Synthesis,characterization and susceptibility of bacteria against Sulfamethoxydiazine complexes of copper(II), zinc(II), nickel(II), cadmium(II), chromium(III) and iron(III)

Complexes of sulfamethoxydiazine with Cu(II), Zn(II), Ni(II), Cd(II), Cr(III) and Fe(III) have been synthesized and characterized on the basis of conductivity measurements, elemental analyses, UV, IR, ¹H?NMR and thermal studies. It is shown that sulfamethoxydiazine behaves as a bidentate ligand, binding the metal ion through the sulfonyl oxygen and sulfonamide nitrogen. In vitro susceptibility tests of these complexes against Escherichia coli, Bacillus subtilis, Proteus vulgaris and Staphylococcus aureus were carried out. The results show that the antibacterial activities of the complexes of Zn(II), Cu(II), Cr(III) and Fe(III) are, in general, stronger than that of sulfamethoxydiazine, while the complexes of Cd(II) and Ni(II) are less active.     

Coordination compounds of some transition metal ions with new Schiff base ligand derived from dibenzoyl methane. Structural characterization,thermal behavior,molecular structure,antimicrobial, anticancer activity and molecular docking studies

Series of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes were prepared with tetradentate Schiff base ligand derived by condensation of 2‐aminophenol with dibenzoylmethane. The novel Schiff base H₂L (2–2′‐((1Z,1Z’)‐(1,3‐diphenyl propane‐1,3 diylidene) bis (azanylylidene) diphenol) and its binary metal complexes were characterized by physicochemical procedures i.e. elemental analysis, FT‐IR, UV–Vis, thermal analyses (TGA/DTG), mass spectrometry, magnetic susceptibility and conductometric measurements. On the basis of these studies, an octahedral geometry for all these complexes was proposed expect Ni(II) complex which had tetrahedral geometry. Molar conductivity values revealed that the complexes were electrolytes except Mn(II), Zn(II) and Cd(II) complexes were non electrolytes. The ligand bound to the metal ions via two azomethine N and two phenolic OH as indicated from the IR and ¹H NMR spectral study. The molecular and electronic structures of H₂L and its zinc complex were optimized theoretically and the quantum chemical parameters were calculated. The antimicrobial activity against a number of bacterial organisms as Streptococcus pneumonia, Bacillus Subtilis, Pseudomonas aeruginosa and Escherichia coli and fungi as Aspergillus fumigates, Syncephalastrum racemosum, Geotricum candidum and Candida albicans by disk diffusion method were screened for the Schiff base and its complexes. The Cd(II) complex has potent antimicrobial activity. Anticancer activity of the Schiff base ligand and its metal complexes were evaluated in human cancer (MCF‐7 cells viability). The Cr(III) complex exhibited higher activity than other complexes and ligand. Molecular docking was used to predict the binding between Schiff base ligand (H₂L) and its Zn(II) complex and the receptors of RNA of amikacin antibiotic (4P20) and human‐DNA‐Topo I complex (1SC7). The docking study provided useful structural information for inhibition studies.     

Synthesis, infrared spectra and thermal studies of Zn(II), Cd(II) and Hg(II) complexes with 2-aminobenzaldehyde phenylhydrazone "nitrin" ligand

The, nitrin, 2-aminobenzaldehyde phenylhydrazone (2ABPH) was synthesis by refluxing 2-nitrobenzaldehyde with phenylhydrazine in ethanolic solvent. Three transition metal (II) complexes of 2ABPH have been prepared. Elemental analysis, molar conductivity, IR, UV, 1H NMR, and mass spectra, as well as TG/DTG have been used to characterize these complexes. The complexes have the general formula [M(2ABPH)2]Cl2.nH2O, where M=Zn, Cd, and Hg and n=4, 2 and 0 for Zn(II), Cd(II) and Hg(II), respectively. The ligand and its complexes have been studied for their possible biological activity including antibacterial and antifungal activity.     

