Charge transfer salt with substituted Lindquist polyoxometalate: Synthesis, crystal structure, and physical properties of α-(BEDT-TTF) 6(VW5O19·DMF·2H2O
Résumé
A new charge transfer salt based on bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and the vanadium substituted Lindquist anion [VW5O 19]3- was synthesized and characterized by X-ray and spectroscopic analysis. Monoclinic, C2, Fw = 3789.2, a = 41.5019(5), b = 11.2600(2), c = 12.7514(2) Å β = 101.877(5)°, Z = 2, R = 0.060, based on 12095 reflections with I > 2σ(I). The structure consists of alternating organic and inorganic layers. The inorganic layer is generated by [VW5O19]3- anions, dimethylformamide (DMF) and water molecules. The organic layer, which is generated by three different BEDT-TTF units, belongs to the α-type of packing and consists of trimerized chains parallel to the c direction. The compound is a semi-conductor with σ300K = 1.1 S·cm -1 and Ea = 0.1 eV. Polarized reflectance spectra of single crystals were measured over the spectral range from 650 to 25000 cm -1. FT-NIR Raman spectra of powdered crystals dispersed in KBr pellets were also recorded. Vibrational and electronic features are discussed.