Successive Synthesis of Well‐Defined Star‐Branched Polymers by “Convergent” Iterative Methodology Using Core‐Functionalized 3‐Arm Star‐Branched Polymer and a Specially Designed 1,1‐Diphenylethylene Derivative

Abstract

Summary:The synthesis of well-defined regular and miktoarm star-branched polymers by a convergent iterative methodology using core-functionalized 3-arm starbranched polymer with 1,1-diphenylethylene (DPE) moiety and a specially designed DPE derivative is described. The methodology involves the following two reaction steps in the entire iterative synthetic sequence: 1) a coupling reaction of a starbranched polymer having an anion at the core with a DPE derivative with two benzyl bromide moieties, 1-{4-[5,5-bis(3-bromomethylphenyl)-7-methylnonyl]phenyl}-1-phenylethylene, and 2) an addition reaction of the resulting core-DPE-functionalized star-branched polymer with sec-BuLi to convert the DPE moiety to a DPE-derived anion. The iterative synthetic sequence including these two reaction steps, 1) and 2), was repeated to successively synthesize star-branched polymers with more arms. Iteration of this synthetic sequence doubled the number of the arms in the starbranched polymer. With this methodology, 6-arm, 12-arm, and 14-arm regular starbranched polystyrenes as well as 6-arm A 2 B 2 C 2 , A 4 B 2 , and 12-arm A 4 B 4 C 4 and A 8 B 4 miktoarm star-branched polymers with well-defined structures have been successfully synthesized.

Successive Synthesis of Miktoarm Star Polymers Having up to Seven Arms by a New Iterative Methodology Based on Living Anionic Polymerization Using a Trifunctional Lithium Reagent

“…The first successful demonstration was a stepwise iterative methodology based on living anionic polymerization using a 1,1-diphenylethylene (DPE) function as a reaction site. By developing this methodology and further modified ones, we successfully synthesized a variety of well-defined μ-star polymers with many arms, such as 3-arm ABC, 4-arm ABCD, 5-arm ABCDE, 6-arm ABCDEF, 7-arm ABCDEFG, 6-arm A 2 B 2 C 2 , 9-arm A 3 B 3 C 3 , 4-arm ABC 2 , 7-arm AB 2 C 4 , 15-arm AB 2 C 4 D 8 , and 31-arm AB 2 C 4 D 8 E 16 μ-star polymers. − However, since the living anionic polymers usable in these methodologies were always required to react with the DPE reaction site, they were limited to only highly reactive living polymers of styrene, 1,3-butadiene, isoprene, and their derivatives.…”

Precise Synthesis of Miktoarm Star Polymers by Using a New Dual-Functionalized 1,1-Diphenylethylene Derivative in Conjunction with Living Anionic Polymerization System

“…The reaction sequence was repeated two more times to successively synthesize a 4-arm ABCD, followed by a 5-arm ABCDE μ-star polymer. Similar iterative methodologies have been further developed to allow access to a wide variety of well-defined μ-star polymers with many arms and components, such as ABC 2 , AB 2 C 2 , A 2 B 2 C 2 , A 3 B 3 C 3 , AB 2 C 4 , ABCD 2 , ABC 2 D 2 , AB 2 C 4 D 8 , ABCD 2 E 2 , and AB 2 C 4 D 8 E 16 μ-star polymers. − …”

Successive Synthesis of Multiarmed and Multicomponent Star‐Branched Polymers by New Iterative Methodology Based on Linking Reaction between Block Copolymer In‐Chain Anion and α‐Phenylacrylate‐Functionalized Polymer

“…By developing the iterative methodology, the synthesis of a wide variety of μ‐star polymers was successfully achieved. They were 3‐arm ABC, 4‐arm ABCD, 5‐arm ABCDE, 6‐arm ABCDEF, 7‐arm ABCDEFG, 6‐arm A 2 B 2 C 2 , 9‐arm A 3 B 3 C 3 , 7‐arm AB 2 C 4 , 15‐arm AB 2 C 4 D 8 , and 31‐arm AB 2 C 4 D 8 E 16 μ‐star polymers, most of which are novel multiarmed and multicomponent μ‐star polymers . The resulting poly­mers were all precisely controlled in molecular weight, molecular weight distribution ( M w / M n ≤ 1.05), composition, and arm number.…”