Antimicrobial Activity Of Ligand Research Articles

New Semicarbazone-Schiff Base Coordination; Synthesis, Characterization and Biological Evaluation

The synthesis and characterisation of a new azo Schiff base ligand generated from a semicarbazone moiety are reported in this study, in addition to its metal complexes. The title ligand, (E)-2-((2-hydroxy-3-((E)-(2-nitrophenyl) diazenyl) naphthalen-1-yl) methylene) hydrazine-1-carboxamide (HL), was synthesised by reacting ((E)-2-hydroxy-3-((2-nitrophenyl) diazenyl)-1-naphthaldehyde) with semicarbazidein a 1:1 molar ratio. Afterward, the interplay between HL and other metal ions (CrШ, MnII, CoII, NiII and CuII) produced monomeric coordination complexes in a 1:1 ligand-to-metal ratio. A range of spectroscopic and analytical techniques, such as magnetic susceptibility, conductance tests, 1H and 13C-NMR, FT-IR, electronic and mass spectroscopy, and elemental microanalysis, were used to extensively characterize these complexes. The synthesis of coordination compounds with six-coordinate geometries was verified by the characterization data. The study also assessed the antimicrobial efficacy of the synthesised compounds against various bacterial and fungal species, revealing that After the complex formed, the ligand's antimicrobial activity was greatly increased.

Structural, Characterization, Biological Activity, and DFT Studies on some Novel Ruthenium 2-Aminomethyl Benzimidazole Complexes

Novel 2-aminomethyl benzimidazole (AMBI) ruthenium complexes were synthesized and thoroughly characterized by elemental analysis, spectroscopy (FTIR, 1HNMR, UV–Vis), magnetic measurements, molar conductivity, and thermal analysis techniques. According to analytical data, all complexes demonstrated a 1:1 metal-to-ligand ratio with an octahedral shape. Thermal analysis showed that the complexes have acceptable thermal stability. Cyclic voltammetry was also used to observe their redox actions, and it was found that all of the complexes had electrochemical activity. Using GAUSSIAN 09 W software, the density functional theory (DFT) method and the 3-21G basis set, optimized structures (HOMO & LUMO) of ruthenium complexes (1-4) were carried out. Additionally, the selected quantum and geometric parameters of bond lengths and angles have been determined. The antimicrobial activity of ligand and ruthenium complexes has been evaluated against bacteria (Escherichia coli, Staphylococcus aureus) and fungi (Candida albicans). Two human cancers, HePG-2(hepatocellular carcinoma) and MCF-7 (Michigan Cancer Foundation-7), were tested for cytotoxic activity of complexes. Using the ABTS technique, the antioxidant function of complexes was evaluated. Using a high-affinity Fab sandwich and a specific PCa antibody, molecular docking was utilized to anticipate how the ligand would bind to a human prostate-specific antigen (PSA) immune system receptor (3qum).

Synthesis, characterization, molecular docking, DNA cleavage properties, and antimicrobial activity studies of mixed ligand complexes

