Centro-symmetric dinuclear complexes of formula [Ln-(tta)(3)(L)](2)center dot xCH(2)Cl(2), (tta(-) = 2-thenoyltrifluoroacetonate anion, x = 0.5 for Ln = Eu (la), Tb (3), and Dy (4) and x = 0 for Ln = Eu (1b) and Nd (2)) have been synthesized using the tetrathiafulvalene-3-pyridine-N-oxide as a bridging ligand (L). X-ray structures have shown the formation of channels with CH2Cl2 solvent inside. 1 is stable with both filled channels (at 150 K) and empty channels (at room temperature). The Dy-III analogue displays a complex butterfly like hysteresis loop at 1.5 K. Photophysical properties of the coordination complexes have been studied by solution and solid-state absorption spectroscopy. Time-dependent density functional theory (TD-DFT) calculations have been carried out on the diamagnetic Y-III derivative to shed light on the absorption spectrum. For 2, the excitation of the charge transfer transitions induces line shape emission in the near-infrared spectral range assigned to F-4(3/2) -> I-4(9/2), F-4(3/2) -> I-4(11/2), and F-4(3/2) -> I-4(13/2) neodymium centered transitions. The reversible redox-activity of the ligand L makes possible an original sensitization process involving a ligand centered charge separation followed by energy transfer to the Nd-III ion upon recombination.
作者:Fabrice Pointillart、Boris Le Guennic、Olivier Maury、Stéphane Golhen、Olivier Cador、Lahcène Ouahab
DOI:10.1021/ic302095h
日期:2013.2.4
Centro-symmetric dinuclear complexes of formula [Ln-(tta)(3)(L)](2)center dot xCH(2)Cl(2), (tta(-) = 2-thenoyltrifluoroacetonate anion, x = 0.5 for Ln = Eu (la), Tb (3), and Dy (4) and x = 0 for Ln = Eu (1b) and Nd (2)) have been synthesized using the tetrathiafulvalene-3-pyridine-N-oxide as a bridging ligand (L). X-ray structures have shown the formation of channels with CH2Cl2 solvent inside. 1 is stable with both filled channels (at 150 K) and empty channels (at room temperature). The Dy-III analogue displays a complex butterfly like hysteresis loop at 1.5 K. Photophysical properties of the coordination complexes have been studied by solution and solid-state absorption spectroscopy. Time-dependent density functional theory (TD-DFT) calculations have been carried out on the diamagnetic Y-III derivative to shed light on the absorption spectrum. For 2, the excitation of the charge transfer transitions induces line shape emission in the near-infrared spectral range assigned to F-4(3/2) -> I-4(9/2), F-4(3/2) -> I-4(11/2), and F-4(3/2) -> I-4(13/2) neodymium centered transitions. The reversible redox-activity of the ligand L makes possible an original sensitization process involving a ligand centered charge separation followed by energy transfer to the Nd-III ion upon recombination.
Single-Molecule Magnet Behaviour in a Tetrathiafulvalene-Based Electroactive Antiferromagnetically Coupled Dinuclear Dysprosium(III) Complex
作者:Fabrice Pointillart、Yann Le Gal、Stéphane Golhen、Olivier Cador、Lahcène Ouahab
DOI:10.1002/chem.201100869
日期:2011.9.5
The reactions between the [Ln(tta)3]⋅2 H2O precursors (tta−=2‐thenoyltrifluoroacetonate anion) and the tetrathiafulvalene‐3‐pyridine‐N‐oxide ligands (L1) lead to dinuclear complexes of formula [Ln(tta)3(L1)}2]⋅x CH2Cl2 (x=0.5 for Ln=DyIII (1) and x=0 for Ln=GdIII (2)). The crystal structure reveals that two Ln(tta)3} moieties are bridged by two donors through the nitroxide groups. The DyIII centre