tBu3 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 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.
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. 