Phenyl-substituted PPV

H Spreitzer, H Becker, E Kluge, W Kreuder, H Schenk, R Demandt, and H Schoo, Soluble phenyl-substituted PPVs — new materials for highly efficient polymer LEDs, Adv. Mater., 10 1340-1343, 1998. 

A totally different route based on dehydrogenation of a saturated polymer precursor was introduced by Francois et al. [49] (Scheme 2.9). The method is based on anionic copolymerization of cyclohexadiene with styrene, followed by oxidation with chloranil. Due to possible coupling of two styrene (or two cyclohexadiene) molecules, a block copolymer, containing oligo(phenylene vinylene) units separated by oligo(phenylacetylene) and oligo(phenylene) blocks, is obtained. To the best of our knowledge, it was, so far, used only in the synthesis of phenyl-substituted PPV 10. 

An important extension to phenyl-substituted PPVs was first reported by Tsutsui and coworkers [115], who used Gilch polymerization to synthesize fluorenyl-substituted PPVs (57,58,59) and studied their performance in PLEDs (Chart 2.11). Due to bulky but rigid fluorene substituents, these polymers have excellent solubility and yet are thermally stable up to 320°C and have a... 

In Aldrich, the widest collection belongs to PPV derivatives, which includes dialkoxy-PPVs (e.g., MEH-PPV 13,14), phenyl-substituted PPV 43, meta-para-linked PPV copolymer 159, etc. Many monomer precursors for PPV synthesis by Gilch and Wittig procedure as well as the Wessling Zimmerman precursor 2 for unsubstituted PPV are also available. 

Substituted-PPVs and a number of PPV copolymers have been synthesized, illustrated in Scheme 46, using the Heck reaction shown above [178-180]. Of these polymers both the phenyl-substituted PPV and the biphenylene vinylenes are soluble in organic solvents while the methyl-, trifluoromethyl-, nitro- and fluoro-substituted analogs displayed poor solubility. 

Scheme 16 Synthesis of phenyl-substituted PPV according to Horhold.

Palladium-mediated catalysis has only been exploited relatively recently in the synthesis of substituted PPV derivatives. The use of aryl dibromides as monomers is particularly useful as it allows the synthesis of PPVs substituted with alkyl rather than alkoxy sidechains. The Suzuki [53, 54], Heck [55], and Stille [56] reactions have been used in the synthesis of new PPV derivatives, but attaining high molecular weight PPV derivatives by these methodologies has proved problematic. A phenyl-substituted PPV material PPPV 31 was synthesized by a Suzuki coupling (Scheme 1-10) of dibromoethene and feA-boronic acid 30. Its absorption (2max = 385 nm) and emission (/li ax=475 nm) maxima were strongly... 

SCHEME 4.7 Oxidation of phenyl-substituted PPVs to form phenanthrene-based polymers. 

Spreitzer, H., H. Becker, E. Kluge, W. Kreuder, H. Schenk, R. Demandt, and H. Schoo. 1998. Soluble phenyl-substituted Ppvs-new materials for highly efficient polymer leds. AdvMater 10 (16) 1340-1343. 

Spreitzer, H., Becker, H., Kluge, E., Kreuter, W., Schenk, H., Schmidt, R. and Schoo, H., (1998), Soluble Phenyl-Substituted PPVs—New Materials for Highly Efficient Polymer LEDs. Ado. Mater. Vol.lO, 1340-1343. 

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