A B S T R A C TCyclic Voltammetric studies of calcium acetate salt [Ca(CH3COO)2] in absence or presence of Methylene blue (MB) were performed to predict and analyze the behavior of complexation between the ligand and metal ion in aqueous solution. From these studies, the values of solvation and kinetic parameters [Ep (peak potential), Ip (peak current), ΔEP (peak potential difference), E½ (half wave potential), D (Diffusion coefficient), Ks (electron transfer rate constant), Г (surface coverage) and Qa (quantity of electricity)] were evaluated. In addition, the effect of different concentration and a scan rate of above the calculated quantities were studied. In case of presence MB, the stability constants and Gibbs free energies were performed.

The electronic structure and spectra of the schiff base derivatives compounds were investigated using TD-DFT/B3LYB/6-311G (d, p) level of theory. The results showed that all the studied compounds 1-4 were non-planar, as indicated from the dihedral angles. The electronic absorption spectra of the studied compounds were recorded in the UV-VIS region, in both ethanol (as polar solvent) and dioxane (as non-polar solvent). Solvent dependence of the band maxima (λmax) and intensities of the observed spectra are explained in terms of blue and red shifts. Electronic configurations contributing to each excited state are identified and the relevant MOs are characterized. The theoretical spectra computed at CAM-B3LYP/6-311G (d, p) in gas phase, ethanol and dioxane nicely reproduce the observed spectra. The natural bond orbital (NBO) analysis were discussed in terms of the extent of delocalization, intermolecular charge transfer, and second order perturbation interactions between the donor and acceptor MOs. The calculated EHOMO and ELUMO energies of the studied compounds can be used to explain the extent of charge transfer in the molecule and to calculate the global properties; the chemical hardness (η), global softness (S), electrophilicity (ω), and electronegativity (χ). The calculated nonlinear optical parameters (NLO); polarizibilty (α), anisotropy of the polarizibility (Δα) and first order hyperpolarizibility (β) of the studied compounds have been calculated at the same level of theory and compared with the proto type Para-Nitro-Aniline (PNA), show promising optical properties. 3D-plots of the molecular electrostatic potential (MEP) for some of the studied compounds are investigated and analyzed showing the distribution of electronic density of orbital's describing the electrophilic and nucleophilic sites of the selected molecules. The biological activity of the studied compounds was tested against gram positive, gram negative and Fungi. A correlation between energetic, global properties and biological activity were investigated and discussed..

The redox mechanisms were examined for copper chloride in the absence and presence of Orange G (OG) as organic ligand at 19.1°C using carbon glassy electrode (CGE). The supporting electrolyte was 0.1 M KCl whose effect of scan rate was also studied for the redox reactions for CuCl2 alone and in the presence of the ligand, orange G (OG). Stability constants for the complex formed from the interaction of CuCl2+ Orange G (OG) were evaluated with the different thermochemical data. Effect of different scan rates was done for cupric chloride in the absence and presence of the ligand Orange G (OG).The different scans are 0.1, 0.05, 0.02 and 0.01 V/Sec. The stability constants and Gibbs free energies of complexation were also estimated for the interaction of CuCl2 with Orange G (OG) in 0.1M KCl supporting electrolyte.

The redox mechanisms were examined for Copper bromide in the absence and presence of (LC) using cyclic voltammetry. The mechanisms of reduction and oxidation were examined while using new glassy carbon electrode prepared in laboratory from pure carbon piece jointed with copper wire and isolated by heat shrink polymer to avoid contact with solutions. In order to explain the type of the used reaction in electrochemical study, the complexation stability constants and Gibbs free energies of complex formation obtained from the interaction of CuBr 2 with (LC) were obtained from the experimental part and their values were discussed. The prepared galssy carbon electrode was polished with Al 2 O 3 and put in a woolen clear piece, washed and used for cyclic voltammetry measurements.

The molar solubility for 2-amino-4,5-dimethylthiophene-3-carboxamide (ADTC) in pure ethanol and mixed ethanol (EtOH)-water solvents were measured at five different temperatures, 293.15, 298.15, 303.15, 308.15, and 313.15 K in the used mixed solvents, the solubility were increase by increase in the mole fraction of ethanol in the mixtures and increase of temperature due to more salvation parameters. All the solvation and thermodynamic parameters for ADTC in mixed EtOH+ H2O solvents were evaluated like solubility products, Gibbs free energies, enthalpies and entropies of solvation and discussed. Theoretical calculations for (ADTC) were done quantum mechanically by using Gaussian on set of calculations in ethanol for evaluating the different thermodynamic parameters.