showed greater cytotoxicity than the free Schiff base ligand.

Synthesis, spectroscopic, biological activities and DFT calculations of nickel(II) mixed-ligand complexes of tridentate Schiff bases

Ni(II) mixed-ligand complexes of [NiLNH3] (where L= N-salicylidene-o-aminophenol (L1), N-(5-methoxysalicylidene-o-aminophenol) (L2) and N-(2-hydroxy-1-naphthalidene)-o-aminophenol) (L3) containing ONO tridentate Schiff bases and ammonia were synthesized and characterized by elemental analysis, infrared, ultraviolet-visible, proton and carbon-13 spectroscopies. Theoretical calculations were also performed on the optimized structures of the Ni(II) mixed-ligand complexes. The Infrared and ultraviolet-visible spectra of the complexes were calculated, and the results compared with the corresponding experimental spectra to augment the experimental structural identification. The elemental analysis data confirmed the formation of 1:1:1 [metal: Schiff base: ammonia] molar ratio. The NMR spectra showed that the Schiff bases coordinated to the Ni(II) ion via the two deprotonated phenolic oxygen and azomethine nitrogen atoms. The biological studies showed that the complexes exhibited higher antibacterial and antioxidant activities than the free Schiff base ligands.

1D Copper(I) Coordination Polymer [Cu2(µ-(2,4-Cl-ba)2bn)(µ-I2)]n with a Flexible Schiff Base Ligand: Synthesis, Crystal Structure, and Thermal Stability

In this paper, bis-monodentate Schiff base ligand (2,4-Cl-ba)2bn and its 1D copper(I) coordination polymer [Cu2(μ-(2,4-Cl-ba)2bn)(μ-I2)]n are synthesized and characterized by the elemental analysis (CHN), FT-IR and 1H NMR spectroscopy. Their crystal structure is determined from the single crystal X-ray diffraction analysis. The thermal behavior of the complex is studied using thermogravimetry in order to evaluate its thermal stability and thermal decomposition pathway. The X-ray results show that the free Schiff base ligand (2,4-Cl-ba)2bn is centrosymmetric and coordinated to copper(I) ions via two iminic nitrogen atoms as a bis-monodentate bridging ligand. The coordination geometry around the copper ions is a distorted triangle formed by one nitrogen and two iodine atoms. The distance between the two symmetry-related copper atoms is very short: 2.4756(8) A.

Synthesis, crystal structure, electrochemical behavior and docking molecular of poly-nuclear metal complexes of Schiff base ligand derived from 2-amino benzyl alcohol

In the present work, we synthesized three novel Cu(II) and Mn(II) complexes (1–3) of a tridentate Schiff base ligand (H2L1) derived from 2-hydroxy-4methoxybenzaldehyde and 2-amino benzyl alcohol. The Schiff base ligand and its complexes were characterized by FT-IR, UV–Vis and elemental analysis. The molecular structures of products were determined by X‐ray diffraction, which confirmed the formation of bi-nuclear (1), tetra-nuclear (2) and tri-nuclear (3) complexes. In addition, the electrochemical properties of the complexes were examined by means of cyclic voltammetry in tetrahydrofuran, which showed the irreversible processes. Molecular docking studies of the free Schiff base ligand and its complexes were performed with BDNA and Interleukin-6 (PDB ID:1BNA and 1alu). The results of docked models showed that ligand and its complexes 1–3 preferentially bind to the minor groove of DNA receptor. In addition, complexes 1–3 exhibit higher binding affinity to Interleukin-6 as compared to ligand and drug of anticancer.

Synthesis, characterization, DNA binding propensity, nuclease efficacy, antioxidant and antimicrobial activities of Cu(II), Co(II) and Ni(II) complexes derived from 4-(trifluoromethoxy)aniline Schiff bases

Abstract A series of binary metal complexes [M(L1)2] and [M(L2)2], (where M = Cu(II), Co(II), Ni(II)) of Schiff bases, HL1 = 2-((E)-(4-(trifluoromethoxy)phenylimino)methyl)-4-methylphenol, HL2 = 2-((E)-(4-(trifluoromethoxy)phenylimino)methyl)-5-methoxyphenol, were synthesized and characterized by different analytical and spectral techniques. The spectral studies revealed that the complexes possess a square planar arrangement around the metal ions. DNA binding studies were investigated against calf thymus DNA and found that the compounds bound to DNA through an intercalation mode. The role of compounds in oxidative and photolytic cleavage of supercoiled pBR322 DNA was considered and emphasized that the complexes can cleave the DNA efficiently. The antioxidant activity of ligands and their complexes was evaluated by DPPH assay method and observed that the complexes found to be potent free radical scavengers. Finally, the in vitro antimicrobial activities by paper disc methods have shown that the complexes are more biocidally active than the free Schiff base ligands.

