Schiff Base Metal Complexes Research Articles

Advancement in schiff base complexes for treatment of colon cancer

Abstract Schiff bases have proven to be beneficial in medicine and have interesting complexation capabilities with transition metals. The +4, +5, and +6 oxidation states of schiff base metal complexes have been the subject of recent review, which have highlighted their notable cytotoxic effects against various colon cancer cell lines (HT-29, HCT-116, SW-480, Coco-2, CT-26, LT-174, LoVo). Extensive research has focused on schiff base metal complexes in the +4 and +6 oxidation states, exhibiting distinct geometries and significant thermodynamic stability. These studies provide IC50 values for these complexes in colon cancer cell lines along with comprehensive structural representations that shed light on how different substituents affect cytotoxicity. When compared to schiff base ligands alone, metal complexes of schiff bases have been shown to significantly reduce colon cancer cell invasion and proliferation. The studied literature emphasizes schiff base metal complexe’s potential in biological applications and suggests that more study may be necessary to fully comprehend their biology. To enable more sophisticated multidisciplinary study in this field, future investigations should focus on synthesizing novel complexes with enhanced bioavailability, solubility, and low toxicity.

Synthesis and catalytic application to form cyclic carbonates of novel Pd(II) Cu(II), and Fe(II) benzoate-based Schiff base metal complexes

This work describes the synthesis and characterisation of six novel Schiff base complexes, Cu(II), Pd(II), and Fe(II), which, under the right circumstances, function as very efficient catalysts for the production of cyclic carbonates from CO2 and epoxides. FT-IR spectroscopy, elemental analysis, UV–Vis spectroscopy, molar conductivity, melting point, and magnetic susceptibility measurements are among the spectroscopic methods used to characterize newly synthesized complexes. The molar conductivity values, ranging from 2.58 to 4.03 µS/cm, suggest that the complexes exhibit no molar conductivity. Co-catalysts, such as 4-(dimethylamino)pyridine, pyridine, triethylamine, and triphenyl phosphine, were used in these processes, both with and without one. 4-(Dimethylamino)pyridine was used as the co-catalyst in the catalytic studies. Additionally, a number of variables that affect the cycloaddition process were examined, including the temperature, CO2 pressure, reaction time, and co-catalyst. All novel catalysts exhibited exceptional catalytic activity and selectivity in the catalytic assays. Regarding the coupling of CO2 and epichlorohydrin as epoxides, the L2-Cu catalyst outperformed other catalysts in terms of catalytic activity (90.7%) and selectivity (98.9%).

Tridentate N-donor Schiff base metal Complexes: Synthesis, Characterization, computational Studies, and assessment of biomedical applications in cancer Therapy, Helicobacter pylori Eradication, and COVID-19 treatment

A unique Schiff base ligand (BCA), 4-(2-((1E,2E)-1-(2-(p-tolyl)hydrazono)propan-2-ylidene)hydrazinyl)quinazoline, was synthesized and complexed with Mn [II], Co [II], Cu [II, and Cd [II] ions, with 1,10-Phenanthroline (PHN) as an auxiliary ligand. The unique Schiff base ligand BCA and its metal complexes were characterized using multiple analytical techniques, including elemental analysis, UV–visible spectroscopy, FT-IR, mass spectrometry, and conductometric measurements. These methods provided detailed insights into the compounds’ structural and electronic properties. Density Functional Theory (DFT) computations complemented the experimental data, elucidating electronic configuration stability, HOMO-LUMO energy gaps, chemical hardness, and dipole moments. The computational results confirmed the distorted octahedral structure of the complexes. Antimicrobial testing against various bacterial and fungal strains revealed that the Cd (II) complex exhibited the highest activity, with inhibition zones ranging from 19.7 ± 0.6 mm to 35.0 ± 1.0 mm, surpassing the activity of standard antibiotics in some cases. Notably, the compounds displayed significant efficacy against Helicobacter pylori, with the Cd (II) complex showing an inhibition zone of 32.67 ± 0.58 mm and a minimum inhibitory concentration (MIC) of 7.8 μg/ml. Anticancer properties were evaluated against MCF-7 (Breast carcinoma) cells, with the [(BCA)(PHN)Cd(H2O)].2Cl·2H2O complex demonstrating superior activity (IC50 = 29.97 μg/ml) compared to the free ligand (IC50 = 183.96 μg/ml) and other metal complexes. Notably, the Cd(II) complex showed reduced cytotoxicity towards normal VERO cells, suggesting potential selectivity for cancer cells. Molecular docking simulations evaluated the complexes’ binding interactions with protein targets associated with Helicobacter pylori, MCF cancer cells, and the COVID-19 virus. The main objective of this research was to design and synthesize a unique Schiff base ligand and its new corresponding Ternary metal complexes and then investigate their potential medical applications. Specifically, the study aimed to evaluate the compounds’ effectiveness as antibiotics, antitumor agents, and possible treatments for COVID-19.