Azo dye with nitrogen donor sets of atoms and its metal complexes: Synthesis,characterization, DFT,biological, anticancer and Molecular docking studies

An azo derivative was synthesized by coupling diazotized 2,6‐diaminopyridine with p‐dimethyl amino benzaldehyde and this new ligand formed a series of metal complexes with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) salts. These complexes were characterized on the basis of elemental analyses, molar conductance, infrared spectroscopy, UV–Vis, ¹H NMR, mass spectrometry, electronic spectra, magnetic susceptibility and ESR spectral studies, conductivity measurements, thermogravimetric analyses (TG‐DTG). The molecular and electronic structure of the azo ligand was optimized theoretically and the quantum chemical parameters were calculated. The ligand and its metal complexes were subjected to X‐ray powder diffraction study. The thermal stability of the ligand and its metal complexes was examined by thermogravimetry. The ligand and its complexes were tested for their in vitro antimicrobial activity, some of the complexes showed good antimicrobial activities against some selected bacterial and fungal strains. Anticancer activity of the ligand and its metal complexes are evaluated against human cancer (MCF‐7 cells viability). Molecular docking was used to predict the binding between azo ligand and the receptors of nucleoside diphosphate kinase of Staphylococcus aureus (3Q8U) and (3HB5) which is breast cancer mutant oxidoreductase. The docking study provided useful structural information for inhibition studies.     

Novel metal complexes of 3-acetylcoumarin-2-hydrazinobenzothiazole Schiff base: Design,structural characterizations,DNA binding,DFT calculations,molecular docking and biological studies

Five new Cu (II), Zn (II), Pd (II), Ru (III) and Ag(I) complexes, derived from the 3-acetylcoumarin-2-hydrazinobenzothiazole Schiff base (Hachbt), have been synthesized and characterized. The structures were established with the aid of elemental analyses (C, H, N), FT-IR, ¹H-NMR, ESR, UV–visible and ESI-mass spectra. The complexes were also investigated by magnetic susceptibility, thermal gravimetric analysis (TG-DTA) and cyclic voltammetry measurements. The results suggest that the Schiff base ligand behaves in two different ways: neutral mono/bidentate or mono-negative bi/tridentate. The calf thymus DNA (CT DNA) binding affinities of Hachbt and its complexes have been examined by UV–visible spectroscopy. The antifungal activity of the compounds was also screened against two fungal species of wood-decay basidiomycetes using the agar dilution method. Different complexes caused a reduction in the fungal colony diameters at a media concentration of 100 μg/ml. The best antifungal activity was observed for the Pd (II) and Ag(I) complexes with a 60% and 79% reduction, respectively. The effect of the complexes on the ability of the same fungi to decolorize poly-R dye on agar plates was also tested. All of the complexes showed an enhanced effect on the decolorization ability and the Cu (II) and Ru (III) complexes exhibited the strongest effect at a media concentration of 5 μg/ml. Theoretical studies were performed for all the complexes using the DFT/B3LYP/6–31 + g(d) basis set for calculations on the ligand atoms and LAN2DZ for the Pd (II) complex. The optimized geometries were found to be in a good agreement with the proposed structures. The molecular docking calculations show that the binding affinity of the Pd (II) complex is −309.170-309.2 kcal/mol, which suggests complexation with the DNA minor groove.     

Synthesis,characterization, DFT calculations and antimicrobial activity of pentagonal-bipyramidal Zn(II) and Cd(II) complexes with 2,6-diacetylpyridine-bis(trimethylammoniumacetohydrazone)

Isothiocyanate complexes of Zn(II) and Cd(II) with the condensation product of 2,6-diacetylpyridine and trimethylammoniumacetohydrazide (Girard’s T reagent) were synthesized, characterized, and their antimicrobial activities were evaluated. The structures of the complexes were determined by elemental analysis, IR, and NMR spectroscopy. The crystal structure of the Zn(II) complex was also determined. Quantum-chemical calculations of the geometry and total energy of isomers of 2,6-diacetylpyridine-bis(trimethylammoniumacetohydrazone) were performed in vacuum and methanol solution, with the aim to explain conformational behavior and E/Z isomerism of this compound. DFT calculations of the molecular structures and the relative stabilities of linkage isomers of the Cd(II) complex showed that the isomer with N–Cd–N coordination of SCN^? is the most stable. Complexes of Zn(II) and Cd(II) exhibited low to moderate activity against the tested microbial strains.     

