Rare earth picrate complexes
with L-leucine (Leu) were synthesized and
characterized. Elemental analysis (CHN), EDTA titrations and thermogravimetric
data suggest a general formula RE(pic)32Leu⋅5H2O
(RE=La–Lu, Y and pic=picrate).
IR spectra indicate the presence of water and suggest that L-leucine is coordinated
to the central ion through the nitrogen of the aminogroup. The absorption
spectrum of the solid Nd compound indicates that the metal-ligand bonds show
a weak covalent character. Emission spectra and biexponential behavior of
the luminescence decay of the Eu compound suggest the existence of polymeric
species. Thermal analysis results indicate that all the compounds present
a similar behavior, with five major thermal decomposition steps. The final
products are rare earth oxides. A slow heating rate is necessary to observe
all decomposition steps.
Captopril (CAP) was the first commercially available angiotensine-converting enzyme (ACE) inhibitor. In the anti-hypertensive
therapy is considered the selected drug has to be therapeutically effective together with reduced toxicity. CAP is an antihypertensive
drug currently being administered in tablet form. In order to investigate the possible interactions between CAP and excipients
in tablets formulations, differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis completed by X-ray powder
diffraction (XRPD) and Fourier transform infrared spectroscopy (FTIR) were used for compatibility studies. A possible drug-excipient
interaction was observed with magnesium stearate by DSC technique.
The aim of this work is to complete our studies on physical properties of binary mixtures of alkane+1-alkanols. This work
reports densities, refractive indices, speeds of sound and isentropic compressibilities of the mixture octane + 1-butanol
at different temperatures, from 288.15 to 308.15 K. From the experimental values, the corresponding excess and deviation values
were computed (excess molar volumes, changes of refractive index on mixing, changes of speed of sound on mixing and changes
of isentropic compressibilities on mixing). The results were fitted to variable-degree polynomials. Excess molar volumes were
compared with the predictions of Nitta-Chao Group Contribution Model.
Rare earth picrate (RE) complexes with L-lysine (Lys) were synthesized and characterized. Elemental analysis (CHN), EDTA titrations and thermogravimetry data suggest
a general formula RE(pic)32Lys2H2O, where RE=La-Lu (without Pm) and Y, pic=picrate). IR spectra suggest that Lys is coordinated to the central ion through the nitrogen of the α-amino group. Parameters
obtained from the absorption spectrum of the Nd compound indicated that the metal-ligand bonds are essentially electrostatic.
Emission spectrum and biexponential behavior of the luminescence decay of the Eu compound suggest the existence of polymeric
species. Thermogravimetric/derivative thermogravimetric (TG/DTG) and differential scanning calorimetry (DSC) curves of all
complexes are very similar, with five events. The final products are the corresponding rare earth oxides and their X-ray diffraction
patterns are identical to the calcinated oxides.</o:p>