Search Results

You are looking at 1 - 9 of 9 items for

  • Author or Editor: Ž. Jaćimović x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

Molecular and crystal structure of diaqua-sulphato(pyridoxal semicarbazone-ONO)iron(II) and dichloroaqua(pyridoxal semicarbazone-ONO)iron(III) complexes with tridentate ONO pyridoxal semicarbazone ligand, PLSC, of formula [FeII(PLSC)(H2O)2SO4] and [FeIII(PLSC)(H2O)Cl2]Cl is reported. Thermal decomposition of the compounds was followed in argon and air gas carriers. The dequation mechanism is discussed in the view of the crystal structure, emphasizing the complexity of the related parameters and processes.

Restricted access

Abstract  

Three watersheds were studied by sampling bulk precipitation deposition, seepage water at 50 cm soil depth and spring water. As the main analytical method for determination of trace elements and heavy metals in water samples, thek 0-based method of INAA was used. The results showed an increased content and concentration range of trace elements in precipitation, soil water and spring water in the vicinity of the otanj Thermal Power Plant. We demonstrated that thek 0-based method of INAA as a multielement nondestructive technique is a highly suitable approach to determining some toxic trace elements in environmental studies of the water cycle.

Restricted access
Restricted access

Abstract  

Adsorption of fine suspended material on the surface of aquatic plants may lead to great problems in the interpretation of results for their trace element composition, since it is quite impossible to clean the inorganic material from the biota completely. A carefully designed field experiment was performed in the River Stella in North-Eastern Italy aimed at studying the adsorption of fine suspended material on benthic algae-periphyton. More than 20 elements, were determined in water, suspended material and biota using k 0-INAA, and enrichment factors were calculated for selected elements using Sc as a normalizing element.

Restricted access

Transition metal complexes with pyrazole based ligands

Part XXV. Deaquation of isostructural cobalt(II) and nickel(II) complexes with 3,5-dimethylpyrazole-1-carboxamidine

Journal of Thermal Analysis and Calorimetry
Authors: Katalin Mészáros Szécsényi, V. Leovac, R. Petković, Ž. Jaćimović, and G. Pokol

Abstract  

The deaquation of two isostructural compounds of general formula [M(HL)2(H2O)2](NO3)2 (M=Co, Ni, HL=3,5-dimethyl-1H-pyrazole-1-carboxamidine) is discussed in the view of their crystal and molecular structure. The compounds contain the same number and type of hydrogen bonds of the adjacent nitrate ions, only in the opposite orientation. On the basis of their deaquation pattern such a small difference may be detected, i.e., methods of thermal analysis are sensitive enough to show very small structural differences.

Restricted access

Abstract  

We report the synthesis and the characterization (elemental analysis, FT-IR spectroscopy, thermal methods and molar conductivity measurements) of the mixed complexes of zinc with acetate and 3-amino-5-methylpyrazole, HL 1, [Zn(OAc)2(HL1)2], or 3-amino-5-phenylpyrazole, HL 2 [Zn(OAc)2(HL2)2], or 4-acetyl-3-amino-5-methylpyrazole, HL 3, [Zn(OAc)(L3)(HL3)]2, with isothiocyanate and HL 2 [Zn(SCN)2(HL2)2], or HL 3 [Zn(SCN)2(HL3)2], and with nitrate, isothiocyanate and 3,5-dimethyl-1-carboxamidinepyrazole, HL 4 [Zn(NO3)(NCS)(HL4)2]. The thermal decomposition of the complexes is generally continuous resulting zinc oxide as end product,except [Zn(OAc)(L3)(HL3)]2 in which case a well-defined intermediate was observed between 570–620 K. On the basis of the IR spectra and elemental analysis data of the intermediate a decomposition scheme is proposed.

Restricted access

Transitionmetal complexes with pyrazole-based ligands

Part 21. Thermal decomposition of copper and cobalt halide complexes with 3,5-dimethyl-1-thiocarboxamidepyrazole

Journal of Thermal Analysis and Calorimetry
Authors: K. Mészáros Szécsényi, V. Leovac, A. Kovács, G. Pokol, and Ž. Jaćimović

Abstract  

The thermal decomposition of Cu2L2Cl4, Cu2L2Cl2, Cu2L2Br2 and Co2L2Cl4 complexes (L=3,5-dimethyl-1-thiocarboxamidepyrazole) is described. The influence of the central ion to ligand mole ratio on the course of complex formation is examined in reaction of L with copper(II) chloride. In Cu(II):L mole ratio of 1:1, in methanolic solution the reaction yields to yellow-green Cu2L2Cl4 crystals. In the filtrate a thermodynamically more stable orange Cu2L2Cl2 copper(I) complex is forming. With a Cu(II):L mole ratio of 1:2 only the latter compound is obtained. The composition and the structure of the compounds have been determined on the basis of customary methods. On the basis of FTIR spectrum of the intermediate which is forming during the thermal decomposition of Cu2L2Cl2 a decomposition mechanism is proposed.

Restricted access

Abstract  

Complexes represented by the general formula [MCl2L2] (M(II)=Zn, Mn, Co) and complexes of [Cu3Cl6L4] and CuSO4L24H2O, CoSO4L23H2O, [ZnSO4L3] where L stands for 3-amino-5-methylpyrazole were prepared. The complexes were characterized by elemental analysis, FT-IR spectroscopy, thermal (TG, DTG, DSC and EGA) methods and molar conductivity measurements. Except for the Zn-complexes, the magnetic susceptibilities were also determined. Thermal decomposition of the sulphato complexes of copper(II) and cobalt(II) and the chloro complexes of cobalt(II) and manganese(II) resulted in well-defined intermediates. On the basis of the IR spectra and elemental analysis data of the intermediates a decomposition scheme is proposed.

Restricted access

Abstract  

The synthesis of copper(II) chloride complexes with 3,5-dimethylpyrazole, 1-carboxamidine-3,5-dimethylpyrazole, 5-amino-4-carboxamide-1-phenylpyrazole and 4-acetyl-3-amino-5-methylpyrazole is described. The compounds are characterized by elemental analysis, FT-IR spectroscopy, thermal methods, magnetic moment and molar conductivity measurements. Thermal decomposition of the dichloro-(3,5-dimethylpyrazole)-copper(II) complex results in an unstable intermediate with a stochiometric composition. The decomposition of the other compounds is continuous.

Restricted access