Premium
Naphthalimide‐Containing Isomeric Urea Derivatives: Mechanoluminescence and Fluoride Recognition
Author(s) -
Devi Kakali,
Sarma Rupam J
Publication year - 2017
Publication title -
chemphotochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 18
ISSN - 2367-0932
DOI - 10.1002/cptc.201700123
Subject(s) - mechanoluminescence , fluorescence , fluoride , chemistry , urea , solvent , proton nmr , photochemistry , intramolecular force , inorganic chemistry , stereochemistry , organic chemistry , luminescence , materials science , optoelectronics , optics , physics
Isomeric ortho , meta and para naphthalimide–urea derivatives ND‐2U , ND‐3U and ND‐4U were synthesized and characterized. Upon gentle mechanical stimulation, the weakly emissive ortho isomeric sample ND‐2U was transformed into a yellow‐green emissive material ( λ em =500 nm), with Δ λ ≈125 nm. The mechanoluminescent emission of this isomer could be “switched off” by exposing the sample to solvent vapour. Moreover, ND‐2U could respond to fluoride anions in solution with a dramatic enhancement of fluorescence at λ =446 nm. The sigmoidal nature of the binding isotherm suggested cooperative binding of fluoride to the ortho isomer. 1 H NMR spectroscopic studies provided vital insights into the nature of ND‐2U /F − complexation, highlighting the role of the proximal 1,8‐naphthalimide motif.