Caterpillar Track Complexes in Template-Directed Synthesis and Correlated Molecular Motion

Small alterations to the structure of a star‐shaped template totally change its mode of operation. The hexapyridyl template directs the conversion of a porphyrin dimer to the cyclic hexamer, but deleting one pyridine site changes the product to the cyclic decamer, while deleting two binding sites ch...

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Bibliographic Details
Published in:Angewandte Chemie (International ed.) 2015-04, Vol.54 (18), p.5355-5359
Main Authors: Liu, Shiqi, Kondratuk, Dmitry V., Rousseaux, Sophie A. L., Gil-Ramírez, Guzmán, O'Sullivan, Melanie C., Cremers, Jonathan, Claridge, Tim D. W., Anderson, Harry L.
Format: Article
Language:English
Subjects:
Binding
Binding sites
Caterpillars
Communications
Correlation
Exchange
molecular gears
molecular motion
Molecular structure
Nanostructure
porphyrinoids
Pyridines
supramolecular chemistry
Synthesis
templated synthesis
Wheels
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Summary:Small alterations to the structure of a star‐shaped template totally change its mode of operation. The hexapyridyl template directs the conversion of a porphyrin dimer to the cyclic hexamer, but deleting one pyridine site changes the product to the cyclic decamer, while deleting two binding sites changes the product to the cyclic octamer. This surprising switch in selectivity is explained by the formation of 2:1 caterpillar track complexes, in which two template wheels bind inside the nanoring. Caterpillar track complexes can also be prepared by binding the hexapyridyl template inside the 8‐ and 10‐porphyrin nanorings. NMR exchange spectroscopy (EXSY) experiments show that these complexes exhibit correlated motion, in which the conrotatory rotation of the two template wheels is coupled to rotation of the nanoring track. In the case of the 10‐porphyrin system, the correlated motion can be locked by binding palladium(II) dichloride between the two templates. Turning in unison: Two wheel‐like templates work together to direct the synthesis of a nanoring. Their rotation is synchronized in the resulting 2:1 caterpillar track complex.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201412293