Search Results

You are looking at 1 - 10 of 28 items for :

  • "4,4′-Bipyridine" x
  • Refine by Access: All Content x
Clear All

applications [ 1 – 6 ]. Here, we focus on lanthanide complexes with 4,4′-bipyridine (4-bpy) and trichloroacetates. 4,4′-Bpy is used as a potential ligand because of the two nitrogen donor atoms. This isomer creates polymeric species [ 7 – 10 ], and constructs

Restricted access

, heretogeneous catalysis, etc. [ 1 ]. These types of compounds are still actual in researches. 4,4′-Bipyridine is used as a potential ligand since two nitrogen donor atoms. This N-donor may create polymeric species [ 2 – 6 ]. Up to now, there are not many papers

Open access

studies of compounds neodymium and erbium with 2-bpy and dibromoacetates. Owing to two nitrogen donor atoms 4,4′-bipyridine is used as a potential ligand. This isomer creating polymeric species [ 31 – 34 ]. In combination with carboxylate groups 4

Open access

Abstract  

A novel mixed-ligand complexes with empirical formulae: Dy(4-bpy)(CCl2HCOO)3 · H2O and Ln(4-bpy)1.5(CCl3COO)3 · 2H2O (where Ln(III) = Ce, Nd) were prepared and characterized by chemical and elemental analysis and IR spectroscopy, conductivity (in methanol, dimethyloformamide and dimethylsulfoxide). Analysis of the diffractograms showed that the obtained complexes are crystalline. Way of metal-ligand coordination discussed. The thermal properties of complexes in the solid state were studied under non-isothermal conditions in air atmosphere. During heating the complexes decompose via intermediate products to the oxides: Ln2O3 (Nd, Dy) and CeO2. TG-MS system was used to analyse principal volatile thermal decomposition and fragmentation products evolved during pyrolysis of Dy(4-bpy)(CCl2HCOO)3 · H2O in air.

Restricted access

Abstract  

The new mixed ligand complexes with formulae Co(4-bpy)2L2⋅2H2O (I), Cu(4-bpy)2L2⋅H2O (II) and Cd(4-bpy)L2⋅H2O (III) (4-bpy=4,4'-bipyridine, L=CCl3COO) were prepared. Analysis of the IR spectra indicate that 4-bpy is coordinated with metal ions and carboxylates groups bond as bidentate chelating ligands. The electronic spectra are in accordance with pseudo-octahedral environment around the central metal ion in the Co(II) and Cu(II) complexes. The thermal decomposition of the synthesized complexes was studied in air. A coupled TG-MS system was used to analyse the principal volatile thermal decomposition products of Co(II) and Cu(II) complexes. Corresponding metal oxides were identified as a final product of pyrolysis with intermediate formation of metal chlorides.

Restricted access

Abstract  

Two bis(bipyridine) polymeric metal nitrate complexes with 4,4’-bipyridine of simple formula like [M(bipy)2](NO3)2⋅xH2O (where M=Co, Ni and Cu; x=4, 2 and 0, respectively) have been prepared and characterized. Their thermal decomposition has been undertaken using simultaneous TG-DTG-DTA and DSC in nitrogen atmosphere and non-isothermal TG in air atmosphere. Isothermal TG has been performed at decomposition temperature range of the complexes to evaluate the kinetics of decomposition by applying model-fitting as well as isoconversional method. Possible mechanistic pathways have also been proposed for the thermolysis. Ignition delay measurements have been carried out to investigate the response of these complexes under the condition of rapid heating.

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  

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  

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