Biological activities of metal complexes with Schiff base

Abstract Schiff bases are a class of synthetic compounds that form when primary amines combine with aldehydes or ketones. These compounds are incredibly important across various fields, such as biology, catalysis, and optics, due to their diverse features. One notable aspect is their ability to form complexes with transition metals, which opens up a wide range of potential uses, particularly in human systems. In the human body, Schiff base metal complexes display a range of biological actions, including antibacterial, antifungal, anticancer, and antimalarial properties. The versatility of Schiff bases in reacting with different transition metals gives these complexes intriguing potential for addressing biological issues and treating diseases. This article explores various examples of Schiff bases, metal complexes, and their associated ligands, highlighting their usefulness in a variety of biological applications. The potential of Schiff base metal complexes as valuable agents in resolving medical difficulties and advancing biomedical research is emphasized.

A biophysical insight into the mechanism of anticancer activity of salicylidene cyclohexanediamine based cobalt and nickel complexes through CT-DNA, BSA binding and docking study

Two novel metal Schiff base complexes, [Co(L)(OH2)(Cl)].2DMF (1) and [Ni(L)].H2O (2) [H2L=N,N'-bis(5-bromo-3-(methoxy)salicylidene)cyclohexane-1,2-diamine] were prepared and structurally characterized through single crystal X-ray crystallography and usual spectroscopic techniques. The inhibitory action of H2L, 1 and 2 via MTT assay on MDA-MB 231, HCT-116, and A549 cell lines was assessed. The complexes exhibit lower IC50 values than the ligand (H2L> 2> 1). On the other hand, with normal human PBMC, they were found to be significantly nontoxic. The interaction of 1 and 2, with CT-DNA and serum albumin (BSA) through different biophysical experiments was checked to have a plausible understanding of their anticancer activity as well as pharmacological relevance. These investigations inferred that 1 had a greater affinity for CT-DNA and BSA than 2. 1 interacts with CT-DNA through intercalation whereas 2 exhibits a mixed mode of interaction (intercalation and groove binding). The complexes exhibit a predominantly hydrophobic interaction with BSA, which is static in nature and causes a prominent structural change of BSA, from α-helix to β-sheet. The rate of hydrolysis of the phospho-ester bond in PNPP was found to be four times faster with 1 than with 2. A molecular docking study was conducted to gain a deeper insight into the molecular interactions along with possible theoretical binding energies of the complexes with CT-DNA and BSA, and this was found to be in agreement with the experimental findings.

