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CC BY-NC-ND 4.0 · Organic Materials 2020; 02(02): 159-164
DOI: 10.1055/s-0040-1710348
Original Article
The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/). (2020) The Author(s).

Reliably Estimating the Length of the Effectively Conjugated Segment in Ladder Poly(para-phenylene)s

Robin Ammenhäuser
a   University of Wuppertal, Macromolecular Chemistry Group, Gauss-Str. 20, D-42119 Wuppertal, Germany
,
Anke Helfer
a   University of Wuppertal, Macromolecular Chemistry Group, Gauss-Str. 20, D-42119 Wuppertal, Germany
,
Ullrich Scherf 
a   University of Wuppertal, Macromolecular Chemistry Group, Gauss-Str. 20, D-42119 Wuppertal, Germany
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Publication History

Received: 02 March 2020

Accepted after revision: 03 April 2020

Publication Date:
29 May 2020 (online)

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Abstract

In 1995 we extrapolated the so-called “effective conjugation length” in (para-phenylene) ladder polymers by relating the optical absorption energy to the reciprocal chain length of ladder-type oligo-(para-phenylene)s, but only based on three short-chain oligomers (a trimer, a pentamer, and a heptamer). The resulting value of 11–12 benzene rings was distinctly lower than the numbers reported for corresponding single-stranded, soluble poly(para-phenylene)s. Here, we report a series of elongated (para-phenylene)-type ladder oligomers that were isolated via repeated recycling size exclusion chromatography steps from an oligomer mixture. Now we are able to extrapolate the length of the “effectively conjugated segment” with much more precision to be 19 ± 2 benzene rings.

Key words

ladder - poly(para-phenylene)s - effectively conjugated segment - SEC

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