A.Z. El-Sonbati

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).

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).

Supramolecular spectral studies on metal-ligand bonding of novel quinoline azodyes.

A series of novel bidentate azodye quinoline ligands were synthesized with various p-aromatic amines like p-(OCH3, CH3, H, Cl and NO2). All ligands and their complexes have been characterized on the basis of elemental analysis, IR, (1)H and (13)C NMR data and spectroscopic studies. IR and (1)H NMR studies reveal that the ligands (HLn) exists in the tautomeric azo/hydrazo form in both states with intramolecular hydrogen bonding. The ligands obtained contain NN and phenolic functional groups in different positions with respect to the quinoline group. IR spectra show that the azo compounds (HLn) act as monobasic bidentate ligand by coordinating via the azodye (NN) and oxygen atom of the phenolic group. The ESR (g|| and g ) and bonding α(2) parameters of the copper ion were greatly affected by substituting several groups position of ring of quinoline and p-aromatic ring. The ESR spectra of copper complexes in powder form show a broad signal with values in order g|| >g > ge > 2.0023. The value of covalency factor β and orbital reduction factor K accounts for the covalent nature of the complexes. All complexes possessed an octahedral and square planar geometry. The thermal properties of the complexes were investigated using TGA and DSC. It is found that the change of substituent affects the thermal properties of complexes.

Polymer complexes. LX. Supramolecular coordination and structures of N(4-(acrylamido)-2-hydroxybenzoic acid) polymer complexes

A number of novel polymer complexes of various anions of copper(II), cobalt(II), nickel(II) and uranyl(II) with N(4-(acrylamido)-2-hydroxy benzoic acid) (ABH) have been synthesized and characterized by elemental analysis, IR, 1H NMR, magnetic susceptibility measurements, electronic spin resonance, vibrational spectra and thermal analysis. The molecular structures of the ligand are optimized theoretically and the quantum chemical parameters are calculated. Tentative structures for the polymeric metal complexes due to their potential application are also suggested. The IR data exhibit the coordination of ONO2/OAc/SO4 with the metal ions in the polymeric metal complex. Vibrational spectra indicate coordination of carboxylate oxygen and phenolic OH of the ligand giving a MO4 square planar chromophore. Ligand field ESR spectra support square planar geometry around Cu(II). The thermal decomposition of the polymer complexes were discussed in relation to structure, and the thermodynamic parameters of the decomposition stages were evaluated applying Coast-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.

Ternary metal complexes of guaifenesin drug: Synthesis, spectroscopic characterization and in vitro anticancer activity of the metal complexes.

The coordination behavior of a series of transition metal ions named Cr(III), Fe(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with a mono negative tridentate guaifenesin ligand (GFS) (OOO donation sites) and 1,10-phenanthroline (Phen) is reported. The metal complexes are characterized based on elemental analyses, IR, (1)H NMR, solid reflectance, magnetic moment, molar conductance, UV-vis spectral studies, mass spectroscopy, ESR, XRD and thermal analysis (TG and DTG). The ternary metal complexes were found to have the formulae of [M(GFS)(Phen)Cl]Cl·nH2O (M=Cr(III) (n=1) and Fe(III) (n=0)), [M(GFS)(Phen)Cl]·nH2O (M=Mn(II) (n=0), Zn(II) (n=0) and Cu(II) (n=3)) and [M(GFS)(Phen)(H2O)]Cl·nH2O (M=Co(II) (n=0), Ni(II) (n=0) and Cd(II) (n=4)). All the chelates are found to have octahedral geometrical structures. The ligand and its ternary chelates are subjected to thermal analyses (TG and DTG). The GFS ligand, in comparison to its ternary metal complexes also was screened for their antibacterial activity on gram positive bacteria (Bacillus subtilis and Staphylococcus aureus), gram negative bacteria (Escherichia coli and Neisseria gonorrhoeae) and for in vitro antifungal activity against (Candida albicans). The activity data show that the metal complexes have antibacterial and antifungal activity more than the parent GFS ligand. The complexes were also screened for its in vitro anticancer activity against the Breast cell line (MFC7) and the results obtained show that they exhibit a considerable anticancer activity.

