Theoretical study of the isomerization of 1-amino-4-phenylamino-9,10-anthraquinone

This paper presents the results of computer simulation of tautomeric transformations of the molecule 1-amino-4-phenylamino-9,10-anthraquinone. It is known from the literature that the presence of substituents in the 1,4-position of anthraquinone-9,10 leads to various tautomeric transformations, with a shift in the absorption maximum and the appearance of absorption bands in the red wave region in electronic spectra. Both the 1-amino-4-hydroxyanthraquinone described in the literature and the 1-amino-4-phenylamino-9,10-anthraquinone are characterized by two types of prototropic tautomerism – keto-enol and amino-imine. Quantum-chemical modeling contributes to the calculation of the relative energies of tautomers and isomers, the barriers of their interconversions, as well as finding their structural parameters. The aim of this study was to study the mechanism of the formation of tautomers during hydrogen transfer in the molecule of 1-amino-4-phenylamino-9,10-anthraquinone, as well as the formation of isomers during migration of the OH group. The calculations were performed using the Gaussian09 program. To study of various tautomers of 1-amino-4-phenylamino-9,10-anthraquinone, the B3LYP method with the def2TZV basis was used. A search was conducted for transition states during hydrogen transfer and OH group migration. The descent along the reaction path was calculated to confirm that the transition state is in the path of the desired reaction. The minima corresponding to the starting material and product were localized. The activation enthalpies of the studied reactions were calculated. Migration of the OH group in the 1-amino-4-phenylamino-9,10-anthraquinone molecule leads to the formation of 4-phenylamino-9-amino-1,10-anthraquinone. As the calculation shows, the keto-form of 1-amino-4-phenylamino-9,10-anthraquinone is energetically more profitable than all the isomers studied in this work, including the enol form. The smallest difference in total potential energies is 23.7 kJ/mol between the initial ketone form of 1-amino-4-phenylamino-9,10-anthraquinone and the last transformation structure – the 4-phenylamino-9-amino-1,10-anthraquinone molecule.

Imide-Aryl Ether Ketone Block Copolymers

ABSTRACTImide-aryl ether ketone block copolymers were prepared and their morphology and thermal and mechanical properties investigated. The key feature of this copolymerization is the preparation of soluble aryl ether ketimine oliogmers which may be subsequently hydrolized to the aryl ether ether ketone form. A bis(amino) aryl ether ketimine oligomer was prepared via a nucleophilic aromatic substitution reaction with a molecular weight of 6,000 g/mol. The oligomer was co-reacted with 4,4′-oxydianiline (OI)A) and pyromellitic dianhydride (PMDA) diethyl ester diacyl chloride in N-methyl-2-pyrrolidone (NMP) in the presence of N-methylmorpholine. The copolymer compositions, determined by II-NMR, of the resulting amic ester based copolymers ranged from 8 to 20 wt% aryl ether ketimine content. Prior to imide formation, the ketimine moiety of the aryl ether ketimine block was hydrolyzed (p-toluene sulfonic acid) to the ketone form producing the aryl ether ether ketone block. Solutions of the copolymers were cast and cured to effect imidization, producing clear films. The copolymers displayed good thermal stability with decomposition temperatures in excess of 450°C. Multiphase morphologies were observed irrespective of the co-block type or composition.