Synthesis, structure and sensitized luminescence of Eu(III) and Tb(III) complexes with Schiff bases
作者:Zainab S. Al-Farsi、Aisha Al-Rashdi、Nawal K. Al-Rasbi
DOI:10.1016/j.poly.2016.06.030
日期:2016.10
A new family of lanthanide/Schiff base complexes have been synthesized and fully characterized from the novel Schiff base ligand: L-1, (E)-N'-(dipyridin-2-ylmethylene)acetohydrazide and L-2, (E)-N'-(pyridin-2ylmethylene)acetohydrazide. The single crystal X-ray structure and mass spectroscopy reveal the isostructural mononuclear complexes: [LnL(2)(NO3)(2)]NO3 and [LnL(HFAC)(3)](3) where Ln = La, Eu, Gd and Tb and HFAC = hexafluoroacetylacetonate. Upon excitation of the Ln(III) complexes in solution, their luminescence spectra display the broad ligand-centred (LC) emission centred at similar to 435 nm as well as the narrow f-f transitions. Generally, the ligands can efficiently sensitize the Tb(III) complexes because of the better triplet state energy match to the Tb(III)-D-5(0) excited states. The luminescence lifetimes of the Ln(III)-nitrate chelates are found shorter than those from the corresponding HFAC complexes. The nitrate chelates can quench the luminescence through energy transfer pathways involving pi*-n transitions. The intrinsic quantum yields for the Eu(III) complexes have also been investigated. The phi(Eu) value for the complex EulN is found the lowest, 2.9% due to deactivation from intramolecular H-bonding NH center dot center dot center dot N involving the pyridine and amine units in the ligand as proved by X-ray crystallography. (C) 2016 Elsevier Ltd. All rights reserved.
METAL ION CHELATORS AND THERAPEUTIC USE THEREOF
申请人:Richardson, Desi Raymond
公开号:EP1608623B1
公开(公告)日:2011-01-19
X-ray crystallographic, spectroscopic, and electrochemical properties of Group 12 metal-chlorides of di-2-pyridyl ketone acetic acid hydrazone (dpkaah)
作者:Mohammed Bakir、Mark A. W. Lawrence、Rebecca R. Conry
DOI:10.1080/00958972.2018.1471685
日期:2018.8.3
carbonyl group (C=O). Infrared measurements confirmed the pseudo-coordination of the carbonyl group to MCl2. The geometries of 3–5 vary, while 5 adopts a square pyramidal geometry, 4 has a structure halfway between square pyramidal and trigonal bipyramidal and 3 is less distorted from square pyramidal than 3. The extended structures of 3–5 exposed extensive networks of non-covalent interactions, and in the