Novel europium(III), terbium(III), and gadolinium(III) Schiff base complexes: Synthesis, structural, photoluminescence, antimicrobial, antioxidant, and molecular docking studies

Three lanthanide (III) complexes, L-Eu, L-Tb, and L-Gd, were synthesized using a Schiff base ligand (H2L) composed of (2,2′-(thiophene-2,5-diylbis(methaneylyl-idene))bis(azaneylyl-idene))diphenol. Complexes with the generic formula LnL(Cl)(H2O)·xH2O, where L is the ligand, was studied using elemental analysis, spectrum analysis (IR, mass- UV–Vis), and molar conductivity. Next, the photoluminescence characteristics of the lanthanide complexes were investigated. An assessment was conducted to ascertain the antioxidant activity of the synthetic compounds compared with that of the stable free radical DPPH. The antibacterial activity of the Schiff base metal complexes was assessed against a strain of yeast as well as against a number of Gram-positive and Gram-negative bacteria. Computational studies were also performed to elucidate the mechanisms of the antimicrobial and antioxidant effects. In molecular docking, 1LL9, 6J2O, 3JPU, 2MBR, and 1HD2 crystal structures were determined as targets and the docking score values of H2L, L-Tb, L-Gd, and L-Eu compounds for these targets were calculated.

Theoretical and experimental investigation of mixed-ligand metal(II) Schiff base complexes using maleic acid as the auxiliary ligand

This work is focused on the synthesis of several transition metal complexes [ML(MA)], where M = Copper (II), Zinc (II), Cobalt (II) and Nickel (II), MA = maleic acid and L = Schiff base generated from benzene-1,2-diamine [o-phenylenediamine] and 4-chlorobenzaldehyde. The characterization using Fourier-Transform Infrared, Nuclear Magnetic Resonance spectroscopy, Ultraviolet-Visible spectra, Mass, Electro Paramagnetic Resonance and elemental analysis confirm the square planar geometry of the complexes. The in vitro antimicrobial potential of the complexes has been tested by the broth dilution method and the antioxidant method has been done by free radical scavenging analysis. The in vitro methods reveal the outstanding biological characteristics of the copper complexes. The molecular structure of the ligand and its metal (II) complexes has been optimized using Density Functional Theory studies performed by the Gaussian-09 software and their parameters have been discussed. Natural Bond Orbital and Frontier Molecular Orbital analyses have assessed the presence of a metal-ligand bond in complexes. In addition, molecular docking studies have also been performed on antiviral activity of all the complexes using a viral protein and their interacting amino acids.

Synthesis, DFT calculation, molecular docking and in vitro anticancer activities of sulphanilamide incorporated Schiff base metal complexes

Transition metal complexes of the type [M(L2)Cl2] (M= Co, Cu, Ni and Zn) were synthesized from Sulphanilamide based novel Schiff base ligand (4-[(oxo-1,2-diphenylethylidene)amino]-benzene-1-sulphonamide) utilizing micro-wave helped blending and characterized by expository and spectroscopic strategies. Based on the findings of the NMR and FT-IR spectroscopy, it was determined that the azomethine nitrogen and oxygen atoms from the ligand are coordinated with the metal ions that correspond to them. The physicochemical properties, drug-like nature and pharmacokinetic properties were predicted by the SwissADME Online webserver. The compound's geometry, electrostatic potential, frontier molecular orbital and quantum chemical descriptors were determined. The most appropriate drug targets were identified by using a polypharmacology approach. To evaluate the ligand and its metal complexes' interactions with the chosen breast cancer targets, molecular docking was used. The findings demonstrated that the metal complexes had good interaction profiles and binding energies. Examining the compounds' in vitro anticancer potential, the results revealed that the biological ability of each molecule to prevent breast cancer varied. In light of this, each of the compounds that were synthesized has the potential to be utilized as possible candidates for breast cancer treatment.

Unraveling the Potential of Mononuclear Zn(II) and Cu(II) Schiff Base Metal Complexes: Microwave‐Aided Synthesis, Theoretical Analysis and Application in Biomimetic Catalysis, CT‐DNA Interaction, and In Vitro Biological Assays