Amalgamation of Novel Schiff Base Ligand and Its Transition Metal Complexes and Their Biological Activity

Schiff base synthesized from 2-hydroxy-1-naphthaldehyde and 2-2’ (ethylene dioxy) bis ethylenediamine (L1) and its Metal complexes, [M (II) (L)6](where M= Mn(II), Ru(III), Cu(II)and V(V) L= Schiff base moiety), have been prepared and characterized by elemental analysis, spectroscopic measurements (infrared, electronic spectroscopy, 1H-NMR, EPR and Mass spectroscopy ). Elemental analysis of the metal complexes was suggested that the stoichiometry ratio is 1:1 (metal-ligand). The electronic spectra suggest an octahedral geometry for MC1and MC2 Schiff base complexes and distorted octahedral for MC3 and MC4 complexes. The Schiff base and its metal chelates have been screened for their invitro test antibacterial activity against three bacteria, gram-positive (Staphylococcus aureus) and gram-negative (Klebsiella pheneuammonia and Salmonella typhi). Two strains of fungus (Aspergillus niger and Candida albicans). The metal chelates were shown to possess more anti fungal activity compare then antibacterial activity and antioxidant properties. The complexes are highly active than the free Schiff-base ligand.
 

In situ alkaline media: Synthesis, spectroscopic, morphology and anticancer assignments of some transition metal ion complexes of 1-((2-aminophenylimino) methyl) naphthalen-2-ol Schiff base

Four Schiff base complexes of Cu(II), Co(II), Ni(II) and Zn(II) metal ions were synthesized by reaction of 1-((2-aminophenylimino)methyl)naphthalen-2-ol (HL) with metal(II) chloride salts. The geometric structures of these complexes were elucidated based on different types of analyses like elemental analyses and spectroscopic instruments (FT-IR, UV–Vis., mass and 1H NMR). Microanalytical analysis was confirmed the 1:1 stoichiometry ratio (metal: HL). The molar conductance values (3.80–5.59 μS) referred that all HL complexes have an electrolytic behavior in comparable with free HL data (1.35 μS) except for non-electrolytic copper(II) complex (1.46 μS). The general formulas of the synthetic complexes were [M(L)(H2O)3]+.Cl−.3H2O (M = Co2+ & Ni2+), [Zn(L)(H2O)]+.Cl− and [Cu(L)(Cl)(H2O)2]. The assignments of FTIR spectra confirmed that the deprotonated HL Schiff base ligand acts as a tridentate NNO chelate through oxygen O of phenolic group and both nitrogen atoms of NH2 and CN azomethine groups. The electronic, magnetic and electron spin resonance analyses revealed that all complexes are six coordinated but zinc(II) complex is four coordinated geometry. The thermogravimetric analyses (TGA/DTG) and differentially thermal analyses (DTA) of the free HL chelate and its complexes have been performed under N2 atmosphere. The final thermal decomposition residue of metal-Schiff base complexes has been MO formula. The crystalline surface morphology of the solid products were investigated dependent on X-ray diffractometer and scanning electron microscopy. The efficiency of antimicrobial (bacteria & fungi) and anticancer of colon carcinoma HCT-116 cell lines were assessed against free HL Schiff base ligand and their four complexes.

1D copper(I) coordination polymer [Cu2(μ-(2,4-Cl-ba)2bn)(μ-I2)]n with a flexible Schiff base ligand: Synthesis, crystal structure, and thermal stability

In this paper, bis-monodentate Schiff base ligand (2,4-Cl-ba)2bn and its 1D copper(I) coordination polymer [Cu2(μ-(2,4-Cl-ba)2bn)(μ-I2)]n are synthesized and characterized by the elemental analysis (CHN), FT-IR and 1H NMR spectroscopy. Their crystal structure is determined from the single crystal X-ray diffraction analysis. The thermal behavior of the complex is studied using thermogravimetry in order to evaluate its thermal stability and thermal decomposition pathway. The X-ray results show that the free Schiff base ligand (2,4-Cl-ba)2bn is centrosymmetric and coordinated to copper(I) ions via two iminic nitrogen atoms as a bis-monodentate bridging ligand. The coordination geometry around the copper ions is a distorted triangle formed by one nitrogen and two iodine atoms. The distance between the two symmetry-related copper atoms is very short: 2.4756(8) Å.