AbstractCu (II), Ni (II), Co (II), and Mn (II) acetato in addition to Cu (II) chloro and nitrato mixed ligand complexes of 4‐([quinolin‐2‐yl]methyleneamino)‐1,2‐dihydro‐2,3‐dimethyl‐1‐phenylpyrazol‐5‐one (L), as a primary ligand and 2,4‐dihydroxy benzaldehyde (H2L), as a secondary ligand have been isolated. The structural features and geometrical arrangements of the synthesized mixed ligand complexes were identified by elemental analysis, Fourier transform infrared spectroscopy (FT‐IR), conductivity measurements, UV‐Vis spectra, magnetic moment measurements, X‐ray diffraction, and electron spin resonance (ESR) spectral and thermogravimetric techniques studies of the mixed ligand complexes confirming the molar ratio 1:1:1 (primary ligand: M: secondary ligand) for Cu (II), Co (II), Mn (II), and UO2(II) chelates. The spectral techniques also confirmed the metal chelates have the formulae (Cu[H2L][L][X]2), where X = Cl−(1); NO3−(2); and (M[L][HL][OAc])YH2O, where M = Cu (II) (3), Co (II) (4); Y = 1, Mn (II) (5); Y = 1 and UO2(II) (6); Y = 2. The kinetic and thermodynamics parameters of the mixed ligand complexes at different decomposition steps were calculated using Coast‐Redfern and Horowiz‐Metzger methods. Also, the antimicrobial activities of ligands and their mixed ligand complexes were screened by Disc Diffusion method. It was found that all mixed ligand complexes (1–6) have high antibacterial activity againstKlebsiella pneumoniaethan penicillin G. By studying the molecular docking between the quinoline‐2‐carbaldehyde, the ligand and the receptors (Escherichia coli(PDB code: 3t88),Staphylococcus aureus(PDB code: 3q8u), lung cancer (PDB code: 1x2j), and colon cancer (PDB code: 2hq6)), it was found that the ligand is efficient compound for all the receptors than the quinoline‐2‐carbaldehyde. The DNA cleavage properties of the two ligands and their complexes have been investigated by gel electrophoresis and the results showed that complex (1) without H2O2and complex (6) with H2O2exhibited a significant partial oxidative cleavage among other complexes.

Synthesis a group of 5(6)‐substituted benzimidazole Zn(II) and Co(II) complexes and investigation their cytotoxic and antimicrobial activities

AbstractA series of 5(6)‐substituted benzimidazole ligand‐zinc(II) and cobalt(II) complexes were synthesized and characterized by1H,13C NMR, IR, CHN analysis techniques. In vitro, anticancer and antimicrobial activities of ligand and complexes were evaluated. The cytotoxic activities of compounds were investigated against the human lung adenocarcinoma (A549) cell lines and healthy human lung bronchial epithelium (BEAS2B) cells. Compounds1,6, and8were observed to exhibit higher cytotoxic activity than the others at the 72nd hour. Also, the compounds showed varying degrees of antimicrobial activity against the microorganisms used. Compounds1,5, and8were most effective against standard strainsPseudomonas aeruginosaATCC 27853 andStaphylococcus aureusATCC 29213. As for the antifungal activity, compounds1,5,6, and8showed high antifungal activity against the yeast type fungiCandida albicansATCC 90028 andCandida tropicalis.

Synthesis and Characterization of Dimeric Thio-Schiff Bases by Nano Cerium Oxide and Examination of Their Antimicrobial Activities

In this work, firstly, CeO2 nanoparticles, which can be used as catalysts in many reactions, were synthesized by preparing aqueous solution of cerium(III) nitrate hexahydrate in basic medium. In the second step, the synthesis of dimeric thio Schiff bases was carried out using two different methods. Effect of catalyst on some parameters such as reaction time and yield of product were investigated. The antimicrobial activities of the ligands have been screened in vitro against the organisms Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae (Gram negative bacteria), Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Bacillus cereus (Gram positive bacteria) and Candida albicans, C. tropicalis, C. guilliermondii, C. glabrata by Disc Diffusion and Microdilution methods. At the same time, antimicrobial activities of ligands were compared to standard antibiotics (Cefotaxime, Amoxicillin/clavulanic acid, Posacanazole, Nystatin and Gentamicin). Generally, the results obtained in this research showed that all tested ligands exhibited more effect towards Gram positive bacteria and Candida species as compared to standard antibiotics.

Spectral, Theoretical and Biological Studies of 3-((4-Mercaptophenyl)imino)- 1-phenylindolin-2-one Schiff Base and Its Organotellurium(IV) Complexes

Schiff base ligand (3-((4-mercaptophenyl)imino)-1-phenylindolin-2-one) of 1-phenylindoline-2,3-dione and 4-aminothiophenol was synthesized by refluxing. Organotellurium(IV) complexes of type (RTeCl3.NPhIATP and R2TeCl2.NPhIATP, where R = 4-hydroxyphenyl, 4-methoxyphenyl and 3-methyl-4-hydroxyphenyl, NPhIATP = Schiff base ligand). The ligand and its organotellurium(IV) complexes (9a-f) were characterized by FT-IR, molar conductance, elemental analyses, UV-vis, mass, 1H & 13C NMR spectral studies. Geometry of all the compounds were optimized and octahedral geometry have been proposed for all the tellurium(IV) complexes. Molecular docking was studied to find the binding interactions between ligand (NPhIATP) and receptor proteins: E. coli (3t88) and S. aureus (3ty7). The antimicrobial activity of ligand and its tellurium(IV) complexes have been screened against bacteria and fungi. All the organotellurium(IV) complexes complexes showed good activity to ligand towards different studied microorganisms.

