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Transition Metal Ions or Acid‐induced Suppression of Photoinduced Proton Transfer and Electron Transfer Reaction in 5‐(4‐Fluorophenyl)‐2‐hydroxypyridine: A Molecule of Dual Mode Fluorosensitivity
Author(s) -
Samanta Anuva,
Paul Bijan Kumar,
Jana Sankar,
Guchhait Nikhil
Publication year - 2010
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2010.00785.x
Subject(s) - chemistry , photochemistry , electron transfer , molecule , fluorescence , photoinduced electron transfer , excited state , metal ions in aqueous solution , ion , quenching (fluorescence) , tautomer , proton , enol , transition metal , atomic physics , stereochemistry , organic chemistry , catalysis , physics , quantum mechanics
The photophysical properties of 5‐(4‐fluorophenyl)‐2‐hydroxypyridine (FP2HP) at different pH and its fluorescence response toward different transition metal ions have been studied by steady‐state absorption and emission spectroscopy in combination with quantum chemical calculations. Although keto‐enol tautomerization is observed in the excited state, the molecule is weakly fluorescent due to the presence of electron‐rich nitrogen atom and relatively electron‐deficient fluorine atom, which may lead to photoinduced electron transfer process. In the presence of the transition metal ions, such as Zn 2+ , Cd 2+ , Hg 2+ , etc., the studied molecule exhibits changes in its absorption and emission properties. The present system shows fluorescence enhancement instead of usual quenching in presence of the transition metal ions, such as Fe 2+ and Cu 2+ . Spectral observation leads to the interpretation that this structurally simple molecule can be effectively utilized as a chelation‐enhanced fluorescence‐based chemosensor for the detection of transition metal ions. The experimental findings corroborate well with theoretical calculations at Hartree–Fock level using 6‐31G** and lanl2dz basis sets.