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The Gilch Synthesis of Poly(p-phenylene vinylenes): Mechanistic Knowledge in the Service of Advanced Materials

Schwalm, Thorsten and Wiesecke, Jens and Immel, Stefan and Rehahn, Matthias (2009):
The Gilch Synthesis of Poly(p-phenylene vinylenes): Mechanistic Knowledge in the Service of Advanced Materials.
In: Macromolecular Rapid Communications, pp. 1295-1322, 30, (15), ISSN 10221336, [Online-Edition: http://dx.doi.org/10.1002/marc.200900104],
[Article]

Abstract

A consistent picture is presented of the mechanistic details and intermediates of the Gilch polymerization leading to poly(p-phenylene vinylenes) (PPVs). In-situ generated p-quinodimethanes are shown to be the real monomers, and spontaneous formation of the initiating radicals is effected by dimerization of some of these monomers to dimer diradicals, the latter also being the reason why significant amounts of [2.2]paracyclophanes are formed as side-products. Chain propagation predominantly proceeds by radical chain growth, occasionally interrupted by polyrecombination events between the growing α,ω-macro-diradicals. Based on this knowledge, oxygen is identified as a very efficient molar-mass regulating agent, and the temporary gelation of the reaction mixtures is interpreted to be the consequence of a very high entanglement of the polymers immediately after their formation. Last but not least, it is rationalized why the usually considered constitutional defects in Gilch PPVs might not be the only and most relevant ones with respect to the efficiency and durability of the organic light emitting devices produced thereof, and why cis-configurated halide-bearing vinylene moieties should be perceived as being among the most critical candidates. These considerations result in the recommendation of straightforward measures that should lead to clearly improved PPVs.

Item Type: Article
Erschienen: 2009
Creators: Schwalm, Thorsten and Wiesecke, Jens and Immel, Stefan and Rehahn, Matthias
Title: The Gilch Synthesis of Poly(p-phenylene vinylenes): Mechanistic Knowledge in the Service of Advanced Materials
Language: English
Abstract:

A consistent picture is presented of the mechanistic details and intermediates of the Gilch polymerization leading to poly(p-phenylene vinylenes) (PPVs). In-situ generated p-quinodimethanes are shown to be the real monomers, and spontaneous formation of the initiating radicals is effected by dimerization of some of these monomers to dimer diradicals, the latter also being the reason why significant amounts of [2.2]paracyclophanes are formed as side-products. Chain propagation predominantly proceeds by radical chain growth, occasionally interrupted by polyrecombination events between the growing α,ω-macro-diradicals. Based on this knowledge, oxygen is identified as a very efficient molar-mass regulating agent, and the temporary gelation of the reaction mixtures is interpreted to be the consequence of a very high entanglement of the polymers immediately after their formation. Last but not least, it is rationalized why the usually considered constitutional defects in Gilch PPVs might not be the only and most relevant ones with respect to the efficiency and durability of the organic light emitting devices produced thereof, and why cis-configurated halide-bearing vinylene moieties should be perceived as being among the most critical candidates. These considerations result in the recommendation of straightforward measures that should lead to clearly improved PPVs.

Journal or Publication Title: Macromolecular Rapid Communications
Volume: 30
Number: 15
Uncontrolled Keywords: conjugated polymers; Gilch synthesis; mechanism elucidation; polymerization (general); poly(p-phenylene vinylenes)
Divisions: DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis > Subproject A5: Synthesis of semiconducting model polymers and their characterization before and after cyclic electrical fatigue
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Date Deposited: 04 Aug 2011 14:36
Official URL: http://dx.doi.org/10.1002/marc.200900104
Additional Information:

SFB 595 A5

Identification Number: doi:10.1002/marc.200900104
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