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Nine lanthanide complexes with a high L:Ln ratio (4:1), [LnL(4)](OTf)(3) (1-8) (L = tetrakis(O-isopropyl)methylenediphosphonate, OTf = SO3CF3, Ln = Ce, Pr, Nd, Sm, Eu, Gd, Dy, Yb) and [DyL4](OTf)(3)center dot DMF (9) have been synthesized through easy and effective methods in air. Each complex was synthesized by the reaction of lanthanide triflate with the L ligand in a solvent mixture (acetonitrile and DMF for 1-8, dichloromethane and DMF for 9). The above complexes, except for complex 9, were synthesized in the presence of 1,10-phenanthroline. The title complexes were characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction analysis, luminescence, NMR spectra and terahertz time-domain spectroscopy (THz-TDS). Structure analysis shows that complexes 1-9 consist of one cation [LnL(4)](3+) and three triflate anions OTf-. Complexes 1-8 crystallized in the orthorhombic system, space group Pbcn, whereas complex 9 belongs to the space group I222. The cationic [LnL(4)](3+) fragments in complexes 1-8 are self-assembled to construct 2D layers with a (8.2.8.4) net topology by hydrogen bonding interactions. The OTf- cations in 9 are attached directly to the [DyL4](3+) cations to form a 2-fold hydrogen-bonded three-dimensional (3D) cage structure framework. Solid luminescence of complex 5 displays the characteristic bands of Eu3+, due to a long emission lifetime (4.04 ms of D-5(0)) and high absolute emission quantum yield (53.30%). Terahertz (THz) time-domain spectroscopy of the complexes was also studied. (C) 2014 Elsevier Ltd. All rights reserved.
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