Halina Głuchowska

Physico-chemical properties of 3-methoxy-2-nitrobenzoates of some rare earth elements(III)

The complexes of 3-methoxy-2-nitrobenzoates of Pr(Ⅲ),Nd(Ⅲ),Sm(Ⅲ),Eu(Ⅲ),Gd(Ⅲ),Tb(Ⅲ),Er(Ⅲ) and Tm(Ⅲ) with the formula:Ln(CsH6NO5)3·2H2O,where Ln=lanthanides(Ⅲ),were synthesized and characterized by elemental analysis,Forier transform irtrared (FTIR) spectroscopy,magnetic and thermogravimetric studies and also by X-ray diffraction (XRD) measurements.The complexes had colours typical for Ln(Ⅲ) ions.The carboxylate groups bound as bidentate chelating.On heating to 1173 K in air they decomposed in the same way,at first,dehydrated in one step to anhydrous salts,and then decomposed to the oxides of respective metals with intermediate formation of the oxycarbonates.The enthalpy values of the dehydration process changed from 133.72 to 44.50 kJ/mol.Their solubility in water at 293 K was of the order of 10-4 mol/dm3.The magnetic moments of analysed complexes were determined by Gouys method in the range of 76-303 K.

Influence of temperature on the crystallization of CuII complex with tetradentate Schiff base

Abstract The complex of copper(II) with N2O2 Schiff base, 2,2′-[1,3-propanediyl)bis(nitriloeth-1-yl-1-ylidene)]diphenol (H2L), has been synthesized from methanol. Crystallization of the complex was conducted at room temperature (20 °C) and at 4 °C. Carrying out the crystallization process at various temperatures leads to the formation of two different complexes CuL·MeOH (1) and [{Cu2L2}{CuL}2]·2MeOH (2). The Schiff base and its complexes were characterized by elemental analysis, X-ray crystallographic techniques, spectroscopic (UV–Vis, IR), and thermal (TG\DSC) methods. Complex 1 crystallizes in the monoclinic space group P21/c. The N2O2 core forms a tetrahedrally distorted square-planar geometry around the metal center. Crystallization of 2 took place in the centrosymmetric triclinic space group (P). In the structure of 2 there are two crystallographically different CuII ions, one is four-coordinate in a square planar geometry, whereas the second has a five-coordinate square pyramidal geometry. The complexes are stable at ambient temperature. After heating at first they lose methanol molecules, then the organic part undergoes gradual fragmentation and combustion.

Thermal and spectroscopic studies of 2,3,5-trisubstituted and 1,2,3,5-tetrasubstituted indoles as non-competitive antagonists of GluK1/GluK2 receptors

This paper reports the thermal stability and thermal degradation of six derivatives of indole by means of TG-DSC (in air) and TG-FTIR (in nitrogen) techniques. The compounds were also characterized by infrared spectroscopy. In addition, IR spectra were calculated and compared with the experimental data. In particular, the potential energy distribution analysis was performed to assign IR signals. The studied compounds are characterized by good thermal stability in oxidizing and inert atmospheres which is important for potential medical application. Thermogravimetric measurements in air atmosphere showed that the decomposition of compounds proceeds in two or three main stages. The thermal degradation of compounds is preceded by the melting process. The pyrolysis of samples is a one-step process. Together with the analyses performed in nitrogen, the FTIR spectra of the evolved gas phase products were recorded. On the FTIR spectra of gaseous products, only the bands of water, carbon dioxide and carbon oxide molecules are present. In the case of indole derivatives containing the p-chlorobenzyl substituent in position 1, the bands of anisole, p-chlorotoluene and chlorobenzene also appear.

New complexes of 3,4-dimethoxyphenylacetic acid with selected transition metal ions: Spectral, thermal, and magnetic properties

Abstract3,4-Dimethoxyphenylacetates of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) of general formula M(C10H11O4)2·nH2O, where n = 1, 2 or 4 depending on M(II) ions, are obtained. The complexes crystallize in monoclinic or triclinic systems. The carboxylate groups act as bidentate chelating or bridging ligands. On heating in the air (293–1173 K) they decompose in three steps finally forming oxides of the corresponding metals(II) or their mixtures. Magnetic moments of compounds were determined in the ranges of 76–303 and 4–300 K.

Lanthanide metal–organic frameworks: Structural, thermal and sorption properties:

Two coordination polymers of erbium(III) and neodymium(III) ions with 1,3,5-benzenetricarboxylic acid were synthesized under the solvothermal conditions from the dimethylformamide solution. They were characterized by the attenuated total reflectance Fourier transform spectroscopy (ATR-FTIR), thermogravimetry and differential scanning calorimetry (TG-DSC), thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TG-FTIR) and X-ray diffractions methods. The single-crystal X-ray analysis confirmed formation of three-dimensional framework of Er(III) 1,3,5-benzenetricarboxylate with the channels occupied by dimethylformamide and water molecules. Porosity of crystalline complexes was investigated by the nitrogen sorption experiments. The Nd and Er compounds exhibit real porosity with the BET surface area of 259 and 225 m2/g, respectively. The Horvath–Kawazoe analysis of pore-size distributions for the obtained complexes points out to their microporous character.

Complexes of 4-chlorophenoxyacetates of Nd(III), Gd(III) and Ho(III)

The complexes of 4-chlorophenoxyacetates of Nd(III), Gd(III) and Ho(III) have been synthesized as polycrystalline hydrated solids, and characterized by elemental analysis, spectroscopy, magnetic studies and also by X-ray diffraction and thermogravimetric measurements. The analysed complexes have the following colours: violet for Nd(III), white for Gd(III) and cream for Ho(III) compounds. The carboxylate groups bind as bidentate chelating (Ho) or bridging ligands (Nd, Gd). On heating to 1173K in air the complexes decompose in several steps. At first, they dehydrate in one step to form anhydrous salts, that next decompose to the oxides of respective metals. The gaseous products of their thermal decomposition in nitrogen were also determined and the magnetic susceptibilites were measured over the temperature range of 76-303K and the magnetic moments were calculated. The results show that 4-chlorophenoxyacetates of Nd(III), Gd(III) and Ho(III) are high-spin complexes with weak ligand fields. The solubility value in water at 293K for analysed 4-chlorophenoxyacetates is in the order of 10-4mol/dm3.