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Sensitized terbium(III) macrocyclic-phthalimide complexes as luminescent pH switches
Gaoyun Chen1, Nicholas J Wardle, Jason Sarris
1School of Human Sciences, Faculty of Life Sciences and Computing, London Metropolitan University, 166-220 Holloway Road, London N7 8DB, UK. n.chatterton@londonmet.ac.uk.
Researchers developed new Tb(III) complexes for pH sensing. These macrocyclic sensors show "switched on" luminescence in a specific pH range, offering high sensitivity and long lifetimes.
Area of Science:
- Coordination Chemistry
- Supramolecular Chemistry
- Luminescent Materials
Background:
- Development of lanthanide complexes for sensing applications.
- Importance of macrocyclic ligands in stabilizing metal ions.
- pH-dependent luminescence in Tb(III) complexes.
Purpose of the Study:
- Synthesize novel macrocyclic-phthalimide ligands.
- Investigate the photophysical properties of their Tb(III) complexes.
- Evaluate their performance as pH sensors.
Main Methods:
- Ligand synthesis via coupling reactions.
- Preparation of Tb(III) complexes.
- Spectroscopic analysis (luminescence) as a function of pH.
Main Results:
- Successful synthesis of four new macrocyclic-phthalimide ligands.
- Tb(III) complexes exhibited pH-dependent luminescence, switching from 'off' to 'on' between pH 4 and 11.
- Activated complexes showed high quantum yields (46%) and long lifetimes (2.4 ms) at pH ~ 6.
- Luminescence intensity decreased with an increased number of chromophores.
Conclusions:
- The synthesized Tb(III) complexes function as effective pH sensors.
- The macrocyclic architecture enhances sensor performance.
- These complexes represent a significant advancement in Tb(III)-based pH sensing technology.
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