Search Results

You are looking at 1 - 10 of 23 items for

  • Author or Editor: D. Czakis-Sulikowska x
  • Refine by Access: All Content x
Clear All Modify Search

The synthesis and characterization of CoL2(NCS)2·2H2O, NiL2(NCS)2·2H2O, CuL(NCS)2· 3H2O (L=4,4′-bipyridyl, 4-bipy) CoX3(NCS)2·H2O, NiX3(NCS)2 and CuX2(NCS)2 (X=2,4′- bipyridyl, 2,4′-bipy) are reported. The IR spectra and other physical properties of these compounds are discussed. The thermal properties of the complexes in the solid state were studied under non-isothermal conditions in air atmosphere. The intermediates of dehydration and decomposition at different temperatures were characterized by X-ray diffraction.

Restricted access

Abstract  

2,4'-Bipyridyl (2,4'-bipy or L) complexes of Mn(II) with the formulae MnL2X2·2H2O (X =Cl, Br, NCS, NO3), MnLSO4·5H2O and MnL4(ClO4)2·2H2O were synthesized and characterized via the IR spectra and magnetic, and conductivity measurements. The nature of the Mn(II)-ligand coordination is discussed. The thermal decompositions of these compounds were studied in air atmosphere. The mode of decomposition depends on the anion present, but the final product in all cases is Mn3O4. Some of the intermediates (MnL2Cl2, MnLCl2, MnL2Br2, MnL2(NCS)2 and MnLSO4) formed during the pyrolysis are isomeric with 2,2'-bipy and 4,4'-bipy complexes.

Restricted access

Abstract  

New mixed-ligand complexes with empirical formulae M(4-bpy)L21.5H2O (M(II)=Mn, Co), Ni(4-bpy)2L2 and Cu(4-bpy) L2H2O (where: 4-bpy=4,4'-bipyridine, L=CC L2HCOO-) have been isolated in pure state. The complexes have been characterized by elemental analysis, ir spectroscopy, conductivity (in methanol, dimethylformamide and dimethylsulfoxide solutions) and magnetic and x-ray diffraction measurements. The Mn(II) and Co(II) complexes are isostructural. The way of metal-ligand coordinations discussed. the ir spectra suggest that the carboxylate groups are bonded with metal(II) in the same way (Ni, Cu) or in different way (Mn, Co). The solubility in water is in the order of 19.4010-31.8810-3ł mol dm-3ł. During heating the hydrate complexes lose all water in one step. The anhydrous complexes decompose to oxides via several intermediate compounds. A coupled TG-MS system was used to analyse the principal volatile products of obtained complexes. The principal volatile products of thermal decomposition of complexes in air are: H2O2 +, CO2 +, HCl+, Cl2 +, NO+ and other.

Restricted access

Abstract  

Four new mixed ligand complexes were prepared by the reaction of title metal dichloroacetates and 2,4'-bipyridine. The general formulae of synthesized compounds are M(2,4'-bpy)2(CCl2HCOO)2 nH2O (where M(II)=Mn, Co, Ni, Cu; 2,4'-bpy=2,4'-bipyridine, n=2 or 4). The complexes have been isolated from aqueous media and characterized by chemical analysis, molar conductance (in MeOH, DMSO and DMF), magnetic, IR and VIS spectral studies. The nature of metal(II)-ligand coordination is discussed. The thermal behaviour of obtained complexes was studied by thermal analysis and TG-MS techniques in air. IR, X-ray powder diffraction and thermoanalytical data were used for the determination of solid intermediate products of the thermal decomposition. The principal volatile products of thermal decomposition of complexes were proved by mass spectroscopy: H2O+, CO+ 2, HCl+ 2, Cl+ 2, NO+ and other.