Novel Cu(II) and Ni(II) complexes of nicotinamide based Mannich base: Synthesis, characterization, DFT calculation, DNA binding, molecular docking, antioxidant, antimicrobial activities

Nicotinamide incorporating Mannich base ligand (L), Cu(II) and Ni (II) complexes of [CuLCl2].2H2O (1) and [NiLCl2].2H2O (2) were synthesized and characterized by elemental analysis, FT-IR, UV–Visible, ESR and mass spectrometric methods. The square planar geometry of the complexes (1 and 2) were confirmed from analytical and diverse spectroscopic methods. Cyclic votammetric behaviors of complexes (1 and 2) were studied. The optimized geometry of L, complexes (1 and 2) were obtained by Density Functional Theory (DFT) calculations. DNA binding ability of complexes (1 and 2) were studied by electronic absorption and fluorescence techniques. Both the spectroscopic results show that complex 1 (9.64 × 104 M−1) has good binding affinity than complex 2 (6.07 × 104 M−1). The interaction of complexes (1 and 2) with CT-DNA was explored by Molecular docking analysis revealed that an efficient interaction of complexes (1 and 2) with the DNA. The results indicate that prepared complexes (1 and 2) have better binding ability with DNA double helix. Antioxidant activities of complexes (1 and 2) have studied by DPPH method and results suggest that prepared complexes (1 and 2) have better radical scavenging ability. Antimicrobial activities of ligand (L) and complexes (1 and 2) were tested against selected bacterial and fungal pathogens results shows that prepared compounds have higher antimicrobial activity against E. coli and A. niger antimicrobial species than others.

Synthesis, Characterization and Biological Evaluation of Schiff Base Transition Metal Complexes Derived from 4-Nitrobenzene-1,2-diamine and 5-Chloroisatin

A series of transition metal complexes of the type [MLX2], where M = Mn(II), Fe(II), Co(II), Ni(II), X = Cl–/CH3COO– and L = Schiff base derived from 4-nitrobenzene-1,2-diamine and 5-chloroisatin have been synthesized and characterized by elemental analysis, molar conductance, IR, UV-visible, magnetic moments measurement, 1H & 13C NMR and mass spectral studies. On the basis of physico-chemical studies and spectral evaluation, an octahedral geometry have been proposed for all metal(II) complexes. The antimicrobial activity of ligand and its metal complexes have been additionally screened against bacteria and fungi. Metal(II) complexes show good activity as compared to ligand towards studied microorganisms and also metal complexes checked for their catalytic properties for benzoylation of phenol.

Synthesis, Spectral Characterization and Biological Evaluation of Cr(III) Complex with Mixed N,N and O-donor Ligands

Objectives: 2-aminobenzonitrile is used as the starting materials for the synthesis of many biologically active compounds. The main objective of the study was to synthesize, characterization and biological evaluation of a binuclear bridged Cr(III) complex containing 2-aminobenzonitrile (N,Ndonor) and octanoate ion (OC) as ligands. Methods: This study formulated, the required mole ratio of 2-aminobenzonitrile in methanol and sodium octanoate in ethanol were added to the chromium chloride in methanol followed by microwave irradiation for few seconds after each addition by using microwave oven and the precipitate was filtered off, washed with 1:1 ethanol: water and characterized by various spectral studies and biological significance. Results: The resulted complex was investigated by the help of elemental analysis, molar conductance, magnetic moment, electronic spectra, FT-IR, cyclic voltammetry, thermal analysis and powder-XRD techniques. The spectral data’s indicates that the geometry of the complex is octahedral. The antimicrobial activities of ligands and their Cr(III) complex were studied by agar-well diffusion method. The free radical scavenging activity of the complex and the ligands has been determined by measuring their interaction with the stable free radical DPPH. DNA-binding properties have been studied by fluorescence-emission method. Conclusion: The formulated Cr(III) complex showed moderate and potential activity against the tested bacteria, enhanced activity against the fungi and larger antioxidant activity as compared to the free ligands. The DNA binding study result suggests that the complex strongly binds to DNA.

