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Schiff bases complexes of Co(II) and Ni(II) ions with diethyl 3,3'-(ethane-1,2-diylbis (azaneylylidene)) (3E, 3′E)-dibutyrate (H2L1) and (3E, 3′E)-3,3'-(ethane-1,2-diylbis (azanylylidene))bis (N-(pyridin-2-yl)butanamide) (H2L2) have been synthesized, characterized and analytically formulated as [Co2(L1)Cl2·2H2O]·H2O (1), [Ni2(L1)Cl2·6H2O]·2H2O (2), [Co2(H2L2)Cl4·2H2O]·H2O (3) and [Ni(H2L2)Cl2]·H2O (4). The IR spectral data revealed that H2L1 ligand behaves as a N2O2 binegative tetradentate in (1) and (2) through the oxygen of both enolized carbonyl (C O) groups and the nitrogen of two newly formed (C N)∗ groups. While H2L2 acts as neutral NNOONN hexadentate in (3) and as a neutral NNOO tetradentate in (4). The spectral and magnetic studies suggests a tetrahedral coordination geometry for complex (1) and octahedral geometry for other complexes. In addition, thermal degradation curves have been discussed for complexes in order to estimate their kinetic and thermodynamic parameters by two comparable methods. Various descriptors have been estimated using DFT calculations. Moreover, the anti-microbial activities and MTT cytotoxicity assay of the compounds have been examined.

Cr(III), Mn(II), Fe(III), Cd(II), Zn(II) and Hg(II) complexes derived from carbohydrazone ligand were synthesized and characterized by spectroscopic methods, DFT calculations and TGA analysis. IR spectra together with DFT optimization revealed that the ligand uses its two (C N)azomthine in coordination with either Mn(II), Fe(III) or Zn(II) ions. While, Cd(II) and Hg(II) ions coordinates via the nitrogen atoms of the two pyridyl groups. On the other hand, the coordination takes place through the two (C N)azomthine and the (C O)carbonyl groups in Cr(III) complex. On the basis of the electronic spectra and as the magnetic measurements, an octahedral coordination geometry was proposed in case of Cr(III) and Fe(III) complexes and a tetrahedral geometry in case of Mn(II) complex. Kinetic and thermodynamic parameters of the isolated complexes were estimated using Coats-Redfern and Horowitz-Metzger models. The antioxidant (DDPH and ABTS methods), anti-hemolytic and cytotoxic activities of the compounds have been screened. The DDPH and ABTS antioxidant activity was investigated and indicated that Zn(II) complex exhibited the highest antioxidant activity. While, Fe(III) complex had significantly the same percentage of hemolysis as that of the positive control. With respect to antitumor activity, H2APEC and Zn(II) complex demonstrated the potent activity followed by Fe(III) complex.

Novel hydrazone 2-(2-((1E,2E)-2-(2-phenylhydrazineylidene)propylidene)hydrazineyl)pyridine and its nickel(II) and copper(II) complexes have been synthesized and characterized. The ligand (H2PGl) was prepared by the condensation reaction of 1-(2-phenylhydrazineylidene)propan-2-one and 2-hydrazinopyridine. The crystal structure of Ni(II) complex was determined. In both Ni(II) and Cu(II) complexes, H2PGl act as a neutral tridentate ligand forming two fused five-membered chelation rings through NNN set of donor atoms. Octahedral geometry is proposed for both chelates as illustrated in both magnetic and spectroscopic data. ESR spectroscopy was performed for Cu(II) complex which exhibited a considerable Cu–Cu interaction and harmonize directly with measured magnetic moment. The molecular modeling structures were optimized and showed the bond length, bond angle, reactivity, MEP and atomic charges for all the title frameworks. Hypothetical infrared intensities and 1H NMR of H2PGl was estimated on the basis of DFT scheme. A comparison of the experimental and theoretical data was very useful in creating correct assignments and understanding the basic chemical shift. Biological activity of the synthesized compounds were investigated versus some Gram positive, Gram negative bacteria and some fungal strains. Also, the antitumor activity was investigated.

In this work, Co2+, Ni2+, Cu2+, Pd2+, and UO22+ complexes of a carbohydrazone isatin ligand (H3L), are synthesized and structurally elucidated via various physic-chemical approaches (elemental analyses, magnetic, and molar conductance measurements, in addition to IR, NMR, UV–vis, PXRD, GC-MS, and ESR spectral studies). The low value of Ʌm suggested the non-electrolytic nature of the complexes. The proposed geometries were recognized using DFT optimization. Thermal degradation and kinetic parameters of the degradation stages were gauged. Optical bandgaps energies were assessed, and their values hinted at the photovoltaic features of the complexes. ESR spectrum of Cu2+ complex pointed out the existence of the last electron in dz2 ground orbital verifying its distorted (compressed) octahedral structure. A study of electrochemical behavior for Co2+ ions in the presence and absence of the ligand reinforced the successful condensation between Co2+ ions and the ligand. Pd2+ complex was investigated for its action in oxidative degradation of an organic azo-dye and exhibited encouraging activity. A new carbon paste electrode for Ni(II) ions determination based on Nˊ, 2-bis(Z)-2-oxoindolin-3-ylidene)hydrazine-1-carbohydrazide ionophore was investigated. The isolated compounds were assessed for their biological activity (antimicrobial activity, ABTS, and SOD-activity), and molecular docking studies were predestined against E. coli and S. aureus targets.

