Advances and Challenges in the Synthesis of Poly(p‐phenylene vinylene)‐Based Polymers

Abstract

We provide an overview of the current progress in the synthesis of poly(p‐phenylene vinylene) (PPV) polymers. The described synthetic approaches can be divided into four main categories: polymerization of quinodimethane intermediates, metathesis polymerization, nucleophilic polycondensation, and palladium‐catalyzed cross‐coupling. While such variety is remarkable and very high‐molecular‐weight PPV can be prepared by some methods, the synthetic chemistry of PPV still limits the structural variety and purity of arylene vinylene polymers. In particular, palladium‐catalyzed cross‐coupling reactions, the method of choice in the contemporary conjugated polymer chemistry, often shows limited success in PPV series. On the other hand, the possibility of using metathesis polymerization creates new opportunities not available for other classes of conjugated polymers.

Polymers with Alkylsulfanyl Side Chains for Bulk Heterojunction Solar Cells: Toward a Greener Strategy

“…The majority of the conjugated polymers currently employed in these studies are synthesized through an environmental unfriendly procedure, i.e., Stille reaction, that is a palladium‐catalyzed coupling between tin‐ and bromine‐functionalized monomers . Other polymerizations employ less toxic intermediates but still use palladium or nickel catalysts, apart those based on Wittig‐type or Knoevenagel reactions. An overview of the synthetic strategies more employed in the field of conductive polymers is reported in Table .…”

Triple Helical Ir(ppy)3 Phenylene Cage Prepared by Diol‐Mediated Benzannulation: Synthesis, Resolution, Absolute Stereochemistry and Photophysical Properties

“…[13] The resulting triene 3 was obtained in good yield as am ixture of stereoisomers. [13] The resulting triene 3 was obtained in good yield as am ixture of stereoisomers.…”

“…The synthesis of tris-bromopyridine 6 begins with Wittig olefination of benzene-1,3,5-tricarbaldehyde 1 with Wittig reagent 2 derived from 2-bromo-5-bromomethylpyridine (Scheme 2). [13] The resulting triene 3 was obtained in good yield as am ixture of stereoisomers. Dihydroxylationo ft riene 3 wasc omplicated by competing alkene oxidative cleavage, which was minimized upon application of Upjohn conditions, [14] providing tris-diol 4 in 45 %y ield as am ixture of stereoisomers.A ttempted ruthenium(0)-catalyzedc ycloaddition of tris-diol 4 with 1,3-butadiene under previously reported conditions using dppe or dppp as ligand were ineffective.…”

“…The structureo ft he N-doped phenylene cage 8 was determined by 1 HNMR, 13 CNMR, ESI-HRMS, and single-crystalX -ray diffraction. The tris-bromopyridine 6 was subjected to athreefold Suzukicross-coupling reaction with tris-pinacol boronate 7 to furnish the racemic triple helical N-doped phenylene cage 8 in 19 %y ield.…”

“…The tris-bromopyridine 6 was subjected to athreefold Suzukicross-coupling reaction with tris-pinacol boronate 7 to furnish the racemic triple helical N-doped phenylene cage 8 in 19 %y ield. The structureo ft he N-doped phenylene cage 8 was determined by 1 HNMR, 13 CNMR, ESI-HRMS, and single-crystalX -ray diffraction. Finally,topromote cyclometalation, the N-doped phenylenec age 8 was exposed to Ir(acac) 3 at 210 8Ct og ive the desired caged fac-Ir(ppy) 3 compound 9 in 45 %y ield.…”