PHYSICAL AND CHEMICAL CHARACTERISTICS OF SUPRAMOLECULAR COMPLEXES OF GLYCIRRIZINIC ACID WITH PHYTOHORMONES

The process of formation of supramolecular complexes of glycyrrhizinic acid with some phytohormones (indolylacetic acid, indolylbutyric acid, α-naphthyl acetic acid and kinetin) were studied with the aim of creation the plant growth stimulator. The complexes structure was studied using IR and UV spectroscopy methods. The prepared compounds described by some physicochemical parameters. The stability constants and stoichiometric composition of complexes were determined in an aqueous solution at pH of 7,2 using UV spectrometry method. In result, all complexes have composition as 1:1 ratio, except the kinetin complex which has 2:1 ratio. The stability constants were equal: KGA:IAA=1,86±1×104; KGA:IBA=2,51±1×103; KGA:NAA =2,70±1×103 и KGA:К=5,07±1×105. The Gibbs free energies of complex formation were calculated.

Syntheses, crystal structures and phosphorescence properties of cyclometalated iridium(III) bis(pyridylbenzaldehyde) complexes with dithiolate ligands

The synthesis of three neutral bis-cyclometalated iridium(III) complexes [Ir(pba)2(S^S)] (pbaH=4-(2-pyridyl)benzaldehyde; S^S=Et2NCS2− (1), iPrOCS2− (2), (nPrO)2PS2− (3)) from [{Ir(μ-Cl)(pba)2}2] and the corresponding sodium or potassium dithiolates in methanol-dichloromethane is described. The composition of complexes 1–3 is discussed on the basis of 1H NMR, 13C NMR, IR, and mass spectroscopy, and the crystal structures of 1 and 3 were determined by X-ray crystallography. The absorption and emission spectra show that the [Ir(pba)2(S^S)] complexes may be effective candidates as green-emitting phosphorescent materials. The stability of the three cyclometalated iridium(III) complexes towards different transition metal ions was also investigated in acetonitrile-water solvent.

SYNTHESIS, CHARACTERIZATION AND ANTIBACTERIAL STUDIES ON DIVALENT TRANSITION METAL COMPLEXES OF HYDRAZINE WITH ARYL SUBSTITUTED ACETIC ACIDS

Metal phenylacetate Sesquihydrazinate hydrates of the formula M(PhAc)2.1.5N2H4.H2O where M=Co,Ni or Cd and Metal phenoxyacetate Sesquihydrazinate hydrates M(PhOAc)2.1.5N2H4.H2O Where M=Co, Ni , Cd or Mn have been prepared and characterized by analytical, IR spectral and thermal studies. The composition of complexes have been determined by analytical studies. Infrared spectral data indicate that the bidentate bridging by hydrazine molecules and monodentate coordination by carboxylate ions to the cental metal ion. Thermogravimetry (TG) and differential thermal analyses (DTA) in air have been used to study the thermal behaviour of the complexes. The simultaneous TG-DTA curves of all the complexes in air resultedin the formation of respective metal or metal oxide as final residue. These complexes decompose exothermically either in single step or decompose through respective metal carboxylate intermediates. The antibacterial activity of the prepared complexes screened against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Proteus mirabilis

Passivation and red-ox processes of refractory metals in carbamide-chloride melt

The electrochemical behavior of refractory metals (Pt, Pd, W, Ti, Nb, Ta) in the low temperature carbamide-NH4Cl melt (texp=120 oC) and the structure of complex ions formed after anodic dissolution have been studied by cyclic voltammetry and spectroscopic methods. The features of the mechanism of metal electrodissolution and possibilities of the cathodic reduction of complexes formed in the melt are presented. A possible correlation between passivation processes on the metal surface, the mechanism of electrodissolution, composition of complexes and the electrochemical activity of metals and their ions are discussed. The data obtained reflect the possibilities to use the carbamide-NH4Cl melt for practical purposes in electroplating and electropolishing.