Poly phenylene vinylene Gilch synthesis

The sulfonium precursor route may also be applied to alkoxy-substituted PPVs, but a dehydrohalogenation-condensation polymerization route, pioneered by Gilch, is favored 37]. The polymerization again proceeds via a quinomethide intermediate, but die syndicsis of the conjugated polymer requires only two steps and proceeds often in improved yields. The synthesis of the much-studied poly 2-methoxy-5-(2-ethylhexyloxy)-l,4-phenylene vinylene], MEH-PPV 15 is outlined in Scheme 1-5 33, 35]. The solubility of MEH-PPV is believed to be enhanced by the branched nature of its side-chain. 

The second approach to PPV, is the Gilch synthesis [147], which consists in the introduction of solubilizing side groups, as represented in the case of the most studied dialkoxy derivative poly[2-methoxy-5-(2 -ethylhexyloxy)-l,4-phenylene vinylene] (MEH-PPV, XII) [29,148-150] (Fig. 9.20). 

Example 6.5 Synthesis of Poly [2-(p-Ethylhexyloxy)-5-Methoxy]-Para-Phenylene Vinylene ("MEH-PPV") Via Gilch Reaction... 

Yin, C., and C.-Z. Yang. 2001. Mechanism analysis of the PEG-participated Gilch synthesis for soluble poly(p-phenylene vinylene) derivatives. J Appl Polym Sci 82 263. 

However, we need to note that other chemical routes, rather than oxidation polymerization, can also be applied for conducting polymer synthesis. For example, polymers such as poly(pheny lene vinylene), poly(phenylene ethynylene), and their derivatives are usually synthesized using the Wittig reaction (Wittig and Schollkopf 1954), Heck reaction (Heck and Nolley 1972), and Gilch... 

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