Preparation, characterization and biological activity of Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) complexes of new cyclodiphosph(V)azane of sulfaguanidine

Novel hexachlorocyclodiphosph(V)azane of sulfaguanidine, H(4)L, l,3-[N'-amidino-sulfanilamide]-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane was prepared and its coordination behaviour towards the transition metal ions Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) was studied. The structures of the isolated products are proposed based on elemental analyses, IR, UV-vis, (1)H NMR, mass spectra, reflectance, magnetic susceptibility measurements and thermogravimetric analysis (TGA). The hyperfine interactions in the isolated complex compounds were studied using 14.4keV gamma-ray from radioactive (57)Co (M?ssbauer spectroscopy). The data show that the ligand are coordinated to the metal ions via the sulfonamide O and deprotonated NH atoms in an octahedral manner. The H(4)L ligand forms complexes of the general formulae [(MX(z))(2)(H(2)L)H(2)O)(n)] and [(FeSO(4))(2) (H(4)L) (H(2)O)(4)], where X=NO(3) in case of UO(2)(II) and Cl in case of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). The molar conductance data show that the complexes are non-electrolytes. The thermal behaviour of the complexes was studied and different thermodynamic parameters were calculated using Coats-Redfern method. Most of the prepared complexes showed high bactericidal activity and some of the complexes show more activity compared with the ligand and standards.     

Synthesis,Spectral, Thermal and Biological Studies of Mn(II), Co(II), Ni(II) and Cu(II) Complexes with 1‐(((5‐Mercapto‐1H‐1,2,4‐triazol‐3‐yl)imino)‐methyl)naphthalene‐2‐ol

Mn(II), Co(II), Ni(II) and Cu(II) complexes of 5‐mercapto‐1,2,4‐triazol‐3‐imine‐2′‐hydroxynaphthaline have been synthesized and characterized by elemental analysis, IR, ¹H NMR, EI‐mass, UV‐Vis, and ESR (electron spin resonance) spectra, molar conductance, magnetic moment measurements, DC conductivity and thermogravimetric analysis. IR spectra confirm that the ligand molecule existed in both thione and thiole forms. The molar conductance values indicate the complexes are nonelectrolyte. The magnetic moment values of the complexes display paramagnetic behavior. All studies confirm the formation of an octahedral geometry for complex 1 and the other complexes have tetrahedral geometrical structures. The structures of the complexes have also been theoretically studied by using the molecular mechanic calculations by the hyperchem. 8.03 molecular modeling program which confirm the proposed structures. The Schiff‐base ligand and its metal complexes have also been screened for their antimicrobial activities.     

Fabrication,spectroscopic characterization,calf thymus DNA binding investigation,antioxidant and anticancer activities of some antibiotic azomethine Cu(II), Pd(II), Zn(II) and Cr(III) complexes

