Polymerization of High Potential Monomers by Transition Metal Complex Catalysts

• Published in: KOBUNSHI RONBUNSHU 2002/06/25, Vol.59(6), pp.342-355
• Main Authors: TAKEUCHI, Daisuke, CHOI, Jun-chul, TAKENAKA, Yasumasa, KIM, Sunwook, OSAKADA, Kohtaro
• Format: Article
• Language: Japanese
• Subjects: Allene; Alternating Copolymerization; Carbon Monoxide; Living Polymerization; Methylenecyclopropane; Ni Complex; Pd Complex; Rh Complex; Ring-Opening Polymerization
• ISSN: 0386-2186; 1881-5685
• DOI: 10.1295/koron.59.342

Transition metal complex-catalyzed polymerization of highly reactive monomers such as methylenecyclopropanes and allenes affords novel polymers containing exo-methylene and enone groups in the repeating units. Pd complexes with diimine ligands promote ringopening polymerization of 2-phenyl-1-methylencecyclopropane to give the polymer with exo-methylene group on main chain. The polymer contains regulated head-to-tail linkages of the monomer units. The polymerization proceeds via 2, 1-insertion of methylenecyclopropane to π-allyl-Pd bond, followed by β-alkyl activation of produced cyclopropyl Pd species. Ni complexes catalyze simple polyaddition of 2-phenyl-1-methylenecyclopropane via 1, 2-insertion of the monomer to produce the polymer with cyclopropylidene groups. The polymer shows high Tg and Tm owing to its rigid polymer chain and its high thermal stability. Alternating copolymerization of 2-aryl-1-methylenecyclopropanes catalyzed by Pd-bpy complexes affords a polyketone with exo-methylene groups. π-Allyl Rh complex, Rh {η3-CH (Ar) C [C (=CHAr) CH2C (=CHAr) CH2CH2CH=CHAr] CH2} (PPh3) 2 (1), initiates alternating copolymerization of arylallens with CO to give a polyketone with well-regulated regioselectivity and narrow molecular weight distribution. Mechanistic studies revealed that the ratedetermining step of the polymerization is insertion of CO to the π-allyl-Rh growing species. 1 is also effective for the living alternating copolymerization of alkylallenes and allenes having an azobenzene moiety with CO. A liquid crystalline polyketone having an azobenzeneterminated long alkyl chain was obtained.