Potentiometric and Thermodynamic Studies of Some Schiff-Base Derivatives of 4-Aminoantipyrine and Their Metal Complexes

The proton-ligand dissociation constant of 4-(4-amino-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-ylideneamino)-phenol () and 4-(4-amino-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-ylideneamino)-benzoic acid () and metal-ligand stability constants of their complexes with metal ions (Mn2

Conducting Polymers. VII. Effect of Doping with Iodine on the Dielectrical and Electrical Conduction Properties of Polyaniline

The oxidative chemical polymerization of aniline monomer in acidic aqueous media by using potassium dichromate as unconventional initiator was carried out at room temperature based on two different comparative methods. In the first method, in situ polymerization of polyaniline, polymerization was carried out in the presence of iodine solution (PANI/I2-In). In the second method, ex situ polymerization, after complete polymerization polyaniline was doped with iodine (PANI/I2-Ex). FTIR, UV measurements, and TGA analysis for undoped polyaniline (PANI), iodine doped polyaniline (PANI/I2-Ex), and iodine doped polyaniline (PANI/I2-In) show that iodine doping process occurred at the quinoid units in the polyaniline backbone of (PANI/I2-Ex) while iodine doping occurred at benzenoid units in polyaniline, in addition the iodination occurred at the rings of polyaniline backbone of (PANI/I2-In.). The data extracted from the XRD patterns shows the crystalline nature of synthesized samples and particles sizes are in the range 37–42 nm. The activation energies of thermal degradation of polyaniline or iodine doped polyaniline were determined from the TGA thermogram for PANI, (PANI/I2-In), and (PANI/I2-Ex) are 24.1, 43.4, and 44.19 KJ/mol, respectively. Doping of PANI with iodine enhances the ac conductivity of PANI whatever the method of doping, The room temperature values of σac measured under test frequency 100 kHz are found to be 6×10−5, 2.5×10−4, and 1×10−3 Ω−1.m−1 for PANI, (PANI/I2-In), and (PANI/I2-Ex), respectively.

Thermal Properties, Antimicrobial Activity of Azo Complexes and Ultrastructure Study of Some Affected Bacteria

A series of copper (II) complexes of bidentate azo rhodanine ligands (HLn) have been synthesized and characterized. The IR spectral and thermogravimetric analysis are used to characterize the isolated complexes. X-ray diffraction patterns show polycrystalline nature for as-synthesized ligand HL2 and its complex. Quantum chemical parameters, absolute hardness, global electrophilicity and additional electronic charge were calculated for HLn. Copper(II) complexes (1-4) are tested against four local bacterial species; namely two Gram positive bacteria (Staphylococcus aureus and Bacillus cereus) and two Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae) and against four local fungal species (Aspergillus niger, Fusarium oxysporium, Penicillium italicum and Alternaria alternata). The tested complexes have good antibacterial activity against Staphylococcus aureus and Escherichia coli and have low antifungal activity against Aspergillus niger, Fusarium oxysporium and Alternaria alternata. We found that the complex (3) is more active than other complexes against Staphylococcus aureus and Escherichia coli as expected from Hammett’s substituent coefficients (σR). Ultrastructure studies of the affected Staphylococcus aureus and Escherichia coli confirmed that complex (3) has bactericidal effect.

Fluorescence enhancement of rhodamine B as a tool for the determination of trace and ultra-trace concentrations of bismuth using dispersive liquid–liquid microextraction

The present work describes a simple, sensitive, selective, and eco-friendly spectrofluorimetric method for bismuth determination in wastewaters and dyed scalp hair. The method is based upon fluorescence enhancement accompanying a direct reaction between rhodamine B (RB) and bismuth(III) ions, and the formed complex was then extracted from aqueous medium into a chloroform phase using dispersive liquid–liquid microextraction (DLLME). The proposed method was capable of bismuth determination even in the presence of 20 common ions in 100-fold excess over the bismuth. The plot of fluorescence enhancement measured at λex/em = 552/572 nm in the organic phase versus bismuth concentration in an aqueous solution was linear over the range of 0.5–100 μg L−1. The LOD and LOQ were found to be 0.16 and 0.532 μg L−1, respectively. The accuracy of the method was verified by analyzing bismuth in a certified standard reference material (SRM-3106). The method was also successfully applied for the analysis of bismuth in wastewaters, and dyed scalp hair samples, and the results were successfully compared with the inductively coupled plasma-mass spectrometry (ICP-MS) results. Furthermore, the structure of the newly synthesized complex was confirmed with the aid of spectroscopic measurements (UV-Vis, IR, fluorescence), and elemental and thermal analyses. These measurements indicated that the enhanced fluorescence response was attributable to coordination of Bi3+ ions with the RB reagent.