Restricted access

Summary  

The new mixed-ligand complexes of d-electron metals (M(II)=Mn, Ni, Cu) with 2,2'-bipyridine (2-bpy) and mono- or dichloroacetates were prepared as crystalline solids. The general formulae of the synthetized complexes are: Cu(2-bpy)2(CClH2COO)22H2O, Mn(2-bpy)2(CCl2HCOO)2, M(2-bpy)2(CCl2HCOO)22H2O (M(II)=Ni, Cu). The compounds were characterized by chemical analysis, IR and VIS spectroscopy. Their magnetic, molar conductivity and thermal properties also were studied. During heating in air complexes decompose via different intermediate products to metal oxides. A coupled TG-MS system was used to analyse the principal volatile thermal decomposition (or fragmentation) products of 2,2'-bipyridine-chloroacetato complexes.

Restricted access

Abstract  

Complexes of the general formulae Mn(2-bpy)2(CCl3COO)2, Co(2-bpy)2(CCl3COO)2H2O and Ni(2-bpy)2(CCl3COO)22H2O (where: 2-bpy=2,2'-bipyridine) have been prepared and characterized by VIS and IR spectroscopy, conductivity and magnetic measurements. The thermal properties of complexes in the solid state were studied under non-isothermal conditions in air atmosphere. During heating the complexes decompose via different intermediate products to the oxides Mn3O4, CoO and NiO. A coupled TG-MS system was used to detection the principal volatile products of thermal decomposition and fragmentation processes of obtained compounds. The principal volatile products of thermal decomposition of complexes are: H2O+, CO2 +, Cl2 + and other.

Restricted access

Abstract  

Two lactates and four new mixed ligand complexes with formulae Co(lact)22H2O, Ni(lact)23H2O, Co(4-bpy)(lact)2, Co(2,4'-bpy)2(lact)2, Ni(4-bpy)(lact)22H2O and Ni(2,4'-bpy)2(lact)2 (where 4-bpy=4,4'-bipyridine, 2,4'-bpy=2,4'-bipyridine, lact=CH3CH(OH)COO-) were isolated and investigated. The thermal behaviour of compounds was studied by thermal analysis (TG, DTG, DTA). In the case of hydrated complexes thermal decomposition starts with the release of water molecules. The compounds decompose at high temperature to metal(II) oxides in air. A coupled TG-MS system was used to analyse the principal volatile products of thermolysis and fragmentation processes of obtained complexes.

Restricted access

Abstract  

New mixed-ligand complexes of general formulae Mn(4-bpy)(CCl3COO)2⋅H2O, Ni(4-bpy)2(CCl3COO)2⋅2H2O and Zn(4-bpy)2(CCl3COO)2⋅2H2O (where 4-bpy=4,4’-bipyridine) were obtained and characterized. The IR spectra, conductivity measurements and other physical properties of these compounds were discussed. The central atoms M(II) form coordinate bonds with title ligands. The thermal behaviour of the synthesized complexes was studied in air. During heating the complexes decompose via different intermediate products to Mn3O4, NiO and ZnO; partial volatilization of ZnCl2was observed. A coupled TG-MS system was used to the analysis of the principal volatile thermal decomposition products of Mn(II) and Ni(II) complexes. The principal volatile mass fragments correspond to: H2O+, OH+, CO+ 2, HCl+, Cl+ 2, CCl+ and other.

Restricted access

Abstract  

The present work provides data concerning thermal decomposition of 2,2′-dipyridyl(2-dipy) and 4,4′-dipyridyl(4-dipy) with rare-earth elements (Ln) based on literature and our own sustained studies which comprised about 100 complexes.

Restricted access

Abstract  

The compounds ML2(NCS)2, (M(II)=Mn, Co), FeL2(NCS)22H2O, NiL3 NCS)23H2O (L=2,2'-bipyridine, 2-bipy) MX2(NCS)22H2O (M(II)=Mn, Fe; X=4,4'-bipyridine, 4-bipy) have been prepared and their IR spectra and molar conductivity studied. The thermal decomposition of the complexes was studied under non-isothermal conditions in air. During heating the hydrated complexes lose crystallization water molecules in one or two steps and then decompose via different intermediate compounds to the oxides Mn3O4, Fe2O3, CoO, NiO.

Restricted access