Synthesis, Spectral Characterization and Pharmacological Significance of Cr(III) and Mn(II) Complexes with Schiff Base and Thiocyanate Ion as Ligands

Cr(III) and Mn(II) metal complexes of Schiff base ligand derived from phenylacetylurea condensed with salicylaldehyde (SBPS) and thiocyanate(SCN-) ion were synthesized by using microwave irradiation. Microwave assisted synthesis gives high yield of the complexes within a very short time. The molecular formulae and the geometry of the complexes have been deduced from elemental analysis, metal estimation, electrical conductance, magnetic moment, electronic spectra, FT- IR, Far IR spectra, cyclic voltammetry, thermal analysis and powder-XRD techniques. The molar conductance values indicate that the complexes are non-electrolyte (1:0) type. FT-IR spectra show that Schiff base and thiocyanate ion are coordinated to the metal ion in a monodentate manner. The electronic spectra and the magnetic moment indicate the geometry of the complexes is found to be octahedral. The antimicrobial activities of ligands and their Cr(III) and Mn(II) complexes were studied against the microorganisms, viz., E. coli, Klebsiella Pneumonia, P. aeruginosa, S. aureus, Bacillus cereus, Aspergillus flavus, Aspergillus niger, Aspergillus oryzae, Aspergillus sojae and Candida albicans by agar well diffusion method. The complexes show moderate activity against the bacteria and enhanced activity against the fungi as compared to free SBPS ligand. The free radical scavenging activity of the complexes and the ligands has been determined by measuring their interaction with the stable free radical, DPPH. The complexes have larger antioxidant activity as compared to the ligand. DNA-binding properties have been studied by fluorescence-emissions method. The results suggest that the complexes strongly bind to DNA because of metal complexes are well-known to speed up the drug action and the ability of a therapeutic agent which can frequently be enhanced upon coordination with a metal ion.

Microwave Irradiation Synthesis and Anti-breast Carcinoma of 6-ethoxy-2-(2-methoxy- benzylideneamino)benzothiazole and its Metal Complexes

Efficient and clean synthesis of Schiff base as a new ligand, 6-ethoxy-2-(2-methoxy benzylideneamino)benzothiazole has been synthesized in equimolar reaction of 2-amino-6-ethoxy-benzothiazole with 2-methoxy benzaldehyde using microwave technique. The prepared Schiff base was reacted with some transition metal ions Ni(II), Cu(II), Pd(II), Ag(I) and Au(III) in equimolar ratio (M:L, 1:1) using microwave technique. The stereochemistry and the bonding characteristics of the ligand and its complexes were achieved based on elemental analysis, FT-IR, UV-Vis., 1HNMR and ESR as well as Thermo-Gravimetric Analysis (TGA). The thermal dehydration and decomposition of Ni(II), Cu(II) and Ag(I) complexes were studied kinetically using the integral method applying the Coats–Redfern and Horowitz Metzger equations. The reactivity of ligand and its Au(III) complex were studied against breast carcinoma cell. The antimicrobial activity of ligand and its Ag(I) complex studied against the bacterial (positive and negative) grams and fungal strains.