ABSTRACTGiven the widespread and diverse effects of transition metal ions such as copper and zinc in multiple biological processes, this research endeavor addresses herein the microwave‐aided synthesis of two novel tetradentate ONNO (L1) and tridentate NNO (L2) donor Schiff base ligands derived from 4,5‐dimethyl‐1,2‐phenylenediamine and 4‐bromo‐2‐hydroxybenzaldehyde in a 1:2 ratio and from 4,5‐dimethyl‐1,2‐phenylenediamine and 5‐methoxy‐2‐hydroxybenzaldehyde in a 1:1 ratio, with their respective zinc, ZnL1(1) and ZnL2(3), and copper, CuL1(2) and CuL2(4), Schiff base metal complexes, which are comprehensively characterized utilizing physiochemical and analytical techniques, along with geometry optimization using the DFT approach. Spectrophotometric analyses have been used to assess the biomimetic activity in the conversion of 3,5‐DTBC to 3,5‐DTBQ with turnover numbers 53.4 and 78 h−1 in methanol for 2 and 4, whereas the zinc complexes are found to be ineffective. With CT‐DNA, possible modes of interaction with the synthesized complexes have been explored using absorption spectroscopy, where the associated binding constants ranged between 1.541 × 105 and 2.186 × 105 M−1. EtBr‐bound DNA was used in the fluorescence quenching experiments with Stern–Volmer constant (Ksv) values in the range 4.084 × 104 and 3.402 × 104 M−1, showing a stronger association with CT‐DNA. The compounds' ability to inhibit bacterial strains was also examined in vitro, as well as their ability to reduce inflammation, through the protein denaturation method and the DPPH assay for antioxidant activity have been performed. Furthermore, molecular docking simulations have been carried out to obtain a deeper comprehension of the molecular‐level interactions with CT‐DNA and cyclooxygenase‐2 (COX‐2).

Investigation of the anticancer effect of newly synthesized palladium conjugate Schiff base metal complexes on non-small cell lung cancer cell line and mouse embryonic fibroblast cell line

Lung cancer remains one of the leading causes of death worldwide. Due to the side effects of chemotherapeutic agents on normal cells and the development of resistance by cancer cells, there is an urgent need for alternative new pharmacological agents. Palladium (Pd)-conjugated Schiff base (SB) compounds represent an alternative approach with promising potential applications in cancer treatment. This study aims to identify novel therapeutic agents on A549 cells through the synthesis and characterization of Schiff base conjugated-Palladium complexes (Pd-L1 and Pd-L2). Additionally, it seeks to elucidate the mechanism of action of these compounds on both the A549 and NIH/3T3 cell lines. In the present study, two new Pd-L1 and Pd-L2 were synthesized for the first time and characterized mainly by single crystal X-ray diffraction and 1H, 13C, 31P NMR techniques. The cytotoxic effect of the compounds was evaluated by MTT assay on A549 and NIH/3T3 cell lines for 24 and 48 h. Cisplatin was used as a positive control group. Based on the cytotoxicity results, the complexes were evaluated for their anticancer activities against A549 cell lines for 48 h through reactive oxygen species (ROS), cell cycle, apoptotic, and necrotic cell analyses. The most potent cytotoxic effects were determined for Pd-L1 (IC50: 23.33 μM), Pd-L2 (IC50: 3.19 μM), and cisplatin (IC50: 33.27 μM) on A549 cells (p < 0.05). The compounds exhibited a significant cytotoxic effect at lower concentrations on A549 cells compared to NIH/3T3 cells (p < 0.05). All compounds showed a significant increase in ROS levels in A549 cells compared to the control group (p < 0.05). While necrosis and apoptosis was observed in A549 cells treated with cisplatin, induction of apoptosis was effective in cell death for A549 cells treated with Pd-L1 and Pd-L2 (p < 0.05). Additionally, it was observed that the compounds inhibited cell proliferation in the G0/G1 and G2/M cell cycle phases (p < 0.05). All compounds induced cell cycle arrest and cell death in A549 cells by increasing ROS levels. The results obtained in the present study could advance the utilization of the compounds as anticancer agents.

