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Aza‐ and Mixed Thia/Aza‐Macrocyclic Receptors with Quinoline‐Bearing Pendant Arms for Optical Discrimination of Zinc(II) or Cadmium(II) Ions
Author(s) -
Garau Alessandra,
Aragoni M. Carla,
Arca Massimiliano,
Bencini Andrea,
Blake Alexander J.,
Caltagirone Claudia,
Giorgi Claudia,
Lippolis Vito,
Scorciapino Mariano Andrea
Publication year - 2020
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.202000444
Subject(s) - chemistry , quinoline , amide , zinc , fluorescence , chelation , metal ions in aqueous solution , potentiometric titration , cadmium , ligand (biochemistry) , metal , selectivity , stereochemistry , coordination complex , medicinal chemistry , crystallography , ion , receptor , inorganic chemistry , organic chemistry , biochemistry , physics , quantum mechanics , catalysis
Abstract The synthesis and coordination properties of two fluorescent chemosensors, featuring [9]aneN 3 (1,4,7‐triazacyclononane; L1 ) and [12]aneNS 3 (1‐aza‐4,7,10‐trithiacyclododecane; L2 ) as receptor units, and a quinoline pendant arm with an amide group as a functional group spacer are described. The optical responses of L1 and L2 in the presence of several metal ions were analysed in MeCN/H 2 O (1 : 4 v/v) solutions. A selective chelation enhancement of fluorescence (CHEF) effect was observed in the presence of Zn 2+ in the case of L1 , and in the presence of Cd 2+ in the case of L2 , following the formation of a 1 : 1 and a 1 : 2 metal/ligand complex, respectively, which was also confirmed by potentiometric measurements. 1 H and 13 C NMR measurements in CD 3 CN/CDCl 3 in combination with molecular mechanics calculations show that for both complexes of L1 and L2 with Zn 2+ and Cd 2+ , respectively, the coordination of the carbonyl group from the pendant arm could be the origin of the observed optical selectivity.