FTIR, H-1 NMR, mass spectral, XRD and thermal characterization studies of Nd-III and Sm-III complexes of glipizide : An oral antidiabetic drug

摘要

The present paper deals with the study of sulphonylurea glipizide (GLP) drug in order to give a thought concerning its coordinating potentiality towards some inner transition metals. Metal complexes of glipizide drug is prepared and characterized based on analytical data, molar conductance, IR, H-1 NMR, mass spectrometery, X-ray diffraction and thermogravimetric analysis (TGA) studies. From the analytical data, the complexes are proposed to have general formulae (C21H26N5O4S)(2)Nd(OH2)(4) and (C21H26N5O4S)(2)Sm(OH2)(4). Low values of molar conductance indicate that complexes have non ionic nature. The conductometric titration using monovariation method reveal that complexes are L2M type which is further confirmed by Job's method of continuous variation as modified by Turner and Anderson. Geometery of complexes are assigned to be hexagonal in which ligand molecules lie horizontally joining the central metal atom and four water molecules attached vertically and horizontally with the metal, supported by IR, H-1 NMR and mass studies. Powder X-ray diffraction data hale been used to calculate particle size, porosity, volume of unit cell and density of synthesized complexes. The thermal decomposition of complexes is studied using thermogravimetric (TGA) techniques. The kinetic parameters such as, energy of activation (E-a), enthalpy (Delta H), entropy (Delta S) and free energy change (Delta G) of the complexes is evaluated by employing the Freeman-Carroll and Sharp-Wentworth methods and the relative thermal stability of the complexes are discussed.