Synthesis of Novel 2-Amino Thiazole Derivatives and Salicyaldehyde based Ligand to have Biological Activity

In inorganic chemistry, Schiff bases and complexes come in a variety of forms. Therefore, the discovery of new organic and inorganic compounds with remarkable anti-fungal, anti-bacterial, and anticancer characteristics represents a major advancement in biochemistry, pharmacy, and medicine. All of the chemicals that were employed in this study were A.R. grade. The following materials provided by SD's fine chemical Ltd. and Merck chemicals, Mumbai were utilised impurification: methanol, calcium hydroxide, sodium acetate, thiourea, ethylacetoacetate, benzoyl chloride, acetyl chloride, 1,4-dioxane, and sulfuric acid. Additionally, this Schiff base may combine with the ions of several transition metals, such as Ni(II), Cu(II), Co(II), and Cd(II), to create complexes. In addition to chemical analysis, conductivity, and magnetic tests, we further characterized the complexes using electronic and infrared spectroscopy in order to examine their structures. Every compound's antibacterial activity was evaluated. In the agar cup test method, all of the Schiff base metal complexes had a moderate level of antibacterial activity. Spectroscopic data suggests that these complexes are all of type ML2.(H2O)2 (M=Mn, Fe, Co, Ni, and Cu).

Synthesis, structural elucidation, and antibacterial activities of novel copper(II), cobalt(II), and nickel(II) complexes with a bidentate Schiff base ligand against pathogenic bacteria

Novel Schiff base metal complexes diaqua(4-chloro-2-{[(4-(dimethylamino)phenyl)methylene]amino}phenolato)M(II) ion, (M = copper/cobalt/nickel) have been synthesized using the ligand 4-chloro-2-((4-(dimethylamino)benzylidene)amino)phenol, which was prepared by reacting 2-amino-4-chlorophenol with 4-(dimethylamino)benzaldehyde in a molar ratio of 1:1. The synthesized compounds were characterized based on elemental analysis, FTIR, UV–vis., 1H and 13C NMR, powder XRD, mass spectrometry and magnetic studies. Spectroscopic investigations demonstrated that the metal atom coordinates to a bidentate Schiff base ligand via the azomethine nitrogen and phenolic oxygen. The appropriate molecular geometry for each metal complex has been proposed through the analysis of spectroscopic and analytical data, Specifically, tetrahedral geometry has been proposed for Co(II), Ni(II), and square planar geometry for Cu(II) complex. Theoretical calculations employing Density Functional Theory (DFT) validated the experimental results, elucidating optimized geometries, frontier molecular orbitals, natural bond orbital distributions, molecular electrostatic potentials, non-linear optical properties, IR vibrational modes, and UV absorbance profiles. Additionally, the compounds' biological efficacy was validated through molecular docking against receptors for Gram(+ve) bacteria, Bacillus subtilis (PDB ID: 5H67), Staphylococcus aureus (PDB ID: 3TY7) and Gram(-ve) bacteria, Escherichia coli (PDB ID: 3T88), Proteus vulgaris (PDB ID: 5I39). The outcome revealed that Co(II) complex exhibited highest binding energy with Escherichia coli and Bacillus subtilis while the ligand with Proteus vulgaris (5I39) and Staphylococcus aureus (3TY7). Further the study was extended to the MD Simulation in water for 100 ns to evaluate the binding affinities and its stabilities by analyzing the deviation, fluctuations, and intermolecular interactions. The research presented here showcase the potential of employing a Schiff base ligand and its Co(II) complex in the synthesis of novel, highly potent antibacterial agents to combat emerging diseases, which holds considerable importance in the field of pharmaceutical science—however, in-vitro studies are needed to validate the results.

Design and synthesis of two new thiosemicarbazide based Schiff base metal complexes of nickel (II): DNA binding study and cytotoxicity profile analysis

