Supramolecular structure, stereochemistry and substituents effect on the spectral studies of novel ruthenium complexes

Correlation between ionic radii of metal azodye complexes and electrical conductivity

5-(2,3-Dimethyl-1-phenylpyrazol-5-one azo)-2-thioxo-4-thiazolidinone (HL) and its metal complexes with copper(II) (1), cobalt(II) (2) and nickel(II) (3) are synthesized and characterized by physico-chemical techniques. The thermal properties of the ligand (HL) and its metal complexes (1-3) are discussed. The thermal activation energies of decomposition (Ea) of HL and its metal complexes with Cu(II), Co(II) and Ni(II) are found to be 48.76, 36.83, 30.59 and 40.45 kJ/mol, respectively. The frequency and temperature dependence of ac conductivity, dielectric constants for HL and its complexes (1-3) are investigated in the temperature range 300-356 K and frequency range 0.1-100 kHz. Both of the ac conductivity and the values of the thermal activation energy for conduction, as well as the dielectric properties of the complexes of HL are found to depend on the nature of the metallic ions. The values of the thermal activation energies of electrical conductivity decrease with increasing the value of test frequency. The small polarons tunneling (SPT) is the dominant conduction mechanism for the ligand (HL), while for complex (2) the overlapping large tunneling model (OLPT) is the dominant conduction mechanism. The correlated barrier hopping (CBH) is the dominant conduction mechanism for both of the complexes (1) and (3).

Correlation between ionic radii of metals and thermal decomposition of supramolecular structure of azodye complexes

An interesting azodye heterocyclic ligand of copper(II), cobalt(II), nickel(II) and uranyl(II) complexes have been synthesized by the reaction of metal salts with 5-(2,3-dimethyl-1-phenylpyrazol-5-one azo)-2-thioxo-4-thiazolidinone (HL) yields 1:1 and 1:2 (M:L) complexes depending on the reaction conditions. The elemental analysis, magnetic moments, spectral (UV-Vis, IR, (1)H and (13)C NMR and ESR) and thermal studies were used to characterize the isolated complexes. The molecular structures of the ligand tautomers are optimized theoretically and the quantum chemical parameters are calculated. The IR spectra showed that the ligand (HL) act as monobasic tridentate/neutral bidentate through the (-N=N), enolic (C-O)(-) and/or oxygen keto moiety groups forming a five/six-membered structures. According to intramolecular hydrogen bond leads to increasing of the complexes stability. The molar conductivities show that all the complexes are non-electrolytes. The ESR spectra indicate that the free electron is in dxy orbital. The calculated bonding parameter indicates that in-plane σ-bonding is more covalent than in-plane π-bonding. The coordination geometry is five/six-coordinated trigonal bipyramidal for complex (1) and octahedral for complexes (2-6). The value of covalency factor β1(2) and orbital reduction factor K accounts for the covalent nature of the complexes. The activation thermodynamic parameters are calculated using Coats-Redfern and Horowitz-Metzger methods. The synthesized ligand (HL) and its Cu(II) complexes (1, 2 and 4) are screened for their biological activity against bacterial and fungal species. The ligand (HL) showed antimicrobial activities against Escherichia coli. The ligand (HL) and its Cu(II) complexes (2 and 4) have very high antifungal activity against Penicillium italicum. The inhibitive action of ligand (HL), against the corrosion of C-steel in 2M HCl solution has been investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS).

Supramolecular spectroscopic and thermal studies of azodye complexes

A series of heterocyclic ligand of copper(II) complexes have been synthesized by the reaction of copper(II) acetate with 5-(4'-derivatives phenylazo)-2-thioxothiazolidin-4-one (HLn) yields 1:1 and 1:2 (M:L) complexes depending on the reaction conditions. The elemental analysis, spectral (IR and ESR), conductance, magnetic measurements, and thermogravimetric analysis (TGA) are used to characterize the isolated complexes. It is found that the change of substituent affects the thermal properties of azodye rhodanine derivatives and their Cu(II) complexes. The molecular and electronic structures of the investigated compounds (HLn) were also studied using quantum chemical calculations. According to intramolecular hydrogen bond leads to increasing of the complexes stability. The data revealed that the coordination geometry around Cu(II) in all complexes (1-4) exhibit a trans square planar by NO monobasic bidentate and the two monobasic bidentate in octahedral complexes (5-7). Electronic, magnetic data and ESR spectra proposed the square planar structure for all complexes (1-4) under investigation. The value of covalency factor [Formula: see text] and orbital reduction factor K accounts for the covalent nature of the complexes. The activation thermodynamic parameters, such as activation energy (Ea), enthalpy (ΔH(*)), entropy (ΔS(*)), and Gibbs free energy change of the decomposition (ΔG(*)) are calculated using Coats-Redfern and Horowitz-Metzger methods.

Supramolecular coordination and antimicrobial activities of constructed mixed ligand complexes

A novel series of copper(II) and palladium(II) with 4-derivatives benzaldehyde pyrazolone (L(n)) were synthesized. The mixed ligand complexes were prepared by using 1,10-phenanthroline (Phen) as second ligand. The structure of these complexes was identified and confirm by elemental analysis, molar conductivity, UV-Vis, IR and (1)H NMR spectroscopy and magnetic moment measurements as well as thermal analysis. The ligand behaves as a neutral bidentate ligand through ON donor sites. ESR spectra show the simultaneous presence of a planar trans and a nearly planar cis isomers in the 1:2 ratio for all N,O complexes [Cu(L(n))(2)]Cl(2)⋅2H(2)O. Schiff bases (L(n)) were tested against bacterial species; namely two Gram positive bacteria (Staphylococcus aureus and Bacillus cereus) and two Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae) and fungal species (Aspergillus niger, Fusarium oxysporium, Penicillium italicum and Alternaria alternata). The tested compounds have antibacterial activity against S. aureus, B. cereus and K. pneumoniae.