Thermal properties and decomposition mechanism of disubstituted fused 1,2,4-triazoles considered as potential anticancer and antibacterial agents

Abstract

Thermal resistance is a very important parameter when assessing the therapeutic usefulness of potential pharmaceutics. Therefore, the thermal behaviour and the decomposition mechanism in the atmosphere of helium and synthetic air of disubstituted fused 1,2,4-triazoles—which may be potential anticancer and antibacterial agents—were studied with a use of simultaneous thermal analysis: thermogravimetry/differential scanning calorimetry (TG/DTG/DSC) coupled online with Fourier transform infrared spectroscopy. It was confirmed that the thermal stability of the tested compounds is directly depended on their structure and thus on the number of chlorine atoms as substituents. The pyrolysis process of disubstituted fused 1,2,4-triazoles in inert conditions runs in two main, non-well-separated stages connected with the emission of NH3, HCN, acetonitrile, aromatics with an OH group, aromatics with a NH2 groups, H2O, CO2 and alkene fragments. However, the thermal stability of those compounds in synthetic air atmosphere is comparable or lower than their thermal stability in helium atmosphere. The decomposition of the tested compounds runs through at least three main stages, resulting in the emission of the same type of volatiles as in inert conditions plus the additional emission of CO and some carbonyl fragments for compounds with no or one chlorine atom as a substituent. The results indicate a simultaneous cleavage of C–N, N–N and C–O bonds during heating of the tested disubstituted fused 1,2,4-triazoles in inert conditions and additional combustion process of pre-formed residues in oxidative conditions.

Thermal stability and degradation mechanism of C60 fullerene‐based polymers

“…Furthermore, at temperatures higher than 400 C, the peaks at 1525 and 1460 cm À1 corresponding to the C C aromatic stretching vibrations appeared (Figure 9), suggesting the decomposition of the benzoate moiety. 30 The above considerations are consistent with previous reports and common knowledge about fullerene chemistry. According to literature data and our own findings, the decomposition of fullerene C 60 in nitrogen atmosphere does not start until 670 C. 31,32 In air, at the heating rate of 10 C/min, the decomposition of fullerene C 60 occurs in the temperature range of 440-725 C, based on the contracting sphere mechanism.…”

“…The presence of the bands in the 2800–3050 cm −1 region, characteristic of the CH stretching vibrations of methylene, methyl, and methine groups, confirmed the aliphatic specificity of these decomposed compounds 28,29 . In addition, the peak at 1268 cm −1 corresponding to the CN stretching vibrations confirmed the decomposition of the 1,2,3‐triazole moieties 30 . As shown in Figure S11, which compares the FTIR spectra of both polymers at approximately the same temperature, the peaks corresponding to the alkyl groups (2800–3050; 810–1100 cm −1 ), and CN (1268 cm −1 ) were more intense in polymer C 60 P2 than in polymer C 60 P1.…”

“…As shown in Figure S11, which compares the FTIR spectra of both polymers at approximately the same temperature, the peaks corresponding to the alkyl groups (2800–3050; 810–1100 cm −1 ), and CN (1268 cm −1 ) were more intense in polymer C 60 P2 than in polymer C 60 P1. Furthermore, at temperatures higher than 400°C, the peaks at 1525 and 1460 cm −1 corresponding to the CC aromatic stretching vibrations appeared (Figure 9), suggesting the decomposition of the benzoate moiety 30 …”

Chemical Modification of Birch Bark (Betula L.) for the Improved Bioprocessing of Cadmium(II), Chromium(VI), and Manganese(II) from Aqueous Solutions

“…The FTIR (Fourier transform infrared spectroscopy) analysis is provided in Figure 3 of all used sorbents and their modifications. In the wavenumber range of 3000-3700 cm −1 , a broad peak of maximum intensity is observed, corresponding to the stretching vibrations of C-H and hydroxyl groups -OH in cellulose [15]. For modifications with NaCl, HNO3, and HCl, the signal in this range exhibits higher intensity compared to NaOH modification and unmodified bark.…”

Pyrolytic Modification of Avocado (Persea americana) Peel for the Enhancement of Cadmium(II) and Chromium(VI) Sorption Properties

“…The gas flow (10 L/h) was controlled with the flowmeter to provide stable environment. The process was carried out for approximately 4 h and then the temperature was gradually lowered until it reached the room temperature ~25 • C [11,16]. The mass of the obtained biochar was equal to 21.4 g. The biochar yield in this particular case is equal to 21.4%.…”