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EPR Sensing of a Cation Species by Aza‐Crown Ethers Incorporating a Persistent Nitroxidic Radical Unit.

Authors :
Poderi, Cecilia
Neira, Iago
Franchi, Paola
Mezzina, Elisabetta
Baù, Ilario
Neviani, Paolo
Lucarini, Marco
Source :
Chemistry - A European Journal. 10/2/2023, Vol. 29 Issue 55, p1-9. 9p.
Publication Year :
2023

Abstract

New nitroxides based on aza‐crown ethers were prepared and employed as selective sensors for the detection of inorganic and organic cations by EPR analysis of the corresponding host–guest complexes. The nitroxide unit behaves as a sensitive probe for a number of alkali and alkaline earth metal cations affording EPR spectra differing in the value of nitrogen hyperfine constants and in the appearance of splitted signals due to the non‐zero nuclear spin of some metal cation upon complexation. Owing to the remarkable EPR spectral differences between the host and the corresponding cation complex the new macrocycles are likely to act as multitasking tools to recognize several cationic species. EPR behaviour of the larger nitroxide azacrown 1⋅ when acting as a wheel in a radical synthetic bistable [2]rotaxane containing both secondary dialkylammonium and 1,2‐bis(pyridinium) molecular stations, was also investigated. Reversible movements of the macrocycle between the two recognition sites in the rotaxane were promptly revealed by EPR, which shows significant changes either in nitrogen coupling constant values (aN) or in the spectral shape in the two rotaxane co‐conformations. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09476539
Volume :
29
Issue :
55
Database :
Academic Search Index
Journal :
Chemistry - A European Journal
Publication Type :
Academic Journal
Accession number :
172756892
Full Text :
https://doi.org/10.1002/chem.202301508