| Autor: |
Li N; Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW, UK. dsw1000@cam.ac.uk., Subramanian GS, Matthews PD, Xiao J, Chellappan V, Rosser TE, Reisner E, Luo HK, Wright DS |
| Jazyk: |
angličtina |
| Zdroj: |
Dalton transactions (Cambridge, England : 2003) [Dalton Trans] 2018 Apr 24; Vol. 47 (16), pp. 5679-5686. |
| DOI: |
10.1039/c8dt00825f |
| Abstrakt: |
Polyoxotitanate (POT) cages have attracted considerable attention recently; much of this from the fact that they can be considered to be structural models for the technologically important semiconductor TiO2. Among the reported POT cages, lanthanide-containing (Ln-POT) cages are of particular interest owing to the fascinating luminescence properties of Ln3+ ions and the versatile coordination environments that they can adopt. In the present study, we report the energy transfer mechanism and photoluminescence properties of a series of isostructural Ln-POT cages coordinated by salicylate ligands, of general formula [LnTi6O3(OiPr)9(salicylate)6] (Ln-1, Ln = La to Er excluding Pm). Both visible (for Pr-1, Sm-1, Eu-1, Ho-1 and Er-1) and near-infrared (for Nd-1 and Er-1) Ln3+-centred photoluminescence can be sensitised in solution, and most importantly, their excitation bands all extend well into the visible region up to 475 nm. With the assistance of steady-state and time-resolved photoluminescence spectroscopy, an energy-transfer mechanism involving the salicylate-to-Ti4+ charge-transfer state is proposed to account for the largely red-shifted excitation wavelengths of these Ln-1 cages. The photoluminescence quantum yield of Nd-1 upon excitation via the charge-transfer state reaches 0.30 ± 0.01% in solution, making it among the highest reported values for Nd3+-complexes in the literature. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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