This study was conducted to prepare novel azomethine chelates of Cu(II), Pd(II), Zn(II) and Cr(III) with tridentate dianionic azomethine OVAP ligand 2‐[(2‐hydroxyphenylimino)methyl]‐6‐methoxyphenol. The prepared compounds were characterized using elemental analyses and spectral, conductivity, magnetic and thermal measurements. The spectroscopic data suggest that the parent azomethine ligand binds to the investigated metal ions through both deprotonated phenol oxygen and azomethine nitrogen atoms, and adopts distorted octahedral geometry in the case of Cr(III) and Cu(II) ions while tetrahedral and square planar geometries for Zn(II) and Pd(II) ions, respectively. In order to confirm the molecular geometry of the investigated azomethine chelator and its complexes, theoretical density functional theory calculations were employed. Correlation between experimental observations and theoretical calculations of geometry optimization results are in a good agreement. Absorption titration was used to explore the interaction of the investigated azomethine metal chelates with calf thymus DNA, and the binding constant as well as Gibbs free energy were evaluated. Viscosity measurements and gel electrophoresis studies suggest intercalative and replacement binding modes of the azomethine metal chelates with calf thymus DNA. Additionally, the antimicrobial activity of the complexes was screened against some pathogenic bacteria and fungi. This biological study shows that the complexes exhibit a marked inhibitory effect compared to the corresponding ligand and standard drug s. Furthermore, the effect of the novel compounds as antioxidants was determined by reduction of 1,1‐diphenyl‐2‐picrylhydrazyl and compared with that of vitamin C. Finally, in vitro cell proliferation via MTT assay was investigated against colon carcinoma cells (HCT‐116), hepatic cellular carcinoma cells (HepG‐2(and breast carcinoma cells (MCF‐7) to calculate the cytotoxicity of the prepared compounds. Cell proliferation is inhibited for all compounds and in a dose‐dependent manner in the sequence of OVAPPd > OVAPCu > OVAPZn > OVAPCr > OVAP azomethine ligand.     

Biomolecular docking,antimicrobial and cytotoxic studies on new bidentate schiff base ligand derived metal (II) complexes

Three new metal complexes [Cu(L)₂] (1), [Co(L)₂] (2) and [Zn(L)₂] (3) have been prepared by the reaction of hydrated salts of metal (II) acetate with new Schiff base ligand HL, [2‐((4‐(dimethylamino)phenylimino)methyl)‐4,6‐di‐t‐butylphenol] and characterized by different physico‐chemical analyses such as elemental analysis, single XRD, ¹H NMR, FTIR and UV–Vis spectroscopic techniques. Their biomolecular docking, antimicrobial and cytotoxicity studies have also been demonstrated. The proposed structure of Schiff base ligand HL and complex 2 are confirmed by Single crystal X‐ray crystallography study. This analysis revealed that metal (II) complexes remain in distorted tetrahedral coordination environments. The electronic properties such as HOMO and LUMO energies are carried out by gaseous phase DFT/B3LYP calculations using Gaussian 09 program. Complex 1 showed a good binding propensity to the DNA and HSA, during the assessment of docking studies. Schiff base ligand HL and its metal (II) complexes, 1–3 screened for their in vitro antimicrobial activities using the disc diffusion method against selected microbes. Complex 1 shows higher antimicrobial activity than complexes 2, 3 and Schiff base ligand HL. According to the results obtained from the cytotoxic studies, Schiff base ligand HL and its metal (II) complexes 1–3 have better cytotoxicity against MCF‐7 cell lines with potency higher than the currently used chemotherapeutic agent cyclophosphamide.     

Molecular structure and spectroscopic studies on novel complexes of coumarin-3-carboxylic acid with Ni(II), Co(II), Zn(II) and Mn(II) ions based on density functional theory

Novel Ni(II), Co(II), Zn(II) and Mn(II) complexes of coumarin-3-carboxylic acid (HCCA) were studied at experimental and theoretical levels. The complexes were characterised by elemental analyses, FT-IR, (1)H NMR, (13)C NMR and UV-Vis spectroscopy and by magnetic susceptibility measurements. The binding modes of the ligand and the spin states of the metal complexes were established by means of molecular modelling of the complexes studied and calculation of their IR, NMR and absorption spectra at DFT(TDDFT)/B3LYP level. The experimental and calculated data verified high spin Ni(II), Co(II) and Mn(II) complexes and a bidentate binding through the carboxylic oxygen atoms (CCA2). The model calculations predicted pseudo octahedral trans-[M(CCA2)(2)(H(2)O)(2)] structures for the Zn(II), Ni(II) and Co(II) complexes and a binuclear [Mn(2)(CCA2)(4)(H(2)O)(2)] structure. Experimental and calculated (1)H, (13)C NMR, IR and UV-Vis data were used to distinguish the two possible bidentate binding modes (CCA1 and CCA2) as well as mononuclear and binuclear structures of the metal complexes.     

