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Pyridine‐Based Macrocyclic and Open Receptors for Urea
Author(s) -
Adhikari Suman,
Kar Debasis,
Fröhlich Roland,
Ghosh Kumaresh
Publication year - 2019
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201902451
Subject(s) - urea , chemistry , intramolecular force , fluorescence , thiourea , fluorescence spectroscopy , hydrogen bond , pyridine , quenching (fluorescence) , monomer , excimer , proton nmr , receptor , photochemistry , molecule , stereochemistry , medicinal chemistry , organic chemistry , polymer , biochemistry , quantum mechanics , physics
Pyridine‐based macrocyclic and open receptors 1–4 have been designed, synthesized and characterized. The macrocycle 1 was characterized by single crystal X‐ray spectroscopy. Compound 2 selectively binds and recognizes urea in CHCl 3 . Fluorescence spectroscopy shows that compound 2 selectively displays quenching of monomer emission followed by formation of an intramolecular excimer upon hydrogen bond mediated complexation of urea. This distinguishes urea from thiourea. The fluorometric detection of urea has also been performed with the open receptors 3 and 4 in CHCl 3 . The detailed study reveals the effectivity of 2 in fluorescence sensing of urea over the structures 3 and 4 . The urea recognition properties of receptors were evaluated by 1 H NMR, fluorescence and UV‐vis studies.