Synthesis, characterization, DNA binding and antitumor activities of Cu(II) complexes

A series of Cu(II) complexes of 5,5-dimethyl-2-(2-arylhydrazono)cyclohexane-1,3-dione (HLn) were synthesized by the coupling of dimedone with aniline and its derivatives. These ligands and their Cu(II) complexes were characterized by elemental analyses, IR, 1H NMR, 13C NMR, UV–Visible, X-ray diffraction analysis and magnetic measurements. Spectral studies revealed that the ligand exist in an internally hydrogen bonded keto-hydrazone form rather than the azo-enol form. The ligands (HLn) acts as a monobasic bidentate ligand by coordinating via the nitrogen atom of the hydrazone moiety (NH) with deprotonation and oxygen atom of the carbonyl (CO) group. The optimized bond lengths, bond angles and quantum chemical parameters of the complexes were calculated. The calf thymus DNA binding activity of the ligands and their Cu(II) complexes were studied by absorption spectra and viscosity measurements. The antimicrobial activities of ligands and Cu(II) complexes were tested against Gram negative bacteria (Escherichia coli), Gram positive bacteria (Staphylococcus aureus) and fungal (Candida albicans). The cytotoxic activity of ligands and Cu(II) complexes was tested against two human cancer HePG-2 (Hepatocellular carcinoma) and MCF-7 (breast cancer). The antioxidant activities of ligands and Cu(II) complexes were performed by ABTS method.

Synthesis, characterization, electrochemical and biological activities of mixed ligand copper(II) complexes with dimethylglyoxime and amino acids

Six new copper (II) complexes with dimethylglyoxime and the amino acids tryptophan, glutamate, proline, arginine and valine were prepared and characterized using elemental analysis, molar conductance, melting points, UV–Vis and IR spectroscopy. The compounds prepared are solids, insoluble in water, ethanol and methanol, but soluble in dimethylsulfoxide (DMSO) and dimethylformamide (DMF). The IR study shows that dimethylglyoxime as primary ligand is coordinated to the metal ion in a bidentate manner with NN donor sites of the oxime function. The secondary ligand is coordinated by the carboxylate oxygen and the N atom of the amino acid, with the exception of glutamate, which is coordinated through the N atom of the amine function. Spectroscopic studies show that all the synthesized copper (II) complexes have an octahedral geometry. The electrochemical behavior of these compounds was determined by cyclic voltammetry, which indicated an irreversible oxidation corresponding to Cu(I) → Cu(II). The antimicrobial activity of ligands and their complexes were studied by the agar diffusion technique using DMSO as solvent on different species of pathogenic bacteria (Escherichia coli and Bacillus cereus) and fungi (Candida albicans and Aspergillus niger). It has been found that some of the complexes are antimicrobially active and show higher activity than the free ligand. Metal chelation affects significantly the antimicrobial behavior of the ligands. In addition, these compounds were screened for their in vitro antioxidant properties using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging. The results obtained show that the antioxidant activity is moderate for complexes with tryptophan and glutamate, but the complex with arginine shows a good antioxidant activity in comparison with ascorbic acid as positive control.

Synthesis, Spectroscopic Characterization, Coordination, and Antimicrobial Activity of Some Metal Complexes Derived From 1, 2-Diphenylethane-1, 2-dione and Dinitrophenyl Hydrazine Schiff Base Ligand

: New Schiff base ligand (L) synthesized by 1, 2-diphenylethane-1, 2-dione and dinitrophenyl hydrazine acts as a bidentate system with O and N as donors readily available for coordination with metal atoms. The metal complexes (ML) were synthesized and characterized by various spectroscopic methods including 1H-NMR (proton NMR, hydrogen-1 NMR), elemental analysis, FT-IR (Fourier transform infrared spectroscopy), molar conductance, and ultraviolet–visible spectroscopy (UV-Vis). Molar conductance and analytical studies confirmed that the complexes exhibit tetrahedral geometry. The antimicrobial activity of ligand and its metal complexes was assessed on different species of pathogenic fungi and bacteria. The results are suggestive of the fact that the synthesized compounds own notable antimicrobial properties.

