The infrared spectra of chelate compounds—I A study of some metal chelate compounds of 8-hydroxyquinoline in the region 625 to 5000 cm −1

TG, DTA Pyrolytic Analysis of Cobalt, Nickel, Copper, Zinc, and 5,8-Dihydroxy-1,4-Naphthoquinone Chelate Complexes

The solid state reactions identified on the TG traces with correspondence to DTG peaks consequent to the nonisothermal decomposition of polymetallic chelates of the naphthazarin with Zn (II), Co (II), Ni (II), and Cu (II) over the temperature range ambient at 800°C have been studied kinetically following the Dave and Chopra method as these solid state reactions exhibited their resemblance with the Freeman recommended reaction for kinetic studies. The solid state reactions as described followed first order kinetics. The kinetic data showed the very low value of Z for each of the solid state reaction in reference, concluding on the solid state reactions (the nonisothermal decomposition of polymetallic chelate of Zn (II), Co (II), Ni (II), and Cu (II) as slow reactions).

Intercalation of calcein into layered silicate magadiite and their optical properties

Calcein-Ca (II), Zn (II) and Al (III) complexes were successfully intercalated into interlayer surfaces of layered silicate magadiite and fluorescence properties of organic metal-chelates in the confined spaces were investigated. Structures, compositions and morphologies of the intercalated magadiites were adequately studied by tests, including X-ray diffraction, energy-dispersive X-ray spectrometer, elemental mapping, X-ray photoelectron spectroscopy, inductively coupled plasma atomic emission spectroscopy, Fourier-transform infrared spectra, ultraviolet-visible spectroscopy, thermo-gravimetric analysis, differential thermal analysis and scanning electron microscopy. Results confirmed that metal-organic chelate species were immobilized onto the silicate sheets via solid-state interaction. Basal spacings between silicate layers decreased by exchanged metal ions and increased after intercalation of calcein into the interlayer spaces of cation-exchanged magadiites. The encapsulation was obtained by a flexible solid-solid reaction, and the present reaction and products had a potential of application to industrial uses. A speculative mechanism was proposed for reaction by solid-state intercalation. Furthermore, it was found that the complexes in the interlayer space also exhibited special fluorescence properties. The significance of this current work was that it provided a possible route for synthesizing metal-organic complexes that encapsulated in phyllosilicate.

Titanium complex formation of organic ligands in titania gels

Thin films of organic ligand-dispersing titania gels were prepared from titanium alkoxide sols containing ligand molecules by steam treatment without heating. The formation of the ligand-titanium complex and the photoinduced electron transfer process in the systems were investigated by photoelectrochemical measurements. The complex was formed between the 8-hydroxyquinoline (HQ) and titanium species, such as the titanium ion, on the titania nanoparticle surface through the oxygen and nitrogen atoms of the quinolate. A photocurrent was observed in the electrodes containing the complex due to the electron injection from the LUMO of the complex into the titania conduction band. A bidentate ligand, 2,3-dihydroxynaphthalene (DHN), formed the complex on the titania surface through dehydration between its two hydroxyl groups of DHN and two TiOH groups of the titania. The electron injection from the HOMO of DHN to the titania conduction band was observed during light irradiation. This direct electron injection was more effective than the two-step electron injection.

Synthesis, Spectral, Thermogravimetric, XRD, Molecular Modelling and Potential Antibacterial Studies of Dimeric Complexes with Bis Bidentate ON–NO Donor Azo Dye Ligands

The dimeric complexes of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) with two new symmetrical ON–NO donor bis bidentate (tetradentate) azo dye ligands, LH2= 4,4′-bis(4′-hydroxyquinolinolinylazo)diphenylsulphone, and L′H2= 4,4′-bis(acetoacetanilideazo)diphenylsulphone have been synthesized. The metal complexes have been characterised by elemental analytical, conductance, magnetic susceptibility, IR, electronic spectra, ESR, NMR, thermogravimetry, X-ray diffraction (powder pattern) spectra, and molecular modelling studies. The Co(II) and Ni(II) complexes are found to be octahedral, Cu(II) complexes are distorted octahedral, and a tetrahedral stereochemistry has been assigned to Zn(II), Cd(II), and Hg(II) complexes. The thermogravimetric study indicates that compounds are quite stable. The energy optimized structures are proposed using the semiempirical ZINDO/1 quantum mechanical calculations. The potential antibacterial study of the ligands and some metal complexes has been made with one gram positive bacteriaStaphylococcus aureusand one gram negative bacteriaE. coliwhich gives encouraging results. Both the Co(II) complexes are found to possess monoclinic crystal system.

Synthesis of polyamides by energy-efficient ultrasonic-assisted direct polycondensation

Four polyamides were synthesized by novel ultrasonic irradiation at 50 °C. Direct polymerization of 2-(morpholino)-4,6-bis(phenoxy-3-carboxy)-s-triazine with different diamines was conducted using a condensing agent. Synthesized polyamides were characterized by particle size distribution, solubility, density, viscosity, Fourier transform infrared spectra, 1H-nuclear magnetic resonance, thermogravimetric analysis and accelerated degradation of polyamides. All polyamides were readily soluble in polar organic solvents like N-methylpyrrolidone, N, N-dimethylacetamide and N, N-dimethylformamide at room temperature. The polyamides had inherent viscosities in the range 0.532–0.643 dL g−1 in dimethyl formamide at room temperature (30 °C) and density 1.137–1.198 g cm−3. All the polyamides showed good thermal stability under N2 atmosphere. Under accelerated condition degradation of polyamide was not observed without altering the surface morphology.

HF and DFT studies of the structure and vibrational spectra of 8-hydroxyquinoline and its mercury(II) halide complexes

The geometry, frequency and intensity of the vibrational bands of 8-hydroxyquinoline (8-HOQ) were obtained by HF and density functional theory (DFT) with BLYP and B3LYP functionals and 6-31G(d) as the basis set. The optimized bond lengths and bond angles are in good agreement with the X-ray data. The vibrational spectra of 8-HOQ which is calculated by the HF and DFT methods, reproduces the vibrational wavenumbers and intensities with an accuracy, which allows reliable vibrational assignments. Complexes of the type Hg(8-HOQ)X(2) [where X = Cl , Br] have been studied in the 4000-200 cm(-1) region, and assignment of all the observed bands were made. The analysis of the infrared spectra indicates that there are some structure-spectra correlations.