A [Cyclentetrakis(methylene)]tetrakis[2‐hydroxybenzamide] Ligand That Complexes and Sensitizes Lanthanide(III) Ions |
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| Authors: | Anthony D'Aléo Jide Xu King Do Gilles Muller Kenneth N. Raymond |
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| Affiliation: | 1. Chemical Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, CA 94720, and Department of Chemistry, University of California, Berkeley, CA 94720‐1460, USA;2. Department of Chemistry, San José State University, San José, CA 95192‐0101, USA |
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| Abstract: | The synthesis of the cyclen derivative H4 L 1 ?2 HBr containing four 2‐hydroxybenzamide groups is described. The spectroscopic properties of the LnIII conplexes of L 1 (Ln=Gd, Tb, Yb, and Eu) reveal changes of the UV/VIS‐absorption, circular‐dichroism‐absorption, luminescence, and circularly polarized luminescence spectra. It is shown that at least two metal‐complex species are present in solution, whose relative amounts are pH dependent. At pH>8.0, an intense long‐lived emission is observed (for [Tb L 1 ] and [Yb L 1 ]), while at pH<8.0, a weaker, shorter‐lived species predominates. Unconventional LnIII emitters (Pr, Nd, Sm, Dy, and Tm) were sensitized in basic solution, both in the VIS and in the near‐IR, to measure the emission of these ions. |
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| Keywords: | Lanthanide complexes Luminescence Circularly polarized luminescence (CPL) |
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