Synthesis and Characterisation of a Paramagnetic [2]Rotaxane Based on a Crown Ether-Like Wheel Incorporating a Nitroxide Motif.

Autor: Bleve V; Department of Chemistry 'Giacomo. Ciamician', University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy., Franchi P; Department of Chemistry 'Giacomo. Ciamician', University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy., Konstanteli E; Department of Chemistry 'Giacomo. Ciamician', University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy.; Nationaland Kapodistria, University of Athens, Greece., Gualandi L; Department of Chemistry 'Giacomo. Ciamician', University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy., Goldup SM; Department of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK., Mezzina E; Department of Chemistry 'Giacomo. Ciamician', University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy., Lucarini M; Department of Chemistry 'Giacomo. Ciamician', University of Bologna, Via S. Giacomo 11, 40126, Bologna, Italy.
Jazyk: angličtina
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2018 Jan 24; Vol. 24 (5), pp. 1198-1203. Date of Electronic Publication: 2017 Dec 14.
DOI: 10.1002/chem.201704969
Abstrakt: The synthesis of the new nitroxide crown ether 8 and its use as the wheel in a bistable [2]rotaxane, containing dialkylammonium and 4,4'-bipyridinium recognition sites, is reported. The synthesis of 8 was achieved by the sequential addition of substituted phenyl groups to a nitrone derivatives leading to the preferential formation of the cis stereoisomer. Due to charge-dipole interactions between the nitroxide unit and the bipyridinium moiety, it was possible to probe the movement of the macrocycle between the two molecular stations of the [2]rotaxane after addition of a base by measuring the nitrogen hyperfine splitting in the corresponding EPR spectra. The equilibrium constant for the complexation of dibenzyl viologen by the macrocycle 8 was also determined by EPR titration.
(© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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