The effective initiation for the chain-growth Horner-Wadsworth-Emmons (HWE) condensation polymerization was succeeded by utilizing an aliphatic aldehyde. Due to the higher electrophilicity of the aliphatic aldehyde compared with the aromatic one, the reactivity of the initiation might be accelerated, producing uniform intermediates to result in the formation of well-defined poly(3-(2-ethylhexyl)thienylene vinylene) (P3EHTV). Consequently, P3EHTV possessed the predictable molecular weight and lower molar-mass dispersity ( Ð M =1.16) value than that of P3EHTV obtained by employing aromatic aldehyde compounds as the initiators. In this polymerization system, neither transition metals nor halogens are utilized to realize low environmental-load synthesis of well-defined  conjugated

Nonstoichiometric polycondensations via Stille coupling reactions are successfully used to obtain high-molecular-weight -conjugated polymers using 2,5-bis(trimethylstannyl)thiophene and a dibromo phthalimide monomer, N-hexyldecyl-3,6-dibromophthalimide (2), in excess from 1:1 to 1:10. The intramolecular Pd(0) catalyst transfer on 2 substituted at the polymer terminal occurs as suggested by the model reaction between 2-(tributylstannyl)thiophene and an equimolar amount of N-octyl-3,6-dibromophthalimide (4), and the reaction generates only the disubstituted compound and excess 4 in an almost 1:1 ratio. The effect of the structures of the ligands and monomers on the polymerization under nonstoichiometric conditions is investigated to elucidate the criteria for the successful intramolecular catalyst transfer. The combination of the imide structure and an electron-rich ligand is important for promoting the catalyst transfer.

Controlled polymerization without a transition metal or halogen.

Regioblock copolythiohenes consisting of head-to-tail poly(3-hexylthiophene) (HT-P3HT) and head-to-head/tail-to-tail P3HT (HHTT-P3HT) segments could be synthesized by Negishi catalyst-transfer polycondensation (NCTP) using tBu2Zn·2LiCl.

Modular synthesis of asymmetric rylenes from commercially available naphthalic anhydride derivatives provides access to novel materials with tunable functional handles at the imide-position, site-specific incorporation of bay position substituents and tailored extension of the molecular core.

Well-defined poly(2,5-dihexyloxyphenylene-1,4-diyl) (PPP) is successfully synthesized by the Negishi catalyst-transfer polycondensation (NCTP) using dilithium tetra(tert-butyl)zincate (t Bu4 ZnLi2 ). The obtained PPP possesses the number-averaged molecular weight (Mn ) values in the range of 2100-22 000 and the molar-mass dispersity (ÐM ) values in the range of 1.09-1.23. In addition, block copolymers containing PPP and poly(3-hexylthiophene) (P3HT) segments (PPP-b-P3HT) are synthesized to confirm the feasibility of chain extension between the different monomers based on NCTP.

An efficient and scalable strategy to prepare libraries of discrete conjugated oligomers (Đ = 1.0) using the combination of controlled polymerization and automated flash chromatography is reported. From this two-step process, a series of discrete conjugated materials from dimers to tetradecamers could be isolated in high yield with excellent structural control. Facile and scalable access to monodisperse libraries of different conjugated oligomers opens pathways to designer mixtures with precise composition and monomer sequence, allowing exquisite control over their physical, optical, and electronic properties.

Well-defined poly(2,5-dihexyloxyphenylene-1,4-diyl) (PPP) is successfully synthesized by the Negishi catalyst-transfer polycondensation (NCTP) using dilithium tetra(tert-butyl)zincate (t Bu4 ZnLi2 ). The obtained PPP possesses the number-averaged molecular weight (Mn ) values in the range of 2100-22 000 and the molar-mass dispersity (ÐM ) values in the range of 1.09-1.23. In addition, block copolymers containing PPP and poly(3-hexylthiophene) (P3HT) segments (PPP-b-P3HT) are synthesized to confirm the feasibility of chain extension between the different monomers based on NCTP.