Two copper (II) complexes of ligands H 2 L 1 and H 2 L 2 have been prepared and investigated. The ligands were prepared by the individually addition of picolinic acid hydrazide and 2-(2-aminothiazol-4-yl) acetohydrazide into benzoyl isothiocyanate. The results of analytical and spectroscopic equipments revealed that H 2 L 1 act as monobasic bidentate with square planner environment. While H 2 L 2 behaves as monobasic tetradentate with Oh geometry. The geometries of ligands and their complexes being carefully studied using Jaguar 9.1 program based on the density functional theory (DFT) to predict properties of materials performed by the hybrid density functional method B3LYP. Additionally, thermal degradation data were evaluated to determine the kinetic and thermodynamic parameters by different methods. Moreover, the anti-oxidant (using DPPH and SOD methods), and anti-bacterial activities of the compounds have been studied. Furthermore, the docking study of ligands and their complexes were applied against gram-positive S. Aureus , negative E. Coli bacterial and C. Albicans fungal strains by Schrodinger suite program using XP glide protocol.

Hg(II), Cd(II) and binuclear Zn(II) complexes derived from the tetradentate N(1)-ethyl-N(2)-(pyridine-2-yl) hydrazine-1, 2-bis (carbothioamide) ligand (H2PET) have been prepared and characterized by conventional techniques. The isolated complexes acquired the formulas, [Hg(HPET)(H2O)2Cl]⋅H2O, [Cd(HPET)Cl] and [Zn2(HPET)(PET)(OAc)]⋅H2O, respectively. IR data revealed that the ligand behaves as monobasic tridentate through (CN)py, (C-S) and new (NC)azomethine(∗) groups in both Hg(II) and Cd(II) complexes. In the binuclear Zn(II) complex, the behavior of ligand contains two types, where H2PET acts as dibasic tetradentate via (CN)py, both deprotonated (C-SH) and the new (NC)azomethine(∗) towards two Zn atoms and also it acts as monobasic tridentate via (CS), deprotonated (C-SH) and (CN)py towards the same Zn atoms. An octahedral geometry for Hg(II) complex and tetrahedral geometry for both Cd(II) and Zn(II) complexes were proposed. The bond lengths, bond angles, HOMO, LUMO and dipole moment have been calculated by DFT using materials studio program to confirm the geometry of ligand and its metal complexes. The association constant of the ligand and the stability constants of its complexes as well as the thermodynamic parameters were calculated by pH metric measurements at 298, 308 and 318K in 50% dioxane-water mixture, respectively. Also, the kinetic and thermodynamic parameters for the different thermal degradation steps of the complexes were determined by Coats-Redfern and Horowitz-Metzger methods. Moreover, the anti-oxidant (using ABTS and DPPH methods), anti-hemolytic, and cytotoxic activities of the compounds have been tested.

Sodium(E)‑4‑hydroxy‑3‑((2‑(pyridin‑2‑ylcarbamothioyl)hydrazineylidene)methyl) benzenesulfonate (NaH3PyTSC) and its cobalt(II), nickel(II) and copper(II) chelates have been isolated. Different spectroscopic techniques have been utilized for elucidation of their structures. The 1HNMR spectrum of NaH3PyTSC illustrated the existence of three different isomers in DMSO solution; syn and anti-conformers of the thione form and the thiol form. The FTIR illustrated that NaH3PyTSC preforms as a bi-negative NOS tridentate in [CoH2PyTSC(H2O)]2.2H2O and [CuH2PyTSC(H2O)]2.H2O through the deprotonated thiol, (C N)azomethine and SO32− groups and also as binegative NNSO tetradentate in [NiH2PyTSC(H2O)]2.4H2O through deprotonated thiol, SO32−, (C N)azomethine and (C N)pyridyl groups. The spectral and magnetic studies proposes a tetrahedrally-coordinated Co(II) and Cu(II) complexes and interior bispin state originating from two distinct Oh and Td geometries for [NiH2PyTSC(H2O)]2.4H2O complex. The ESR data and its discussion coincide with the suggestion of distorted Td geometry for [CuH2PyTSC(H2O)]2.H2O complex. The ligand displayed maximum luminescent intensity at about 19,960 cm−1 whereas all complexes show an emission band at about 28,409 cm−1 and therefore they are photoactive compound. The cyclic voltammogram of copper complex indicates a reversible system including the transfer of one electron on every step in case of Cu(II) while that of Co(II) complex shows the transfer of two electrons in only one step. Kinetic and thermodynamic parameters of the isolated complexes for all decomposition steps are discussed. DFT optimization has been used to estimate different descriptors e.g. HOMO, LUMO, MEP and theoretical IR. DNA bioassay, antibacterial, antifungal, antioxidant and anticancer behaviors of the isolated frameworks have been studied.