Synthesis, characterization, antioxidative activity and DNA binding properties of the copper(II), zinc(II), nickel(II) complexes with 1,2-Di(4'-iminonaringenin)ethane

A novel naringenin Schiff base ligand (1,2-di(4'-iminonaringenin)ethane, H6L) and its three transition metal complexes [Cu(II) complex (1), Zn(II) complex (2), and Ni(II) complex (3)] have been prepared and characterized on the basis of elemental analysis, molar conductivity, 1H-NMR, mass spectra, UV-vis spectra, and IR spectra. The DNA-binding properties of the ligand and its complexes have been investigated by absorption spectroscopy, fluorescence spectroscopy, ethidium bromide (EB) displacement experiments, and viscosity measurement. The results indicated that the ligand and its complexes can bind to DNA. The binding affinity of the Cu(II) complex (1) is higher than that of the ligand and the other two complexes. The intrinsic binding constant (Kb) of the complex (1) is 3.3x10(6). In addition, the suppression ratio for O2-. and HO. was determined. The 50% inhibition obtained for the ligand and its three complexes demonstrates that, compared to the ligand, the complexes exhibit higher antioxidative activity in the suppression of O2-. and HO..     

New transition metal complexes of 9,10‐phenanthrenequinone p‐toluyl hydrazone Schiff base: Synthesis,spectroscopy, DNA and HSA interactions,antimicrobial, DFT and docking studies

The new complexes of Cu (II) and Ni (II) of a tridentate Schiff base ligand derived from 9,10‐phenanthrenequinone and p‐toluic hydrazide have been synthesized and characterized by elemental analysis, electrical conductometry, FT‐IR, Mass, NMR and UV–Vis. The DFT calculations were carried out at B3LYP/6‐31G*(d) level for the determination of the optimized structure of the ligand and its complexes. The as‐synthesized compounds were screened for their antimicrobial activity. Also, their binding behavior with fish salmon‐DNA (FS‐DNA) and human serum albumin (HSA) were studied by different kinds of spectroscopic and molecular modeling techniques. The fluorescence data at different temperatures were applied in order to estimate the thermodynamics parameters of interactions of ligand and its complexes with DNA and HSA. The results showed that the as‐made compounds could bind to FS‐DNA and HSA via the groove binding as the major binding mode. According to molecular docking calculation and competitive binding experiments, these compounds bind to the minor groove of DNA and hydrophobic residues located in the subdomain IB of HSA. In addition, the molecular docking results kept in good consistence with experimental data.     

Synthesis,structural features and biochemical activity assessment of N,N′‐bis‐(2‐mercaptophenylimine)‐2,5‐thiophenedicarboxaldehyde Schiff base and its Co(II), Ni(II), Cu(II) and Zn(II) complexes

The tetradentate Schiff base ligand (SB), N,N′‐bis‐(2‐mercaptophenylimine)‐2,5‐thiophenedicarboxaldehyde was prepared via condensation of 2,5‐thiophene‐dicarboxaldehyde with 2‐aminothiophenol in a 1:2 molar ratio by conventional method. Additionally, its Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized and fully characterized by elemental analysis, FT‐IR, ¹H NMR, ¹³C NMR, UV–Vis, ESR, ESI‐mass, conductivity and magnetic susceptibility measurements. Spectral studies suggested that, the Schiff base coordinate metal ions through the azomethine N‐ and deprotonated thiol S‐ atoms. Based on UV–Vis absorption and magnetic susceptibility data, tetrahedral geometry was assigned for both Co(II) and Zn(II) complexes, whereas on the other hand, square planar geometry for both Ni(II) and Cu(II) complexes. The Schiff base and its metal complexes were screened for their in vitro antimicrobial activity by minimum inhibitory concentration (MIC) method. Free radical scavenging activity of the novel compounds was determined by elimination of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radicals. In addition, the interactions of the free ligand and its complexes with calf thymus DNA (CT‐DNA) were explored using absorption, emission and viscosity measurements techniques.     