Two new nickel (II) substituted thiosemicarbazone Schiff base complexes [Ni(meph)2] (1) [where H2meph = (2E)-N-methyl-2-[1-(pyridin-2-yl)ethylidene]hydrazine-1-carbothioamide] and [Ni(hmm)2](NO3)2·2H2O (2) [where H2hmm = (2E)-2-[(2-hydroxyphenyl)methylidene]-N-methylhydrazine-1-carbothioamide] have been designed and synthesized by the condensation of 4-methyl-3-thiosemicarbazide with 2-acetylpyridine and salicylaldehyde respectively. Both the metal complexes 1 and 2 are characterized using different available spectroscopic techniques like FT-IR, UV–Vis spectroscopy, elemental analysis, and single crystal X-ray structure analysis. X-ray crystal structure analysis reveal that complex 1 and 2 are octahedral Ni(II) complexes. The calf-thymus CT-DNA-binding property of 1 and 2 has been evaluated by employing UV–Vis and fluorescence spectral titration. All the results show that CT-DNA binds with both nickel(II) complexes 1 and 2. In vitro cytotoxicity activity of complexes 1 and 2 toward A375 and MDA-MB-231 was evaluated using MTT assay and other methods which confirm that both complexes 1 and 2 behave as promising anti-cancer agents.

Structural and Potential Biological Properties of SBDTC and SMDTC Containing Metal Complexes: A Brief Review

S-benzyldithiocarbazate (SBDTC) and S-methyldithiocarbazate (SMDTC) are working as a preliminary reactant for the synthesis of several Schiff base ligands. SBDTC and SMDTC can act as NS, SNNS, SNNNS, and NOS chelating agents and have biological and chemical potential for synthesizing many transition and inner transition metal complexes. The metal complexes prepared from SBDTC, SMDTC, and their derivatives have shown promising biological activities like antibacterial, cytotoxicity, antioxidant, antitumor, and anticancer activity. Last few decades, a lot of works have been reported on SBDTC and SMDTC containing Schiff base metal complexes. In this review, it is cosidered to show the various synthesis procedures, and structural and biological activities of SBDTC and SMDTC-containing metal complexes.

Triazole-Based Schiff Base Metal Complexes: Synthesis, Characterization, Computational Studies and Biomedical Activity Against Cancer, H. pylori, and COVID-19

Triazole-Based Schiff Base Metal Complexes: Synthesis, Characterization, Computational Studies and Biomedical Activity Against Cancer, H. pylori, and COVID-19

Preparation of Schiff base metal catalyst and its catalytic synthesis of propylene carbonate from CO2

In recent years, research on the conversion of CO2 into fine chemical products has emerged as a prominent and dynamic area of study. In this study, four ligands were synthesized using salicylaldehyde, o-phenylenediamine, ethylenediamine, hexanediamine, and 2,6-diaminopyridine as precursors. Subsequently, these ligands were reacted with cobalt nitrate, zinc chloride, and aluminum chloride to synthesize 12 Schiff base metal complexes, which were employed as catalysts for the synthesis of propylene carbonate from CO2 and epichlorohydrin. The findings reveal that the SF-L/Co catalyst demonstrated superior performance, potentially attributed to the robust chelating capability of Co, leading to the provision of more acidic metal centers. Characterization of SF-L/Co was conducted utilizing scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) techniques. Process conditions were optimized, resulting in the achievement of a 100% yield and selectivity of propylene carbonate under optimal reaction conditions, without the generation of any by-products. Furthermore, the catalyst exhibited remarkable reusability, demonstrating consistent catalytic activity over five successive cycles without a substantial decrease in performance.

Synthesis of biologically active cefpodoxime and vanillin-based schiff base metal complexes with the detailed biological evaluations.