Cr(III), Mn(II) and Fe(III) complexes derived from the quadruple potential dithione heterocyclic thiosemicarbazide ligand (H 2 PET) have been prepared and characterized by conventional techniques. The isolated complexes were assigned the formulae, [Cr(HPET)(H 2 O) 2 Cl 2 ]·3H 2 O, [Mn(HPET)(H 2 O)Cl] 2 and [Fe(HPET)(H 2 O) 2 Cl 2 ]·H 2 O, respectively. IR data revealed that the ligand behaves as monobasic bidentate through (C N) py and (C S) groups in both Cr(III) and Fe(III) complexes. In the binuclear Mn(II) complex, H 2 PET acts as NSNS monobasic tetradente via (C N) py , (C S), (C S) and the new azomethine, (N C) * groups. An octahedral geometry for all complexes was proposed. The bond lengths, bond angles, HOMO, LUMO and dipole moment have been calculated by DFT using materials studio program to confirm the geometry of H 2 PET and its metal complexes. The ligand association constant and the stability constants of its complexes in addition to the thermodynamic parameters were calculated from pH metrically at 298, 308 and 318°K in 50% dioxane–water mixture, respectively. Also, the kinetic and thermodynamic parameters for the different thermal degradation steps of the complexes were determined by Coats–Redfern and Horowitz–Metzger methods. Moreover, the anti-oxidant (using ABTS and DPPH methods), anti-hemolytic, and cytotoxic activities of the compounds have been tested.

A new series of metal complexes formed by the reaction of 2-oxo-N′-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohydrazide(H2L) and Cu(II), Co(II), Ni(II), Cd(II), Zn(II), Hg(II) and U(VI) O 2 2 + ions. The isolated complexes have been characterized by elemental analyses, spectral (IR, UV–visible and 1H NMR) as well as magnetic and thermal measurements. The data revealed that the ligand acts as neutral ON or ONO as well as mononegative ONO. On the basis of magnetic and electronic spectral data an octahedral geometry for the Co(II), Cu(II) and U(VI)O2 complexes, a tetrahedral structure for the Ni(II), Cd(II), Zn(II) and Hg(II) complexes have been proposed. The bond length, bond angle, HOMO, LUMO, dipole moment and charges on the atoms have been calculated to confirm the geometry of the ligand and the investigated complexes. Also, kinetic parameters were determined for each thermal degradation stage of some complexes using Coats–Redfern and Horowitz-Metzger methods. Moreover, the ligand and its complexes were screened against Bacillus thuringiensis (Bt) as Gram positive bacteria and Pseudomonas aeuroginosa (Pa) Gram negative bacteria using the inhibitory zone diameter.

The present work carried out a study on the ligational behavior of the new ligand, Vanillin- 4 N-(2-pyridyl) thiosemicarbazone (H 2 VPT) 1 towards some transition metal ions namely, Mn 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ ,Cd 2+ , Hg 2+ and U 6+ . These complexes namely [Mn(HVPT)Cl] 2 , [Co(VPT)(H 2 O)] 2 H 2 O 3 , [Ni(HVPT)Cl(H 2 O)] 4 , [Cu(HVPT)Cl(H 2 O)] 5 , [Zn(VPT)(H 2 O)]H 2 O 6 , [Cd(HVPT)Cl(H 2 O)] 7 , [Hg(VPT)(H 2 O)]H 2 O 8 and [UO 2 (H 2 VPT)(OAc) 2 ]H 2 O 9 , were characterized by elemental analysis, spectral (IR, 1 H NMR and UV–vis) and magnetic moment measurements. The suggested structures were confirmed by applying geometry optimization and conformational analysis. Thermal properties and decomposition kinetics of all compounds are investigated. The interpretation, mathematical analysis and evaluation of kinetic parameters ( E , A , Δ H , Δ S and Δ G ) of all thermal decomposition stages have been evaluated using Coats–Redfern equation. ESR spectra of [Cu(HVPT)Cl]H 2 O at room temperature show broad signal, indicating spin-exchange interactions between copper(II) ions.