Preparation, Characterization and Thermodynamical Parameters of Some Picolinate Complexes

A. A. Ben–Aweisha; F. M. Elmagbari; S. E. Mansour; M. A. Abu–Youssef

Volume : IV, Issue : X, October - 2015

Preparation, Characterization and Thermodynamical Parameters of Some Picolinate Complexes

A. A. Ben Aweisha, F. M. Elmagbari, S. E. Mansour, M. A. Abu Youssef

Abstract :

In this work, the complexes were synthesized by the interaction between the picolinic acid with some metal ions [Cr(III), Mn(II) and Ni(II)], then salted–in. The geometrical structures and the chemical formula of the complexes were characterized by several techniques; such as, elemental analysis, molar conductivity, thermal analysis, and thermodynamical parameters. The complexes after salting–in were fairly stable under normal atmospheric condition. Salting–in of chromium picolinate complex shows no change in the coordination sphere. The salting–in of bis–picolinato manganese (II) complex in different simple salts, KI, CaCl2 and Guanidinium hydrochloride, gives change in water of crystallization after several days; in all cases the complexes contains one extra water molecule. While in the case of Nickel picolinate it gives the same structure with Guanidinium hydrochloride and KI. For the two nickel complexes TGA were thermally decomposed in four successive steps, leaving NiO residue at >550C�, Thermodynamic parameters for the decomposition steps, by employing the CR and HM equations, the thermal stability of the complex reflected from the high values of the ΔE* the negative sign of the ΔS*