Stereocontrolled Synthesis and Characterization of cis-Poly(arylenevinylene)s

• Published in: Macromolecules Vol. 39; no. 6; pp. 2039 - 2048
• Main Authors: Katayama, Hiroyuki, Nagao, Masato, Nishimura, Tatsuro, Matsui, Yukio, Fukuse, Yosuke, Wakioka, Masayuki, Ozawa, Fumiyuki
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 21.03.2006
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; End group; Molecular structure; Phenylenevinylene derivative copolymer; Experimental study; Stereoregular copolymer; Cis stereoisomer; Suzuki coupling; Conjugated copolymer; Preparation; Interfacial polymerization; Alternating copolymer; Stereospecificity; Fluorene derivative copolymer; Phenylenevinylene copolymer
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma052183l

A highly stereocontrolled synthesis of five kinds of cis-poly[(arylenevinylene)-alt-(2,5-dioctyloxy-1,4-phenylenevinylene)]s has been accomplished by Suzuki−Miyaura-type polycondensation [arylene = p-phenylene (3af), m-phenylene (3bf), 4,4‘-biphenylene (3cf), 2,7-fluorenylene (3df), 9,9-dihexyl-2,7-fluorenylene (3ef)]. Reactions of (Z,Z)-bis(2-bromoethenyl)arenes (1a − e) with 2,5-dioctyloxybenzene-1,4-diboronic acid (2fx) in toluene in the presence of Pd(PPh3)4 catalyst, aqueous KOH base, and Bu4NBr as a phase-transfer catalyst at 80 °C for 24 h form 3af − ef with number-average molecular weight (M n) of 5700−9500 in 77−99% yields. The stereoregularity of vinylene linkages in the polymer backbone has been found at least 95%. The starting monomers (1a − e) were prepared in almost geometrically pure forms (≥99% cis), either by ruthenium-catalyzed hydrosilylation of diethynylarenes followed by bromodesilylation of the resulting bis(2-bromoethenyl)arenes or by addition of bromine to arenediacrylic acids followed by debrominative decarboxylation promoted by Et3N. MALDI-TOF-MS analysis of cis-3af has revealed the presence of two types of polymers having different end groups. Type I polymer bears (Z)-4-(2-bromoethenyl)phenyl and 2,5-dioctyloxyphenyl group at each end, whereas type II polymer has 2,5-dioctyloxyphenyl groups at both ends. Type I polymer is successfully converted to type II polymer by palladium-catalyzed reaction with 2,5-dioctyloxybenzeneboronic acid to obtain cis-poly[(p-phenylenevinylene)-alt-(2,5-dioctyloxy-1,4-phenylenevinylene)] in a single form.