1. Influence of upper rim dibromo-substitution in bis-1,3-diketone calix[4]arenes on spectral properties of ligands and their lanthanide complexes
- Author
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Rinas N. Nagimov, Dmitry V. Lapaev, Gulnaz Sh. Gimazetdinova, Nataliya Shamsutdinova, Victor V. Syakaev, Aidar T. Gubaidullin, Asiya R. Mustafina, Sergey N. Podyachev, and Svetlana N. Sudakova
- Subjects
Diketone ,Lanthanide ,010405 organic chemistry ,Chemistry ,Ligand ,Organic Chemistry ,Antenna effect ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Crystallography ,Excited state ,Drug Discovery ,Calixarene ,Triplet state ,Luminescence - Abstract
The present work introduces the synthesis and characterization of upper rim dibromo-substituted bis-1,3-diketone calix[4]arenes with hydroxy and propyloxy groups at the lower rim as ligands for Gd3+ and Tb3+ complexes. The dibromo-substitution does not affect 1:1 complex formation with the lanthanide ions arising from their coordination via two 1,3-diketonate groups incorporated at the upper rim of the calix[4]arene. The analysis of the time-resolved luminescence spectra of the Gd3+ complexes clearly demonstrates the notable enhancement of the decay time of the ligand triplet state, while the energy of the triplet state for the new dibromo-bis-1,3-diketones remains practically unchanged versus its non-substituted analogues. The latter tendency points to the heavy-atom effect on the energy transfer from the excited state to vibration levels of the dibromo-substituted ligand resulting in a decreased radiationless decay contribution. Measurements of Tb3+-centered luminescence indicate a better antenna effect (∼1.7) of dibromo-calix[4]arenes compared with its non-substituted counterpart.
- Published
- 2017