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Structural and luminescence studies of trivalent europium complexes with pentaethylene glycol and 18-crown-6 ligands in the presence of picrate anion
- Source :
-
Journal of Luminescence . Oct2007, Vol. 126 Issue 2, p871-880. 10p. - Publication Year :
- 2007
-
Abstract
- Abstract: Two new isostructural complexes of europium picrate (Eu-Pic) with pentaethylene glycol (EO5) and 18-crown-6 (18C6) ligands formed complexes of molecular formula [Eu(Pic)2(18C6)]+(Pic)− I and [Eu(Pic)2(EO5)]+(Pic)− II have been isolated and characterised. Compound I showed 10-coordination number through six oxygen atoms from the 18C6 ligand and two bidentate picrate anions. Meanwhile, compound II exhibited 9-coordination number via six oxygen atoms from EO5 ligand, two oxygen atoms from a bidentate and one oxygen atom from monodentate picrate anions. Photoluminescence (PL) spectra of the solid-state europium complexes display sharp lines which are assigned to 5D0→7F0–4 and 5D1→7F1,2,4 transitions. No emission of polyether ligands is observed, indicating that the energy transfer from the polyether ligands to the Eu3+ ion is quite efficient. The PL spectra of [Eu(Pic)2(OH2)6]+(Pic)−·6H2O III, [Eu(NO3)3(OH2)3]·(18C6) IV, [Eu(NO3)3·6H2O] V and Eu2O3 VI are also observed. Compounds I–IV exhibited high Ω 2 intensity parameter values, namely 16.93, 10.23, 17.10 and 12.35 (in units of 10−20 cm2), respectively. These relatively high values reflect the hypersensitive behaviour of the 5D0→7F2 transition and indicate that the Eu3+ ion is located in a highly polarisable chemical environment. [Copyright &y& Elsevier]
- Subjects :
- *LUMINESCENCE
*PHOTOLUMINESCENCE
*ANIONS
*POLYETHERS
Subjects
Details
- Language :
- English
- ISSN :
- 00222313
- Volume :
- 126
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Journal of Luminescence
- Publication Type :
- Academic Journal
- Accession number :
- 25127707
- Full Text :
- https://doi.org/10.1016/j.jlumin.2007.01.017