Macromol. Rapid Commun. 12/2009

Preparation of poly(p-phenylene vinylene) derivatives by a debromination–chain polymerization–debromination sequence

“…Nonzero values for Br obtained for P1b-P1c prepared by the DPD route presumably arise when the growing PPV chains precipitate from solution above a certain molecular weight. [7] It is SCHEME 2 Proposed mechanism for DPD route to PPV important to note that there are twice as many bromo substituents per repeat unit in the precursor monomer for the DPD route compared to the precursor monomer in the Gilch route (Scheme 1A, top pathway). Nonetheless, P1b produced by the DPD protocol features less than one third the number of unreacted bromides compared to P1b produced by the Gilch route.…”

“…[4,5] Unfortunately, several of the more common synthetic avenues that can be used to prepare high molecular weight PPVs, such as Gilch, Wessling and Vanderzande routes, [6][7][8] involve polymerization of asymmetric active monomers and thus lead to polymers with small percentages of defects in the conjugated backbone (Scheme 1A). Even a small amount of such defects can diminish or alter the optoelectronic performance of PPVs leading to irreproducible performance [9,10] or performance deficiencies.…”

Conducting Polymers

“…2.2.3.2 Poly(p-Phenylene) (PPP) and Poly(Phenylenevinylene) (PPPV) [883][884][885][886][887][888][889][890][891] Poly(p-Phenylene) (PPP) [883][884][885][886][887] n PPP Synthesis: reductive coupling of dihalogenophenyl compounds in the presence of Ni 0 complexes [883][884][885] or oxidative coupling of cation radicals originating from either benzene or biphenyl species in weakly nucleophilic media [887]. Highly crystalline PPP films have been prepared by electrochemical oxidation from benzene/96% H 2 SO 4 solution [885,886].…”

“…Poly(Phenylenevinylene) (PPPV) [888][889][890][891] Synthesis: electrochemical reduction of a,a,a 0 ,a 0 -tetrabromo-p-xylene TEABF 4 / DMF + 0.2% H 2 O at À2.3 V [888]. Poly(1-methoxy-4-(2-ethyl-hexyloxy)-pphenylenevinylene) (MEH-PPV) was prepared by chemical synthesis [890].…”

Donor–Acceptor 1,4‐Fluorenylene Chromophores: Photophysics, Electrochemistry, and Synthesis through a Route for Asymmetric Chromophore Preparation

“…It is possible to substitute a styryl units for one of two substituents of a 1,4-X 2 -benzene precursor, but this approach generally requires tedious separation of starting materials, monosubstituted and disubstituted materials and consequently produces poor overall yields. Although this strategy worked well on the bipyridine derivative, it is not directly as useful for preparing 1,4-distyrylbenzene derivatives because the electronic communication between the two benzylic sites leads to side reactions such as polymerization through Gilch-like pathways [33] upon exposure to the base required for the Wittig reaction stage. Alternatively, a Wittig reaction can be carried out to yield a stilbene moiety having a halogen substituent that can be subsequently converted into either an aldehyde for the second Wittig-type coupling or used for Heck coupling to yield the second olefin linkage (Scheme 1, B).…”