Synthesis, characterization and antioxidant activity of naringenin Schiff base and its Cu(II), Ni(II), Zn(II) complexes

A new ligand, naringenin-2-hydroxy benzoyl hydrazone (H(5)L), was prepared by condensation of naringenin with 2-hydroxy benzoyl hydrazine. Its Cu(II), Ni(II), Zn(II) complexes have also been synthesized and characterized on the basis of (1)H-NMR, IR, UV-Vis spectra, elemental analyses, molar conductivity and thermal analyses. The general formula of these complexes was M(H(3)L) [M=Cu(II), Ni(II) and Zn(II)]. In addition, the antioxidant activities (superoxide and hydroxyl radical) of the free ligand and its complexes were determined in vitro. These compounds were found to possess potent antioxidant activity and be better than standard antioxidants like vitamin C and mannitol. In particular, the Cu(II) complex displayed excellent activity on the superoxide radical.     

Transition metal complexes of Schiff base ligand based on 4,6-diacetyl resorcinol

Novel Schiff base ligand based on the condensation of 4,6-diacetyl resorcinol with 2-amino-4-methylthiazole in addition to its metal complexes with Cr (III), Mn (II), Fe (III), Co (II), Ni (II), Cu (II), Zn (II) and Cd (II) ions have been synthesized. The structure, electronic properties, and thermal behaviour of Schiff base and its metal complexes have been studied by elemental analysis, mass, ¹H NMR, IR spectra, thermal analysis, and theoretically by density function theory. The ligand acted as mononegative bidentate (NO) ligand and all complexes showed octahedral geometry except Cu (II) showed tetrahedral geometry as indicated from the spectral and magnetic studies. The Cu (II), Zn (II) and Cd (II) complexes were non electrolytes while the rest of the complexes were electrolytes. The antibacterial plus anticancer activities of the parent Schiff base and its metal complexes were screened. In addition, the molecular docking study was performed to explore the possible ways for binding to Crystal Structure of Human Astrovirus capsid protein (5ibv) receptor.     

Synthesis, spectroscopic characterization, insulin-enhancment, and competitive DNA binding activity of a new Zn(II) complex with a vitamin B6 derivative--a new fluorescence probe for Zn(II)

This paper describes the activity of a Schiff base ligand, derived from pyridoxal, as a promising fluorescence probe for biologically important Zn(II) ion sensing. This is the first report of a vitamin based ligand as a fluorescent probe for sensing Zn(II) ions. The Schiff base H(2)pydmedpt, derived from the condensation of pyridoxal (pyd) and N,N-bis[3-aminopropyl]methylamine (medpt), exhibits around a 325-fold increase in fluorescence quantum yield due to zinc triggered fluorescence switching. The response is specific for Zn(II) ions, and remains unaffected by the presence of alkali and alkaline earth metals but is suppressed to varying degrees by transition metal ions. The corresponding Zn(II)-complex, [Zn(pydmedpt], is isolated. The DFT optimized structure of the complex is compatible with elemental analysis, mass spectrometry, FT-IR, electronic and NMR spectra. The isolated complex, having pK(a) values of ～5.3 and ～5, is a moderate intercalator for DNA with an apparent binding constant of 2.3 × 10(6) M(-1). The complex also shows insulin-enhancing activity at par with other reported complexes, with an IC(50) value of 0.65 with respect to ZnSO(4).     