Schiff bases of existing antimicrobial drugs are an area, which is still to be comprehensively explored to improve drug efficiency against consistently resisting bacterial species. In this study, we have targeted a new and eco-friendly method of condensation reaction that allows the "green synthesis" as well as improved biological efficacy. The transition metal complexes of cefpodoxime with well-enhanced biological activities were synthesized. The condensation reaction product of cefpodoxime and vanillin was further reacted with suitable metal salts of [Mn (II), Cu (II), Fe (II), Zn (II), and Ni (II)] with 1:2 molar ratio (metal: ligand). The characterization of all the products were carried out by using UV-Visible, elemental analyzer, FTIR, 1H-NMR, ICP-OES, and LC-MS. Electronic data obtained by UV-Visible proved the octahedral geometry of metal complexes. The biological activities Schiff base ligand and its transition metal complexes were tested by using in-vitro anti-bacterial analysis against various Gram-negative, as well as Gram-positive bacterial strains. Proteinase and protein denaturation inhibition assays were utilized to evaluate the products in-vitro anti-inflammatory activities. The in vitro antioxidant activity of the ligand and its complexes was evaluated by utilizing the 2,2-diphenyl-1-picrylhydrazyl(DPPH) in-vitro method. The final results proved metal complexes to be more effective against bacterial microorganisms as compared to respective parent drug as well as their free ligands. Patch Dock, a molecular docking tool, was used to dock complexes 1a-5e with the crystal structure of GlcN-6-P synthase (ID: 1MOQ). According to the docking results, complex 2b exhibited a highest score (8,882; ACE = -580.43kcal/mol) that is well correlated with a high inhibition as compared to other complexes which corresponds to the antibacterial screening outcomes.

Novel Schiff base metal complexes and their biological applications Walaa H. Mahmoud 1 , Moustafa M. Goha1 , Taha M. Eldebss1 and Ahmed A. El-Sherif 1

Novel Schiff base metal complexes and their biological applications Walaa H. Mahmoud 1 , Moustafa M. Goha1 , Taha M. Eldebss1 and Ahmed A. El-Sherif 1

In vitro anti-microbial, DNA-binding, In silico pharmacokinetics and molecular docking studies of Schiff-based Cu(II), Zn(II) and Pd(II) complexes

Synthesis of salen type Schiff base ligand by the condensation of butane 1,4-diamine with 5-bromosalicyaldehyde has been done. Further, three new mononuclear Schiff based complexes of Cu(II), Zn(II) and Pd(II) have been prepared by the reaction of the Schiff base ligand with appropriate metal salts. The developed Schiff base ligand and metal complexes of Cu(II), Zn(II) and Pd(II) have been well characterized by various spectroscopic techniques like UV–Vis, FT-IR, 1H-NMR, 13C-NMR, EPR, Mass and powder XRD. All the synthesized Schiff base compounds have been tested for antibacterial, antifungal, hemolysis assay and DNA binding activities. The zone inhibition measurements revealed the supremacy and enhanced efficiency of metal complexes as compared to free ligand. The molecular modelling studies were carried to analyze the bonding affinity and inhibition probability of the synthesized complexes with the S. aureus nucleoside diphosphate kinase receptor. The in-silico pharmacokinetics studies such as Lipinski's rule, Veber's rule, drug-likeness score and physiochemical parameters analysis predicted the drug-likeness of the synthesized compounds.

Synthesis, structural characterization and biological applications of mono- and binuclear Cu(II) and Ni(II) complexes with N2O2 Schiff bases

The present work aims to synthesize and characterize new Schiff base metal complexes (Cu(II) and Ni(II)) derived from 4,5-Dichloro-o-phenylenediamine and 3,5-Dichloro-2-hydroxyacetophenone. The synthesized Schiff base and their complexes have been characterized with the support of more than a few standard physicochemical techniques such as elemental analysis, spectroscopic, thermal, and cyclic voltammetry studies. Further the molecular structures are ascertained by computational methods like density functional theory (DFT) methods. The newly synthesized Schiff base ligand acts as ONNO donor tetradentate chelate and coordinated through an azomethine nitrogen and phenoxo oxygen atom to the Cu(II) and Ni(II). Moreover, all the newly prepared compounds exhibit moderate biological activity such as antibacterial. The synthesized compounds were screened for their antibacterial by the disc agar diffusion method. Spectral analysis exhibits square planar geometry for Cu(II) & Ni(II) mono and binuclear complexes. The antimicrobial results indicate that the homo binuclear copper (II) complex was more active than the other mono and binuclear complexes. The theoretical DFT calculations were applied to verify the molecular geometry of chelators and their complexes. The DFT optimized geometries of the complexes are in agreement with experimental observations.