High-T_g Functional Aromatic Polymers

Abstract

A novel series of linear, high-molecular-weight polymers and copolymers were synthesized by one-pot, metal-free superacid-catalyzed polymerization of aliphatic 1,2-diketones (2,3-butanedione (1a), 2,3-hexadione (1b), 3,4-hexadione (1c), 2,3-butanedione monoxime (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 hydrocarbons terphenyl (A), biphenyl (B), fluorene (C), and N-ethyl carbazole (D). Depending on the reaction system, the polymerizations were carried out as stoichiometric or non stoichiometric, with direct or inverse monomer addition. Copolymers were obtained by polymerization of 1,2-diketones with a mixture of aromatic hydrocarbons. In the course of the polymerization only one carbonyl group of a 1,2-diketone reacts to form C−C bonds with aromatic fragments while the other functional groups (including the second carbonyl group) are incorporated unchanged into polymer chain. The polymerizations performed at room temperature in the Brønsted superacid CF 3 SO 3 H (TFSA) and in a mixture of TFSA with methylene chloride or trifluoroacetic acid (TFA) tolerant of carbonyl, acetyl, N-oxime, carboxy, methoxy, and bromomethyl groups. The polymers obtained were soluble in most common organic solvents, and flexible transparent, colorless films could be cast from the solutions. 1 H and 13 C NMR analyses of the polymers synthesized revealed high regio-selectivity of the polymerizations and yielded linear structures with para-substitution in the phenylene fragments of the main chains. An electron affinity (EA) of the carbonyl component and the heterolytic C−O bond dissociation energy (DE) in carbinol 3 (correlating with the activation energy of carbocation 4 formation) have been used to rationalize the reactivity of carbonyl components. The calculations show the following reactivity order of the diketones. 1f > 1g ≈ 1e> 1a> 1d > 1h> 1b>1c which is totally in agreement with the experimental data. The new functional polymers obtained demonstrate good processability, high T g and thermal stability. Unexpected white light emission was observed for polymer 2gA.

Alternating Intramolecular and Intermolecular Catalyst‐Transfer Suzuki–Miyaura Condensation Polymerization: Synthesis of Boronate‐Terminated π‐Conjugated Polymers Using Excess Dibromo Monomers

“…Nomura conducted pioneer work on unstoichiometric polycondensation of AA and BB monomers through intramolecular transfer of Pd catalyst by using the Tsuji–Trost reaction of malonic acid ester with allyl acetate . In addition, some conventional polycondensations without transition metal catalysts showed unstoichiometric polycondensation behavior, for example, polyformal synthesis from diphenol and dihalomethane and superacid‐catalyzed polycondensation of aliphatic 1,2‐diketones and nonactivated aromatic hydrocarbons . However, π‐conjugated polymers have not been synthesized by means of unstoichiometric coupling polymerization of AA and BB monomers with a transition metal catalyst.…”

Polymer Synthesis Based on Self‐Accelerating 1,3‐Dipolar Cycloaddition Click Reactions†

“…To date, several stoichiometric imbalance‐promoted homogeneous step polymerization methods have been developed based on varied self‐accelerating reactions. They include palladium‐catalyzed allylation [ 53 ] and etherification polymerization, [ 54 ] palladium‐catalyzed Suzuki‐Miyaura and Stille coupling polycondensations, [ 13,55‐56 ] rhodium‐catalyzed oxidative polycoupling of internal diynes and phenylpyrazole [ 14 ] or arylboronic acids, [ 57 ] polycondensation of Friedel−Crafts acylation [ 17,58 ] or hydroxyalkylation reaction, [ 59‐61 ] poly‐Radziszewski reaction, [ 16 ] polycondensations of dibromomethane and 4,4’‐thiobisbenzenethiol [ 62 ] or bisphenol A, [ 63 ] and polycondensation of bisphenol A with 2,2‐dichloro‐1,3‐benzodioxole. [ 64 ] These stoichiometric imbalance‐ promoted homogeneous step polymerization methods have been summarized in recent review papers.…”

Sol-Gel Synthesis of Ceria-Zirconia-Based High-Entropy Oxides as High-Promotion Catalysts for the Synthesis of 1,2-Diketones from Aldehyde

“…Because of their antitumor and photochemical activities, among others, much attention has been given to the synthesis of 1,2 diketones and their derivatives for a long time [18][19][20][21][22]. In this context, several synthesis strategies have been designed and developed along with methodologies under catalytic conditions [23][24][25].…”