Select Page

M Velasco, C Krapacher, R de Rossi, LI Rossi – Dalton Transactions, 2016

The characterization of non-crystalline complexes is particularly difficult when techniques like X-ray diffraction or NMR cannot be used. We propose a simple procedure to characterize the physicochemical properties of amorphous new coordination compounds between cyclodextrins (CD) and Cu2+ salts, by means of the integration of the information provided by several techniques including elemental analysis, flame atomic absorption, TGA, UV-Vis diffuse reflectance, colorimetry, FT-IR and EPR. On the basis of these procedures, we suggest geometrical and structural approximations resulting in an octahedral or distorted octahedral geometry with diverse positions for the metallic centre. According to the EPR spectrum, only one of the complexes may have rhombic symmetry. We also analyzed enthalpy–entropy compensation and the isokinetic effect. In addition, general trends in thermal stability, spectroscopic properties and inclusion in the cavity were analysed. This complete characterization methodology becomes essential for their future application as catalysts.

Structure characterization of the non-crystalline complexes of copper salts with native cyclodextrins

calculated from experimental thermograms. 147 2.6. UV-Vis diffuse reflectance 148 For the analysis of the samples, BLACK-Comet StellarNet Inc spectrometer 149 equipment was used with UV-VIS optical fibers suitable for measuring diffuse reflectance 150 and colorimetry.

Read more …