Synthesis and DNA binding studies of Ni(II), Co(II), Cu(II) and Zn(II) metal complexes of N1,N5-bis[pyridine-2-methylene]-thiocarbohydrazone Schiff-base ligand

The thiocarbohydrazone Schiff-base ligand with a nitrogen and sulphur donor was synthesized through condensation of pyridine-2-carbaldehyde and thiocarbohydrazide. Schiff-base ligands have the ability to conjugate with metal salts. A series of metal complexes with a general formula [MCl2(H2L)]·nH2O (MNi, Co, Cu and Zn) were synthesized by forming complexes of the N1,N5-bis[pyridine-2-methylene]-thiocarbohydrazone (H2L) Schiff-base ligand. These metal complexes and ligand were characterized by using ultraviolet-visible (UV-Vis), Fourier Transform Infrared (FT-IR), 1H and 13C NMR spectroscopy and mass spectroscopy, physicochemical characterization, CHNS and conductivity. The biological activity of the synthesized ligand was investigated by using Escherichia coli DNA as target. The DNA interaction of the synthesized ligand and complexes on E. coli plasmid DNA was investigated in the aqueous medium by UV-Vis spectroscopy and the binding constant (Kb) was calculated. The DNA binding studies showed that the metal complexes had an improved interaction due to trans-geometrical isomers of the complexes than ligand isomers in cis-positions.     

Spectroscopic,morphology and electrical conductivity studies on Co(II), Ni(II), Cu(II) and Mn(II)-oxaloyldihydrazone complexes

Cobalt (II), nickel (II), copper (II) and manganese (II) complexes of dihydrazone derived from the condensation of oxaloyldihydrazide with 2-hydroxybenzaldehyde have been synthesized. The dihydrazone ligand/chelates were characterized on the basis of their elemental analyses, spectral (UV–Vis., FT-IR, mass, ¹H NMR), magnetism, thermal (TGA) measurements and structures of the compounds have been established. The surface morphology of the desired complexes was studied by SEM. The ligand is coordinated to the Ni(II), Co(II), Mn(II) and Cu(II) centers in bi, tetra, penta and hexadentate way giving mono-nuclear complexes except in case of manganese and copper the bi-nuclear complexes were formed. The nickel complex has tetrahedral geometry while the other complexes are suggested to have octahedral configurations. The prepared samples have been assayed for their electrical activities. The electrical activity (DC and AC conductivity) for ligand and its metal complexes has been examined at different frequencies (1, 10, 100 kHz) in the temperature ranges 303–573 and 300–625 K, respectively. The DC and AC conductivity are viewed as thermally activated process at higher temperatures and a marked increment was seen in case of Mn(II) complex. The dielectric permittivity was determined in the temperature area of 300–625 K and diminished with augmentation of frequency proposing a typical behavior of dielectrics.     

Synthesis,Spectral, Modeling,Docking and Cytotoxicity Studies on 2-(2-aminobenzoyl)-N-ethylhydrazine-1-carbothioamide and its divalent metal complexes

2-(2-aminobenzoyl)-N-ethylhydrazine-1-carbothioamide (H₃L) and its Cu (II), Co (II), Ni (II) and Zn (II) complexes have been synthesized. The structures of the isolated compounds were suggested based on elemental analyses, spectral analyses (FTIR, ¹H and ¹³CNMR, MS, ESR and UV–Visible) and magnetic moments measurements. The free ligand exists in the keto-thione form, while in the metal complexes; it exists in the enol form and coordinates as mononegative bidentate via deprotonated enolic oxygen and N²H nitrogen. Both Co (II) and Ni (II) complexes have an octahedral, while Cu (II) complex has a square planar geometry. The compounds have direct electronic transitions with optical band gap (E_g) values in the range 3.14–3.40 eV. The ligand and its complexes were optimized using DFT/B3LYP methodology. The ligand optimization results supported the involvement of the carbonyl oxygen, thione sulfur and N²H hydrogen atoms in hydrogen bonding formation. Furthermore, the obtained structures of the ligand and its complexes were subjected to molecular docking study to predict interactions cause their cytotoxicity. Finally, the in vitro cytotoxicity activities of the ligand and its complexes were investigated against Hela and WISH cell lines where the Zn (II) complex exhibited higher activity than the other compounds against the two cell lines in accordance with molecular docking suggestion.