Elucidating the thermal degradation of carbazole‐containing platinum–polyyne polymers

Abstract

ABSTRACTIn this article, we present the significant influence of the substitution pattern of carbazole on the thermal stability of carbazole‐containing platinum(II)–polyyne polymers. A series of the studies on the dynamic and isotherm conditions revealed a better thermal stability for the 3,6‐carbazole based platinum(II)–polyyne polymer (36CbzPtP), where alkynes were located at the p‐phenylene positions relative to the carbazole nitrogen atom, compared to that for the 2,7‐carbazole based counter polymer (27CbzPtP), where the alkynes were located at the m‐phenylene positions relative to the carbazole nitrogen atom. On the other hand, the thermogravimetry–mass spectrometry–Fourier transform infrared technique applied to the two polymers revealed the same degradation mechanism, which probably involved the thermal decomposition of triethyl phosphine moieties and which was followed by the CC scission of hexadecyl chains. The carbazole moieties eventually underwent degradation when the temperature exceeded 415 °C. Molecular modeling showed that polymer 27CbzPtP formed a linear structure, whereas polymer 36CbzPtP adopted a curved structures; this led to different packing modes of the polymer chains. This structural difference affected the efficiency of the initial degradation event of the triethyl phosphine groups. The curved structures of 36CbzPtP sterically protected the triethyl phosphine groups; this led to an increased thermal stability over that of 27CbzPtP. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47639.