Evidence map›Paper›PMID 41660852›Full record

ArticleChemistry (Weinheim an der Bergstrasse, Germany)2026

Chain Versus Ring: Characterization of a Meta-Phenylene Ladder Polymer and Its Octameric Macrocycle.

Paulo D Nunes Barradas, Hauke J Jötten, Ngoc B B Nguyen, Ullrich Scherf, J Sérgio de Seixas de Melo

Abstract read
In one paragraph

Article in Chemistry (Weinheim an der Bergstrasse, Germany), 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0cells of the map it votes in
0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Paulo D Nunes BarradasCQC-IMS, Department of Chemistry, University of Coimbra, Coimbra, Portugal.
Hauke J JöttenMacromolecular Chemistry Group (buwmakro) and Wuppertal Center for Smart Materials and Systems (Cm@S), Bergische Universität Wuppertal, Wuppertal, Germany.
Ngoc B B NguyenMacromolecular Chemistry Group (buwmakro) and Wuppertal Center for Smart Materials and Systems (Cm@S), Bergische Universität Wuppertal, Wuppertal, Germany.
Ullrich ScherfMacromolecular Chemistry Group (buwmakro) and Wuppertal Center for Smart Materials and Systems (Cm@S), Bergische Universität Wuppertal, Wuppertal, Germany.ORCID https://orcid.org/0000-0001-8368-4919
J Sérgio de Seixas de MeloCQC-IMS, Department of Chemistry, University of Coimbra, Coimbra, Portugal.ORCID https://orcid.org/0000-0001-9708-5079

Funding

Coimbra Chemistry Centre-Institute of Molecular Sciences (CQC-IMS),Fundação para a Ciência e a TecnologiaPortuguese Agency for Scientific Research
6 · The paper itself

Abstract

A methyl-substituted ladder meta-phenylene macrocycle (MeLMMP) and its corresponding ladder polymer (MeLPMP), a meta-analogue of the well-known ladder-type poly(para-phenylene), LPPP, were synthesized and comprehensively investigated. Both compounds exhibit limited conjugation due to the meta-linked phenylene units, resulting in absorption and emission features shaped by cross-conjugation. Despite having a longer chain, MeLPMP and MeLMMP exhibit nearly identical electronic and photophysical behavior, suggesting that the number of repeat units has minimal influence. MeLPMP exhibits enhanced vibronic resolution compared to MeLMMP due to a broadening of the optical bands of the macrocycle caused by the presence of a mixture of stereoisomers formed during the non-stereoselective ladderization step. A small amount of fluorenone-type keto defects produces a weak emission near 500 nm, more evident in the macrocycle, and introduces radiationless decay pathways that compete with fluorescence. This decay pathway, together with the weak π,π* conjugation in these angular compounds, lowers the fluorescence quantum yield when compared with the linear MeLPPP, while promoting singlet-triplet conversion and phosphorescence. The data indicate the presence of three chromophoric populations: pristine oligo(meta-phenylene) units; units quenched by nearby keto defects; and intramolecular charge-transfer complexes (ICTCs) formed between oligo(meta-phenylene) units and keto defects. These findings clarify the photophysics of meta-phenylene ladder systems, showing that the MeLMMP macrocycle can act as a structural and electronic model for related ladder polymers.

Indexed as

aromatic ladder polymersladder‐type meta‐phenylene macrocyclemeta‐phenylene ladder polymertime‐correlated single‐photon counting

Identifiers

PMID41660852
PMCPMC13109684

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