Xanthate-Mediated Controlled Radical Polymerization ofN-Vinylindole Derivatives

Abstract

The polymerization of three N-vinylindole derivatives, N-vinylindole (NVIn), 2-methyl-N-vinylindole (2MNVIn), and 3-methyl-N-vinylindole (3MNVIn), were carried out by reversible addition−fragmentation chain transfer (RAFT)/macromolecular design via interchange of xanthate (MADIX) process. Five chain transfer agents (CTAs), S-benzyl-O-ethyldithiocarbonate (CTA 1), O-ethyl-S-(1-phenylethyl)dithiocarbonate (CTA 2), O-ethyl-S-[(2-cyano)prop-2-yl]dithiocarbonate (CTA 3), benzyl 1-pyrrolecarbodithioate (CTA 4), and benzyl dithiobenzoate (CTA 5), were compared for these polymerizations with 2,2‘-azobis(isobutyronitrile) as an initiator. The xanthate-type RAFT agent (CTA 2) is the most efficient for obtaining poly(2MNVIn) with controlled molecular weights (M n = 1700−19 400) and narrow molecular weight distributions (M w/M n = 1.20−1.40). The effects of several parameters, such as solvent, temperature, monomer concentration, and CTA-to-initiator molar ratio, were examined in order to determine the conditions leading to optimal control of the polymerization. The resulting polymers gave clear spectroscopic evidence of the formation of charge-transfer complexes with efficient sensitizers, such as 7,7,8,8-tetracyanoquinodimethane (TCNQ), tetracyanoethylene (TCNE), and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), for photoconductivity. The poly(2MNVIn)s obtained by RAFT polymerization showed molecular weight dependence on the glass transition temperature (T g = 150−190 °C) and thermal stability ( = 300−430 °C).

Living Radical Polymerization by the RAFT Process - A Second Update

“…C Compounds not used as RAFT agents directly but served as precursors to other RAFT agents. (VAc) [55] NVP [55,379] 366 [380] NVPI [220] 367 [380] 368 [380] O S S 209 210* [283,381] O S S NVC [283,382,383] NVCL [384] NVP [381] NVPI [220] 366 [380] 367 [380] 368 [380] (VAc) [55] (NVP) [55] NVC-b-310 [382] NVC-b-311 [382] NVP-b-VAc [381] O S S O OH 211* [385] 212 [386] BA [387] (DEGMA) [386] EHA [387] St [72] VAc [388] (BA-b-AA) [386] VAc [55,385] NVP [55] (DEGMA-b-AA) [386] 213* [283] …”

“…St [72] VAc [389] VB [389] NVPI [220] VAc [391] VAc/VB [389] (NIPAM/369) [390] (Continued) [60] BA/AA [279] VAc [283] O S S 217* [381] 218 [392] O N 3 S S (NVCL) [384] (NVPI) [220] NVP [381] 366 [380] 367 [380] 368 [380] VAc [392] NVP-b-VAc [381] S O S O 219* OH 220 [169] …”

“…Styrene derivatives subjected to RAFT polymerization 348 [100,199] O 349 [138] O N N N 350 [158,309] N VBTAC 351 [159] Cl Ϫ Nϩ 352 [459] HN O 353 [321] O F F F F 354 [313] O F F F F 355 [313] [244] VBTPC 359 [34] Cl Ϫ P ϩ 360 [244] 361 [250] O N O 362 [207] O O O 363 [134] O O O Fe 364 [102] N 365 [102] N Table 23. Vinyl derivatives subjected to RAFT polymerization 366 [380] N 367 [380] N 368 [380] N 369 [390] N O O G. Moad, E. Rizzardo, and S. H. Thang [111,135] 370 [135,146] 375 [136] 376 [195] 377 [150] 378 [410] O O (H 3 C) 3 Si 372 [338,346,347] 373 [201] 374 [459] O [466] NAS 380 [160,299,317,345,347] 381 [178] 382 [222] [149,…”

Controlled RAFT Polymerization of N‐Vinylphthalimide and its Hydrazinolysis to Poly(vinyl amine)

“…[38,39] Recently, we reported the xanthate-mediated controlled radical polymerization of representative N-vinyl monomers involving N-vinylcarbazole [42] and N-vinylindole derivatives. [43] In general, controlled radical polymerization of N-vinyl and O-vinyl monomers had been difficult, since the generated radical species are highly reactive due to their non-conjugated nature and strong electron donating pendant groups.…”

Synthesis of Star Poly(N-vinylcarbazole) by Microwave-Assisted Reversible Addition-Fragmentation Chain Transfer Polymerization (RAFT)

“…However, dithiocarbamates used as CTAs provided PVK with broader polydispersities than xanthates [14][15][16]. A similar behavior was observed in RAFT polymerization of N-vinylindole with xanthates and dithiocarbamates as CTAs, explainable by the ratio between the leaving and re-initiation ability of the R-group [24]. Nonlinear first-order kinetic plots are also observed, suggesting that radical concentrations are not constant.…”