Synthesis, spectroscopic, DFT and in vitro biological studies of vanadium(III) complexes of aryldithiocarbonates

Vanadium(III) tris(dithiocarbonates), [(ROCS2)3V] (R=o-, m-, p-CH3C6H4 and 4-Cl-3-CH3C6H3) and donor stabilized addition complexes [(ROCS2)2V(Cl)·L] [L=NC5H5 or P(C6H5)3] were synthesized and characterized by elemental analyses, IR, mass, TGA/DTA, SEM magnetic susceptibility and heteronuclear NMR (1H, 13C and 31P) spectroscopic studies. The cytotoxicity of the complexes was measured in vitro using the cultivated human cell lines. In addition, the antioxidant activities of the ligands and its vanadium complexes were also investigated through their scavenging effect on DPPH radicals. The antimicrobial activity of ligands and some complexes has been conducted against three bacterial strains and fungus. The density functional theory (DFT) calculations of ligands and vanadium complexes were performed by the DFT/B3LYP/LANL2DZ method to obtain the optimized molecular geometry, vibrational frequencies, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), thermodynamic properties and various other quantum-mechanical parameters.

Synthesis and antimicrobial activity of tetradentate ligands bearing hydrazone and/or thiosemicarbazone motifs and their diorganotin(IV) complexes

Four novel ligands derived from 2,3-butanedione have been synthesized, two dissymmetric thiosemicarbazone/3-hydroxy-2-naphthohydrazone ligands, H2L1 (bearing 4-isopropyl-3-thiosemicarbazone) and H2L2 (containing 4-cyclohexyl-3-thiosemicarbazone) and the symmetric H2L3, diacetyl bis(3-hydroxy-2-naphthohydrazone), and H2L4, diacetyl bis(4-cyclohexyl-3-thiosemicarbazone). Their reactivity with SnR2Cl2 (R=methyl, n-butyl and phenyl) was explored and the resulting complexes were characterized by elemental analysis, molar conductivity, mass spectrometry, IR, 1H, 13C and 119Sn NMR and seven of them also by single crystal X-ray diffraction. The results showed that the reactivity of the dissymmetric ligands is strongly different and while the cyclohexyl derivative is very stable, with isopropyl easily undergoes a symmetrization reaction to yield the corresponding symmetric ligands. The antimicrobial activity of the ligands and the corresponding diorganotin(IV) complexes was investigated in vitro against seven species of microorganisms and minimum inhibitory concentrations (MICs) were determined. The results showed that the ligand H2L2 and several of its derivatives, together with methyl and phenyl complexes of H2L1, have the ability of inhibiting the growth of tested bacteria and fungi to different extents. Bacillus subtilis and Staphylococcus aureus Gram positive strains were the most sensitive microorganisms.

Spectroscopic, thermal analysis and antimicrobial activities of supramolecular Cu(II) complexes

A series of Cu(II) complexes of azo dye ligands 4-(4-hydroxy-5-(aryldiazenyl)-2-thioxothiazol-3(2H)-yl)benzenesulfonamide (HLn) were synthesized by the coupling of 3-sulfamoylphenylrhodanine with aniline and its p-derivatives. These ligands and their [Cu(Ln)(CH3COO)(OH2)]H2O complexes were characterized by elemental analyses, IR, 1H NMR, UV–Visible and magnetic measurements as well as thermal analysis and X-ray diffraction. The molar conductance measurements proved that all the complexes are non-electrolytes. IR spectra showed that the ligands (HLn) acts as a monobasic bidentate ligand by coordinating via the nitrogen atom of the azo group (–NN–) and oxygen atom of the deprotonated –OH group moiety, thereby forming a six-membered chelating ring and concomitant formation of an intramolecular hydrogen bond. Spectral studies revealed that the ligand exist in an internally hydrogen bonded azo-enol form rather than the keto-hydrazone form a coordinated to the metal ion in a bidentate fashion. Analytical data revealed that all the complexes exhibited 1:1 metal-ligand ratio. Based on the ESR and electronic spectral data, the bonding parameters of these complexes have been calculated. The thermodynamic parameters of the ligands (HLn) and their Cu(II) complexes are calculated using Coats–Redfern and Horowitz-Metzger methods. The antimicrobial activities of ligands were tested against gram negative bacteria (Escherichia coli), gram positive bacteria (Staphylococcus aureus) and fungal (Candida albicans). The cytotoxic activity of ligands (HLn) was tested against two human cancer HePG-2 (Hepatocellular carcinoma) and MCF-7 (breast cancer). The antioxidant activities of ligands (HLn) were performed by ABTS method.

