Caracterização Térmica e Espectroscópica de Piridin-2-ilaminometileno derivados dos Ácidos de Meldrum

Abstract

Solid compounds of pyridin-2-ylaminomethylene meldrun’s acid derivatives was synthesized and characterized by nuclear magnetic resonance (1H and 13C NMR), mass spectrometry (MS), Infrared spectroscopy (FTIR), simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC). The results provided information on the thermal stability and thermal decomposition of the compounds with different substituent groups. The TG-DTA curves show mass losses in two or three steps between 441-978 K. The molecular geometry of the compounds were optimized using B3LYP method and 6-311G basis set. The molecular vibration of the optimized compounds was calculated in comparison with the experimental values. The molecular vibration frequencies calculated are generally higher than the corresponding experimental quantities, and it are due to a combination of effects of electronic correlation. General procedure for the synthesis of pyridyl-2-aminomethylene Meldrum’s acid derivatives