Biomimetic complexes: thermal stability, kinetic study and decomposition mechanism of Co(II)-, Ni(II)- and Cu(II)-4(5)-hydroxymethyl-5(4)-methylimidazole complexes

A thermoanalytical study of 4(5)-hydroxymethyl-5(4)-methylimidazole complexes with divalent cobalt, nickel and copper, with a general formula ML4(NO3)2 is reported: the thermal stability and the decomposition steps were determined by thermogravimetry (TG) and derivative thermogravimetry (DTG). The released products, due to the thermal decomposition, were analyzed by on-line coupling a FT-IR spectrometer to the thermobalance; the so obtained evolved gas analysis (EGA) allowed to prove the proposed decomposition steps. The decomposition kinetics was examined by using the Flynn–Wall–Ozawa and Kissinger methods. From the former method the E dependencies were presented and connected with the corresponding steps mass loss; from the latter method the activation energies and the pre-exponential factor were computed.