ic901052b_si_002.cif (109.92 kB)
Download file

4-(2-Tetrathiafulvalenyl-ethenyl)pyridine (TTF−CHCH−Py) Radical Cation Salts Containing Poly(β-diketonate) Rare Earth Complexes: Synthesis, Crystal Structure, Photoluminescent and Magnetic Properties

Download (109.92 kB)
posted on 2009-08-03, 00:00 authored by Fabrice Pointillart, Olivier Maury, Yann Le Gal, Stéphane Golhen, Olivier Cador, Lahcène Ouahab
The reactions between the redox-active 4-(2-tetrathiafulvalenyl-ethenyl)pyridine ligand (TTF−CHCH−Py) and the tris(1,1,1,5,5,5-hexafluoroacetylacetonate)Ln(III) (Ln = La and Nd) lead to the formation of compounds with the formulas {[La(hfac)5][(TTF−CHCH−Py•+)]2} (1), {[Nd(hfac)4(H2O)][(TTF−CHCH−Py•+)]}2 (2), and {[Nd(hfac)4(H2O)][(TTF−CHCH−Py•+)]}2(H2O)(C6H14)0.5 (3) (hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate anion). These compounds have been characterized by single-crystal X-ray diffraction, optical, and magnetic measurements. Compounds 1, 2, and 3 crystallize in the monoclinic C2/c, triclinic P1̅, and monoclinic P21/c space groups, respectively. La(III) adopts a tetradecahedral geometry, while Nd(III) stands in a distorted capped square antiprism one. In 1, the inorganic network is formed by the [La(hfac)5]2− dianionic complexes, while it is formed by a pseudo-dimeric dianionic unit of formula {[Nd(hfac)4(H2O)]2}2− in 2 and 3. In all crystal structures, the organic network is constituted by the TTF−CHCH−Py•+ radical cations. The inorganic and organic networks interact through intermolecular contacts between the pyridine moieties of the TTF−CHCH−Py•+ radical cations and the Ln(III) ions. The luminescence properties of the Nd(III) ions (9400 cm−1) and fluorescence band of the TTF−CHCH−Py•+ radical cations (10200 cm−1) have been observed and studied for compound 2. Complexes 2 and 3 are paramagnetic because of Nd(III) ions. Compound 2 is a paramagnetic luminescent TTF-radical-cation-based material. Resistivity measurements have also been performed on these materials.