Synthesis, characterization, antimicrobial and cytotoxicity studies of some transition metal complexes with gemifloxacin

The preparation and characterization are reported of the new solid complexes formed from the reaction of gemifloxacin with Y(III), Zr(IV), La(III), Ce(IV), and U(VI) at room temperature. The infrared spectra proof that metal–ligand coordination involves one oxygen atom of carboxylic group and the oxygen atom of pyridone group. The kinetic parameters of thermogravimetric (TGA) and its differential (DTG), such as activation energy, entropy of activation, enthalpy of activation, and Gibbs free energy evaluated using Coats-Redfern and Horowitz-Metzger equations for ligand and complexes were carried out at different n values. The calculated bond length and force constant, F(U=O), in the uranyl complex are 1.751 Ǻ and 642.62 N m−1, respectively. The antimicrobial activity of ligand and metal complexes was tested against some of the gram-positive and gram-negative bacteria and fungi. The in vitro growth inhibitory activity of the synthesized compounds against human breast carcinoma (MCF-7) and colon carcinoma (HCT-116) cell lines was investigated.

Stereospecific ligands and their complexes. Part XXI. Synthesis, characterization, circular dichroism and antimicrobial activity of cobalt(III) complexes with some edda-type of ligands. Crystal structure of potassium-Δ-(−)589-s-cis-oxalato-(S,S)-ethylenediamine-N,N′-di-(2-propanoato)-cobaltate(III)-semihydrate, K-Δ-(−)589-s-cis-[Co(S,S-eddp)(ox)]·0.5H2O

The octahedral cobalt(III) complexes with (S,S)-ethylenediamine-N,N′-di-2-propionic (S,S-eddp) and (S,S)-ethylenediamine-N,N′-di-2-(3-methyl)-butanoic (S,S-eddv) acids and oxalato and malonato ligands, as additional bidentate ligands, were prepared and characterized. The complexes were purified by ion-exchange chromatography. The geometry of the complexes has been supposed on the basis of the infrared, electronic absorption and NMR spectra. The Δ absolute configurations of the isolated complexes have been predicted on the basis of their circular dichroism (CD) spectra and it was confirmed by single-crystal X-ray analysis of potassium-Δ-(−)589-s-cis-oxalato-(S,S)-ethylenediamine-N,N′-di-(2-propanoato)-cobaltate(III)-semihydrate, K-Δ-(−)589-s-cis-[Co(S,S-eddp)(ox)]·0.5H2O. Antimicrobial activity of ligands and obtained cobalt(III) complexes was evaluated by determining the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) in relation to 13 species of microorganisms (five strains of pathogenic bacteria, five species pathogenic fungi and three species of probiotic). Tested ligands and complexes demonstrated moderate and low antibacterial and antifungal activity. There was no difference in activities between the ligands and complexes.

Structural, spectral, DFT and biological studies of (E)-3-(2-(2-hydroxybenzylidene)hydrazinyl)-3-oxo-N-(p-tolyl)propanamide complexes

Hydrazone complexes of Co(II), Ni(II), Cu(II), Pd(II), Zn(II) and U(VI)O2 with (E)-3-(2-(2-hydroxybenzylidene)hydrazinyl)-3-oxo-N-(p-tolyl)propanamide (H2SHAH) were synthesized. The complex structure was elucidated by analysis (elemental and thermal), spectroscopy (1H NMR, IR, UV–visible, MS) and physical measurements (magnetic susceptibility and molar conductance). The kinetic and thermodynamic parameters for the different decomposition steps of some complexes were calculated using the Coats–Redfern and Horowitz–Metzger methods. Also, the bond length, bond angle, HOMO, LUMO, dipole moment and charges on the atoms were estimated to confirm the geometry of the ligand and the investigated complexes. Moreover, antimicrobial activity of ligand and its complexes was tested against gram positive bacteria Staphylococcus aureus, gram-negative bacteria; Escherichia coli and pathogenic fungi; Candida albicans by using MICs method. Moreover, the antioxidant of the isolated compounds was studied by using the ABTS method. Finally, the compounds were also screened for antitumor study against HePG2 liver cells.