Influence of the aromatic substitutes in the thermal and kinetic behavior of mesoionic compounds of the 1,3-thiazole-5-tiolate system

In this work, three mesoionic compounds of the 1,3-thiazole-5-tiolat system were studied, derived from amino acids of the glycerin through 1,3-dipolar cyclo-addition/reversion reaction. The mesoionic compounds were characterized as: MI-1 (mesoionic 2-(4-chlorophenyl)-3-methyl-4-phenyl-1,3-thiazole-5-tiolat); MI-2 (mesoionic 2-(4-chlorophenyl)-3-methyl-4-(4-isopropylphenyl)-1,3-thiazole-5-tiolat) and MI-3 (Mesoionic 2-(4-clorophenyl)-3-methyl-4-(methoxyphenyl)-1,3-thiazole-5-tiolate). These compounds were characterized by infrared spectroscopy (IR), nuclear magnetic resonance (NMR), thermogravimetry (TG) and differential scanning calorimeter (DSC). Also, the kinetic study of the thermal decomposition by non-isothermal thermogravimetry has been realized, presenting, the kinetic and thermal behavior of these compounds. The results of the spectroscopic analysis confirmed the structure of the synthesized mesoionic compounds. The DSC curves of the mesoionic compounds MI-1, MI-2, and MI-3 indicated the fusion of two of them followed by a subsequent decomposition. The TG/DTG curves showed that the decomposition of the mesoionic compounds MI-1, MI-2 and MI-3 occurred in several steps.