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Synthesis, structure and tuneable white‐light emission of dinuclear Eu(III),Tb(III)‐mixed Schiff base complexes
Author(s) -
AlBahri Amani,
AlZakwani Amina S.,
AlFarsi Suhaib M.,
AlRasbi Nawal K.
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201600262
Subject(s) - isostructural , schiff base , luminescence , lanthanide , excited state , ligand (biochemistry) , chemistry , crystallography , emission spectrum , photochemistry , crystal structure , materials science , spectral line , ion , atomic physics , organic chemistry , optoelectronics , biochemistry , physics , receptor , astronomy
Abstract A new family of lanthanide‐Schiff base complexes have been synthesized and fully characterized from the novel Schiff base ligand: H 2 L 1 (acetic acid 2‐hydroxy‐benzylidene‐hydrazide). The single crystal X‐ray structure and mass spectroscopy reveal the isostructural dinuclear complexes: [Ln 2 L 1 (HL 1 ) 3 (NO 3 )] where Ln = Sm, Eu, Gd and Tb. Upon excitation of the Ln III complexes in solution, their luminescence spectra display the broad ligand centred (LC) band at ∼470 nm as well as the narrow f–f transitions. In Eu III complex, the LC emission is efficiently quenched, because of the better triplet state energy match to the Eu III – 5 D 4 excited states. Doping methods of Eu III with Tb III into the complexes: [Eu x Tb 1‐x (L 1 )(HL 1 ) 3 (NO 3 )], x = 0.5 (A), 1.0 (B) and 1.5 (C); in MeOH/DCM (1:10), have revealed variable colours. By careful control of the amounts of Eu III and Tb III in the dinuclear mixed EuTb‐complexes, white‐light emission is obtained from blue LC band, green Tb III luminescence and red Eu III luminescence. Such behaviour is attributed to the efficient sensitization of Eu III by the ligand and the metal to metal energy transfer from Tb III to Eu III excited 4f states.