Bright green luminescent molecular terbium plastic materials derived from 3,5-bis(perfluorobenzyloxy)benzoateElectronic supplementary information (ESI) available: NMR spectra of ligand, FT-IR spectra of ligand, complexes, PMMA and polymer films, TG data, phosphorescence spectrum of gadolinium complex 3, low-temperature luminescence decay profiles for complexes 1-2 and polymer films. See DOI: 10.1039/c2jm30535f

• Main Authors: Sivakumar, Sarika, Reddy, M. L. P
• Format: Article
• Language: English
• ISSN: 0959-9428; 1364-5501
• DOI: 10.1039/c2jm30535f

Luminescent lanthanide complexes (Eu 3+ ( 1 ) or Tb 3+ ( 2 )) involving a highly fluorinated aromatic carboxylate, namely, 3,5-bis(perfluorobenzyloxy)benzoic acid which acts as an antenna chromophore and sensitizes the visible emitting lanthanides, have been synthesized and characterized and their photophysical properties investigated. The results demonstrated that the replacement of high-energy C-H vibrations with fluorinated phenyl groups in the 3,5-bis(benzyloxy)benzoate effectively improves the luminescence intensity and lifetimes of lanthanide complexes. It is interesting to note that the designed fluorinated carboxylate is well suited for the sensitization of Tb 3+ emission ( Φ sen = 52%), thanks to a favorable position of the triplet state of the ligand as investigated in the Gd 3+ complex. On the other hand, the corresponding Eu 3+ complex shows weak luminescence efficiency ( Φ sen = 24%) due to poor match of the triplet state of the ligand with the emissive excited states of the metal ion. In the present work, efforts have also been made to isolate luminescent molecular terbium plastic materials by combining the unique optical properties of lanthanides with the mechanical characteristics, thermal stability, flexibility and film-forming tendency of polymers (PMMA). The photoluminescence quantum yields of polymer-lanthanide hybrid materials are significantly enhanced (53-65%) as compared to that of the Tb 3+ -3,5-bis(perfluorobenzyloxy)benzoate complex. This work focuses on the development of bright green luminescent molecular terbium plastic materials, which exhibit impressive quantum yields (65%) and excited state lifetime values (1.49 ms).