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.

International audienceThe 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) give \[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 compds. were characterized by single-crystal x-ray diffraction, optical, and magnetic measurements. Compds. 1-3 crystallize in the monoclinic C2/c, triclinic P1̅, and monoclinic P21/c space groups, resp. La(III) adopts a tetradecahedral geometry, while Nd(III) stands in a distorted capped square antiprism one. In 1, the inorg. network is formed by the [La(hfac)5]2- dianionic complexes, while it is formed by a pseudo-dimeric dianionic unit \[Nd(hfac)4(H2O)]2\2- in 2 and 3. In all crystal structures, the org. network is constituted by the TTF-CH=CH-Py·+ radical cations. The inorg. and org. networks interact through intermol. 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) were obsd. and studied for compd. 2. Complexes 2 and 3 are paramagnetic because of Nd(III) ions. Compd. 2 is a paramagnetic luminescent TTF-radical-cation-based material. Resistivity measurements also were performed on these materials