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Abstract  

Conditions for the preparation of light lanthanide 4-chlorophthalates were investigated and their composition, solubility in water at 295 K, IR spectra and thermal decomposition were determined. 4-Chlorophthalates of La–Nd(III) were prepared as complexes with general formula NaLn[ClC6H3(CO2)2]2, whereas compounds of Sm and Eu have general formula Ln2[ClC6H3(CO2)2]36H2O. During heating all complexes decompose to oxides with intermediate formation of oxochlorides. The carboxylate groups in the complexes studied are bidentate bridging (Sm, Eu) or bidentate chelating and bridging (La–Nd).

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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.

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Abstract  

Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) 2,5-dichlorobenzoates were prepared and their compositions and solubilities in water at 295 K were determined. The IR spectra and X-ray diffractograms of the obtained complexes were recorded. The complexes of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) were obtained as solids with a 1:2 molar ratio of metal to organic ligand and different degrees of hydration. When heated at a heating rate of 10 K min-1, the hydrated complexes lose some (Co, Zn) or all (Ni, Cu, Cd) of the crystallization water molecules and then decompose to oxide MO (Co, Ni) or gaseous products (Cu, Zn, Cd). When heated at a heating rate of 5 K min-1, the complexes of Ni(II) and Cu(II) lose some (Ni) or all (Cu) of the crystallization water molecules and then decompose directly to MO.

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Abstract  

The complexes of yttrium and lanthanide with 1,1-cyclobutanedicarboxylic acid of the formula: Ln2(C6H6O4)3nH2O, where n=4 for Y, Pr–Tm, n=5 for Yb,Lu, n=7 for La, Ce have been studied. The solid complexes have colours typical of Ln3+ ions. During heating in air they lose water molecules and then decompose to the oxides, directly (Y, Ce, Tm, Yb) or with intermediate formation. The thermal decomposition is connected with released water (313–353 K), carbon dioxide, hydrocarbons(538–598 K) and carbon oxide for Ho and Lu. When heated in nitrogen they dehydrate to form anhydrous salt and next decompose to the mixture of carbon and oxides of respective metals. IR spectra of the prepared complexes suggest that the carboxylate groups are bidentate chelating.

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Abstract  

Rare earth element 3-methyladipates were prepared as crystalline solids with general formula Ln2(C7H10O4)3nH2O, where n=6 for La, n=4 for Ce,Sm–Lu, n=5 for Pr, Nd and n=5.5 for Y. Their solubilities in water at 293 K were determined (2⋅10–3–1.5⋅10–4 mol dm–3). The IR spectra of the prepared complexes suggest that the carboxylate groups are bidentate chelating. During heating the hydrated 3-methyladipates lose all crystallization water molecules in one (Ce–Lu) or two steps (Y) (except of La(III) complex which undergoes tomonohydrate) and then decompose directly to oxides (Y, Ce) or with intermediate formation of oxocarbonates Ln2O2CO3 (Pr–Tb) or Ln2O(CO3)2 (Gd–Lu). Only La(III) complex decomposes in four steps forming additionally unstable La2(C7H10O4)(CO3)2.

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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.

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Abstract  

Ethylenediaminotetramethylenephosphonic acid (EDTMP, H8L) was prepared and its complexes with some lanthanide ions (La, Eu, Gd and Sm) were isolated under various conditions. IR spectra and thermal stabilities of EDTMP and its complexes were studied. The experimental conditions of the preparation influence to the composition of the complexes were shown. In alkaline solution (pH=8) deprotonated (P(O)(O)2), and in acidic solution (pH=3–4) deprotonated and partly protonated (P(O)(O)(OH)) and non-protonated (P(O)(OH)2) phosphonic groups are present in the complexes. All the complexes contain coordinated water molecules. The complexes containing a protonated phosphonic group contain coordinated and hydrogen-bonded water molecules.

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Abstract  

Conditions for the preparation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) 4-methylphthalates were investigated and their composition, solubility in water at 295 K and magnetic moments were determined. IR spectra and powder diffraction patterns of the complexes prepared with molar ratio of metal to organic ligand of 1.0:1.0 and general formula: M [ CH3C6H3(CO2)2]nH2o (n=1-3) were recorded and their decomposition in air were studied. During heating the hydrated complexes are dehydrated in one (Mn, Co, Ni, Zn, Cd) or two steps (Cu) and next the anhydrous complexes decompose to oxides directly (Cu, Zn), with intermediate formation of carbonates (Mn, Cd), oxocarbonates (Ni) or carbonate and free metal (Co). The carboxylate groups in the complexes studied are mono- and bidentate (Co, Ni), bidentate chelating and bridging (Zn) or bidentate chelating (Mn, Cu, Cd). The magnetic moments for paramagnetic complexes of Mn(II), Co(II), Ni(II) and Cu(II) attain values 5.92, 5.05, 3.36 and 1.96 M.B., respectively.

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Summary  

Mixed ligand nickel(II) complexes of different compositions were prepared with water, sulfate ion and 1,2-ethanediol as ligands. The magnetic susceptibility data, the IR spectra and the thermoanalytical curves of the complexes were recorded. Oxygen atoms bound by one or two coordinate bonds to the metal ion, or by hydrogen-bonds in the crystal state were observed. All complexes are sensitive for moisture. The bis complex proved to be the more stable complex.

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Abstract  

The complexes of the general formula MLSCN (M=Cu(I), Ag(I), L=2,2′-bipyridine=2-bipy, 4,4′-bipyridine=4-bipy or 2,4′-bipyridine=2,4′bipy) have been prepared and their IR spectra examined. The nature of metal-ligand coordination is discussed. Thermal decomposition in air of these complexes occurred in several successive endothermic and exothermic processes and the residue was Cu2O and Ag, respectively.

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