IJSR - International Journal of Scientific Research

Ana Lucia Ramalho Merce; Jamal Rafique; Bruno Szpoganicz

Volume : VII, Issue : II, February - 2018

Synthesis and structural characterization of Gallium (III) and Palladium (II) on the formation of ternary supramolecular assemblies. Part 1: ?–cyclodextrin – cholecalciferol

Ana Lucia Ramalho Merce, Jamal Rafique, Bruno Szpoganicz

Abstract :

β–cyclodextrin (βCD) has been previously shown to encapsulate cholecalciferol (VitD) and the supramolecular structure, to present chelating abilities. In this work, spectroscopic parameters for the chelating power of supramolecular structures were investigated in the presence of Ga³⁺ and Pd²⁺, two important metal ions especially in the medical science. The ternary obtained complexes, although presenting some degree of insolubility in many organic solvents and in different mixed proportions among them, could be studied by a number of analytical techniques. The binding constants for the complexes in a major aqueous solution were not possible to be determined by Potentiometric Titrations and the possible reasons are addressed. In the complexation, it was inferred that according to the host in the βCD structure and to the binded metal ion, the participating basic sites are different, consequently leading to a different spatial conformation and, in some cases, to a distortion in the 3D structure. Bragg‘s peak values, 2q, for all binary and ternary assemblies are given. Near infrared spectroscopy provided some important wavelengths for the differentiation of the metal complexes. The most probable deprotonated –OH groups mainly involved in the complexation in the ternary complexes were of C–3 from VitD and of C–6, C–3 and C–2 from βCD. The analytical techniques of ¹³C NMR, powder XRD and UV–NIR spectroscopies, characterized the binary and the ternary supramolecular structures.