Our recently developed Negishi-type catalyst-transfer polycondensation (NCTP) method using a zincate complex of t Bu4ZnLi2 is attractive for synthesizing well-defined π-conjugated polymers such as regioregular poly(3-hexylthiophene)s. To accomplish the NCTP without side reactions, the precise preparation of monomer intermediates is a crucial factor to control the molecular weights and dispersities of the obtained polymers. In this article, we report the effects of stoichiometry in the presence or absence of LiCl on the results of the zinc-iodine exchange reaction between 2-bromo-3-hexyl-5-iodothiophene (1) and t Bu4ZnLi2, and those of Ni catalysts on the results of NCTP. It was revealed that the presence of LiCl strongly affects the stoichiometry in preparing the monomer intermediates and the optimized condition for NCTP. Consequently, it was found that an atom-economical NCTP using a 0.25 equivalent of zinc metal could be realized only when t Bu4ZnLi2·2LiCl was employed for the zinc-iodine exchange reaction.

Negishi-type Catalyst-Transfer Polymerization (NCTP) of electron-deficient monomers has been attempted for the first time. Imide or ketone groups in such monomers show an excellent electron-deficient property. However, these functional groups cannot generally tolerate towad highly reactive Grignard reagents. In this work, we applied a zincate complex with lower basicity, Bu4ZnLi2, for the polymerization of a naphthalene-diimide-containing monomer. Zinc-halogen exchange reaction was quantitatively conducted at 60 degrees C for 1 h without any protection of the imide group. Then, the polymerization was carried out by adding the Pd catalyst to afford an electron-deficient polymer, PTNDIT (M-n = 8,400 and D = 1.35).

ABSTRACTPolyisocyanurates have been successfully prepared by the thermal rearrangement of polycyanurates, which were obtained from 2,4‐dichloro‐6‐methoxy‐1,3,5‐triazine and bisphenol monomers. The thermal rearrangement was carried out in the presence of a small amount of tetrabutylammonium bromide (TBAB) as a catalyst at 200 °C for 30 or 60 min in an argon atmosphere, and the degree of arrangement was greater than 95%. Transparent and amorphous polyisocyanurate films were obtained and showed a good thermal stability with a 5% weight loss temperature above 340 °C in nitrogen and the glass transition temperature above 210 °C. Films with a 10‐µm thickness exhibited an excellent transparency above 90% at 400 nm. Furthermore, the thermal rearrangement of 2,6‐bis(4‐methoxyphenyl)‐6‐methoxy‐1,3,5‐triazine to 1,3‐bis(4‐methoxyphenyl)‐5‐methyl‐1,3,5‐triazinane‐2,4,6‐trione was investigated in detail. It was found that the complete thermal rearrangement was successfully accomplished in the presence of 2 wt % TBAB at 150 °C for 20 min in an argon atmosphere. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 692–698

Novel conjugated polymers composed of benzo[1,2‐b:4,5‐b′]dithiophene and thieno[3,4‐b]pyrazine or dithieno[3′,2′:3,4;2″,3″:5,6]benzo[1,2‐d]imidazole units are synthesized by Stille polycondensation. The resulting polymers display a longer wavelength absorption and well‐defined redox activities. The effective intramolecular charge‐transfer and energy levels of all polymers are elucidated by computational calculations. Bulk‐heterojunction solar cells based on these polymers as p‐type semiconductors and [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PC₆₁BM) as an n‐type semiconductor are fabricated, and their photovoltaic performances are for the first time evaluated. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1067–1075

Novel conjugated polymers composed of benzo[1,2-b:4,5-b]dithiophene and thieno[3,4-b]pyrazine or dithieno[3,2:3,4;2,3:5,6]benzo[1,2-d]imidazole units are synthesized by Stille polycondensation. The resulting polymers display a longer wavelength absorption and well-defined redox activities. The effective intramolecular charge-transfer and energy levels of all polymers are elucidated by computational calculations. Bulk-heterojunction solar cells based on these polymers as p-type semiconductors and [6,6]-phenyl-C-61-butyric acid methyl ester (PC61BM) as an n-type semiconductor are fabricated, and their photovoltaic performances are for the first time evaluated. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1067-1075

A nonstoichiometric Stille coupling polycondensation was first succeeded between 2,5-bis(trimethylstannyl)thiophene (1) and 4,9-dibromo-2,7-bis(2-decyltetradecyl)benzo[lmn][3,8]-phenanthroline-1,3,6,8-tetraone (2) with ratios ranging from 1:1 to 1:10. The model reaction using 2-(tributylstannyl)thiophene (3) and 4,9-dibromo-2,7-bis(2-hexyl)benzo[lmn][3,8]-phenanthroline-1,3,6,8-tetraone (4) at a 1:1 molar ratio in the presence of catalytic Pd2(dba)3/P(o-tolyl)3 indicated that the rate constant of the second substitution reaction (k2) is 15 times higher than that of the first one (k1). It was found that the selective intramolecular catalyst transfer was promoted by the naphthalene-diimide (NDI) skeleton. The results also provided a new one-pot symmetrical end-functionalization method to synthesize an NDI-based n-type polymer with NDI groups at both α,ω-chain ends.

