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Cycloparaphenylenes and Their Catenanes: Complex Macrocycles Unveiled by Ion Mobility Mass Spectrometry
Author(s) -
Zhang Wen,
Abdulkarim Ali,
Golling Florian E.,
Räder Hans Joachim,
Müllen Klaus
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201611943
Subject(s) - catenane , mass spectrometry , chemistry , phenylene , ion mobility spectrometry , homologous series , ion , aromatization , combinatorial chemistry , molecule , computational chemistry , stereochemistry , crystallography , organic chemistry , chromatography , catalysis , polymer
The insoluble product mixture obtained from cycloparaphenylene (CPP) synthesis from Suzuki coupling and reductive aromatization was analyzed. Traditional mass spectrometry suggests a homologous series of macrocycles with 12 to 84 phenylene units. Ion‐mobility mass spectrometry, however, unravels an unexpected complexity of isomers with identical chemical formula, but different topologies. Whereas macrocycles containing up to 30 phenylene units show only one structure, the homologue with 36 phenylene units forms at least four different isomers with significant molecular size differences. They can be assigned to catenanes composed of CPPs with 2×18 and 12+24 phenylene units together with the ordinary [36]CPP macrocycle. Most likely, a trefoil knot of the CPP with 36 moieties is also present. For the first time, catenanes can be elucidated in a simple reaction mixture by analyzing their ions in the gas phase, an analysis which lies beyond the scope of traditional analytical methods.