Search

A novelseries of linear, high-molecular-weight polymers and copolymerswere synthesized by one-pot, metal-free superacid-catalyzed polymerizationof aliphatic 1,2-diketones (2,3-butanedione (1a), 2,3-hexadione(1b), 3,4-hexadione (1c), 2,3-butanedionemonoxime (1d), pyruvic acid (1e), 1,4-dibromo-2,3-butanedione(1f), 2-bromopyruvic acid (1g), and methyl-3,3,3-trifluoropyruvate(1h) with linear, nonactivated, multiring aromatic hydrocarbonsterphenyl (A), biphenyl (B), fluorene (C), and N-ethyl carbazole (D). Depending on the reaction system, the polymerizations were carriedout as stoichiometric or non stoichiometric, with direct or inversemonomer addition. Copolymers were obtained by polymerization of 1,2-diketoneswith a mixture of aromatic hydrocarbons. In the course of the polymerizationonly one carbonyl group of a 1,2-diketone reacts to form C–Cbonds with aromatic fragments while the other functional groups (includingthe second carbonyl group) are incorporated unchanged into polymerchain. The polymerizations performed at room temperature in the Brønstedsuperacid CF3SO3H (TFSA) and in a mixture ofTFSA with methylene chloride or trifluoroacetic acid (TFA) tolerantof carbonyl, acetyl, N-oxime, carboxy, methoxy, andbromomethyl groups. The polymers obtained were soluble in most commonorganic solvents, and flexible transparent, colorless films couldbe cast from the solutions. 1H and 13C NMR analysesof the polymers synthesized revealed high regio-selectivity of thepolymerizations and yielded linear structures with para-substitutionin the phenylene fragments of the main chains. An electron affinity(EA) of the carbonyl component and the heterolytic C–Obond dissociation energy (DE) in carbinol 3(correlating with the activation energy of carbocation 4formation) have been used to rationalize the reactivity of carbonylcomponents. The calculations show the following reactivity order ofthe diketones. 1f> 1g≈ 1e> 1a> 1d> 1h> 1b>1cwhich is totally in agreementwith the experimentaldata. The new functional polymers obtained demonstrate good processability,high Tgand thermal stability. Unexpectedwhite light emission was observed for polymer 2gA. [ABSTRACT FROM AUTHOR]

A novel series of linear, high-molecular-weight polymers was synthesized by one-pot, metal-free superacid-catalyzed reaction of isatins (1a−d) with linear, nonactivated, multiring aromatic hydrocarbons: biphenyl (A), p-terphenyl (B), p-quaterphenyl (C), 2-(4-biphenylyl)-6-phenylbenzoxazole (D), 9H-fluorene (E), 9,9-dimethyl-9H-fluorene (F), 2,2′-[2,5-bis(trifluoromethyl)-1,4-phenylene]bis(9,9-dimethyl-9H-fluorene) (G), oligo-9,9-bis(2,6-ethylhexyl)-9H-fluorene (H), biphenol (I), and bi-2-napththol (J). The reactions were performed at room temperature in the Brønsted superacid trifluoromethanesulfonic acid (CF3SO3H, TFSA) and in a mixture of TFSA with methylene chloride or TFA tolerant of hydroxyl, carboxy, and cyano groups. The polymers obtained were soluble in most common organic solvents, and flexible transparent films could be cast from the solutions. 1H and 13C NMR analyses of the polymers synthesized revealed their linear structure with para-substitution in the phenylene fragments of the main chain. The molecular weights Mwand Mnof the polymers ranged from 54200 to 742000 and from 40140 to 438500 g/mol, respectively. Most of the polymers also possess narrow polydispersity (1.15−1.50). The oxindole groups of the polymers react smoothly with alkyl bromides under basic conditions in N-methylpyrrolidinone (NMP). The amount of “click”able allyl- and propargyl- functionalities is readily controlled by adjusting the reaction ratio of polymer to alkyl bromides. The demonstrated efficiency and orthogonality of isatin-based polymer chemistry shows it to be an essential addition to the family of polymer “click” reactions. [ABSTRACT FROM AUTHOR]

A novel series of linear, high molecular weight high performance and functional polymers were synthesized by a one-pot, superacid-catalyzed polyhydroxylakylation reaction of carbonyl compounds containing electron-withdrawing substituents, adjacent or relatively close to a carbocation center with non-activated aromatic hydrocarbons. The reactions were performed at room temperature in the Brønsted superacid CF3SO3H (trifluoromethanesulfonic acid, TFSA) and in a mixture of TFSA with methylene chloride, which was used as both solvent and a medium for generation of electrophilic species from the carbonyl component. Polycondensations of 1,1,1-trifluoroacetone, 2,2,2-trifluoroacetohenone, 2,7-dinitrofluorenone, acenaphthenequinone and isatin with aromatic hydrocarbons proceed readily in the presence of superacid at room temperature. The polymers obtained were found to be soluble in the common organic solvents, and flexible transparent films could be cast from the solutions. 1H and 13C NMR analyses of the polymers synthesized revealed their linear, highly regular structure. The polymers also possess high thermostability. [ABSTRACT FROM AUTHOR]