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Start Over Author "Yokoyama, Akihiro" Journal macromolecular rapid communications
12 results on '"Yokoyama, Akihiro"'

12. Precision synthesis of poly(3-hexylthiophene) from catalyst-transfer Suzuki-Miyaura coupling polymerization.

Author

Yokozawa T, Suzuki R, Nojima M, Ohta Y, and Yokoyama A

Subjects
Catalysis, Crown Ethers chemistry, Cycloparaffins chemical synthesis, Fluorenes chemistry, Hydrogen chemistry, Magnetic Resonance Spectroscopy, Molecular Weight, Organometallic Compounds chemistry, Palladium chemistry, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization methods, Water chemistry, Polymerization, Polymers chemical synthesis, Thiophenes chemical synthesis
Abstract

(t)Bu(3) PPd(Ph)Br (1)-catalyzed Suzuki-Miyaura coupling polymerization of 2-(4-hexyl-5-iodo-2-thienyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2) was investigated. Monomer 2 was polymerized with 1 at 0 °C in the presence of CsF and 18-crown-6 in THF containing a small amount of water to yield P3HT with a narrow molecular weight distribution and almost perfect head-to-tail regioregularity. The M(n) values increased up to 11,400 g · mol(-1) in proportion to the feed ratio of 2 to 1. The MALDI-TOF mass spectra showed that P3HT with moderate molecular weight uniformly had a phenyl group at one end and a hydrogen atom at the other, indicating involvement of a catalyst-transfer mechanism. Successive 1-catalyzed polymerization of fluorene monomer 3 and then 2 yielded a well-defined block copolymer of polyfluorene and P3HT., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2011
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