Much attention has recently been paid to block copolymers (BCPs) containing pi-conjugated stiff-rod segments, because of their many potential optical and electronic applications, including batteries, capacitors, light-emitting diodes, transistors, photovoltaics, and so on, by exploiting their semiconductivity. Based on the discoveries of living/controlled polymerization systems, including anionic, cationic, radical, and, recently, condensative chain-growth polymerization, a huge number of BCPs and related heterophase copolymers have been synthesized and well characterized so far. The chemically bonded structure between dissimilar polymer segments in BCPs induces self-organization, resulting in the formation of microphase separated domains at the molecular level. Recently, a wide variety of novel BCPs containing stiff rod polythiophene segments have been competitively synthesized by many researchers and their unique self-assembly behavior has been studied in detail. Due to the rigidity/crystallinity of polythiophene segments in addition to the heterophase structure, the self-assembly behavior of such BCPs becomes rather more complicated than that of conventional coil-based BCPs. Nevertheless, there are numerous merits for developing these BCPs, taking into consideration that the functions of rod and opto/electronically active segments would be useful resources for high-performance materials in actual device application. Therefore, this area is still attractive at the present time. In this chapter, recent progresses in the synthesis of well-defined BCPs containing polythiophenes, their morphology, and representative application to organic solar cells are reviewed.

Regioregular poly(3-hexylthiophene) (P3HT) has been a commonly used p-type semiconducting material for solution processable organic electronics. To establish a living system of "Negishi-type catalyst-transfer polycondensation (NCTP)" using zincate complex as a synthetic method for well-defined P3HT having predictable molecular weight (MW) and low dispersity (-D), the ligands of Ni catalyst were optimized. As a result, a ligand of 1,2-bis(dicyclohexylphosphino) ethane produced P3HTs with highly controlled number average MWs (1650-32,800) and very low -D values (1.03-1.17). The polymerization results were strongly influenced by steric hindrance based on the factors of cone angle and bite angle of Ni catalysts, and/or electron-donating ability of phosphine ligands. In addition, we succeeded in the two-stage polymerization of P3HT and the synthesis of P3HT-b-poly(3-octadecylthiophene), the latter of which is the first demonstration by NCTP using zincate complex. (c) 2014 Wiley Periodicals, Inc.

The recent progress in the development of zincate-complex metathesis polymerization (ZCMP) is reviewed. The Zn–I exchange reaction between 2-bromo-3-hexyl-5-iodothiophene and dilithium tetra-tbutyl zincate (tBu4ZnLi2) and subsequent polymerization initiated with a Ni catalyst afforded poly(3-hexylthiophene)s (P3HTs) with predictable molecular weights and low polydispersity indices (PDIs). The direct synthesis of poly(3-(6-hydroxyhexyl)thiophene) was successfully demonstrated without protection of the hydroxyl group. The ligands of the Ni catalyst were further tuned for the preparation of extremely low-polydisperse P3HTs with high reproducibility. Then, the bulkiness and/or the electron-donating effect of the ligands were found to be very important for accessing a living system for ZCMP. Consequently, the modified ZCMP system with the Ni(dcpe)Cl2 catalyst accomplished the preparation of well-defined P3HTs (Mn up to 33 000 g mol−1) with extremely low PDIs (1.03–1.11). In addition, an all-conjugated block copolythiophene, P3HT-b-poly(3-octadecylthiophene)(P3ODT), was synthesized for the first time through the sequential monomer addition approach with ZCMP. This paper reviews the development of zincate-complex metathesis polymerization (ZCMP) and its application to protection-free direct synthesis of poly(3-(6-hydroxyhexyl)thiophene) as well as block copolythiophene. The modified ZCMP system using Ni(dcpe)Cl2 as a catalyst accomplished the preparation of well-defined poly(3-hexylthiophene)s (P3HTs) (Mn up to 35 000 g mol−1) with extremely low PDI (1.03∼1.11). In addition, the first example of all-conjugated block copolythiophene, P3HT-b-poly(3-octadecylthiophene), could be synthesized on the basis of the sequential monomer addition approach based on ZCMP.