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).
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.
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.
The complexes of yttrium and lanthanide with 1,1-cyclobutanedicarboxylic acid of the formula: Ln2(C6H6O4)3⋅nH2O, 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.
Authors:W. Brzyska, A. Bartyzel, K. Zieniewicz, and A. Zwolińska
Rare earth element 3-methyladipates were prepared as crystalline solids with general formula Ln2(C7H10O4)3⋅nH2O, 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.
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.
Authors:E. Princz, I. Szilágyi, K. Mogyorósi, and I. Labádi
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.
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.
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.
Authors:D. Czakis-Sulikowska, J. Kałużna, and J. Radwańska-Doczekalska
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.