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

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 center dot+)](2)} (1), {[Nd(hfac)(4)(H2O)][(TTF-CH = CH-Py center dot+)]}(2) (2), and {[Nd(hfac)(4)(H2O)][(TTF-CH = CH-Py center dot+)]}(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 P (1) over bar, and monoclinic P2(1)/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 center dot+ radical cations. The inorganic and organic networks interact through intermolecular contacts between the pyridine moieties of the TTF-CH = CH-Py center dot+ 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 center dot+ 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-ration-based material. Resistivity measurements have also been performed on these materials.