Mechanistic Aspects of Polynaphthalimide Synthesis from NMR Analysis

Abstract

The mechanism of the polycondensation reaction leading to naphthalimide polymers has been investigated using a model compound. In complement to 19 F-NMR analysis, 1 H-and 13 C-NMR spectroscopies were used to identify the intermediate compound. It was concluded that there was no evidence for the formation of an isoimide, but the formation of an amide-acid intermediate was clearly demonstrated.

Determination of the second-order 1H NMR parameters for the aromatic protons in 4-fluoroaniline and application to the analysis of the 1H NMR spectra for the aromatic protons in N4-(4′-fluorophenyl)succinamic acid and in N4-(4′-fluorophenyl)-3,3-difluorosuccinamic acid

“…The 2 0 ,6 0 protons shift from d 6.64 ppm to d 7.67 ppm while the 3 0 ,5 0 protons at d 6.82 ppm shift to d 7.05 ppm. Similar observations have been reported for other derivatives of 4-fluoroaniline, for example, 4-fluoroacetanilide [23,24], N-fluorophenyl-1,8-naphthalimide [25], N-arylpyridinium salts [14], and trimethylammonium salts [14], as well as 4-fluoroaniline in the presence of a lanthanide shift reagent [12]. As for 4-fluoroaniline, simultaneous simulations of the 1 H NMR spectrum (Fig.…”

“…The 1 H NMR spectrum for the aromatic protons of other derivatives of 4-fluoroaniline have been described by a first-order analysis: methyl N 4 -(4 0 -fluorophenyl)succinamate [19], 4-fluoroacetanilide [20][21][22][23][24][26][27][28], Nfluorophenyl-1,8-naphthalimide [25], 5-N-(N-4 0 -fluorophenylacetamide)-10,20-diphenylporphyrin [29], and N-(4-fluorophenyl)-5-(1-methyl-3-trifluoromethyl-1H-pyrazol-5-yl)-2-thiophenecarboxamide [30]. The 1 H NMR spectrum for the aromatic protons of 2 ( Fig.…”

Two‐step route polycondensation for polynaphthalimides synthesis through high molar mass soluble precursors: A kinetic study

“…Moreover, two research groups have published prominent studies concerning the optimization of the synthetic procedure of PNI, both regarding just to the formation of imide groups, emphasizing the need of such synthetic conditions. [15][16][17][18] However, the isolation of the PAA intermediate in a two-step polycondensation route represents a single opportunity to obtain a soluble polymeric precursor for PNI. To the best of our knowledge, the literature lacks studies on the kinetics of PAA formation, its neutralization and formation of a PAAS.…”