Novel trivalent europium beta-diketonate complexes with N-(pyridine-2-yl)amides and N-(pyrimidine-2-yl)amides as ancillary ligands: Photophysical properties and theoretical structural modeling
authors Lima, GBV; Bueno, JC; da Silva, AF; Neto, ANC; Moura , RT; Teotonio, EES; Malta, OL; Faustino, WM
nationality International
journal JOURNAL OF LUMINESCENCE
author keywords Europium; beta-diketonates; N-(pyridine-2-yl)amides; N-(pyrimidine-2-yl)amides; Intensity parameters; Photoluminescence
keywords TRIPLET-STATE ENERGY; SPECTROSCOPIC PROPERTIES; INTENSITY PARAMETERS; QUANTUM YIELDS; LUMINESCENT PROPERTIES; ELECTRONIC-STRUCTURE; 4F-4F TRANSITIONS; EU(III) COMPLEXES; MIXED COMPLEXES; AB-INITIO
abstract Eighteen new Eu3+ complexes and their Gd3+ analogues with 1,3-diketonate as main ligands and N-(pyridine-2-yl)amides or N-(pyrimidine-2-yl)amides as ancillary ligands were synthesized. The replacement of water molecules by those amides in the Eu3+ complexes increase the intrinsic quantum yields of luminescence, making them comparable or even more efficient than Eu3+ complexes with standard ancillary ligands such as 2,2'-bipyridine. The luminescence spectra of Gd3+ complexes in comparison with the Eu3+ ones show that efficient ligand-tometal intramolecular energy transfer processes take place. In most cases the experimental Judd-Ofelt intensity parameters (Omega(2) and Omega(4)) for the Eu3+ complexes show variations as a function of the temperature (77 and 300K) that overall apparently does not follow clearly any trend. For this reason, geometric variations (on the azimuthal angle phi and ancillary ligands distances) were carried out in the coordination polyhedron for simulating thermally induced structural changes. It has been observed that, in this way, the Omega(2) and Omega(4) can be satisfactorily reproduced by in silica experiments. It was concluded that, at low-temperature, the ancillary ligands become closer to the Eu3+ ion and the angular variations affect more Omega(2) than Omega(4), in agreement to the theoretical calculations. The use of N-(pyridine-2-yl)amides or N-(pyrimidine-2-yl)amides as ancillary ligands in Eu3+ 1,3-diketonates looks to be a good strategy for obtaining highly luminescent complexes.
publisher ELSEVIER
issn 0022-2313
isbn 1872-7883
year published 2020
volume 219
digital object identifier (doi) 10.1016/j.jlumin.2019.116884
web of science category Optics
subject category Optics
unique article identifier WOS:000507896800048
  ciceco authors
  impact metrics
journal analysis (jcr 2019):
journal impact factor 3.28
5 year journal impact factor 2.824
category normalized journal impact factor percentile 78.866
dimensions (citation analysis):
altmetrics (social interaction):



 


Sponsors

1suponsers_list_ciceco.jpg